US20030205203A1 - Method and installation for densifying porous substrates by chemical vapour infiltration - Google Patents
Method and installation for densifying porous substrates by chemical vapour infiltration Download PDFInfo
- Publication number
- US20030205203A1 US20030205203A1 US10/417,037 US41703703A US2003205203A1 US 20030205203 A1 US20030205203 A1 US 20030205203A1 US 41703703 A US41703703 A US 41703703A US 2003205203 A1 US2003205203 A1 US 2003205203A1
- Authority
- US
- United States
- Prior art keywords
- oven
- reactive gas
- gas
- substrates
- installation
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
- C04B41/45—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
- C23C16/04—Coating on selected surface areas, e.g. using masks
- C23C16/045—Coating cavities or hollow spaces, e.g. interior of tubes; Infiltration of porous substrates
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/71—Ceramic products containing macroscopic reinforcing agents
- C04B35/78—Ceramic products containing macroscopic reinforcing agents containing non-metallic materials
- C04B35/80—Fibres, filaments, whiskers, platelets, or the like
- C04B35/83—Carbon fibres in a carbon matrix
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
- C23C16/44—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating
- C23C16/455—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating characterised by the method used for introducing gases into reaction chamber or for modifying gas flows in reaction chamber
- C23C16/45563—Gas nozzles
- C23C16/4557—Heated nozzles
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S427/00—Coating processes
- Y10S427/10—Chemical vapor infiltration, i.e. CVI
Definitions
- the invention relates to densifying porous substrates by chemical vapour infiltration (CVI).
- thermostructural composite material i.e. out of a composite material that not only possesses mechanical properties that enable it to be used for making structural parts, but that also has the ability to conserve these properties at high temperatures.
- thermostructural composite materials are carbon/carbon (C/C) composites having a reinforcing fabric of carbon fibers densified by a pyrolytic carbon matrix, and ceramic matrix composites (CMCs) having a reinforcing fabric of refractory fibers (carbon or ceramic) densified by a ceramic matrix.
- a well known process for densifying porous substrates to make C/C composite or CMC parts is chemical vapour infiltration.
- the substrates to be densified are placed in a loading zone of an oven in which they are heated.
- a reactive gas containing one or more gaseous precursors of the material that is to constitute the matrix is introduced into the oven.
- the temperature and pressure inside the oven are adjusted to enable the reactive gas to diffuse within the pores of the substrates and deposit matrix-constituting material therein by one or more components of the reactive gas decomposing or reacting together, said components constituting the matrix precursor.
- the process is performed under low pressure in order to encourage the reactive gas to diffuse into the substrates.
- the transformation temperature of the precursor(s) to form the matrix material such as pyrolytic carbon or ceramic, is usually greater than 900° C., and is typically close to 1000° C.
- Such ovens usually also include a zone situated between the reactive gas inlet into the oven and the loading zone of the oven in which the reactive gas is heated.
- the gas heating zone comprises a plurality of perforated plates through which the reactive gas passes.
- the gas-heating plates are heated because they are present in the oven.
- the oven is generally heated by means of a susceptor, e.g. made of graphite, which defines the side wall of the oven and which is inductively coupled to an induction coil surrounding the oven, or is heated by resistors surrounding the susceptor.
- a susceptor e.g. made of graphite
- a significant example is that of densifying substrates constituted by annular preforms of carbon fibers or pre-densified annular blanks for use in making C/C composite brake disks.
- the substrates are placed in one or more vertical stacks in the loading zone above the gas heating zone which is situated at the bottom of the oven.
- a temperature gradient is observed between the bottom of the loading zone and the remainder thereof, with the temperature close to substrates situated at the bottom of the stack possibly being several tens of ° C. lower than the temperature that applies in the remainder of the stack. This gives rise to a large densification gradient between the substrates, depending on the position of a substrate within the stack.
- the object of the invention is to propose a method of densification by chemical vapour infiltration which makes it possible to obtain a temperature gradient which is very small throughout the loading zone, but without requiring a large volume for the zone that heats the reactive gas, and thus without deteriorating, and possibly even improving the productivity of such ovens.
- the reactive gas is preheated prior to entering into the oven so that on entering into the oven it is brought to an intermediate temperature between ambient temperature and the temperature to which the substrates are heated.
- Preheating the reactive gas outside the loading zone enables the heating zone situated within the oven to be more effective in bringing the reactive gas to the desired temperature as soon as it penetrates into the substrate loading zone.
- the reactive gas is preheated prior to entering into the oven so that on entering the oven it is at a temperature which is preferably not less than 200° C. Nevertheless, it is preferable for the temperature to which the gas is preheated not to exceed 900° C., or even 600° C., in order to avoid any unwanted deposits due to the precursor(s) being transformed prior to penetrating into the oven, and in order to make it possible to use relatively ordinary materials for the pipework feeding the oven with preheated reactive gas and for components such as valves and gaskets mounted in said pipework.
- Preheating can be performed at a gas pressure that is substantially equal to the pressure that exists inside the oven, or else at a higher pressure. When performed at a higher pressure, the preheated reactive gas is expanded before entering the oven.
- the invention also seeks to provide an installation enabling the method to be implemented.
- an oven a zone for loading substrates into the oven, means for heating substrates in the loading zone, at least one inlet for admitting reactive gas into the oven, and at least one gas heating zone situated in the oven between the reactive gas inlet and the loading zone,
- At least one gas preheating device situated outside the oven and connected to at least one reactive gas inlet to the oven, so as to preheat the reactive gas before it enters the oven.
- the preheating device comprises an electrical heater tube inserted in a duct for feeding reactive gas to the reactive gas inlet of the oven.
- the preheater device comprises a gas boiler or an electric oven having at least one duct or bundle of tubes passing therethrough for conveying the reactive gas to be preheated.
- FIG. 1 is a highly diagrammatic section view of a first embodiment of a densifying installation of the invention
- FIG. 2 is a graph showing curves that illustrate how the temperature of the reactive gas varies from prior to entering the oven to immediately after entering the substrate loading zone, both with preheating of the reactive gas and without preheating of the reactive gas;
- FIG. 3 is a highly diagrammatic section view of a second embodiment of a densifying installation of the invention.
- FIG. 4 shows another way of loading substrates in a densifying installation
- FIG. 5 is a diagram showing yet another way of loading substrates in an oven in the form of a plurality of annular stacks
- FIG. 6 is a highly diagrammatic section view on plane VI-VI of FIG. 5;
- FIG. 7 is a fragmentary view of a densifying installation showing a variant implementation of the reactive gas feed of the oven, in which the load in the oven is formed by a plurality of stacks of substrates.
- FIG. 1 is a diagram showing an oven 10 defined by a cylindrical side wall 12 , a bottom wall 14 , and a top wall 16 .
- the wall 12 constitutes a secondary transformer circuit or susceptor, e.g. being made out of graphite, and it is coupled with a primary transformer circuit or induction coil 18 situated outside the oven, with insulation 20 interposed between them.
- the oven is heated by the susceptor 12 when electricity is fed to the induction coil 18 .
- the reactive gas is introduced into the oven via a passage 22 formed through the bottom wall 14 , and the effluent gas is extracted via a passage 24 formed through the top wall 16 , the passage 24 being connected by a pipe 26 to suction means such as a vacuum pump (not shown).
- Substrates 32 to be densified are placed so as to form an annular vertical stack which is closed at the top by a cover 34 .
- the stacked substrates thus subdivide the inside volume of the loading zone 30 into a volume 36 inside the stack constituted by the aligned central passages of the substrates, and a volume 38 outside the stack.
- the stack of substrates stands on a bottom support plate 40 , and it can be subdivided into a plurality of superposed sections that are separated by one or more intermediate plates 42 , the plates 40 , 42 having central passages 41 , 43 in alignment with the passages of the substrates 32 .
- a plurality of stacks could be placed side by side in the oven 10 , as described below.
- each substrate 32 is spaced apart from an adjacent substrate, or where appropriate a plate 40 , 42 or the cover 34 , by spacers 44 which leave gaps 46 .
- the spacers 44 are arranged to leave passages for the gas between the volumes 36 and 38 via the gaps 46 .
- These passages can be provided in such a manner as to ensure pressures in the volumes 36 and 38 are in equilibrium, as described in U.S. Pat. No. 5,904,957, or in such a manner as to constitute simple leakage passages for maintaining a pressure gradient between the volumes 36 and 38 , as described in the French patent application filed under the No. 01/03004.
- a gas heating zone 50 extends between the bottom 14 of the oven and the bottom support plate 40 .
- the heating zone 50 comprises a plurality of perforated plates 52 , e.g. made of graphite, C/C composite or CMC, placed one above the other, and spaced apart from one another.
- the plates 52 can be received in a housing having a bottom 54 and a side wall 56 , and defining the heating zone.
- a pipe 58 connects the reactive gas inlet 22 to the heating zone 30 through the bottom 54 .
- Underframes and legs 48 support the gas-heating housing and the plates 40 , 42 . All of these elements are made out of graphite, for example.
- the reactive gas admitted into the oven via the inlet 22 passes through the heating zone 50 and penetrates into the volume 36 through the central orifice 41 of the plate 40 .
- the reactive gas flows from the volume 36 towards the volume 38 by passing through the pores of the substrate 32 and through the passages provided in the gaps 46 .
- the effluent gas is extracted from the volume 38 via the outlet 24 .
- the volume 36 can be closed at the bottom and put into communication with the outlet 24 at the top.
- the reactive gas coming from the heating zone 30 is then admitted into the volume 38 of the loading zone and gas flows through said zone from the volume 38 towards the volume 36 , the volume 38 then being closed at the top.
- the reactive gas inlet can be provided through the top wall 16 of the oven, in which case the heating zone is situated in the top portion of the oven. That one of the two volumes 36 and 38 which is communication with the heating zone is closed at its bottom end, while the other one of said two volumes communicates with a gas outlet formed through the bottom wall of the oven.
- the reactive gas contains one or more precursors of carbon, such as hydrocarbons. Commonly used precursors are methane, propane, or a mixture thereof. Chemical vapour infiltration is performed at a temperature which is generally greater than 900° C., for example in the range 950° C. to 1100° C., and at low pressure, for example at a pressure of less than 0.1 kilopascals (kPa).
- precursors of carbon such as hydrocarbons.
- Commonly used precursors are methane, propane, or a mixture thereof.
- Chemical vapour infiltration is performed at a temperature which is generally greater than 900° C., for example in the range 950° C. to 1100° C., and at low pressure, for example at a pressure of less than 0.1 kilopascals (kPa).
- the reactive gas is preheated prior to being admitted into the oven by passing through a preheater device 60 connected by a feed pipe 62 to the inlet 22 of the oven.
- the pipe 62 is preferably thermally insulated.
- An isolating valve 64 is installed on the pipe 62 immediately upstream from the inlet 22 to the oven so as to make it possible, where appropriate, to isolate the oven from the reactive gas feed circuit.
- the preheater device comprises an electrical heater tube 66 which conveys the reactive gas coming from a source 68 and which is connected to the pipe 62 .
- Electrical heater tubes are known devices for heating flowing fluids. Heat is produced by the Joule effect by allowing an electrical current to flow through a section of the tube.
- the tube constitutes simultaneously an electrical resistance element, a fluid flow duct, and a heat exchange surface.
- the electrical current is produced by an electrical power supply circuit 70 delivering a voltage U and connected to the ends of the tube section.
- Circuit 70 receives information delivered by a sensor 72 , e.g. a thermocouple, placed at the outlet from the preheater device.
- the preheating temperature is regulated to a predetermined value by automatically adjusting the voltage U as a function of the temperature measured by the sensor 72 .
- the reactive gas can be heated under the low pressure that exists inside the oven, with an expander 74 being located at the outlet from the gas source 68 .
- the reactive gas can be heated under pressure that is greater than that which exists inside the oven, i.e. at a pressure that is intermediate between the pressure in the source 68 and the pressure in the oven. Under such circumstances, the preheated reactive gas is expanded prior to entering into the oven, e.g. by passing through a calibrated orifice fitted in the feed pipe 62 .
- the purpose of preheating the reactive gas is to ensure that after the gas has been further heated by passing through the heating zone 50 , it penetrates into the loading zone at a temperature that is equal or close to the temperature necessary for avoiding a significant temperature gradient between the bottom of the loading zone and the remainder thereof.
- the reactive gas should preferably be preheated so that the gas delivered to the inlet of the oven is at a temperature of at least 200° C.
- the preheating temperature i.e. the temperature at the outlet from the preheating device, must nevertheless be limited in order to avoid the risk of forming unwanted deposits (soot) in the feed pipe 62 , and also because of constraints of a technological nature.
- the preheating temperature is selected to be no greater than 800° C. in order to avoid unwanted deposits, and preferably no greater than 600° C. so as to make it possible to use materials of affordable cost for the pipe 62 (e.g. steel) and for the isolating valve 64 and for any other components that are exposed to the preheated gas, such as sealing gaskets.
- the temperature of the preheated gas can drop to a greater or lesser extent after leaving the preheating device and before entering the oven.
- the temperature of the gas can lose a few degrees to a few tens of degrees before penetrating into the oven, or possibly a little upstream therefrom due to the influence of the atmosphere inside the oven.
- Tests have been performed feeding an oven similar to that shown in FIG. 1 with a reactive gas preheated to 600° C.
- the temperature of the gas was measured at the outlet from the preheating device, along the feed pipe, at the inlet into the oven, and at the outlet from the heating zone 50 situated inside the oven.
- Curve A in FIG. 2 shows the observed variation in temperature.
- preheating the gas serves to avoid a temperature gradient liable to give rise to a significant gradient in densification between substrates situated at the bottom of the stack and the other substrates.
- preheating to 500° C. conserves its effectiveness with a significantly increased flow rate since the temperature at the inlet to the loading zone was about 950° C. (curve C). Preheating thus makes it possible to increase the flow rate of the reactive gas, which is favorable to decreasing the total duration of the densification process.
- FIG. 3 shows a variant embodiment of the densification installation which differs from that of FIG. 1 in that the preheating device 80 is not formed by an electrical heater tube, but by a gas boiler.
- the boiler 80 has a burner 82 fed with fuel gas, e.g. a gaseous hydrocarbon such as natural gas, via a pipe 75 having a regulator valve 76 mounted thereon.
- fuel gas e.g. a gaseous hydrocarbon such as natural gas
- the burner 82 is fed with dilution air via a pipe 78 having a compressor 79 and a regulator valve 84 mounted thereon.
- the resulting combustion gases pass through a heat exchanger 86 prior to being evacuated via a chimney 88 .
- the reactive gas coming from the source 68 flows through the heat exchanger 86 via a duct 87 prior to being admitted into the oven via the feed pipe 62 .
- the regulator valves 76 and 84 are controlled by a regulator circuit 90 as a function of a signal supplied by a temperature sensor 72 at the outlet from the boiler 80 so as to set the temperature to which the reactive gas is preheated to the desired value.
- a fraction of the effluent gas can be taken from the pipe 26 for mixing with the fuel gas which feeds the burner of the boiler.
- the reactive gas could be preheated by flowing along a tube or a bundle of tubes in an oven that is heated by electrical resistance elements, with the temperature of the reactive gas at the outlet from the heater device being regulated by controlling the power supplied to the electrical resistance elements.
- FIG. 4 shows a variant technique for loading the substrates 32 .
- the gaps 46 between adjacent substrates or between a substrate and a plate 40 , 42 or cover 34 are provided with annular spacers which close off the gaps 46 in leaktight manner.
- the reactive gas can pass from the volume 36 into the volume 38 solely by passing through the pores in the substrates, thereby giving rise to a quite significant pressure gradient between these two volumes.
- FIGS. 5 and 6 show a variant loading configuration for the substrates which differs from the loading shown in FIG. 1 in that the substrates 32 are disposed as a plurality of annular stacks 31 a, 31 b, 31 c, 31 d, 31 e, 31 f, and 31 g all standing on the support plate 40 .
- the support plate has a plurality of passages such as 41 a in alignment with the inside volumes 36 a to 36 g of the stacks, and each stack is closed on top by a cover such as 34 a.
- the reactive gas flows through the heating zone 50 and then the inside volumes of the stacks from which the gas passes into the volume 38 outside the stacks inside the loading zone 30 .
- seven stacks are shown in FIG. 6, the number of stacks could naturally be different, and in particular it could be greater than seven.
- FIG. 7 shows another way of feeding an oven with reactive gas when the load is in the form of a plurality of annular stacks. This embodiment differs from that of FIG. 5 in that the stacks are fed individually with reactive gas.
- a plurality of passages are formed through the bottom 14 of the oven substantially in alignment with the inside volumes of the stacks.
- FIG. 7 only three passages 22 a, 22 c, and 22 f can be seen, in alignment with the inside volumes 36 a, 36 c, and 36 f of the stacks 32 a, 32 c, and 32 f.
- Individual reactive gas feed pipes such as 62 a, 62 c, and 62 f are connected to passages formed in the bottom of the oven.
- the stacks supported by the plate 40 surmount individual heating zones such as 50 a, 50 c, and 50 f.
- the heating zones are defined by respective vertical cylindrical walls 56 a, 56 c, and 56 f, a common bottom 54 , and the plate 40 .
- Pipes such as 58 a, 58 c, and 58 f connect the openings formed through the bottom of the oven to the various heating zones via respective orifices formed in the bottom 54 of the heater housing.
- Each heater zone comprises a plurality of perforated plates 52 placed one above another.
- Valves such as 64 a, 64 c, and 64 f are fitted in the individual feed pipes.
- reactive gas coming from the preheater device flows along a common pipe 62 to which the individual pipes such as 62 a, 62 c, and 62 f are connected.
- the stacks are then fed with reactive gas that has been preheated to a common temperature.
- the individual pipes such as 62 a, 62 c, and 62 f can be connected to respective preheater devices. This makes it possible for the preheating temperature of the reactive gas to be adjusted individually as a function of the position within the oven of the particular stack of substrates to which the reactive gas is delivered.
- the field of application of the invention is not limited in any way to making C/C composite brake disks, but also extends to making other parts out of C/C composite material, for example the diverging portions of rocket engine nozzles, as shown in particular in U.S. Pat. No. 5,904,957 cited above. More generally, the invention can be implemented for making parts out of any type of thermostructural composite material, i.e. not only out of C/C composite materials, but also out of CMCs. With CMCs, the reactive gas is selected as a function of the particular nature of the ceramic matrix.
- Gaseous precursors for ceramic matrices are well known, for example methyltricholosilane (MTS) and hydrogen gas (H 2 ) to form a matrix of silicon carbide.
- MTS methyltricholosilane
- H 2 hydrogen gas
Abstract
An installation for densification of porous substrates by CVI comprises an oven, a zone for loading substrates in the oven, means for heating substrates loaded in the loading zone, at least one inlet for admitting reactive gas in the oven, and at least one gas heating zone situated in the oven between the reactive gas inlet and the loading zone. At least one gas preheating device is located outside the oven and is connected to the gas inlet so as to preheat the reactive gas before it enters the oven.
Description
- This application is a divisional application under §1.53(b) of prior application Ser. No. 10/034,848 filed Dec. 26, 2001, entitled: METHOD AND INSTALLATION FOR DENSIFYING POROUS SUBSTRATES BY CHEMICAL VAPOUR INFILTRATION.
- The invention relates to densifying porous substrates by chemical vapour infiltration (CVI).
- The field of application of the invention is that of making parts out of thermostructural composite material, i.e. out of a composite material that not only possesses mechanical properties that enable it to be used for making structural parts, but that also has the ability to conserve these properties at high temperatures. Typical examples of thermostructural composite materials are carbon/carbon (C/C) composites having a reinforcing fabric of carbon fibers densified by a pyrolytic carbon matrix, and ceramic matrix composites (CMCs) having a reinforcing fabric of refractory fibers (carbon or ceramic) densified by a ceramic matrix.
- A well known process for densifying porous substrates to make C/C composite or CMC parts is chemical vapour infiltration. The substrates to be densified are placed in a loading zone of an oven in which they are heated. A reactive gas containing one or more gaseous precursors of the material that is to constitute the matrix is introduced into the oven. The temperature and pressure inside the oven are adjusted to enable the reactive gas to diffuse within the pores of the substrates and deposit matrix-constituting material therein by one or more components of the reactive gas decomposing or reacting together, said components constituting the matrix precursor. The process is performed under low pressure in order to encourage the reactive gas to diffuse into the substrates. The transformation temperature of the precursor(s) to form the matrix material, such as pyrolytic carbon or ceramic, is usually greater than 900° C., and is typically close to 1000° C.
- In order to enable substrates throughout the loading zone of the oven to be densified as uniformly as possible, whether in terms of increasing density or in terms of the microstructure of the matrix material that is formed, it is necessary for the temperature throughout the loading zone to be substantially uniform.
- Such ovens usually also include a zone situated between the reactive gas inlet into the oven and the loading zone of the oven in which the reactive gas is heated. Typically the gas heating zone comprises a plurality of perforated plates through which the reactive gas passes.
- The gas-heating plates, like the substrates, are heated because they are present in the oven. The oven is generally heated by means of a susceptor, e.g. made of graphite, which defines the side wall of the oven and which is inductively coupled to an induction coil surrounding the oven, or is heated by resistors surrounding the susceptor.
- The Applicants have found that the presence of a zone for heating the reactive gas does not always give the desired result. A significant example is that of densifying substrates constituted by annular preforms of carbon fibers or pre-densified annular blanks for use in making C/C composite brake disks. The substrates are placed in one or more vertical stacks in the loading zone above the gas heating zone which is situated at the bottom of the oven. In spite of the reactive gas being heated, a temperature gradient is observed between the bottom of the loading zone and the remainder thereof, with the temperature close to substrates situated at the bottom of the stack possibly being several tens of ° C. lower than the temperature that applies in the remainder of the stack. This gives rise to a large densification gradient between the substrates, depending on the position of a substrate within the stack.
- In order to solve that problem, it would be possible to increase the efficiency with which the reactive gas is heated by increasing the heating zone. Nevertheless, for given total volume of the oven, that would reduce the working volume available in the loading zone. Unfortunately, chemical vapour infiltration processes require large amounts of industrial investment and they are very lengthy to perform. It is therefore highly desirable for ovens to have high productivity, whether they be ovens already in service or new ovens yet to be built, and thus as high as possible a ratio of working volume dedicated to the load of substrates over the volume which is dedicated to heating the reactive gas.
- The object of the invention is to propose a method of densification by chemical vapour infiltration which makes it possible to obtain a temperature gradient which is very small throughout the loading zone, but without requiring a large volume for the zone that heats the reactive gas, and thus without deteriorating, and possibly even improving the productivity of such ovens.
- This object is achieved by a method of the type comprising the steps of:
- loading substrates for densification in a loading zone of an oven;
- heating the substrates in the oven so as to raise them to a temperature at which the desired matrix material is formed from the precursor gas(es) contained in the reactive gas;
- admitting the reactive gas to one end of the oven; and
- heating the reactive gas after it has entered into the oven by passing it through a gas heating zone situated upstream from the loading zone in the flow direction of the reactive gas in the oven;
- in which method, according to the invention:
- the reactive gas is preheated prior to entering into the oven so that on entering into the oven it is brought to an intermediate temperature between ambient temperature and the temperature to which the substrates are heated.
- Preheating the reactive gas outside the loading zone enables the heating zone situated within the oven to be more effective in bringing the reactive gas to the desired temperature as soon as it penetrates into the substrate loading zone.
- When infiltration is performed at a temperature greater than 900° C., the reactive gas is preheated prior to entering into the oven so that on entering the oven it is at a temperature which is preferably not less than 200° C. Nevertheless, it is preferable for the temperature to which the gas is preheated not to exceed 900° C., or even 600° C., in order to avoid any unwanted deposits due to the precursor(s) being transformed prior to penetrating into the oven, and in order to make it possible to use relatively ordinary materials for the pipework feeding the oven with preheated reactive gas and for components such as valves and gaskets mounted in said pipework.
- Preheating can be performed at a gas pressure that is substantially equal to the pressure that exists inside the oven, or else at a higher pressure. When performed at a higher pressure, the preheated reactive gas is expanded before entering the oven.
- The invention also seeks to provide an installation enabling the method to be implemented.
- This object is achieved by means of an installation of the type comprising:
- an oven, a zone for loading substrates into the oven, means for heating substrates in the loading zone, at least one inlet for admitting reactive gas into the oven, and at least one gas heating zone situated in the oven between the reactive gas inlet and the loading zone,
- in which installation, according to the invention, there is also provided at least one gas preheating device situated outside the oven and connected to at least one reactive gas inlet to the oven, so as to preheat the reactive gas before it enters the oven.
- In an embodiment of the invention, the preheating device comprises an electrical heater tube inserted in a duct for feeding reactive gas to the reactive gas inlet of the oven.
- In other embodiments of the invention, the preheater device comprises a gas boiler or an electric oven having at least one duct or bundle of tubes passing therethrough for conveying the reactive gas to be preheated.
- Other features and advantages of the method of the invention and of installations of the invention will appear on reading the following description given by way of non-limiting indication and with reference to the accompanying drawings, in which:
- FIG. 1 is a highly diagrammatic section view of a first embodiment of a densifying installation of the invention;
- FIG. 2 is a graph showing curves that illustrate how the temperature of the reactive gas varies from prior to entering the oven to immediately after entering the substrate loading zone, both with preheating of the reactive gas and without preheating of the reactive gas;
- FIG. 3 is a highly diagrammatic section view of a second embodiment of a densifying installation of the invention;
- FIG. 4 shows another way of loading substrates in a densifying installation;
- FIG. 5 is a diagram showing yet another way of loading substrates in an oven in the form of a plurality of annular stacks;
- FIG. 6 is a highly diagrammatic section view on plane VI-VI of FIG. 5; and
- FIG. 7 is a fragmentary view of a densifying installation showing a variant implementation of the reactive gas feed of the oven, in which the load in the oven is formed by a plurality of stacks of substrates.
- Implementations of the method and embodiments of the installation of the invention are described below in the context of an application to densifying annular porous substrates. The latter may constitute carbon fiber preforms or pre-densified blanks for making brake disks out of C/C composite material, the pre-densified blanks being obtained by pre-densification of performs by chemical vapour infiltration or by liquid (resin) impregnation followed by carbonization. Such brake disks are commonly used for aircraft landing gears and for racing cars.
- FIG. 1 is a diagram showing an
oven 10 defined by acylindrical side wall 12, abottom wall 14, and atop wall 16. Thewall 12 constitutes a secondary transformer circuit or susceptor, e.g. being made out of graphite, and it is coupled with a primary transformer circuit orinduction coil 18 situated outside the oven, withinsulation 20 interposed between them. The oven is heated by thesusceptor 12 when electricity is fed to theinduction coil 18. - The reactive gas is introduced into the oven via a
passage 22 formed through thebottom wall 14, and the effluent gas is extracted via apassage 24 formed through thetop wall 16, thepassage 24 being connected by apipe 26 to suction means such as a vacuum pump (not shown). -
Substrates 32 to be densified are placed so as to form an annular vertical stack which is closed at the top by acover 34. The stacked substrates thus subdivide the inside volume of theloading zone 30 into avolume 36 inside the stack constituted by the aligned central passages of the substrates, and avolume 38 outside the stack. - The stack of substrates stands on a
bottom support plate 40, and it can be subdivided into a plurality of superposed sections that are separated by one or moreintermediate plates 42, theplates central passages substrates 32. Although only one stack is shown in FIG. 1, a plurality of stacks could be placed side by side in theoven 10, as described below. - As shown by the detail in FIG. 1, each
substrate 32 is spaced apart from an adjacent substrate, or where appropriate aplate cover 34, byspacers 44 which leavegaps 46. Thespacers 44, or at least a fraction of them, are arranged to leave passages for the gas between thevolumes gaps 46. These passages can be provided in such a manner as to ensure pressures in thevolumes volumes - A
gas heating zone 50 extends between the bottom 14 of the oven and thebottom support plate 40. In conventional manner, theheating zone 50 comprises a plurality ofperforated plates 52, e.g. made of graphite, C/C composite or CMC, placed one above the other, and spaced apart from one another. Theplates 52 can be received in a housing having a bottom 54 and aside wall 56, and defining the heating zone. Apipe 58 connects thereactive gas inlet 22 to theheating zone 30 through the bottom 54. - Underframes and
legs 48 support the gas-heating housing and theplates - The reactive gas admitted into the oven via the
inlet 22 passes through theheating zone 50 and penetrates into thevolume 36 through thecentral orifice 41 of theplate 40. The reactive gas flows from thevolume 36 towards thevolume 38 by passing through the pores of thesubstrate 32 and through the passages provided in thegaps 46. The effluent gas is extracted from thevolume 38 via theoutlet 24. - In a variant embodiment, the
volume 36 can be closed at the bottom and put into communication with theoutlet 24 at the top. The reactive gas coming from theheating zone 30 is then admitted into thevolume 38 of the loading zone and gas flows through said zone from thevolume 38 towards thevolume 36, thevolume 38 then being closed at the top. - In yet another variant, the reactive gas inlet can be provided through the
top wall 16 of the oven, in which case the heating zone is situated in the top portion of the oven. That one of the twovolumes - To form a matrix of pyrolytic carbon, the reactive gas contains one or more precursors of carbon, such as hydrocarbons. Commonly used precursors are methane, propane, or a mixture thereof. Chemical vapour infiltration is performed at a temperature which is generally greater than 900° C., for example in the range 950° C. to 1100° C., and at low pressure, for example at a pressure of less than 0.1 kilopascals (kPa).
- In accordance with the invention, the reactive gas is preheated prior to being admitted into the oven by passing through a
preheater device 60 connected by afeed pipe 62 to theinlet 22 of the oven. Thepipe 62 is preferably thermally insulated. An isolatingvalve 64 is installed on thepipe 62 immediately upstream from theinlet 22 to the oven so as to make it possible, where appropriate, to isolate the oven from the reactive gas feed circuit. - In the embodiment of FIG. 1, the preheater device comprises an
electrical heater tube 66 which conveys the reactive gas coming from asource 68 and which is connected to thepipe 62. - Electrical heater tubes are known devices for heating flowing fluids. Heat is produced by the Joule effect by allowing an electrical current to flow through a section of the tube. The tube constitutes simultaneously an electrical resistance element, a fluid flow duct, and a heat exchange surface.
- The electrical current is produced by an electrical
power supply circuit 70 delivering a voltage U and connected to the ends of the tube section.Circuit 70 receives information delivered by asensor 72, e.g. a thermocouple, placed at the outlet from the preheater device. The preheating temperature is regulated to a predetermined value by automatically adjusting the voltage U as a function of the temperature measured by thesensor 72. - The reactive gas can be heated under the low pressure that exists inside the oven, with an
expander 74 being located at the outlet from thegas source 68. - In a variant, the reactive gas can be heated under pressure that is greater than that which exists inside the oven, i.e. at a pressure that is intermediate between the pressure in the
source 68 and the pressure in the oven. Under such circumstances, the preheated reactive gas is expanded prior to entering into the oven, e.g. by passing through a calibrated orifice fitted in thefeed pipe 62. - The purpose of preheating the reactive gas is to ensure that after the gas has been further heated by passing through the
heating zone 50, it penetrates into the loading zone at a temperature that is equal or close to the temperature necessary for avoiding a significant temperature gradient between the bottom of the loading zone and the remainder thereof. - In order to be effective, the reactive gas should preferably be preheated so that the gas delivered to the inlet of the oven is at a temperature of at least 200° C.
- The preheating temperature, i.e. the temperature at the outlet from the preheating device, must nevertheless be limited in order to avoid the risk of forming unwanted deposits (soot) in the
feed pipe 62, and also because of constraints of a technological nature. - Thus, the preheating temperature is selected to be no greater than 800° C. in order to avoid unwanted deposits, and preferably no greater than 600° C. so as to make it possible to use materials of affordable cost for the pipe62 (e.g. steel) and for the isolating
valve 64 and for any other components that are exposed to the preheated gas, such as sealing gaskets. - Depending on the length of the
pipe 62 and how well it is heat-insulated, the temperature of the preheated gas can drop to a greater or lesser extent after leaving the preheating device and before entering the oven. Thus, with preheating to 600° C., the temperature of the gas can lose a few degrees to a few tens of degrees before penetrating into the oven, or possibly a little upstream therefrom due to the influence of the atmosphere inside the oven. - Tests have been performed feeding an oven similar to that shown in FIG. 1 with a reactive gas preheated to 600° C. The temperature of the gas was measured at the outlet from the preheating device, along the feed pipe, at the inlet into the oven, and at the outlet from the
heating zone 50 situated inside the oven. Curve A in FIG. 2 shows the observed variation in temperature. - Other tests have been performed with preheating to a temperature of 500° C., respectively with the reactive gas flowing at the same rate and with the gas flowing at a rate increased by about 42%. Curves B and C in FIG. 2 show the measured temperature variations.
- By way of comparison, tests were performed without preheating, the reactive gas being admitted into the
pipe 62 at a temperature of 20° C. and at the same flow rate as for preheating at 600° C. Curve D in FIG. 2 shows the measured variation in the temperature of the reactive gas until it penetrated into the oven loading zone. - For a given flow rate of reactive gas, and using the same heating zone, preheating the gas to 600° C. and to 500° C. (curves A and B) make it possible to raise the gas to temperatures of about 993° C. and 975° C. on entry into the loading zone, whereas without preheating (curve D), said temperature was considerably lower at 850 C.°.
- Thus preheating the gas serves to avoid a temperature gradient liable to give rise to a significant gradient in densification between substrates situated at the bottom of the stack and the other substrates.
- The Applicants estimate that increasing the efficiency of the
heating zone 50 so as to make it possible without gas preheating to achieve a result similar to that obtained with gas preheating would require at least 5% of the loading volume to be taken for that purpose. Preheating the reactive gas outside the oven thus makes it possible to improve oven productivity significantly. - In addition, preheating to 500° C. conserves its effectiveness with a significantly increased flow rate since the temperature at the inlet to the loading zone was about 950° C. (curve C). Preheating thus makes it possible to increase the flow rate of the reactive gas, which is favorable to decreasing the total duration of the densification process.
- FIG. 3 shows a variant embodiment of the densification installation which differs from that of FIG. 1 in that the preheating
device 80 is not formed by an electrical heater tube, but by a gas boiler. - The
boiler 80 has aburner 82 fed with fuel gas, e.g. a gaseous hydrocarbon such as natural gas, via apipe 75 having aregulator valve 76 mounted thereon. Theburner 82 is fed with dilution air via apipe 78 having acompressor 79 and aregulator valve 84 mounted thereon. The resulting combustion gases pass through aheat exchanger 86 prior to being evacuated via achimney 88. The reactive gas coming from thesource 68 flows through theheat exchanger 86 via aduct 87 prior to being admitted into the oven via thefeed pipe 62. - The
regulator valves regulator circuit 90 as a function of a signal supplied by atemperature sensor 72 at the outlet from theboiler 80 so as to set the temperature to which the reactive gas is preheated to the desired value. - A fraction of the effluent gas can be taken from the
pipe 26 for mixing with the fuel gas which feeds the burner of the boiler. - Naturally, other types of fluid heater device could be used for preheating the reactive gas.
- Thus, the reactive gas could be preheated by flowing along a tube or a bundle of tubes in an oven that is heated by electrical resistance elements, with the temperature of the reactive gas at the outlet from the heater device being regulated by controlling the power supplied to the electrical resistance elements.
- FIG. 4 shows a variant technique for loading the
substrates 32. As shown in the detail of FIG. 4, thegaps 46 between adjacent substrates or between a substrate and aplate gaps 46 in leaktight manner. As a result, the reactive gas can pass from thevolume 36 into thevolume 38 solely by passing through the pores in the substrates, thereby giving rise to a quite significant pressure gradient between these two volumes. - FIGS. 5 and 6 show a variant loading configuration for the substrates which differs from the loading shown in FIG. 1 in that the
substrates 32 are disposed as a plurality ofannular stacks support plate 40. The support plate has a plurality of passages such as 41 a in alignment with theinside volumes 36 a to 36 g of the stacks, and each stack is closed on top by a cover such as 34 a. The reactive gas flows through theheating zone 50 and then the inside volumes of the stacks from which the gas passes into thevolume 38 outside the stacks inside theloading zone 30. Although seven stacks are shown in FIG. 6, the number of stacks could naturally be different, and in particular it could be greater than seven. - FIG. 7 shows another way of feeding an oven with reactive gas when the load is in the form of a plurality of annular stacks. This embodiment differs from that of FIG. 5 in that the stacks are fed individually with reactive gas.
- Thus, a plurality of passages are formed through the bottom14 of the oven substantially in alignment with the inside volumes of the stacks. In FIG. 7, only three
passages inside volumes stacks - The stacks supported by the
plate 40 surmount individual heating zones such as 50 a, 50 c, and 50 f. The heating zones are defined by respective verticalcylindrical walls common bottom 54, and theplate 40. Pipes such as 58 a, 58 c, and 58 f connect the openings formed through the bottom of the oven to the various heating zones via respective orifices formed in the bottom 54 of the heater housing. Each heater zone comprises a plurality ofperforated plates 52 placed one above another. - Valves such as64 a, 64 c, and 64 f are fitted in the individual feed pipes.
- In the installation shown, reactive gas coming from the preheater device (not shown in FIG. 7) flows along a
common pipe 62 to which the individual pipes such as 62 a, 62 c, and 62 f are connected. The stacks are then fed with reactive gas that has been preheated to a common temperature. - In a variant, in order to accommodate possible temperature differences within the heating zones and at the bottoms of the stacks, depending on the locations of the stacks within the oven, the individual pipes such as62 a, 62 c, and 62 f can be connected to respective preheater devices. This makes it possible for the preheating temperature of the reactive gas to be adjusted individually as a function of the position within the oven of the particular stack of substrates to which the reactive gas is delivered.
- Finally, it should be observed that the field of application of the invention is not limited in any way to making C/C composite brake disks, but also extends to making other parts out of C/C composite material, for example the diverging portions of rocket engine nozzles, as shown in particular in U.S. Pat. No. 5,904,957 cited above. More generally, the invention can be implemented for making parts out of any type of thermostructural composite material, i.e. not only out of C/C composite materials, but also out of CMCs. With CMCs, the reactive gas is selected as a function of the particular nature of the ceramic matrix. Gaseous precursors for ceramic matrices are well known, for example methyltricholosilane (MTS) and hydrogen gas (H2) to form a matrix of silicon carbide. Reference can be made to French patent No. 2 401 888 which describes methods of forming various kinds of ceramic.
Claims (11)
1. An installation for densifying porous substrates by chemical vapour infiltration, the installation comprising:
an oven,
a zone for loading substrates into the oven,
means for heating substrates in the loading zone,
at least one inlet for admitting reactive gas into the oven,
at least one gas heating zone situated in the oven between the reactive gas inlet and the loading zone, and
at least one gas preheating device situated outside the oven and connected to at least one reactive gas inlet to the oven, so as to preheat the reactive gas before it enters the oven.
2. An installation according to claim 1 , wherein the preheating device comprises an electrical heater tube inserted in a duct for feeding reactive gas to the reactive gas inlet of the oven.
3. An installation according to claim 1 , wherein the preheating device comprises a gas boiler having at least one duct passing therethrough to convey a flow of reactive gas to be preheated.
4. An installation according to claim 3 , wherein the boiler is connected to an outlet for removing effluent gas from the oven so as to use at least a fraction of the effluent gas as fuel gas for the boiler.
5. An installation according to claim 1 , wherein the preheating device comprises an electrically heated oven having at least one tube passing therethrough to carry a flow of reactive gas to be preheated.
6. An installation according to claim 1 , further including an expander located between the preheating device and the inlet for reactive gas into the oven.
7. An installation according to claim 1 , wherein the preheating device includes temperature regulator means.
8. An installation according to claim 1 , for densifying annular substrates placed in a plurality of stacks, the installation including a plurality of heater zones each situated between a respective inlet for reactive gas into the oven and a respective location for an annular stack in the loading zone.
9. An installation according to claim 8 , having a plurality of individual feed pipes for preheated reactive gas connected to the reactive gas inlets into the oven.
10. An installation acorn to claim 9 , wherein the individual feed pipes are connected to a preheating device via a common pipe.
11. An installation according to claim 9 , wherein the individual feed pipes are connected to respective devices for preheating reactive gas.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/417,037 US20030205203A1 (en) | 2001-12-26 | 2003-04-16 | Method and installation for densifying porous substrates by chemical vapour infiltration |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/034,848 US6953605B2 (en) | 2001-12-26 | 2001-12-26 | Method for densifying porous substrates by chemical vapour infiltration with preheated gas |
US10/417,037 US20030205203A1 (en) | 2001-12-26 | 2003-04-16 | Method and installation for densifying porous substrates by chemical vapour infiltration |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/034,848 Division US6953605B2 (en) | 2001-12-26 | 2001-12-26 | Method for densifying porous substrates by chemical vapour infiltration with preheated gas |
Publications (1)
Publication Number | Publication Date |
---|---|
US20030205203A1 true US20030205203A1 (en) | 2003-11-06 |
Family
ID=21878976
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/034,848 Expired - Lifetime US6953605B2 (en) | 2001-12-26 | 2001-12-26 | Method for densifying porous substrates by chemical vapour infiltration with preheated gas |
US10/417,037 Abandoned US20030205203A1 (en) | 2001-12-26 | 2003-04-16 | Method and installation for densifying porous substrates by chemical vapour infiltration |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/034,848 Expired - Lifetime US6953605B2 (en) | 2001-12-26 | 2001-12-26 | Method for densifying porous substrates by chemical vapour infiltration with preheated gas |
Country Status (17)
Country | Link |
---|---|
US (2) | US6953605B2 (en) |
EP (1) | EP1458902B1 (en) |
JP (1) | JP4426302B2 (en) |
KR (1) | KR100896854B1 (en) |
CN (1) | CN100371493C (en) |
AT (1) | ATE340880T1 (en) |
AU (1) | AU2002364339B2 (en) |
BR (1) | BR0215313B1 (en) |
CA (1) | CA2471672C (en) |
DE (1) | DE60215048T2 (en) |
ES (1) | ES2274121T3 (en) |
HU (1) | HUP0402078A2 (en) |
IL (1) | IL162659A0 (en) |
MX (1) | MXPA04006329A (en) |
RU (1) | RU2319682C2 (en) |
UA (1) | UA78733C2 (en) |
WO (1) | WO2003056059A1 (en) |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20070014990A1 (en) * | 2005-07-14 | 2007-01-18 | Honeywell International Inc. | Support structure for radiative heat transfer |
US20070184179A1 (en) * | 2006-02-09 | 2007-08-09 | Akshay Waghray | Methods and apparatus to monitor a process of depositing a constituent of a multi-constituent gas during production of a composite brake disc |
US20140220244A1 (en) * | 2013-02-07 | 2014-08-07 | Uchicago Argonne Llc | Ald reactor for coating porous substrates |
US10648075B2 (en) * | 2015-03-23 | 2020-05-12 | Goodrich Corporation | Systems and methods for chemical vapor infiltration and densification of porous substrates |
US11111578B1 (en) | 2020-02-13 | 2021-09-07 | Uchicago Argonne, Llc | Atomic layer deposition of fluoride thin films |
CN113683436A (en) * | 2021-08-27 | 2021-11-23 | 清华大学 | Air inlet assembly, vapor deposition device and preparation method of composite material of vapor deposition device |
US11512024B2 (en) | 2018-08-10 | 2022-11-29 | Safran Ceramics | Method for densifying porous annular substrates by chemical vapour infiltration |
US11901169B2 (en) | 2022-02-14 | 2024-02-13 | Uchicago Argonne, Llc | Barrier coatings |
Families Citing this family (39)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7476419B2 (en) * | 1998-10-23 | 2009-01-13 | Goodrich Corporation | Method for measurement of weight during a CVI/CVD process |
US6669988B2 (en) * | 2001-08-20 | 2003-12-30 | Goodrich Corporation | Hardware assembly for CVI/CVD processes |
US20040255862A1 (en) * | 2001-02-26 | 2004-12-23 | Lee Chung J. | Reactor for producing reactive intermediates for low dielectric constant polymer thin films |
US6758909B2 (en) * | 2001-06-05 | 2004-07-06 | Honeywell International Inc. | Gas port sealing for CVD/CVI furnace hearth plates |
FR2834713B1 (en) * | 2002-01-15 | 2004-04-02 | Snecma Moteurs | PROCESS AND PLANT FOR DENSIFICATION OF SUBSTRATES BY CHEMICAL STEAM INFILTRATION |
US20050158468A1 (en) * | 2004-01-20 | 2005-07-21 | John Gaffney | Method for manufacturing carbon composites |
US20060201426A1 (en) * | 2004-05-25 | 2006-09-14 | Lee Chung J | Reactor for Producing Reactive Intermediates for Transport Polymerization |
US7799375B2 (en) * | 2004-06-30 | 2010-09-21 | Poco Graphite, Inc. | Process for the manufacturing of dense silicon carbide |
US7332195B2 (en) * | 2004-08-26 | 2008-02-19 | Honeywell International Inc. | Chemical vapor deposition method |
FR2881145B1 (en) * | 2005-01-24 | 2007-11-23 | Snecma Propulsion Solide Sa | METHOD OF GAS PHASE CHEMICAL INFILTRATION FOR THE DENSIFICATION OF POROUS SUBSTRATES WITH PYROLYTIC CARBON |
FR2882064B1 (en) | 2005-02-17 | 2007-05-11 | Snecma Propulsion Solide Sa | PROCESS FOR THE DENSIFICATION OF THIN POROUS SUBSTRATES BY CHEMICAL VAPOR PHASE INFILTRATION AND DEVICE FOR LOADING SUCH SUBSTRATES |
US20060194059A1 (en) * | 2005-02-25 | 2006-08-31 | Honeywell International Inc. | Annular furnace spacers and method of using same |
US20060194060A1 (en) * | 2005-02-25 | 2006-08-31 | Honeywell International | Furnace spacers for spacing preforms in a furnace |
US20060274474A1 (en) * | 2005-06-01 | 2006-12-07 | Lee Chung J | Substrate Holder |
FR2897422B1 (en) * | 2006-02-14 | 2008-05-16 | Messier Bugatti Sa | SEALING DEVICE FOR GAS INTAKE OF AN OVEN OR THE LIKE |
US7771194B2 (en) * | 2006-05-26 | 2010-08-10 | Honeywell International Inc. | Gas preheater for chemical vapor processing furnace having circuitous passages |
AU2007316209B2 (en) * | 2006-10-29 | 2012-03-15 | Messier-Bugatti-Dowty | Method of densifying porous articles |
FR2924426B1 (en) * | 2007-11-30 | 2011-06-03 | Messier Bugatti | PROCESS FOR MANUFACTURING COMPOSITE MATERIAL PARTS WITH CARBON FIBER REINFORCEMENT |
JP5730496B2 (en) * | 2009-05-01 | 2015-06-10 | 株式会社日立国際電気 | Heat treatment apparatus, semiconductor device manufacturing method, and substrate processing method |
US8177884B2 (en) * | 2009-05-20 | 2012-05-15 | United Technologies Corporation | Fuel deoxygenator with porous support plate |
US20110064891A1 (en) * | 2009-09-16 | 2011-03-17 | Honeywell International Inc. | Methods of rapidly densifying complex-shaped, asymmetrical porous structures |
US8075692B2 (en) * | 2009-11-18 | 2011-12-13 | Rec Silicon Inc | Fluid bed reactor |
US20120090805A1 (en) * | 2010-10-18 | 2012-04-19 | Uzialko Stanislaw P | Systems and methods for a thermistor furnace |
FR2993044B1 (en) * | 2012-07-04 | 2014-08-08 | Herakles | LOADING DEVICE AND INSTALLATION FOR THE DENSIFICATION OF POROUS, TRUNCONIC AND STACKABLE PREFORMS |
FR2993555B1 (en) * | 2012-07-19 | 2015-02-20 | Herakles | INSTALLATION OF HEAVY DUTY CHEMICAL INFILTRATION WITH HIGH LOAD CAPACITY |
US9523149B2 (en) | 2013-03-14 | 2016-12-20 | Rolls-Royce Corporation | Rapid ceramic matrix composite production method |
FR3007511B1 (en) * | 2013-06-19 | 2017-09-08 | Herakles | INSTALLATION FOR THERMAL TREATMENTS OF PRODUCTS IN COMPOSITE MATERIAL COMPRISING DELOCALIZED TEMPERATURE MEANS |
FR3018526B1 (en) * | 2014-03-14 | 2021-06-11 | Herakles | CVI DENSIFICATION INSTALLATION INCLUDING A HIGH-CAPACITY PREHEATING ZONE |
TWI624554B (en) * | 2015-08-21 | 2018-05-21 | 弗里松股份有限公司 | Evaporation source |
MY190445A (en) | 2015-08-21 | 2022-04-21 | Flisom Ag | Homogeneous linear evaporation source |
RU2607401C1 (en) * | 2015-09-25 | 2017-01-10 | Олег Викторович Барзинский | Method of producing carbon-carbon composite material |
CN105463410B (en) * | 2015-12-15 | 2018-09-21 | 西安鑫垚陶瓷复合材料有限公司 | The method and gas piping structure that a kind of CVI for open containers is densified |
US10407769B2 (en) * | 2016-03-18 | 2019-09-10 | Goodrich Corporation | Method and apparatus for decreasing the radial temperature gradient in CVI/CVD furnaces |
US20200386723A1 (en) * | 2017-12-05 | 2020-12-10 | Mécanique Analytique Inc. | Gas chromatography modular oven |
CN108048817A (en) * | 2017-12-12 | 2018-05-18 | 湖南顶立科技有限公司 | A kind of chemical vapor deposition stove |
CN114225843B (en) * | 2021-12-06 | 2022-08-05 | 中南大学 | Zone-limited directional flow full-saturation infiltration reactor and method for preparing carbon/carbon composite material brake disc |
FR3130276A1 (en) * | 2021-12-15 | 2023-06-16 | Safran Ceramics | Installation of thermochemical treatment and method of manufacturing a friction part in composite material |
US11932941B1 (en) | 2021-12-29 | 2024-03-19 | Rolls-Royce High Temperature Composites, Inc. | Load assemblies for loading parts in a furnace |
FR3132718A1 (en) * | 2022-02-16 | 2023-08-18 | Safran Landing Systems | Gas phase chemical infiltration densification process with monopile trays for semi-forced flow |
Citations (33)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3663283A (en) * | 1969-10-02 | 1972-05-16 | Richard A Hebert | Process and apparatus for the production of finely-divided metal oxides |
US4094897A (en) * | 1975-08-12 | 1978-06-13 | Matsushita Electric Industrial Co., Ltd. | Resin-bonded graphite body for a dry cell |
US4141696A (en) * | 1978-04-28 | 1979-02-27 | Texaco Inc. | Process for gas cleaning with reclaimed water and apparatus for water reclamation |
US4416748A (en) * | 1981-09-08 | 1983-11-22 | Concord Scientific Corporation | Process for reduction of the content of SO2 and/or NOx in flue gas |
US4582632A (en) * | 1983-04-11 | 1986-04-15 | Kabushiki Kaisha Kobe Seiko Sho | Non-permeable carbonaceous formed bodies and method for producing same |
US4738272A (en) * | 1984-05-21 | 1988-04-19 | Mcconnell Christopher F | Vessel and system for treating wafers with fluids |
US4835074A (en) * | 1987-09-25 | 1989-05-30 | The Electrosynthesis Company, Inc. | Modified carbons and electrochemical cells containing the same |
US4920017A (en) * | 1986-11-20 | 1990-04-24 | Electric Power Research Institute, Inc. | Porous and porous-nonporous composites for battery electrodes |
US4957593A (en) * | 1989-03-07 | 1990-09-18 | University Of Connecticut | Modified composite electrodes with renewable surface for electrochemical applications and method of making same |
US5225378A (en) * | 1990-11-16 | 1993-07-06 | Tokyo Electron Limited | Method of forming a phosphorus doped silicon film |
US5254374A (en) * | 1992-04-08 | 1993-10-19 | The United States Of America As Represented By The United States Department Of Energy | Chemical vapor infiltration using microwave energy |
US5362228A (en) * | 1991-11-04 | 1994-11-08 | Societe Europeenne De Propulsion | Apparatus for preheating a flow of gas in an installation for chemical vapor infiltration, and a densification method using the apparatus |
US5480678A (en) * | 1994-11-16 | 1996-01-02 | The B. F. Goodrich Company | Apparatus for use with CVI/CVD processes |
US5496410A (en) * | 1992-03-10 | 1996-03-05 | Hitachi, Ltd. | Plasma processing apparatus and method of processing substrates by using same apparatus |
US5567267A (en) * | 1992-11-20 | 1996-10-22 | Tokyo Electron Limited | Method of controlling temperature of susceptor |
US5582802A (en) * | 1994-07-05 | 1996-12-10 | Spokoyny; Felix E. | Catalytic sulfur trioxide flue gas conditioning |
US5803959A (en) * | 1996-06-14 | 1998-09-08 | Cabot Corporation | Modified carbon products and ink jet inks, inks and coatings containing modified carbon products |
US5840414A (en) * | 1996-11-15 | 1998-11-24 | International Fuel Cells, Inc. | Porous carbon body with increased wettability by water |
US5904957A (en) * | 1995-04-18 | 1999-05-18 | Societe Europeenne De Propulsion | Vapour phase chemical infiltration process for densifying porous substrates disposed in annular stacks |
US5942347A (en) * | 1997-05-20 | 1999-08-24 | Institute Of Gas Technology | Proton exchange membrane fuel cell separator plate |
US6024848A (en) * | 1998-04-15 | 2000-02-15 | International Fuel Cells, Corporation | Electrochemical cell with a porous support plate |
US6051071A (en) * | 1994-12-05 | 2000-04-18 | Societe Nationale D'etude Et De Construction De Moteurs D'aviation | Device for extracting gas from an oven for chemical vapor deposition or infiltration in an installation for fabricating composite material parts |
US6132515A (en) * | 1998-03-12 | 2000-10-17 | Cosmos Factory, Inc. | Liquid precursor delivery system |
US6144802A (en) * | 1999-06-29 | 2000-11-07 | Hyundai Electronics Industries Co., Ltd. | Fluid heater for semiconductor device |
US6248434B1 (en) * | 1996-12-24 | 2001-06-19 | Widia Gmbh | Composite body comprising a hard metal, cermet or ceramic substrate body and method of producing same |
US6258476B1 (en) * | 1999-09-02 | 2001-07-10 | International Fuel Cells, Llc | Porous carbon body with increased wettability by water |
US6336965B1 (en) * | 1998-04-03 | 2002-01-08 | Cabot Corporation | Modified pigments having improved dispersing properties |
US6370897B1 (en) * | 1999-07-02 | 2002-04-16 | Tokyo Electron Limited | Semiconductor manufacturing facility |
US20030042205A1 (en) * | 2001-08-31 | 2003-03-06 | Gaudet Gregory T. | Material for chromatography |
US20030049372A1 (en) * | 1997-08-11 | 2003-03-13 | Cook Robert C. | High rate deposition at low pressures in a small batch reactor |
US20030091891A1 (en) * | 2001-01-16 | 2003-05-15 | Tomoaki Yoshida | Catalyst composition for cell, gas diffusion layer, and fuel cell comprising the same |
US20030106495A1 (en) * | 2000-05-31 | 2003-06-12 | Takanobu Asano | Heat treatment system and method |
US6645287B2 (en) * | 2001-04-27 | 2003-11-11 | Cabot Corporation | Coating compositions comprising high t-area carbon products |
Family Cites Families (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS6220309A (en) | 1985-07-18 | 1987-01-28 | Nec Corp | Light irradiation furnace |
JPS62249423A (en) | 1986-04-23 | 1987-10-30 | Hitachi Ltd | Processing apparatus |
JPH0828335B2 (en) | 1992-11-30 | 1996-03-21 | 株式会社半導体プロセス研究所 | Semiconductor device manufacturing equipment |
US5348774A (en) * | 1993-08-11 | 1994-09-20 | Alliedsignal Inc. | Method of rapidly densifying a porous structure |
FR2711647B1 (en) * | 1993-10-27 | 1996-01-19 | Europ Propulsion | Process for the chemical vapor infiltration of a material into a porous substrate at a controlled surface temperature. |
FR2711646B1 (en) * | 1993-10-27 | 1996-02-09 | Europ Propulsion | Method of chemical vapor infiltration of a pyrocarbon matrix within a porous substrate with establishment of a temperature gradient in the substrate. |
FR2714076B1 (en) * | 1993-12-16 | 1996-03-15 | Europ Propulsion | Method for densifying porous substrates by chemical vapor infiltration of silicon carbide. |
JP3754450B2 (en) * | 1994-11-16 | 2006-03-15 | グッドリッチ・コーポレイション | Pressure gradient CVI / CVD method |
FR2732677B1 (en) * | 1995-04-07 | 1997-06-27 | Europ Propulsion | CHEMICAL STEAM INFILTRATION PROCESS WITH VARIABLE INFILTRATION PARAMETERS |
FR2754813B1 (en) | 1996-10-18 | 1999-01-15 | Europ Propulsion | DENSIFICATION OF POROUS SUBSTRATES DISPOSED IN ANNULAR CELLS BY CHEMICAL VAPOR INFILTRATION WITH TEMPERATURE GRADIENT |
FR2784695B1 (en) * | 1998-10-20 | 2001-11-02 | Snecma | DENSIFICATION OF POROUS STRUCTURES BY CHEMICAL STEAM INFILTRATION |
US6440220B1 (en) | 1998-10-23 | 2002-08-27 | Goodrich Corporation | Method and apparatus for inhibiting infiltration of a reactive gas into porous refractory insulation |
US6572371B1 (en) * | 2002-05-06 | 2003-06-03 | Messier-Bugatti | Gas preheater and process for controlling distribution of preheated reactive gas in a CVI furnace for densification of porous annular substrates |
-
2001
- 2001-12-26 US US10/034,848 patent/US6953605B2/en not_active Expired - Lifetime
-
2002
- 2002-12-24 ES ES02799114T patent/ES2274121T3/en not_active Expired - Lifetime
- 2002-12-24 HU HU0402078A patent/HUP0402078A2/en unknown
- 2002-12-24 DE DE60215048T patent/DE60215048T2/en not_active Expired - Lifetime
- 2002-12-24 EP EP02799114A patent/EP1458902B1/en not_active Expired - Lifetime
- 2002-12-24 MX MXPA04006329A patent/MXPA04006329A/en active IP Right Grant
- 2002-12-24 CA CA2471672A patent/CA2471672C/en not_active Expired - Fee Related
- 2002-12-24 CN CNB028260562A patent/CN100371493C/en not_active Expired - Lifetime
- 2002-12-24 WO PCT/FR2002/004554 patent/WO2003056059A1/en active IP Right Grant
- 2002-12-24 AU AU2002364339A patent/AU2002364339B2/en not_active Ceased
- 2002-12-24 RU RU2004118418/02A patent/RU2319682C2/en active
- 2002-12-24 IL IL16265902A patent/IL162659A0/en not_active IP Right Cessation
- 2002-12-24 KR KR1020047010048A patent/KR100896854B1/en not_active IP Right Cessation
- 2002-12-24 AT AT02799114T patent/ATE340880T1/en active
- 2002-12-24 JP JP2003556573A patent/JP4426302B2/en not_active Expired - Fee Related
- 2002-12-24 UA UA20040605015A patent/UA78733C2/en unknown
- 2002-12-24 BR BRPI0215313-0A patent/BR0215313B1/en not_active IP Right Cessation
-
2003
- 2003-04-16 US US10/417,037 patent/US20030205203A1/en not_active Abandoned
Patent Citations (35)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3663283A (en) * | 1969-10-02 | 1972-05-16 | Richard A Hebert | Process and apparatus for the production of finely-divided metal oxides |
US4094897A (en) * | 1975-08-12 | 1978-06-13 | Matsushita Electric Industrial Co., Ltd. | Resin-bonded graphite body for a dry cell |
US4141696A (en) * | 1978-04-28 | 1979-02-27 | Texaco Inc. | Process for gas cleaning with reclaimed water and apparatus for water reclamation |
US4416748A (en) * | 1981-09-08 | 1983-11-22 | Concord Scientific Corporation | Process for reduction of the content of SO2 and/or NOx in flue gas |
US4582632A (en) * | 1983-04-11 | 1986-04-15 | Kabushiki Kaisha Kobe Seiko Sho | Non-permeable carbonaceous formed bodies and method for producing same |
US4738272A (en) * | 1984-05-21 | 1988-04-19 | Mcconnell Christopher F | Vessel and system for treating wafers with fluids |
US4920017A (en) * | 1986-11-20 | 1990-04-24 | Electric Power Research Institute, Inc. | Porous and porous-nonporous composites for battery electrodes |
US4835074A (en) * | 1987-09-25 | 1989-05-30 | The Electrosynthesis Company, Inc. | Modified carbons and electrochemical cells containing the same |
US4957593A (en) * | 1989-03-07 | 1990-09-18 | University Of Connecticut | Modified composite electrodes with renewable surface for electrochemical applications and method of making same |
US5225378A (en) * | 1990-11-16 | 1993-07-06 | Tokyo Electron Limited | Method of forming a phosphorus doped silicon film |
US5362228A (en) * | 1991-11-04 | 1994-11-08 | Societe Europeenne De Propulsion | Apparatus for preheating a flow of gas in an installation for chemical vapor infiltration, and a densification method using the apparatus |
US5496410A (en) * | 1992-03-10 | 1996-03-05 | Hitachi, Ltd. | Plasma processing apparatus and method of processing substrates by using same apparatus |
US5254374A (en) * | 1992-04-08 | 1993-10-19 | The United States Of America As Represented By The United States Department Of Energy | Chemical vapor infiltration using microwave energy |
US5567267A (en) * | 1992-11-20 | 1996-10-22 | Tokyo Electron Limited | Method of controlling temperature of susceptor |
US5582802A (en) * | 1994-07-05 | 1996-12-10 | Spokoyny; Felix E. | Catalytic sulfur trioxide flue gas conditioning |
US5480678A (en) * | 1994-11-16 | 1996-01-02 | The B. F. Goodrich Company | Apparatus for use with CVI/CVD processes |
US6109209A (en) * | 1994-11-16 | 2000-08-29 | Rudolph; James W. | Apparatus for use with CVI/CVD processes |
US6051071A (en) * | 1994-12-05 | 2000-04-18 | Societe Nationale D'etude Et De Construction De Moteurs D'aviation | Device for extracting gas from an oven for chemical vapor deposition or infiltration in an installation for fabricating composite material parts |
US5904957A (en) * | 1995-04-18 | 1999-05-18 | Societe Europeenne De Propulsion | Vapour phase chemical infiltration process for densifying porous substrates disposed in annular stacks |
US5803959A (en) * | 1996-06-14 | 1998-09-08 | Cabot Corporation | Modified carbon products and ink jet inks, inks and coatings containing modified carbon products |
US5885335A (en) * | 1996-06-14 | 1999-03-23 | Cabot Corporation | Modified carbon products and inks and coatings containing modified carbon products |
US5840414A (en) * | 1996-11-15 | 1998-11-24 | International Fuel Cells, Inc. | Porous carbon body with increased wettability by water |
US6248434B1 (en) * | 1996-12-24 | 2001-06-19 | Widia Gmbh | Composite body comprising a hard metal, cermet or ceramic substrate body and method of producing same |
US5942347A (en) * | 1997-05-20 | 1999-08-24 | Institute Of Gas Technology | Proton exchange membrane fuel cell separator plate |
US20030049372A1 (en) * | 1997-08-11 | 2003-03-13 | Cook Robert C. | High rate deposition at low pressures in a small batch reactor |
US6132515A (en) * | 1998-03-12 | 2000-10-17 | Cosmos Factory, Inc. | Liquid precursor delivery system |
US6336965B1 (en) * | 1998-04-03 | 2002-01-08 | Cabot Corporation | Modified pigments having improved dispersing properties |
US6024848A (en) * | 1998-04-15 | 2000-02-15 | International Fuel Cells, Corporation | Electrochemical cell with a porous support plate |
US6144802A (en) * | 1999-06-29 | 2000-11-07 | Hyundai Electronics Industries Co., Ltd. | Fluid heater for semiconductor device |
US6370897B1 (en) * | 1999-07-02 | 2002-04-16 | Tokyo Electron Limited | Semiconductor manufacturing facility |
US6258476B1 (en) * | 1999-09-02 | 2001-07-10 | International Fuel Cells, Llc | Porous carbon body with increased wettability by water |
US20030106495A1 (en) * | 2000-05-31 | 2003-06-12 | Takanobu Asano | Heat treatment system and method |
US20030091891A1 (en) * | 2001-01-16 | 2003-05-15 | Tomoaki Yoshida | Catalyst composition for cell, gas diffusion layer, and fuel cell comprising the same |
US6645287B2 (en) * | 2001-04-27 | 2003-11-11 | Cabot Corporation | Coating compositions comprising high t-area carbon products |
US20030042205A1 (en) * | 2001-08-31 | 2003-03-06 | Gaudet Gregory T. | Material for chromatography |
Cited By (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20070014990A1 (en) * | 2005-07-14 | 2007-01-18 | Honeywell International Inc. | Support structure for radiative heat transfer |
US20070184179A1 (en) * | 2006-02-09 | 2007-08-09 | Akshay Waghray | Methods and apparatus to monitor a process of depositing a constituent of a multi-constituent gas during production of a composite brake disc |
US20140220244A1 (en) * | 2013-02-07 | 2014-08-07 | Uchicago Argonne Llc | Ald reactor for coating porous substrates |
US11326255B2 (en) * | 2013-02-07 | 2022-05-10 | Uchicago Argonne, Llc | ALD reactor for coating porous substrates |
US10648075B2 (en) * | 2015-03-23 | 2020-05-12 | Goodrich Corporation | Systems and methods for chemical vapor infiltration and densification of porous substrates |
US11639545B2 (en) * | 2015-03-23 | 2023-05-02 | Goodrich Corporation | Methods for chemical vapor infiltration and densification of porous substrates |
US11512024B2 (en) | 2018-08-10 | 2022-11-29 | Safran Ceramics | Method for densifying porous annular substrates by chemical vapour infiltration |
US11111578B1 (en) | 2020-02-13 | 2021-09-07 | Uchicago Argonne, Llc | Atomic layer deposition of fluoride thin films |
CN113683436A (en) * | 2021-08-27 | 2021-11-23 | 清华大学 | Air inlet assembly, vapor deposition device and preparation method of composite material of vapor deposition device |
CN113683436B (en) * | 2021-08-27 | 2022-09-16 | 清华大学 | Air inlet assembly, vapor deposition device and preparation method of composite material of vapor deposition device |
US11901169B2 (en) | 2022-02-14 | 2024-02-13 | Uchicago Argonne, Llc | Barrier coatings |
Also Published As
Publication number | Publication date |
---|---|
KR100896854B1 (en) | 2009-05-12 |
ES2274121T3 (en) | 2007-05-16 |
AU2002364339B2 (en) | 2008-09-04 |
CN1608142A (en) | 2005-04-20 |
UA78733C2 (en) | 2007-04-25 |
DE60215048D1 (en) | 2006-11-09 |
US6953605B2 (en) | 2005-10-11 |
CA2471672C (en) | 2011-03-22 |
IL162659A0 (en) | 2005-11-20 |
RU2319682C2 (en) | 2008-03-20 |
JP2005512940A (en) | 2005-05-12 |
CA2471672A1 (en) | 2003-07-10 |
BR0215313A (en) | 2004-10-19 |
JP4426302B2 (en) | 2010-03-03 |
AU2002364339A1 (en) | 2003-07-15 |
RU2004118418A (en) | 2005-06-10 |
KR20040071754A (en) | 2004-08-12 |
BR0215313B1 (en) | 2011-11-29 |
MXPA04006329A (en) | 2004-10-04 |
CN100371493C (en) | 2008-02-27 |
HUP0402078A2 (en) | 2005-01-28 |
US20030118728A1 (en) | 2003-06-26 |
EP1458902A1 (en) | 2004-09-22 |
EP1458902B1 (en) | 2006-09-27 |
ATE340880T1 (en) | 2006-10-15 |
WO2003056059A1 (en) | 2003-07-10 |
DE60215048T2 (en) | 2007-05-10 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US6953605B2 (en) | Method for densifying porous substrates by chemical vapour infiltration with preheated gas | |
US6572371B1 (en) | Gas preheater and process for controlling distribution of preheated reactive gas in a CVI furnace for densification of porous annular substrates | |
EP0832863B1 (en) | Pressure gradient CVI/CVD apparatus, process, and product | |
JP4960264B2 (en) | Method for densifying thin porous substrate by chemical vapor infiltration and loading device for the substrate | |
JP4495970B2 (en) | Method and apparatus for densification of substrate by chemical vapor infiltration | |
US5738908A (en) | Method of densifying porous substrates by chemical vapor infiltration of silicon carbide |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |