Sample holder for a flame test bench

Abstract

The invention relates to a sample holder (1) for a test bench (2) comprising a support (3) having a housing (4) for receiving a sample (5) made of ceramic material including a thermal protection coating (6), a first face (7) of the support (3) and the thermal protection coating (6) being intended to be positioned opposite a heating device (8) of the test bench (2) to be heated by a flame (9) emitted by the heating device (8), wherein the sample holder (1) includes a thermal protection layer (10) positioned opposite the first face (7) of the support (3). Fig. 1.

Description

Title of the invention: Sample holder for a flame test bench technical field

[0001] The present invention relates to a sample holder for a test bench, in particular a flame test bench, intended to characterize the durability of a thermal protection coating of a component of a high-pressure turbine of an aircraft engine. Previous technique

[0002] Aeronautical engines include a turbine, for example a high-pressure turbine, comprising components such as blades and distributors which are subjected to very high temperatures, between 1000 °C and 1500 °C, generated by a combustion chamber for very long periods.

[0003] These components are covered by a thermal protection coating forming a thermal barrier to protect the blades from these high temperatures. The thermal protection coating conventionally comprises a metallic bonding underlayer covered by a ceramic bonding layer, which may optionally be covered by an anti-CMAS (CaO-MgO-Al2O3-SiO2) environmental protection layer.

[0004] To understand and characterize the durability of thermal protection coatings and environmental protection layers, samples of thermal protection coating covered or not with environmental protection layers are tested in test benches of the flame bench type which are representative of the thermal and environmental stresses of the combustion chamber and the high pressure turbine of aircraft engines.

[0005] High-temperature thermal cycling tests, ranging from 300 °C to 1500 °C, are performed on samples of thermal protection coating in the flame test bench. The thermal protection coating comprises a bonding underlayer deposited on a single-crystal superalloy substrate and a ceramic bonding layer, forming a thermal barrier, deposited on the bonding underlayer.

[0006] One face of each sample supporting the thermal protection coating is heated by a flame while a second face of the sample, opposite the first face, is cooled with compressed air to create a thermal gradient within the sample, and in particular within the thermal protection coating. After this heating step, a cooling phase is carried out by simultaneously cooling the first and second faces of the sample. to create a thermal shock. The heating and cooling phases are repeated respectively until a certain percentage of the thermal protection is eroded.

[0007] Tests were carried out on a sample supporting a standard thermal barrier comprising a partially stabilized yttria-based zirconia bonding ceramic layer deposited on a conventional single-crystal material (AM1+ (Ni-Al)-Pt) by an electron-beam physical vapor deposition (EBPVD) process.

[0008] The sample was supported by a tungsten sample holder.

[0009] The tests demonstrated that a low thermal gradient (less than 0.47 ± 0.13°C / pm for a burner power of 5.9kW) occurred in the thickness of the thermal barrier.

[0010] This phenomenon is caused by heat transfer by conduction from the tungsten substrate holder to the sample. Indeed, this heat transfer is favored by the high thermal conductivity of tungsten (X ~ 177 Wm*.K'), heating the thermal protection coating despite the presence of cooling on the second face of the sample.

[0011] In addition, a significant degradation of tungsten due to its oxidation and corrosion at high temperature was observed.

[0012] By substituting the tungsten of the sample holder with a low sulfur single-crystal AMI superalloy exhibiting lower thermal conductivity (X ~ 26 Wm'.K'), thermal cycle tests in the flame bench showed that the thermal gradient in the thickness of the thermal protection is higher (on the order of 0.60 ± 0.13°C / pm for a burner power of 5.9kW) than with the tungsten sample holder.

[0013] The AMI sample holder allows for a slightly greater increase in the thermal gradient within the sample, but there is a need to obtain an even greater thermal gradient within the thickness of the thermal protection with parallel isotherms while limiting the degradation of the sample holder. Description of the invention

[0014] The invention therefore aims to resolve at least in part these drawbacks by proposing a sample holder for a test bench of the flame bench type allowing to obtain a greater thermal gradient in the thickness of the thermal protection with parallel isotherms while limiting the degradation of the sample holder during thermal cycle tests.

[0015] The invention relates to a sample holder for a test bench comprising a support having a housing for receiving a sample comprising a Thermal protection coating. One side of the support and the thermal protection coating are designed to be positioned opposite a heating device on the test bench to be heated by a flame emitted from the heating device. The sample holder includes a thermal protection layer positioned opposite the first side of the support.

[0016] The invention thus provides a sample holder for a flame test bench, enabling a greater thermal gradient to be obtained through the thickness of the thermal protection with parallel isotherms during thermal cycling tests. Heat transfer from the sample holder to the sample by conduction is limited.

[0017] Furthermore, the sample holder exhibits increased resistance to successive thermal cycles at high temperature. The degradation of the sample holder is thus limited.

[0018] In some embodiments, the thermal protection layer has a thermal conductivity between 0.01 Wm*.K1 and 1.2 Wm*.K'.

[0019] In some embodiments, the thermal protection layer has a thickness between 1 pm and 2000 pm.

[0020] In some embodiments, the thermal protection layer comprises a metallic-type bonding underlayer and a ceramic bonding layer covering at least partially the bonding underlayer.

[0021] In some embodiments, the bonding underlayer is of metallic type, the ceramic bonding layer being chosen from partially stabilized yttria zirconia, zirconia partially stabilized by one or more rare earths and perovskites.

[0022] In some embodiments, the ceramic bonding layer has a thickness greater than 1 pm and less than 1000 pm, preferably greater than 1 pm and less than 500 pm.

[0023] In some embodiments, the thermal protection layer includes an environmental protection layer covering at least partially the ceramic bonding layer.

[0024] During tests in a flame bench under a CMAS environment, i.e. under an oxidizing and corrosive environment, the environmental layer makes it possible to extend the durability of the sample holder without modifying the performance of the ceramic adhesion layer.

[0025] In some embodiments, the environmental protection layer has a thickness greater than 1 pm and less than 1000 pm, preferably greater than 1 pm and less than 500 pm.

[0026] In some embodiments, the thermal protection layer is deposited on the first face of the substrate. The thermal protection layer covers at least partially the first face of the substrate.

[0027] In certain embodiments, the sample holder includes a thermal deflector positioned opposite the first face of the sample holder support. The thermal deflector is located away from the first face of the sample holder and includes an opening positioned opposite the housing of the sample holder support. The thermal deflector has a deflection face positioned opposite the first face of the sample holder support and intended to be heated by the flame, the deflection face being at least partially covered by the thermal protection layer.

[0028] The invention also relates to a test bench comprising a heating device intended to emit a flame and a sample holder as defined above, intended to support a sample heated by the flame.

[0029] The aforementioned features and advantages, as well as others, will become apparent from the following detailed description of examples of embodiments of the sample holder. This detailed description refers to the attached drawings. Brief description of the drawings

[0030] The attached drawings are schematic and are intended primarily to illustrate the principles of the exposition.

[0031] On these drawings, from one figure to another, identical elements (or parts of elements) are identified by the same reference signs.

[0032] [Fig. 1] The [Fig. 1] schematically represents a flame test bench comprising a sample holder having a support covered with a thermal protection layer, according to an embodiment of the invention;

[0033] [Fig.2] Fig.2 schematically represents a flame test bench comprising a sample holder having a support covered with a thermal protection layer including an environmental layer;

[0034] [Fig.3] Fig.3 schematically represents a flame test bench comprising a sample holder equipped with a thermal deflector, according to another embodiment of the invention;

[0035] [Fig.4] Fig.4 schematically represents a front view of the sample holder of Fig.3;

[0036] [Fig.5] Fig.5 schematically represents another example of a sample holder. Description of the implementation methods

[0037] To make the explanation more concrete, an example of a sample holder is described in detail below, with reference to the accompanying drawings. It should be noted that the invention is not limited to this example.

[0038] Fig. 1 represents a test bench 2, which is a flame test bench in this example, comprising a sample holder 1 having a support 3 with a housing 4 passing through the support 3 and receiving a sample 5 made of ceramic material comprising a thermal protection coating 6.

[0039] The sample holder 1 may include several supports 3, each supporting a sample 5. The support 3 may comprise two parts 17, 18 movable relative to each other to allow the sample 5 to be inserted into the housing 4. The support 3 may include a rib formed on an internal peripheral wall 30 delimiting the housing 4, with the sample 5 being inserted into the rib. The internal peripheral wall 30 completely surrounds the sample 5. The sample holder 1 and / or the support 3 may be circular or quadrilateral in shape.

[0040] The housing 4 may have a circular section receiving a disc-shaped sample 5 or have a quadrilateral shape receiving a quadrilateral-shaped sample 5.

[0041] The test bench 2 includes a heating device 8, such as a burner, positioned opposite a first face 7 of the support 3. The heating device 8 emits a flame 9 to heat the thermal protection coating 6 to a temperature of up to approximately 1500°C. The first face 7, and especially the area of ​​the first face 7 surrounding the housing 4, are also heated to a high temperature.

[0042] The test bench 2 reproduces the temperature conditions generated by a combustion chamber of an aircraft engine for very long periods of time.

[0043] The support 3 comprises a second face 19, opposite the first face 7, which is cooled with compressed air to create a thermal gradient within the sample 5, particularly within the thermal protection coating 6. The dashed arrows represent airflow. After this heating step, a cooling phase is carried out by simultaneously cooling the first and second faces 7, 19 of the sample 5 to create a thermal shock. The heating and cooling phases are repeated until a certain percentage of the thermal protection coating 6 has chipped away.

[0044] The sample 5 comprises, for example, a single-crystal superalloy substrate 20 on which the thermal protection coating 6 is deposited. The thermal protection coating 6 comprises a metallic bonding underlayer 21 covered by a ceramic bonding layer 22, forming a thermal barrier.

[0045] The thermal protection coating 6 is intended to cover a turbine blade to form a thermal barrier protecting the blade from high temperatures.

[0046] The test bench 2 is also suitable for reproducing the conditions under a CMAS environment of a turbine. In the corrosive environment of a turbine, CMCs (SiC / SiC), for example, can be subjected to oxidation leading to the formation of silicon oxide, and to the volatilization of this silicon oxide under the effect of water vapor, producing CMAS.

[0047] In this case, the ceramic bonding layer 22 is covered by an anti-CMAS environmental protection layer 23 (CaO-MgO-Al2O3-SiO2).

[0048] The thermal conductivity of the support 3 is less than 28 Wm*.K'.

[0049] The support 3 of the sample holder 1 is composed of a single-crystal nickel-based superalloy such as low-sulfur AMI, CMSX4 SLS, CMSX4 SLS PLUS or MCNG, for example.

[0050] Housing 4 opens outside support 3 through the first and second faces 7, 19 of support 3.

[0051] In the example of [Fig.1], the sample holder 1 includes a thermal protection layer 10 covering at least part of the first face 7 of the support 3. The thermal protection layer 10 completely surrounds the housing 4 of the support 3 and is positioned between the first face 7 of the support 3 and the heating device 8 so that the first face 7 is not in direct contact with the flame 9.

[0052] Preferably, the thermal protection layer 10 completely covers the first face 7 of the support 3.

[0053] The thermal protection layer 10 has a thermal conductivity at high temperature (from 300°C to 1500°C) between 0.01 Wm *.K1 and 1.2 Wm *.K', and a thickness between 1 pm and 2000 pm.

[0054] The thermal gradients inside the thermal protection layer 10 are between 0.2 C / pm and 1.5 C / pm.

[0055] The thermal protection layer 10 exhibits high structural stability at temperatures between 1000°C and 1500°C and high resistance to thermal shock.

[0056] The thermal protection layer 10 includes a metallic bonding underlayer 11 which is deposited on the first face 7 of the support 3.

[0057] The bonding sublayer 11 can be formed of an MCrAlY alloy (M=Ni, Co, Ni / Co), a nickel aluminide doped or not by a ternary element (Pt for example), a nickel aluminide of type [3-NiAl (modified or not by Pt, Hf, Zr, Y, Si or combinations of these elements), an aluminide of alloy y-Ni-y'-Ni3Al (modified or not by Pt, Cr, Hf, Zr, Y, Si or combinations of these elements), of MAX phases (Mn+1AXn (n=1,2,3) where M = Sc, Y, La, Mn, Re, W, Hf, Zr, Ti; A = groups IIIA, IVA, VA, VIA ; X = C,N)) or a combination of these elements.

[0058] The bonding underlayer 11 is deposited on the first face 7 of the support 3 by a physical vapor deposition (PVD) method, atmospheric pressure plasma spraying (APS), high velocity liquid fuel spray coating (HVOF), low pressure plasma spraying (LPPS) or derivatives, inert plasma spraying (IPS), chemical vapor deposition (CVD), vapor phase aluminization (APVS), spark plasma sintering or electrolytic deposition, for example.

[0059] The bonding underlayer 11 is covered at least partially by at least one ceramic bonding layer 12 having high resistance to high temperatures to form a thermal barrier.

[0060] The ceramic bonding layer 12 is selected from, for example, partially stabilized yttria-stabilized zirconia, zirconia partially stabilized by one or more rare earth elements, or perovskites. The ceramic bonding layer 12 also ensures good performance in terms of cyclic oxidation / thermal shock life and also in terms of thermal insulation.

[0061] The ceramic bonding layer 12 has a thickness between 1 pm and 1000 pm, and preferably between 1 pm and 500 pm.

[0062] The ceramic bonding layer 12, in particular, makes it possible to isolate the support 3 of the sample holder 1 from the thermal flux delivered by the burner flame and consequently to limit the heat transfer from the substrate holder 3 to the sample 5.

[0063] The example in [Fig.1] shows a test carried out in a flame test bench 2 with a sample holder 1 comprising a support 3 in low sulfur single-crystal AMI superalloy of 3 mm thick and having a thermal conductivity of 26 W.m1 .K1.

[0064] The support 3 is covered by a thermal protection layer 10 comprising a bonding underlayer 11 based on NiCrALY and a ceramic bonding layer 12 based on 8YPSZ covering the bonding underlayer 11. The bonding underlayer 11 and the ceramic bonding layer 12 are deposited by thermal spraying. The ceramic bonding layer 12 has a thermal conductivity of 1 Wm*.K'.

[0065] The bonding underlayer 11 has a thickness of 80 pm and the ceramic bonding layer 12 has a thickness of 200 pm.

[0066] Sample 5 tested has a thickness of 3 mm and a thermal conductivity of 26 Wm*.K'. Sample 5 comprises a single-crystal superalloy substrate covered by a thermal protection coating 6 having a thickness of 200 µm and comprising a metallic bonding sublayer 21 covered by a ceramic bonding layer 22 based on 8YPSZ deposited on the bonding sublayer 21 by the EB-PVD electron beam evaporation method. The ceramic bonding layer 22 has a thermal conductivity of 1.8 Wm*.K1 and the bonding sublayer 11 has a thickness of 60 µm.

[0067] The presence of the thermal protection layer 10 on the support 3 makes it possible to approach a sample 5 of infinite size and thus to overcome the lateral thermal conduction which contributes to limiting the thermal gradient in the sample 5.

[0068] Preferably, the sample 5 and the support 3 covered with the thermal protection layer 10 have the same or almost the same thickness.

[0069] Preferably, the thermal protection layer 10 of the support 3 is aligned with the thermal protection coating 6 of the sample 5. The thermal protection layer 10 should be as close as possible to the thermal protection coating 6 in terms of thickness, composition and thermal conductivity.

[0070] High temperature thermal cycle tests, between 300 °C and 1500 °C, were carried out in the test bench 2 and show that, with iso-cooling, iso-heating and iso-thermal barrier system, the thermal gradient obtained experimentally with the sample holder 1 according to the invention (Grad TCceramic / metal " 0.80 ± 0.13°C / pm at 5.9kW) is higher than the thermal gradients obtained respectively with a tungsten sample holder 1 (Grad TCceramic / metal < 0.47 ± 0.13°C / pm at 5.9kW) and an AMI sample holder 1 (Grad TCceramic / metal ~ 0.60 ± 0.13°C / pm at 5.9kW).

[0071] An environmental layer can be optionally added for tests carried out in the flame bench under CMAS environment in order to extend the life of the sample holder 1.

[0072] The thermal protection layer 10 comprises an environmental protection layer 13 or a stack of environmental protection layers 13 covering at least partially the ceramic bonding layer 12.

[0073] The environmental protection layer 13 is selected from among rare earth zirconates RE2Zr2O7 (RE= Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Yb, Dy, Ho, Er, Tm, Tb, Lu), rare earth cerates, rare earth aluminates, partially / fully stabilized and optionally doped zirconias, delta phases A4B3Oi2 (A = Y —> Lu and B = Zr, Hf), spinels MgAl2O4, composites including Y2O3 with ZrO2 and / or Al2O3 and / or TiO2, hexa-aluminates, complex perovskites, spinels, rare earth mono- and disilicates (rare earth = Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu), as well as any other anti-CMAS composition and mixtures of all of these.

[0074] The ceramic bonding layer 12 and the environmental layer 13 can be implemented by atmospheric pressure plasma spraying (APS), suspension plasma spraying (SPS), solution plasma spraying (SPPS), high velocity oxygen fuel (HVOF), high velocity suspension flame spray (HVSFS), electron-beam physical vapor deposition (EB-PVD), physical vapor deposition (PVD), sol-gel, electrophoresis, for example, or by any additive coating process, in a non-exhaustive manner.

[0075] The example in [Fig.2] shows another test carried out in a flame test bench 2 with a sample holder 1 comprising a support 3 in low sulfur single-crystal AMI superalloy of 3 mm thick and having a thermal conductivity of 26 Wm*.K', identical to that of the example in [Fig.1], except that the ceramic bonding layer 12 is covered by an environmental protection layer 13.

[0076] The support 3 is covered by a thermal protection layer 10 comprising a bonding underlayer 11 based on NiCrALY and a ceramic bonding layer 12 based on 8YPSZ covering the bonding underlayer 11. The ceramic bonding layer 12 has a thermal conductivity of 1 Wm*.K'.

[0077] The bonding underlayer 11 has a thickness of 80 pm and the ceramic bonding layer 12 has a thickness of 200 pm.

[0078] The environmental layer 13 is based on gadolinium zirconate (Gd2 Zr2O7). The bonding sublayer 11, the ceramic bonding layer 12, and the environmental layer 13 are deposited by thermal spraying. The environmental layer 13 has a thickness of 200 pm and a thermal conductivity of 1 Wm*.K'.

[0079] The tested sample 5 has a thickness of 3 mm and a thermal conductivity of 26 Wm*.K'. Sample 5 comprises a single-crystal superalloy substrate covered by a thermal protection coating 6 with a thickness of 200 pm and having a metallic bonding sublayer 21 covered by an 8YPSZ-based ceramic bonding layer 22 deposited on the bonding sublayer 21 by the EB-PVD electron beam evaporation method. The ceramic bonding layer 22 is covered by an environmental layer 23. The ceramic bonding layer 22 has a thermal conductivity of 1.8 W / m².K and the bonding sublayer 11 has a thickness of 60 µm. The environmental layer 23 has a thickness of 300 µm and a thermal conductivity of 1 W / m².K

[0080] High temperature thermal cycle tests, between 25°C and 1500°C, were carried out in the test bench 2 and show that, at iso cooling, iso heating and iso thermal barrier system, the thermal gradient in the sample obtained experimentally with the sample holder 1 according to this second embodiment is identical to the thermal gradient obtained with the sample holder 1 according to the first embodiment in which the support 3 does not include an environmental layer 13.

[0081] The support with the additional environmental layer 13 is used for tests in a flame test bench under a CMAS environment. The environmental layer 13 extends the durability of the sample holder 1 without altering the thermal protection performance of the ceramic bonding layer 12.

[0082] Figures 3 and 4 illustrate another embodiment in which the sample holder 1 includes a thermal deflector 14 positioned opposite the first face 7 of the support 3 of the sample holder 1. The thermal deflector 14 is distant from the first face 7 of the sample holder 1 and includes an orifice 15 positioned opposite the housing 4 of the support 3 of the sample holder 1.

[0083] The thermal deflector 14 has a deflection face 16 positioned opposite the first face 7 of the support 3 of the sample holder 1, and covered at least partially by the thermal protection layer 10.

[0084] In the test bench 2, the thermal deflector 14 is positioned between the support 3 and the heating device 8. The sample 5 is housed in the housing 4 of the support 3, opposite the orifice 15 of the thermal deflector 14, so that the thermal protection coating 6 of the sample 5 is in contact with the flame 9 of the heating device 8.

[0085] The thermal protection layer 10 of the support 3 is also positioned opposite the heating device 8 and in contact with the flame 9 of the heating device 8.

[0086] In this embodiment, the sample 5 is held in the housing 4 of the support 3 by a gripping device comprising set screws 24 bearing against a peripheral wall 27 of the sample 5 and distributed uniformly around the sample 5. In this example, the gripping device comprises four set screws 24. The peripheral wall 27 of the sample 5 is not in contact with the inner peripheral edge 25 of the support 3 delimiting the housing 4. An annular space 26 is formed between the peripheral wall 27 of the sample 5 and the inner peripheral edge 25 of the support 3.

[0087] The set screws 24 pass radially through the support 3, which is circular in this example. The set screws 24 are suitable for being screwed into a threaded channel in the support 3.

[0088] The peripheral wall 27 of the sample 5 includes a groove 28 in which one end 29 of each set screw 24 fits when the set screws 24 are screwed into the support 3 in order to hold the sample 5.

[0089] This gripping device makes it possible to limit the heat transfer from the sample holder 1 to the sample 5 during the tests by minimizing the contact area between the sample holder 1 and the sample 5.

[0090] The thermal deflector 14 comprises a nickel-based single-crystal superalloy selected from low-sulfur AMI, CMSX4 SLS, CMSX4 SLS PLUS and MCNG on which is deposited a thermal protection layer 10 as described above for the embodiments shown in Figures 1 and 2. The thermal protection layer 10 comprises a bonding sub-layer 11 deposited on the single-crystal superalloy.

[0091] Alternatively, the thermal deflector 14 can be based on a bare or coated ceramic composite matrix (or in English “Ceramic Matrix Composite” CMC: SiC / SiC). In the case of a coated ceramic composite matrix, the bonding sublayer 11 is then based on silicon, boron-doped silicon, hafnium oxide-doped silicon or rare earth elements ((RE = Y, Yb, Gd)) with added dopants (Zr, Hf, Ta, N, Al), SiAlON and Si-HfB2, SiC-HfO2, SiC-HfO2-HfB2.

[0092] The bonding sublayer 11 is formed, but not exclusively, by a physical vapor deposition (PVD) method, atmospheric pressure plasma spraying (APS), high velocity liquid fuel spray coating (HVOF), low pressure plasma spraying (LPPS) or derivatives, inert plasma spraying (IPS), chemical vapor deposition (CVD), vapor phase aluminization (APVS), spark plasma sintering or electrolytic deposition, for example.

[0093] The bonding sublayer 11 has a thickness of 1 pm to 100 pm.

[0094] The bonding sub-layer 11 is covered by a ceramic bonding layer 12 as described in the embodiments of Figures 1 and 2. The ceramic bonding layer 12 is selected from partially stabilized yttria-stabilized zirconia, zirconia partially stabilized by one or more rare earth elements or perovskites, for example. For example, the ceramic bonding layer 12 can be based on 8YPSZ. The ceramic bonding layer 12 has a thermal conductivity of 1 Wm*.K⁻¹

[0095] Optionally, the ceramic bonding layer 12 is covered by an environmental protection layer 13 selected from rare-earth disilicates Re2Si2O7, (Re = RE = Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Yb, Dy, Ho, Er, Tm, Tb, Lu) and co-doped, rare-earth silicates Re2SiO5 and co-doped, barium strontium aluminosilicate (BSAS, (BaO)x.(SrO)i x.Al2O3.2SiO2 with 0 < x < 1), hafnium-doped rare-earth silicate, rare-earth-doped hafnium, mullite, spinels MgAl2O4, garnets (Y3Al15Oi2), partially / fully stabilized and optionally doped zirconias, delta phases A4B30i2 (A = Y —> Lu and B = Zr, Hf), composites including Y2O3 with ZrO2 and / or A12O3 and / or TiO2, hexa-aluminates, complex perovskites as well as any other composition of environmental barriers and mixtures of all of these.

[0096] The environmental protection layer 13 has a thickness of 1 pm to 1000 pm.

[0097] The environmental protection layer 13 or the stacking of layers of Environmental protection 13 can be implemented by a physical vapor deposition (PVD) method, atmospheric pressure plasma spraying (APS), high velocity liquid fuel spray coating (HVOF), low pressure plasma spraying (LPPS) or derivatives, inert atmosphere plasma spraying (IPS), chemical vapor deposition (CVD), vapor phase aluminization (APVS), spark plasma sintering or electrolytic deposition, for example or, non-exhaustively, by any additive coating process.

[0098] Alternatively, the gripping device comprising set screws 24 can be used to hold the sample 5 on a support 3 of sample holder 1 as described in the embodiments of figures 1 and 2.

[0099] Alternatively, an insulating ceramic foam (not shown) can be used between the peripheral wall 27 of the sample 5 and the internal peripheral edge 25 of the support 3, regardless of the embodiment, i.e. whether the thermal protection layer 10 is positioned directly on the support 3 or offset on the thermal deflector 14.

[0100] The insulating ceramic foam makes it possible to limit the heat transfer from the sample holder 1 to the sample 5 during the tests by minimizing the contact area between the sample holder 1 and the sample 5.

[0101] According to a variant shown in [Fig.5], the sample holder 1 has a cylindrical shape and can be attached to a cooling nozzle.

[0102] The sample holder 1 comprises a single support 3 having a housing 4 having a circular cross-section suitable for receiving a disc-shaped sample 5.

[0103] The support 3 includes a first face 7 intended to be positioned opposite a heating device 8 and a second face 19, opposite the first face 7, which is intended to be fixed on the cooling nozzle to be cooled via compressed air.

[0104] The support 3 is composed of a single-crystal nickel-based superalloy such as low-sulfur AMI, CMSX4 SLS, CMSX4 SLS PLUS or MCNG, for example.

[0105] Housing 4 opens outside support 3 through the first and second faces 7, 19 of support 3.

[0106] The support 3 includes a thermal protection layer 10, as described above, covering at least part of the first face 7 of the support 3. The thermal protection layer 10 completely surrounds the housing 4 of the support 3 and is positioned between the first face 7 of the support 3 and the heating device 8 so that the first face 7 is not in direct contact with the flame 9.

[0107] The support 3 includes a ring 31 projecting from the second face 19. The ring 31 includes fixing holes 36 for receiving screws to fix the ring 31 to the cooling nozzle.

[0108] The support 3 includes grooves 32 extending radially over the second face 19 and around the ring 31. The grooves 32 extend from an orifice 33 through the ring 31 and communicating with the housing 4. The grooves 32 radially diffuse an airflow from the cooling nozzle to cool the second face 19.

[0109] The support 3 includes an annular wall 34 through which threaded holes 35 are passed for receiving set screws to hold the sample.

[0110] In an alternative (not shown), the sample holder 1 includes a thermal deflector, as described above, positioned opposite the first face 7 of the support 3 of the sample holder 1. The thermal deflector is distant from the first face 7 of the sample holder 1 and includes a central orifice positioned opposite the housing 4 of the support 3 of the sample holder 1.

[0111] The thermal deflector has a deflection face positioned opposite the first face 7 of the support 3 of the sample holder 1, and covered at least partially by a thermal protection layer 10 as described previously. In this case, the first face 7 of the support 3 does not include a thermal protection layer 10.

[0112] The thermal deflector can be made of a composite material and acts as a thermal screen.

[0113] Although the present invention has been described with reference to specific embodiments, it is evident that modifications and changes can be made to these examples without departing from the general scope of the invention as defined by the claims.

[0114] In particular, individual features of the various embodiments illustrated / mentioned can be combined in additional embodiments. Therefore, the description and drawings should be considered in an illustrative rather than a restrictive sense.

Claims

Demands

1. Sample holder (1) for a test bench (2) comprising a support (3) having a housing (4) for receiving a sample (5) comprising a thermal protection coating (6), a first face (7) of the support (3) and the thermal protection coating (6) being intended to be positioned opposite a heating device (8) of the test bench (2) to be heated by a flame (9) emitted by the heating device (8), the sample holder (1) comprising a thermal protection layer (10) positioned opposite the first face (7) of the support (3).

2. Sample holder (1) according to claim 1, wherein the thermal protection layer (10) has a thermal conductivity between 0.01 Wm⁻².K⁻¹ and 1.2 Wm⁻².K⁻¹

3. Sample holder (1) according to any one of claims 1 or 2, wherein the thermal protection layer (10) has a thickness between 1 pm and 2000 pm.

4. Sample holder (1) according to any one of claims 1 to 3, wherein the thermal protection layer (10) comprises a metallic bonding underlayer (11) and a ceramic bonding layer (12) at least partially covering the bonding underlayer (11).

5. Sample holder (1) according to claim 4, wherein the bonding sublayer (11) is of the metallic type, the ceramic bonding layer (12) being selected from partially stabilized yttria zirconia, zirconia partially stabilized by one or more rare earths and perovskites.

6. Sample holder (1) according to any one of claims 4 or 5, wherein the ceramic bonding layer (12) has a thickness greater than 1 pm and less than 1000 pm, preferably greater than 1 pm and less than 500 pm.

7. Sample holder (1) according to any one of claims 4 to 6, wherein the thermal protection layer (10) comprises an environmental protection layer (13) covering at least partially the ceramic bonding layer (12).

8. Sample holder (1) according to any one of claims 1 to 7, wherein the thermal protection layer (10) covers at least partially the first face (7) of the support (3).

9. Sample holder (1) according to any one of claims 1 to 7, comprising a thermal deflector (14) positioned opposite the first face (7) of the support (3) of the sample holder (1), the thermal deflector (14) being distant from the first face (7) of the sample holder (1), the thermal deflector (14) comprising an orifice (15) positioned opposite the housing (4) of the support (3) of the sample holder (1) and having a deflection face (16) positioned opposite the first face (7) of the support (3) of the sample holder (1) and intended to be heated by the flame (9), the deflection face (16) being at least partially covered by the thermal protection layer (10).

10. Test bench (2) comprising a heating device (8) for emitting a flame (9) and a sample holder (1) as defined according to any one of claims 1 to 9, and for supporting a sample (5) heated by the flame (9).

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