CA1246950A - Covering for photothermal conversion - Google Patents
Covering for photothermal conversionInfo
- Publication number
- CA1246950A CA1246950A CA000424724A CA424724A CA1246950A CA 1246950 A CA1246950 A CA 1246950A CA 000424724 A CA000424724 A CA 000424724A CA 424724 A CA424724 A CA 424724A CA 1246950 A CA1246950 A CA 1246950A
- Authority
- CA
- Canada
- Prior art keywords
- layer
- substrate
- deposited
- covering according
- infrared radiation
- 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.)
- Expired
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
- F24S70/00—Details of absorbing elements
- F24S70/30—Auxiliary coatings, e.g. anti-reflective coatings
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
- F24S70/00—Details of absorbing elements
- F24S70/20—Details of absorbing elements characterised by absorbing coatings; characterised by surface treatment for increasing absorption
- F24S70/225—Details of absorbing elements characterised by absorbing coatings; characterised by surface treatment for increasing absorption for spectrally selective absorption
-
- 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
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/40—Solar thermal energy, e.g. solar towers
-
- 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
- Y10S126/00—Stoves and furnaces
- Y10S126/907—Absorber coating
- Y10S126/908—Particular chemical
-
- 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
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/12—All metal or with adjacent metals
- Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
- Y10T428/12535—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.] with additional, spatially distinct nonmetal component
- Y10T428/12542—More than one such component
-
- 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
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/12—All metal or with adjacent metals
- Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
- Y10T428/12535—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.] with additional, spatially distinct nonmetal component
- Y10T428/12597—Noncrystalline silica or noncrystalline plural-oxide component [e.g., glass, etc.]
-
- 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
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/12—All metal or with adjacent metals
- Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
- Y10T428/12535—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.] with additional, spatially distinct nonmetal component
- Y10T428/12597—Noncrystalline silica or noncrystalline plural-oxide component [e.g., glass, etc.]
- Y10T428/12604—Film [e.g., glaze, etc.]
-
- 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
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/12—All metal or with adjacent metals
- Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
- Y10T428/12535—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.] with additional, spatially distinct nonmetal component
- Y10T428/12625—Free carbon containing component
-
- 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
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/12—All metal or with adjacent metals
- Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
- Y10T428/12771—Transition metal-base component
- Y10T428/12861—Group VIII or IB metal-base component
- Y10T428/12889—Au-base component
-
- 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
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/12—All metal or with adjacent metals
- Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
- Y10T428/12771—Transition metal-base component
- Y10T428/12861—Group VIII or IB metal-base component
- Y10T428/12896—Ag-base component
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- 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
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/12—All metal or with adjacent metals
- Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
- Y10T428/12771—Transition metal-base component
- Y10T428/12861—Group VIII or IB metal-base component
- Y10T428/12903—Cu-base component
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- 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
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/12—All metal or with adjacent metals
- Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
- Y10T428/12771—Transition metal-base component
- Y10T428/12861—Group VIII or IB metal-base component
- Y10T428/12903—Cu-base component
- Y10T428/12917—Next to Fe-base component
- Y10T428/12924—Fe-base has 0.01-1.7% carbon [i.e., steel]
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- 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
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/12—All metal or with adjacent metals
- Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
- Y10T428/12771—Transition metal-base component
- Y10T428/12861—Group VIII or IB metal-base component
- Y10T428/12951—Fe-base component
- Y10T428/12972—Containing 0.01-1.7% carbon [i.e., steel]
- Y10T428/12979—Containing more than 10% nonferrous elements [e.g., high alloy, stainless]
Abstract
ABSTRACT OF THE DISCLOSURE
Covering for photothermal conversion.
It comprises an infrared radiation reflecting substrate, a first layer deposited on the substrate and formed from a metallic material, and a second layer deposited on the first layer and constituted by a solar radiation absorbing an amorphous material, such as amorphous carbon. The substrate can be formed from an infrared radiation reflecting layer, deposited on a primary substrate.
Application to the photothermal conversion of solar energy.
Covering for photothermal conversion.
It comprises an infrared radiation reflecting substrate, a first layer deposited on the substrate and formed from a metallic material, and a second layer deposited on the first layer and constituted by a solar radiation absorbing an amorphous material, such as amorphous carbon. The substrate can be formed from an infrared radiation reflecting layer, deposited on a primary substrate.
Application to the photothermal conversion of solar energy.
Description
COVERING FOR PHOTOTHERMAL CONVERSION
The present invention relates to a covering for photothermal conversion and more particularly applies to the photothermal conversion of solar energy.
It is known that so-called "selective"
surfaces are being increasingly used for the photo-thermal conversion of solar energy, because they make it possible to significantly improve conversion efficiencies. These surfaces are such that they heat by absorbing incident solar radiation in the same way as a black body, but unlike the latter, they only emit very little infrared radiation, so that their heat losses are minimized. Among -the different known methods for producing them, that which is most fre-quently used at present consists of depositing a thin layer of a material absorbing solar radiation on an only slightly ernissive layer, i.e. which reflects infrared radiation.
At present there are two main groups of methods used for depositing -the thin layer of absorb-ent materials, namely liquid phase deposition methods (chemical and electrolytic deposits, deposits by immersion, etc.), and vapour phase deposition methods (vacuum evaporation, cathodic sputtering, e-tc).
The methods of the second group are more difficult to realize than those of the first group, but nevertheless offer the possibili-ties of producing composite materials, which it would be difficult or even impossible to obtain by using liquid phase deposi-tion methods.
However, the me-thods of the first and second groups have one point in common, namely with said methods, an attempt is generally made to produce a thin absorbant layer of the "cermet" type, which is a 5~
very fine dispersion of a phase having a metallic nature in a matrix having a dielectric nature and in order to increase still further the absorbing proper-ties of the cermet, its composition is made variable in its thickness. Thus~ attempts are made to obtain a cermet having a metallic nature at the interface with the infrared radia-tion reflecting layer and with a dielectric nature at the interface with the ambient medium (air) to obtain a so-called "graded'l cermet.
The optical properties of -the numerous cermets are now well known and have been widely publicized in the literature. For example, reference can be made to cermets obtained by the reactive cathodic sputtering of a s-tainless steel target in a residual atmosphere of argon and acetylene. Cermets of this type are, for example, envisaged in U.S.
Patent 4 309 261 and in a communication entitled 'IIn line production system for sputter deposition of graded index solar absorbing films", by D.R. McKenzie et al., 8th International Vacuum Congress, Cannes, September 1980.
Apart from the fact that reactive cathodic sputtering is much more difficul-t to control than non-reactive cathodic sputtering due, inter alia, to the pressure gradient of the reactive gas which has to be maintained in the sputtering chamber, the layers of the type reerred to in the aforementioned paragraph and obtained by reactive cathodic sput-tering, contain a large proportion of hydrogen, as has been stated in the article entitled "Properties of hydrogenated carbon film~ produced by reactive magnetron sputter-ing", by D.R. McKenzie et al., published in Solar Energy Materials, 6, 1981, pp. 97 - 106.
The presence of hydrogen in the deposited layer is prejudicial to the production of a vacuum transducer for photothermal conversion, because it 6~50 makes the degassing operations which have to be carried ou-t during its production more difficult.
Moreover, the desorption of this hydrogen during heat treatment seems to be one of the most important reasons for the deterioration in the optical proper-ties of graded cermets produced from stainless steel and carbon.
Coverings for photothermal conversion are also known, which are obtained by a method consisting of depositing a graphite layer on an infrared radi-ation reflecting layer, the latter being itself deposited on a substrate and which can be of copper, silver, nickel or titanium. This method is described in the article entitled "Effect of substrate on graphite and o-ther solar selective surfaces", by D.R.
McKenzie, published in Applied Optics, vol. 17, no.
12, 1978, pp. 1984 to 1988. It is much simpler than the reactive cathodic sputtering method and can there-fore be much more easily controlled, because it only involves the superimposing of two elemen-tary homogene-ous layers. Moreover, these layers are free from prejudicial foreign atoms, such as hydrogen atoms, due to the procedure used for depositing the graphite layer, namely vacuum evaporation by an electron gun.
Unfortunately, the graphite layers obtained by this method are not sufficiently absorbant to be suitable for industrial applications. Thus, their solar absorp-tion factor is only 0.70 for graphite deposited on copper and 0.80 for graphite deposited on 3~ titanium.
The present invention relates to a covering for photothermal conversion, which does not suffer from the disadvantages of the known coverings de-scribed hereinbefore. Thus, it can be produced in a simple manner and has thermally s-table layers, which are free from hydrogen and whose solar absorption 5~
factor can be equal to or higher than 0.90.
More specifically, the present invention relates to a covering for photothermal conversion, wherein it comprises an infrared radiation reflecting substrate, a first layer deposited on this substrate and constituted by at least one metallic compound, and a second layer deposited on the first layer, said second layer being constituted by an amorphous materi-al and is able to absorb solar radiation.
According to another feature of the covering according to the invention, the substrate is formed by an infrared radiation reflecting layer and a primary substra-te, the infrared radiation reflecting layer being deposited on the primary substrate.
In other words, the first and second ].ayers can be deposited on a solid infrared radiati.on re-flecting substrate, or on an infrared radiation re-flecting layer, previously deposited on the so-called primary substra-te.
It is only as a result of the use of a me-tallic layer, between the infrared radiation reflect-ing substrate and the absorban-t layer (second layer), and the use of such a non-crystalline, amorphous, absorban-t layer (unlike graphite, which has a crystal-line structure), that it is possible to obtain a covering having a high reflection factor, whilst still retaining a very low emission factor in the infrared.
The infrared radia-tion reflecting substrate can, for example, be constituted by copper, silver or gold.
3Q According to another special feature of the covering according to the invention, -the first layer is produced from at least one of the materials taken in the group including transition metals and their alloys. The first layer is, for example, obtained from a stainless steel, due -to i-ts ease of production and low cos-t.
AGcording to yet another feature, the thick-ness of the first layer is approximately a :Eew dozen nanometres, e.g. approximately 10 to 50 nm.
According to another fea-ture, the second layer is an amorphous carbon layer.
According to a preferred feature, the thick-ness of the second layer is equal to or greater than that of the first layer, e.g. has a thickness of approximately 50 to 150 nm.
According to yet another feature, the first and second layers are deposited by cathodic sputter-ing.
Finally, according to yet another feature, when the substrate is constituted by the infrared radiation reflecting layer on the primary substrate, the infrared radiation reflecting layer and the first and second layers are deposited by cathodic sputter-ing.
Other fea-tures and advantages of the cover-ing for photothermal conversion according to theinvention will become more apparent from the following description relative to a non-limitative embodiment and with reference to the attached drawing, which diagrammatically shows part of a covering according to Z5 the invention.
In this embodiment, the covering according to the invention comprises an infrared radiation re-flecting layer 1, deposited on a primary substrate 2, so as to form an infrared radiation reflecting sub-strate 3 and a first layer ~, together with a secondlayer 5, successivel.y deposited on the infrared radi-ation reflecting layer.
The different layers are successively depo-sited on the primary substrate by cathodic sputtering in an inert gas, such as argon. Thus, on to the primary substrate, formed for example from a boro-sllicate glass (marketed under -the trademark PYREX), the infrared radiation reflecting layer, which is a thin layer made e.g. from copper, in preference to silver or gold, which are expensive metals. This is followed by the successive deposition of a first metallic layer, then a second amorphous layer, which are very thin and homogeneous and serve to form a very selective covering, combined with the copper layer.
The first layer is obtained by the depo-1~ sition of a very thin metallic film having a thicknessbetween 10 and 50 nm. To achieve this, -the material used is, for example, stainless steel, due to -the fact that it is simple to produce and inexpensive.
The second layer is then obtained by the cathodic sputtering of a carbon target in a residual argon atmosphere. The second amorphous carbon layer preferably has a thickness which is at least equal -to that of the first layer. For example, the thickness of the second layer is between 50 and 150 nm.
The present invention relates to a covering for photothermal conversion and more particularly applies to the photothermal conversion of solar energy.
It is known that so-called "selective"
surfaces are being increasingly used for the photo-thermal conversion of solar energy, because they make it possible to significantly improve conversion efficiencies. These surfaces are such that they heat by absorbing incident solar radiation in the same way as a black body, but unlike the latter, they only emit very little infrared radiation, so that their heat losses are minimized. Among -the different known methods for producing them, that which is most fre-quently used at present consists of depositing a thin layer of a material absorbing solar radiation on an only slightly ernissive layer, i.e. which reflects infrared radiation.
At present there are two main groups of methods used for depositing -the thin layer of absorb-ent materials, namely liquid phase deposition methods (chemical and electrolytic deposits, deposits by immersion, etc.), and vapour phase deposition methods (vacuum evaporation, cathodic sputtering, e-tc).
The methods of the second group are more difficult to realize than those of the first group, but nevertheless offer the possibili-ties of producing composite materials, which it would be difficult or even impossible to obtain by using liquid phase deposi-tion methods.
However, the me-thods of the first and second groups have one point in common, namely with said methods, an attempt is generally made to produce a thin absorbant layer of the "cermet" type, which is a 5~
very fine dispersion of a phase having a metallic nature in a matrix having a dielectric nature and in order to increase still further the absorbing proper-ties of the cermet, its composition is made variable in its thickness. Thus~ attempts are made to obtain a cermet having a metallic nature at the interface with the infrared radia-tion reflecting layer and with a dielectric nature at the interface with the ambient medium (air) to obtain a so-called "graded'l cermet.
The optical properties of -the numerous cermets are now well known and have been widely publicized in the literature. For example, reference can be made to cermets obtained by the reactive cathodic sputtering of a s-tainless steel target in a residual atmosphere of argon and acetylene. Cermets of this type are, for example, envisaged in U.S.
Patent 4 309 261 and in a communication entitled 'IIn line production system for sputter deposition of graded index solar absorbing films", by D.R. McKenzie et al., 8th International Vacuum Congress, Cannes, September 1980.
Apart from the fact that reactive cathodic sputtering is much more difficul-t to control than non-reactive cathodic sputtering due, inter alia, to the pressure gradient of the reactive gas which has to be maintained in the sputtering chamber, the layers of the type reerred to in the aforementioned paragraph and obtained by reactive cathodic sput-tering, contain a large proportion of hydrogen, as has been stated in the article entitled "Properties of hydrogenated carbon film~ produced by reactive magnetron sputter-ing", by D.R. McKenzie et al., published in Solar Energy Materials, 6, 1981, pp. 97 - 106.
The presence of hydrogen in the deposited layer is prejudicial to the production of a vacuum transducer for photothermal conversion, because it 6~50 makes the degassing operations which have to be carried ou-t during its production more difficult.
Moreover, the desorption of this hydrogen during heat treatment seems to be one of the most important reasons for the deterioration in the optical proper-ties of graded cermets produced from stainless steel and carbon.
Coverings for photothermal conversion are also known, which are obtained by a method consisting of depositing a graphite layer on an infrared radi-ation reflecting layer, the latter being itself deposited on a substrate and which can be of copper, silver, nickel or titanium. This method is described in the article entitled "Effect of substrate on graphite and o-ther solar selective surfaces", by D.R.
McKenzie, published in Applied Optics, vol. 17, no.
12, 1978, pp. 1984 to 1988. It is much simpler than the reactive cathodic sputtering method and can there-fore be much more easily controlled, because it only involves the superimposing of two elemen-tary homogene-ous layers. Moreover, these layers are free from prejudicial foreign atoms, such as hydrogen atoms, due to the procedure used for depositing the graphite layer, namely vacuum evaporation by an electron gun.
Unfortunately, the graphite layers obtained by this method are not sufficiently absorbant to be suitable for industrial applications. Thus, their solar absorp-tion factor is only 0.70 for graphite deposited on copper and 0.80 for graphite deposited on 3~ titanium.
The present invention relates to a covering for photothermal conversion, which does not suffer from the disadvantages of the known coverings de-scribed hereinbefore. Thus, it can be produced in a simple manner and has thermally s-table layers, which are free from hydrogen and whose solar absorption 5~
factor can be equal to or higher than 0.90.
More specifically, the present invention relates to a covering for photothermal conversion, wherein it comprises an infrared radiation reflecting substrate, a first layer deposited on this substrate and constituted by at least one metallic compound, and a second layer deposited on the first layer, said second layer being constituted by an amorphous materi-al and is able to absorb solar radiation.
According to another feature of the covering according to the invention, the substrate is formed by an infrared radiation reflecting layer and a primary substra-te, the infrared radiation reflecting layer being deposited on the primary substrate.
In other words, the first and second ].ayers can be deposited on a solid infrared radiati.on re-flecting substrate, or on an infrared radiation re-flecting layer, previously deposited on the so-called primary substra-te.
It is only as a result of the use of a me-tallic layer, between the infrared radiation reflect-ing substrate and the absorban-t layer (second layer), and the use of such a non-crystalline, amorphous, absorban-t layer (unlike graphite, which has a crystal-line structure), that it is possible to obtain a covering having a high reflection factor, whilst still retaining a very low emission factor in the infrared.
The infrared radia-tion reflecting substrate can, for example, be constituted by copper, silver or gold.
3Q According to another special feature of the covering according to the invention, -the first layer is produced from at least one of the materials taken in the group including transition metals and their alloys. The first layer is, for example, obtained from a stainless steel, due -to i-ts ease of production and low cos-t.
AGcording to yet another feature, the thick-ness of the first layer is approximately a :Eew dozen nanometres, e.g. approximately 10 to 50 nm.
According to another fea-ture, the second layer is an amorphous carbon layer.
According to a preferred feature, the thick-ness of the second layer is equal to or greater than that of the first layer, e.g. has a thickness of approximately 50 to 150 nm.
According to yet another feature, the first and second layers are deposited by cathodic sputter-ing.
Finally, according to yet another feature, when the substrate is constituted by the infrared radiation reflecting layer on the primary substrate, the infrared radiation reflecting layer and the first and second layers are deposited by cathodic sputter-ing.
Other fea-tures and advantages of the cover-ing for photothermal conversion according to theinvention will become more apparent from the following description relative to a non-limitative embodiment and with reference to the attached drawing, which diagrammatically shows part of a covering according to Z5 the invention.
In this embodiment, the covering according to the invention comprises an infrared radiation re-flecting layer 1, deposited on a primary substrate 2, so as to form an infrared radiation reflecting sub-strate 3 and a first layer ~, together with a secondlayer 5, successivel.y deposited on the infrared radi-ation reflecting layer.
The different layers are successively depo-sited on the primary substrate by cathodic sputtering in an inert gas, such as argon. Thus, on to the primary substrate, formed for example from a boro-sllicate glass (marketed under -the trademark PYREX), the infrared radiation reflecting layer, which is a thin layer made e.g. from copper, in preference to silver or gold, which are expensive metals. This is followed by the successive deposition of a first metallic layer, then a second amorphous layer, which are very thin and homogeneous and serve to form a very selective covering, combined with the copper layer.
The first layer is obtained by the depo-1~ sition of a very thin metallic film having a thicknessbetween 10 and 50 nm. To achieve this, -the material used is, for example, stainless steel, due to -the fact that it is simple to produce and inexpensive.
The second layer is then obtained by the cathodic sputtering of a carbon target in a residual argon atmosphere. The second amorphous carbon layer preferably has a thickness which is at least equal -to that of the first layer. For example, the thickness of the second layer is between 50 and 150 nm.
2~ Apart from a high thermal stability, -the covering obtained has very interesting optical proper-ties for the photo-thermal conversion of solar energy.
Thus, it is possible -to obtain, by operating in the manner described hereinbefore, coverings having an absorption factor equal to or higher than 0.90, but whose emission factor remains equal to or below 0.05.
As an illustrative and non-limitative exam-ple, the following experimental conditions can be used for producing with the aid of a cathodic sputtering 3a installation for producing deposi-ts on cylindrical substra-tes, whereby said known installation is called a cylindrical magnetron, a covering according to -the invention on a diameter 28 mm PYREX tube used as the primary subs-trate.
- 7 - ~ ~ ~6~
- Notations:
1) Type of cathode 2) Argon pressure
Thus, it is possible -to obtain, by operating in the manner described hereinbefore, coverings having an absorption factor equal to or higher than 0.90, but whose emission factor remains equal to or below 0.05.
As an illustrative and non-limitative exam-ple, the following experimental conditions can be used for producing with the aid of a cathodic sputtering 3a installation for producing deposi-ts on cylindrical substra-tes, whereby said known installation is called a cylindrical magnetron, a covering according to -the invention on a diameter 28 mm PYREX tube used as the primary subs-trate.
- 7 - ~ ~ ~6~
- Notations:
1) Type of cathode 2) Argon pressure
3) Cathode current density
4) Sputtering voltage
5) Sputtering time
6) Deposit thickness ~ Deposition of the infrared radiation reflecting layer:
1) Of copper 2)Between 6.10 and 2.10 Torr, op-timum 10 Torr 3) " 5 " 8 mA/cm " 6.0 mA/cm 4) " 500 V
5) " 45 " 65 s " 55 s 6) " 350 " 550 nm " 450 nm - Deposition of the first layer:
1) Of stainless steel 2)Between 6.10 and 2.10 Torr, optimum 10 2 Torr 3)" 5 " 20 mA/cm " 10 mA/cm 4)" 580 V
5)" 2.5 " 12 s " 5.5 s 6)" 10 " 50 nm " 22.5 nm - Deposition of the second layer; produced from carbon:
1) Of carbon 2)Between 6.10 and 2.10 Torr, optimum 10 2 Torr 3) "5 " 8 mA/cm ll 6 mA/cm 4) " 650 V
5) "55 " 165 s " 90 s 6) " 50 150 nm " 80 nm Under the aforementioned conditions and using a method which is very simple for the expert to perform, it is possible to obtain a coveri.ng with a 3S solar absorption factor of 0.91 and an emission factor of 0.04.
~2~ 5~
~ nder the same experimental conditions as hereinbefore, it is possible to produce the covering by directly placing -the stainless steel layer and the amorphous carbon layer on a polished infrared radi-ation reflecting tube, made e.g. from copper, withoutusing the primary PYREX substrate.
Obviously, the invention does not only relate to coverings for photothermal conversion, depo-sited on -tubular or cylindrical substrates. It also lQ relates to coverings, produced by cathodic sputtering, on substrates having different shapes and forms, by using adapted, known electrodes. For example, in the case of a planar substrate, the latter is held by a substrate holder and a cathode is arranged in parallel and facing the substrate.
Finally, the invention is not limited to the coverings obtained by cathodic spu-ttering. For the deposition of the absorbent layer, e.g. of amorphous carbon, it is possible to use all known methods, such as evaporation or chemical deposition in the vapour phase in the presence of a plasma.
1) Of copper 2)Between 6.10 and 2.10 Torr, op-timum 10 Torr 3) " 5 " 8 mA/cm " 6.0 mA/cm 4) " 500 V
5) " 45 " 65 s " 55 s 6) " 350 " 550 nm " 450 nm - Deposition of the first layer:
1) Of stainless steel 2)Between 6.10 and 2.10 Torr, optimum 10 2 Torr 3)" 5 " 20 mA/cm " 10 mA/cm 4)" 580 V
5)" 2.5 " 12 s " 5.5 s 6)" 10 " 50 nm " 22.5 nm - Deposition of the second layer; produced from carbon:
1) Of carbon 2)Between 6.10 and 2.10 Torr, optimum 10 2 Torr 3) "5 " 8 mA/cm ll 6 mA/cm 4) " 650 V
5) "55 " 165 s " 90 s 6) " 50 150 nm " 80 nm Under the aforementioned conditions and using a method which is very simple for the expert to perform, it is possible to obtain a coveri.ng with a 3S solar absorption factor of 0.91 and an emission factor of 0.04.
~2~ 5~
~ nder the same experimental conditions as hereinbefore, it is possible to produce the covering by directly placing -the stainless steel layer and the amorphous carbon layer on a polished infrared radi-ation reflecting tube, made e.g. from copper, withoutusing the primary PYREX substrate.
Obviously, the invention does not only relate to coverings for photothermal conversion, depo-sited on -tubular or cylindrical substrates. It also lQ relates to coverings, produced by cathodic sputtering, on substrates having different shapes and forms, by using adapted, known electrodes. For example, in the case of a planar substrate, the latter is held by a substrate holder and a cathode is arranged in parallel and facing the substrate.
Finally, the invention is not limited to the coverings obtained by cathodic spu-ttering. For the deposition of the absorbent layer, e.g. of amorphous carbon, it is possible to use all known methods, such as evaporation or chemical deposition in the vapour phase in the presence of a plasma.
Claims (11)
1. A covering for photothermal conversion, wherein it comprises an infrared radiation reflecting substrate, a first layer deposited on this substrate and constituted by at least one metallic compound, and a second layer deposited on the first layer, said second layer being constituted by an amorphous material and is able to absorb solar radiation.
2. A covering according to claim 1, wherein the substrate is formed by an infrared radiation reflecting layer and a primary substrate, the infrared radiation reflecting layer being deposited on the primary substrate.
3. A covering according to claim 2, wherein the infrared radiation reflecting layer is constituted by one of the materials taken from the group including copper, silver and gold.
4. A covering according to claim 1, wherein the first layer is produced from at least one of the materials included in the group of transition metals and their alloys.
5, A covering according to claim 4, wherein the first layer is made from stainless steel.
6. A covering according to any one of the claims 1 to 3, wherein the thickness of the first layer is approximately 10 to 50 nm.
7. A covering according to any one of the claims 1 to 3, wherein the second layer is an amorphous carbon layer.
8. A covering according to claim 1, wherein the thickness of the second layer is equal to or greater than that of the first layer.
9. A covering according to claim 8, wherein the thickness of the second layer is approximately 50 to 150 nm.
10. A covering according to any one of the claims 1 to 3, wherein the first and second layers are deposited by cathodic sputtering.
11. A covering according to claim 2, wherein the infrared radiation reflecting layer and the first and second layers are deposited by cathodic sputtering.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR8205531A FR2524618B1 (en) | 1982-03-31 | 1982-03-31 | COATING FOR PHOTOTHERMAL CONVERSION |
| FR8205531 | 1982-03-31 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1246950A true CA1246950A (en) | 1988-12-20 |
Family
ID=9272597
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000424724A Expired CA1246950A (en) | 1982-03-31 | 1983-03-29 | Covering for photothermal conversion |
Country Status (8)
| Country | Link |
|---|---|
| US (1) | US4504553A (en) |
| EP (1) | EP0092452A1 (en) |
| JP (1) | JPS58182059A (en) |
| AU (1) | AU554165B2 (en) |
| CA (1) | CA1246950A (en) |
| ES (1) | ES8402066A1 (en) |
| FR (1) | FR2524618B1 (en) |
| IL (1) | IL68208A (en) |
Families Citing this family (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60190557A (en) * | 1984-03-13 | 1985-09-28 | Meidensha Electric Mfg Co Ltd | Coating material and its manufacture |
| US4546050A (en) * | 1984-11-23 | 1985-10-08 | Ford Motor Company | Coated glass article as a new article of manufacture |
| US4634637A (en) * | 1985-11-22 | 1987-01-06 | Gila River Products, Inc. | Solar control film |
| US4763641A (en) * | 1986-05-29 | 1988-08-16 | Smith William F | Solar energy absorber |
| JPS63269103A (en) * | 1987-04-28 | 1988-11-07 | Toshiba Electric Equip Corp | Reflector |
| JP3542859B2 (en) * | 1995-10-05 | 2004-07-14 | 理想科学工業株式会社 | Double printing device |
| JPH1086545A (en) * | 1996-09-13 | 1998-04-07 | Riso Kagaku Corp | Composition for heat-sensitive stencil paper plate-making and plate-making method |
| US20020051286A1 (en) * | 2000-10-27 | 2002-05-02 | Honeywell, Inc. | Wavlength specific coating for mirrored optics and method for reducing reflection of white light |
| CN100439092C (en) * | 2006-06-08 | 2008-12-03 | 复旦大学 | Light heat energy conversion device having metal and non-metal multilayer film structure |
| US7538938B2 (en) * | 2006-06-13 | 2009-05-26 | Uchicago Argonne, Llc | Optical filter for flash lamps in pulsed thermal imaging |
| JP2015049015A (en) * | 2013-09-04 | 2015-03-16 | 日立造船株式会社 | Collector |
Family Cites Families (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3198674A (en) * | 1962-01-25 | 1965-08-03 | Fiber Products Res Ct Inc | Infrared absorbent aluminum phosphate coatings and method of manufacture |
| US4022947A (en) * | 1975-11-06 | 1977-05-10 | Airco, Inc. | Transparent panel having high reflectivity for solar radiation and a method for preparing same |
| DE2604019A1 (en) * | 1976-02-03 | 1977-08-11 | Philips Patentverwaltung | SELECTIVE ABSORBER FOR RADIATION FROM THE AREA OF THE SOLAR SPECTRUM |
| US4048980A (en) * | 1976-03-08 | 1977-09-20 | The United States Of America As Represented By The United States Energy Research And Development Administration | Solar radiation absorbing material |
| CH624755A5 (en) * | 1976-06-10 | 1981-08-14 | Univ Sydney | Solar energy collector and method of manufacturing it |
| AU507748B2 (en) * | 1976-06-10 | 1980-02-28 | University Of Sydney, The | Reactive sputtering |
| US4098956A (en) * | 1976-08-11 | 1978-07-04 | The United States Of America As Represented By The Secretary Of The Interior | Spectrally selective solar absorbers |
| CH611341A5 (en) * | 1976-09-09 | 1979-05-31 | Balzers Hochvakuum | |
| US4334523A (en) * | 1980-06-23 | 1982-06-15 | Owens-Illinois, Inc. | Solar energy collector having solar selective coating of low reflectance |
| AU7174581A (en) * | 1980-07-28 | 1982-03-02 | Owens-Illinois Inc. | Solar energy collector having semiconductive coating formed from metal and dielectric |
| DE3031346C2 (en) * | 1980-08-20 | 1983-03-17 | Dornier System Gmbh, 7990 Friedrichshafen | Solar absorber layer and process for its production |
-
1982
- 1982-03-31 FR FR8205531A patent/FR2524618B1/en not_active Expired
-
1983
- 1983-03-23 IL IL68208A patent/IL68208A/en unknown
- 1983-03-24 AU AU12806/83A patent/AU554165B2/en not_active Ceased
- 1983-03-25 EP EP83400632A patent/EP0092452A1/en not_active Ceased
- 1983-03-29 CA CA000424724A patent/CA1246950A/en not_active Expired
- 1983-03-29 ES ES521108A patent/ES8402066A1/en not_active Expired
- 1983-03-30 US US06/480,483 patent/US4504553A/en not_active Expired - Fee Related
- 1983-03-31 JP JP58054092A patent/JPS58182059A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| FR2524618B1 (en) | 1987-11-20 |
| ES521108A0 (en) | 1984-01-01 |
| AU1280683A (en) | 1983-10-06 |
| EP0092452A1 (en) | 1983-10-26 |
| AU554165B2 (en) | 1986-08-07 |
| IL68208A (en) | 1988-03-31 |
| US4504553A (en) | 1985-03-12 |
| IL68208A0 (en) | 1983-06-15 |
| ES8402066A1 (en) | 1984-01-01 |
| JPS58182059A (en) | 1983-10-24 |
| FR2524618A1 (en) | 1983-10-07 |
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