WO2009027457A2

WO2009027457A2 - Method for measuring the thickness of a layer on a carrier

Info

Publication number: WO2009027457A2
Application number: PCT/EP2008/061289
Authority: WO
Inventors: Jens Dahl Jensen; Jens Klingemann; Ursus KRÜGER; Daniel Körtvelyessy; Volkmar LÜTHEN; Ralph Reiche; Oliver Stier
Original assignee: Siemens Aktiengesellschaft
Priority date: 2007-08-29
Filing date: 2008-08-28
Publication date: 2009-03-05
Also published as: DE102007041433A1; WO2009027457A3

Abstract

The invention relates to a method for measuring the thickness (d) of a layer (40) on a carrier (20). According to the invention, the layer contains particles (80) of a magnetizable material and the thickness is measured with the aid of a magnetic measuring method.

Description

description

Method for measuring the thickness of a layer on a support

The invention relates to a method for measuring the thickness of a layer on a support.

As is known, objects, elements, for example, turbine or the like, provided with protective layers which are the lifetime of the objects during their operation ver ^¬ lengthen.

Also, for example, from the German patent application DE 101 37 460 Al known to provide input and display devices with nanoparticle-containing protective layers.

The object of the invention is to specify a method with which the thickness of a layer located on a support can be measured particularly simply but nevertheless very accurately.

This object is achieved by a method having the features according to claim 1. Advantageous embodiments of the method according to the invention are specified in subclaims.

Thereafter, a method for measuring the thickness of a layer located on a carrier is provided according to the invention, wherein the layer contains particles of a magnetizable material and the thickness is measured by means of a magnetic measuring process ^¬ driving. A significant advantage of the method according to the invention is the fact that this allows a very precise measurement of the layer thickness even with very thin layers, because the thickness of the layer to be measured is very easily detectable due to the presence of the magnetizable particles.

A further significant advantage of the method according to the invention is that due to the particles it is also possible to measure the layer thickness in situ during the application of the layer in a contactless manner.

Preferably, a material is selected for the particles, which can be magnetized very easily and generates a very strong magnetic field in the case of magnetization. Suitable materials for the particles are, for example, iron, cobalt and nickel-containing materials and materials comprising a magnetic ceramic material, Fe ₈ O ₂ -containing Mate ^¬ material, material of 1, 4, 7-Triazacyclononane material group, Fe ₈ O ₂ (OH ) i2 (1, 4, 7-triazacyclononanes) ₆ Br ₈ .9H ₂ O and / or Hexafer- ritmaterial at least also included. The thickness of the layer is to be measured, the greater the Magneti ^¬ sierbarkeit of the particles is compared with the magnetization of the carrier material, the more accurate.

The distribution of the particles in the layer may be uniform or have a gradient, for example the concentration of the particles may decrease or increase with increasing layer thickness.

Preferably, the material of the particles to a hard magnetic material and the material of the Trä ^¬ gers to a soft magnetic material. In such an embodiment of the method, the thickness of the layer may be added. For example, be determined by using a magnetization ^¬ step, the hard magnetic particles are magnetized. The thickness of the layer can then be characterized, for example, be ^¬ true that the induction effect of the hartmagneti- see particles is measured in an electrical coil. Such a measurement is also referred to as "eddy-current" - measurement method, because the induction current in the coil, the so-called "eddy-current", is measured.

Is the article made of a ceramic material or a

Oxyd, so can the incorporation of nanoparticles in the base ^¬ material improve or increase their ability to build when nanoparticles are introduced or embedded with a core shell structure. Such nanoparticles preferably have a core of a metal or a metal mixture and a shell of an oxide or ceramic material that is compatible with the base material of the object to be characterized so far that incorporation of the nanoparticles in the base material is made possible, at least better than at a nanoparticle surface of metal. In addition, a sleeve may prevent the metal material of the particles diffuses into the material of the layer and its Schichtei ^¬ properties deteriorated.

As oxide for the particle shell, for example, aluminum ^¬ oxide, copper oxide or zirconium oxide may be used.

A core-shell structure is also recommended if iron nanoparticles are to be used. Iron can namely with chlorides (Cl ^" ) Ferrichloride (FeCl ₃ ) bil ^¬ those, which are very corrosive and can chemically attack, for example, the base material of the carrier, remain through a corresponding encapsulation in a nuclear envelope structure Although the iron cores are magnetically active and measurable, they are chemically isolated and chemically inactive.

The material of the layer may be a magnetizable or also a non-magnetizable material han ^¬ spindles, the same applies to the base material of the support.

Preferably, nanoparticles are used as particles. Nanoparticles are particles having a particle have large in the nanometer range (1 nm to 1000 nm), and usually show chemical and physical properties that differ from those of their particulate material as such under ^¬. The different properties of the nanoparticles are based on the relatively large outer surface relative to their volume.

With regard to the implementation of the magnetic measuring method, it is also considered advantageous if a magnetic field is generated and coupled into the layer, the magnetic resistance of the layer and / or a directly or indirectly related to this measure, preferably location-dependent, is measured and the thickness of the layer is determined on the basis of the magnetic resistance and / or the measured ^variable . As a measured variable, for example, the inductance of the layer, the AC resistance of a magnetic field generating coil or coil assembly, the size of an alternating current in a magnetic erzeu ^¬ ing coil or coil assembly at a constant AC voltage and / or the size of an AC voltage to a magnetic field generating coil or Coil arrangement are measured and evaluated at constant alternating current through the coil or coil assembly. Alternatively or additionally, the induction of an electrical voltage in a coil or coil arrangement can be measured and evaluated due to a magnetic field generated by the particles.

For example, eddy-current measuring methods with which a magnetic alternating field is generated and coupled into the material of the layer are particularly suitable as magnetic measuring methods.

For eddy current measurement, it is possible, for example, to use sensors which have a meander-shaped conductor structure for magnetic field generation and a meander-shaped conductor structure complementary thereto for magnetic field measurement. Suitable eddy current measuring devices of this and other types are sold, for example, by JENTEC Sensors, 110-1 Clematis Avenue, Waltham, MA 02453, USA.

Magnetic measurement methods currently a measurement resolution of up to 3 mm can be achieved measuring depth, for here be ^¬ specified measuring application, such as for the thickness measurement of thermal protection layers of machine elements in general is quite enough, since there thicknesses are within the specified measuring range ,

The thickness of the layer can for example be measure by the measuring ^¬ frequency and the excitation frequency of the generated magnetic field is changed in the implementation of the magnetic measurement method; because at low frequencies Mag ^¬ netfeld penetrates deeper into the surface than at high Frequen ^¬ zen, where magnetic fields are generated very close to the surface. If the measuring frequency is varied during the measurement, a layer to be characterized in the depth-that is to say vertical to the surface-can be scanned very accurately and its thickness determined very precisely. Also, the magnetic field can be generated with a superconducting quantum interference unit (SQUID: Superconducting Quantum Interference Device), as known for example from raster SQUID microscopes. The operation of a quantum interference unit is generally based on the effect of flux quantization in superconducting rings and the so-called Josephson effect.

The thickness of the layer can for example be measured very simply and thus advantageously by determining the respective thickness of the layer on the basis of at least one calibration curve which has been generated and stored in advance on the basis of known thicknesses of the layer material.

The thickness already be able to adjust precisely as possible when applied to the carrier, it will be advantageous angese ^¬ hen, if the thickness of the layer already during the Aufbrin- gene of the layer on the support - is measured, and the application is stopped - so situ when it is determined based on the measured thickness that a predetermined desired thickness it has been sufficient ^¬.

Also, the thickness of the layer during the bestimmungsge ^¬ MAESSEN use of the coated substrate can be measured and a maintenance signal is generated when the thickness of the layer falls below a predetermined minimum thickness.

Preferably, layer thicknesses of protective layers in machine elements are measured. For example, the method for measuring the thickness of a thermal protective layer of a

Turbine element, in particular a turbine blade, are ^¬ sets. Particular preference is given to thicknesses of TBC (thermal barrier coating) layers, for example zirconium oxide ceramic layers with a columnar structure, or of layers of MCrAlY material (metal matrix material based on chromium, aluminum and yttrium) measured in the manner described.

As the invention is further provided a method of manufacturing a turbine element, in particular a turbine acting ^¬ fel considered. According to the invention, it is provided that a protective layer, in particular of zirconium oxide ceramic material with a columnar structure or of MCrAlY material, is applied to a base material of the turbine element, wherein particles of a magnetizable material are incorporated in the protective layer, during the application of the protective layer whose thickness is continuous , regular or un ^¬ regularly according to a method as described above, the WOR is measured and the application of further

When it is determined based on the measured thickness of the protective layer, that a specified ^differently bene target thickness has been reached is ended layer material.

In addition, a method for measuring the wear of a turbine element, in particular a ^turbine blade as the invention, is viewed. According to the invention, it is provided that the turbine element has a base material which has been coated with a protective layer, in particular of a zirconium oxide ceramic having a columnar structure and / or of MCrAlY material, wherein particles of a magnetizable material are contained in the protective layer , the thickness of the protective layer during the intended use of the turbine member according to a process - is measured and a maintenance signal is generated when the thickness of the protective layer falls below a predetermined min ^¬ least thick - de- scribe above. The invention will be explained in more detail with reference to Ausführungsbeispie ^¬ len; thereby show by way of example

1 shows a turbine blade with a protective layer,

FIGS. 2-4 show an exemplary embodiment of the production of the turbine blade according to FIG. 1, by means of which an exemplary embodiment of the thickness measuring method according to the invention is also explained, and

Figures 5-7, the turbine blade according to Figure 1 during turbine operation, with a further embodiment of the inventive thickness measurement method is carried out during the Turbi ^¬ nenbetriebs.

For reasons of clarity, the same reference numbers are always used in the figures for identical or comparable components.

In the figure 1 can be seen a turbine blade 10 having an airfoil 20 and a foot 30 in a dreidimensiona ^¬ len representation. The airfoil 20 of the turbine blade 10 consists of a base material 35 and is provided with a protective ^¬ layer 40.

The base material 35 of the airfoil 20 may be, for example, Inconel (Ni-Cr alloys, as described, for example, in the publication "Corrosion-resistant Nickel Alloys" (Advanced Materials & Processes, June 2007, pages 37 to 39) in detail described) or co-based crystals A ^¬ or even a material containing Inconel or Co-based single crystals at least. The protective layer 40 may, for example, of ceramic or of TBC (Thermal Barrier Coating) material based on a pillar-shaped zirconia ceramic layer or MCrAlY mA TERIAL (metal matrix material based on chromium, Alumi ^¬ nium and yttrium) exist. The foot 30 of the turbine blade 10 is preferably uncoated.

In connection with FIGS. 2 to 4, an embodiment for producing the turbine blade 10 will be explained below.

In the figure 2, the base material 35 in cross section ge ^¬ shows. One recognizes the surface 60 before it has been provided with the protective layer 40.

FIG. 2 also shows a magnetic field generating and magnetic field measuring device 100 which generates an alternating magnetic field 110 as part of a magnetic eddy current measuring method and couples this into the surface 60. For example, a coil 120 is provided for generating the alternating magnetic field 110. The field lines B of the magnetic field 110 penetrate through the surface 60 and also penetrate the base material 35, so that a magnetic flux B occurs in the base material 35.

The magnetic field generating and magnetic field measuring ^device 100 will measure the resulting magnetic field 110 and, for example, determine the magnetic resistance and, based on this, determine whether a protective layer 40 is already present and how thick it may be. By a relative movement in the x direction between Magnetfelderzeugungs- and magnetic ^¬ measuring device 100 and the turbine blade 10 can be on the basis of appearance and disappearance of a Magnetfeldver- Strengthen the thickness d of an existing protective layer 40 also location-dependent, preferably two-dimensional measure.

FIG. 3 shows the turbine blade 10, after which a protective layer with the thickness d 1 and with a nanoparticle 80 made of a magnetizable material has been deposited on the surface 60. Is used for the nanoparticles 80 is preferably one of the following materials: magneti ^¬ ULTRASONIC ceramic material, Fe ₈ O ₂ -containing material, the material of the 1, 4, 7-triazacyclononanes material group, Fe ₈ O ₂ (OH) ₁₂ (1, 4, 7-triazacyclononanes) ₆ Br ₈ .9H ₂ O and / or hexaferrite material.

It can be seen that the nanoparticles 80 ^¬ because of their small size, but also because of their particular ren surface finish, especially because of its large ratio between surface area and volume, very evenly distributed in the base material 35 and is very even increase the magnetization ,

Using calibration curves which have been taken in advance by known film thicknesses of the protective layer 40, can now be the respective thickness d of the protective ^¬ layer determine 40 since the absolute magnitude of the magnetic field compared to an uncoated base material 35 is changed by the nanoparticles 80 ,

The thickness of the protective layer 40 may be in addition also because ^¬ determined by, that the coupling of the magnetic field 110 is influenced with the coil 120; In this case, the external excitation also determines which depth ^{ranges of} the protective layer 40 or the base material 35 are to be scanned by the magnetic field generating and magnetic field measuring device 100. In this way can be Depth areas down to the millimeter range selectively for the presence of nanoparticles 80 examine and measure.

For example, in the implementation of the magnetic measuring method, the measuring frequency or the exciting frequency of the generated magnetic field is changed; because at low frequencies, a magnetic field penetrates deeper into the surface than at high frequencies, where magnetic fields are generated only very close to the surface. Now, the measurement frequency varies during the measurement, the layer may be characterized in the depth - in other words viewed vertical to the surface - are sampled very ge ^¬ precisely.

In FIG. 4, the turbine blade 10 is shown, after which further layer material has been applied and the

Thickness of the protective layer 40 has a predetermined desired value d2 ^¬ he has enough. Upon reaching the target value d2, the magnetic field generating and magnetic field measuring device 100 will generate a control signal ST indicating the completion of the protective layer 40. In this case, the application of additional layer material is terminated.

For example, a measuring device with a superconducting quantum interference unit (Superconducting Quantum Interference Device) can be used as the magnetic field generating and magnetic field measuring device 100. Alternatively or additionally, sensors can also be used for the eddy-current measurement which have a meander-shaped conductor structure for magnetic field generation and a meander-shaped conductor structure for magnetic field measurement complementary thereto (eg sold by JENTEC Sensors, 110-1 Clematis Avenue, Waltham, MA 02453). USA) . In connection with FIGS. 5-7, an exemplary embodiment for the operation of the turbine blade 10 according to FIG. 1 will be explained below.

In Figure 5 one can see the base material 35 in cross-section ^¬ after the protective layer 40, for example as described in connection with Figures 2 through 4, has been applied.

FIG. 5 also shows a magnetic field generating and magnetic field measuring device 100 which generates an alternating magnetic field 110 as part of a magnetic eddy current measuring method and couples it into the surface 60. For example, a coil 120 is provided for generating the alternating magnetic field 110.

The magnetic field generating and magnetic field measuring device 100 will preferably be arranged at a location in a turbine housing, at which a measurement of the layer thickness d of the protective layer 40 in a particularly stressed area of the turbine blade 10 is possible. For example, the magnetic field generating and magnetic field measuring device 100 is arranged such that the field lines B of the magnetic field 110 magnetically couple into the front edge of the airfoil.

In Figure 6, the turbine blade is shown after the thickness d of the protective layer due to wear has become smaller. The corresponding residual thickness d1 is measured by the magnetic field generating and magnetic field measuring device 100.

In Figure 7, the turbine blade 10 is shown according to which the thickness d ^¬ has reached a predetermined minimum thickness due to wear dm. In this case, the magnetic field supply and magnetic field measuring device 100 generate a maintenance signal W, which indicates that the turbine blade is worn and must be provided with a new protective layer 40.

Claims

claims

1. A method for measuring the thickness (d) on a support (20) located layer (40), characterized in that the layer comprises particles (80) of a magnetizable material and the thickness is measured by means of a magnetic measuring process ^¬ proceedings ,

2. The method according to claim 1, characterized in that the particles are formed by nanoparticles (80).

3. The method according to any one of the preceding claims, characterized in that is used as a magnetic measuring method, an eddy current measuring method, with which generates a magnetic alternating field and is coupled into the layer (40).

4. The method according to any one of the preceding claims, characterized in that

-A magnetic field generated (110) and into the layer (40) is inserted ^¬ coupled,

The magnetic resistance of the layer (40) and / or a directly or indirectly related thereto

Measured variable, in particular location-dependent, is measured and - the thickness (d) of the layer is determined based on the magnetic resistance ^¬ and / or the measured variable.

5. The method according to any one of the preceding claims, characterized in that on the basis of at least one calibration curve, which in advance generated by means of layers of known thickness and stored has been determined, the respective thickness of the layer (40) is determined.

A method according to any one of the preceding claims, characterized in that the thickness of a layer is measured comprising particles (80) of a magnetic ceramic material, Fe ₈ O ₂ -containing material, material of the 1, 4, 7-triazacyclononane material group, Fe ₈ O ₂ (OH) i ₂ (1, 4, 7-triazacyclononanes) contains ₆ Br ₈ .9H ₂ O and / or hexaferrite material.

7. The method according to any one of the preceding claims, characterized in that

Nanoparticles are incorporated or embedded with a core-shell structure in the layer (40).

8. The method according to claim 7, characterized in that at least one shell material of the nanoparticles consists of an oxide or a ceramic or at least also contains an oxide or a ceramic.

9. The method according to claim 8, characterized in that the shell material consists of one of the following oxides or at least also comprises such an oxide: alumina, Kup ^¬ feroxid, zirconium oxide.

10. The method according to any one of the preceding claims, characterized in that the thickness (d) of the layer (40) during the application of the layer (40) on the carrier (20) is measured and the on ^¬ bring is terminated as soon as based measured thickness it is determined that a predetermined target thickness (d2), it is sufficient ^¬.

11. The method according to any one of the preceding claims, characterized in that the thickness of the layer is measured during the intended use of the coated carrier and a maintenance signal (W) is generated when the thickness of the layer falls below a predetermined minimum thickness (dm).

12. The method according to any one of the preceding claims, characterized in that the thickness of a protective layer (40) on a turbine element (10), in particular a turbine blade (20), is measured.

13. The method according to any one of the preceding claims, characterized in that the thickness of a zirconia ceramic layer with a columnar structure or the thickness of a layer of MCrAlY material ge ^¬ measured.

14. The method according to any one of the preceding claims, characterized in that the magnetic field with a superconducting quantum interference unit (Superconducting Quantum Interference Device) is generated.

15. A method for producing a turbine element (10), in particular a turbine blade, wherein

-A protective layer (40), in particular of zirconium oxide ceramic material having columnar structure or MCrAlY material on a base material (35) of Turbi ^¬ nenelements (20) is applied, in which particles (80) a magnetizable material in the protective layer is to be ^¬ embeds

- During the application of the protective layer whose thickness (d) continuously, regularly or irregularly measured by a method according to one of the preceding claims 1-9, and

- The application of further layer material is terminated as soon as it is determined ^¬ based on the measured thickness of the protective layer, that a predetermined desired thickness (d2) has been reached.

16. A method for measuring the wear of a Turbinenele ^¬ ment, in particular a turbine blade (10), wherein

- The turbine element has a base material (35) which has been coated with a protective layer (40), in particular of zirconia ceramic with columnar structure and / or MCrAlY material, wherein in the protective layer particles (80) a magnetizable material is contained, - the thickness (d) of this protective layer is measured during the intended use of the turbine element according to a method according to one of the preceding claims 1-9

- And a maintenance signal (W) is generated when the thickness of the protective layer a predetermined minimum thickness (dm) under ^¬ stride.