A thermal barrier coating material, a thermal barrier coating, its preparation method and application

Abstract

This invention provides a thermal barrier coating material, a thermal barrier coating, its preparation method, and its applications. The thermal barrier coating material comprises RE-doped zirconium hafnium oxide, wherein the RE is Yb and / or Lu. The thermal barrier coating possesses a ferroelastic domain structure. The thermal barrier coating provided by this invention has a single non-thermodynamic equilibrium tetragonal t' phase ferroelastic domain structure similar to YSZ, exhibiting both good fracture toughness and excellent thermophysical properties (temperature resistance up to 1500℃), preventing cracking during thermal cycling and demonstrating strong resistance to spalling; it has significant application value in hot-end components of aero-engines and gas turbines.

Description

Technical Field

[0001] This invention belongs to the field of thermal barrier coating technology, and relates to a thermal barrier coating material, and more particularly to a thermal barrier coating material, a thermal barrier coating, its preparation method and application. Background Technology

[0002] Thermal barrier coatings (TBCs) are a thermal protection technology that involves depositing high-temperature resistant and highly insulating ceramic materials on the surface of high-temperature metals or superalloys. This reduces the surface temperature of hot-end components, improves the oxidation and corrosion resistance of the substrate material, and ultimately enhances the thrust-to-weight ratio and thermal efficiency of engines. TBCs act as thermal insulation for the substrate material, reducing its temperature and enabling devices made from them (such as engine turbine blades) to operate at high temperatures. They can also improve the thermal efficiency of devices (engines, etc.) by more than 60%, and have wide applications in aerospace, shipbuilding, and weaponry.

[0003] Currently, yttrium-stabilized zirconia (YSZ) ceramic materials are widely used in thermal barrier coatings, particularly in hot-end components in the aerospace field. YSZ coatings possess a pseudo-tetragonal t' phase ferroelastic domain structure, which acts as a ferroelastic toughening agent, giving the coating both good fracture toughness and thermophysical properties. However, with the increasing demand for higher thrust-to-weight ratios in engines, YSZ coatings undergo phase transformations and severe sintering in service environments exceeding 1200°C, making them unsuitable for use in ultra-high temperature environments.

[0004] Researchers have discovered that rare earth zirconates possess advantages such as low thermal conductivity, resistance to sintering, high-temperature phase structure stability, and good corrosion resistance. CN 116770215A discloses a high-thermal-insulation DVC structure rare earth zirconate ultra-high-temperature thermal barrier coating and its preparation method. This thermal barrier coating is a coating structure system consisting of a bonding layer + 8YSZ micro / nano structure layer + rare earth zirconate micro / nano structure layer + rare earth zirconate DVC coating. It exhibits high bonding strength and excellent thermal cycling performance, but its coefficient of thermal expansion is lower than that of YSZ. Furthermore, due to the lack of phase transformation toughening and ferroelastic toughening mechanisms found in YSZ, its fracture toughness is relatively low. CN 108546907A discloses a yttrium oxide-stabilized zirconium oxide-doped lanthanum cerate coating material, which exhibits excellent mechanical properties at high temperatures, improving its fracture toughness. However, lanthanum cerate does not undergo a phase transformation at 1400℃, and YSZ decomposes and undergoes a phase transformation above 1200℃, severely affecting their application in high-temperature environments above 1500℃.

[0005] Therefore, to address the shortcomings of existing technologies, there is a need to provide a thermal barrier coating material that has a YSZ material t' phase ferroelastic domain structure and can withstand high temperatures of 1500℃. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a thermal barrier coating material, a thermal barrier coating, its preparation method, and its applications. The thermal barrier coating provided by this invention possesses a single non-thermodynamically balanced tetragonal ferroelastic domain structure similar to YSZ, exhibiting both good fracture toughness and excellent thermophysical properties, making it of significant application value in hot-end components of aero-engines and gas turbines.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a thermal barrier coating material comprising RE-doped zirconium hafnium oxide, wherein the RE is Yb and / or Lu.

[0009] In this invention, zirconium hafnium oxide can form a continuous solid solution, which can effectively improve its overall temperature and phase transition temperature. After RE doping is introduced into the zirconium hafnium oxide lattice, trivalent Yb and / or Lu elements replace tetravalent zirconium hafnium ions, resulting in limited solid solution in zirconium hafnium oxide and producing lattice distortion. At the same time, a certain amount of oxygen vacancies are generated, which enhances phonon scattering and is beneficial to improving phase stability and reducing thermal conductivity.

[0010] As a preferred embodiment of the present invention, the chemical formula of the thermal barrier coating material is: 9(Hf x Zr 1- x O2)·0.5(RE2O3), where 0<x≤0.5, for example, it can be 0.1, 0.2, 0.3, 0.4 or 0.5, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0011] In a second aspect, the present invention provides a thermal barrier coating, the thermal barrier coating comprising the thermal barrier coating material provided in the first aspect;

[0012] The thermal barrier coating has a ferroelastic domain structure; the thickness of the thermal barrier coating is 0.8 to 1.5 mm, for example, it can be 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm or 1.5 mm, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0013] Due to the unique chemical composition of the thermal barrier coating material of this invention, the thermal barrier coating provided by this invention has a single non-thermodynamic equilibrium tetragonal t' phase ferroelastic domain structure similar to YSZ, which has both good fracture toughness and excellent thermophysical properties (temperature resistance up to 1500℃), can avoid cracking during thermal cycling, and has strong anti-stripping ability.

[0014] In addition, excessive thickness of the thermal barrier coating can lead to excessive internal stress and defects such as cracks, while insufficient thickness can shorten the thermal shock life of the coating.

[0015] Thirdly, the present invention provides a method for preparing a thermal barrier coating as provided in the first aspect, the method comprising the following steps:

[0016] (1) Mix Zr source, Hf source and RE source according to atomic stoichiometry, and then mix with water to obtain a mixed solution;

[0017] (2) Mix the precipitant and the mixed solution obtained in step (1), precipitate, pre-treat and calcinate to obtain the thermal barrier coating material;

[0018] (3) Granulate the thermal barrier coating material obtained in step (2) to obtain spray powder;

[0019] (4) The thermal barrier coating is obtained by atmospheric plasma spraying using the spray powder obtained in step (3).

[0020] As a preferred technical solution of the present invention, the Zr source in step (1) includes ZrCl4 and / or ZrOCl2.

[0021] Preferably, the Hf source includes any one or a combination of at least two of HfCl4, Hf(SO4)2, or HfOCl2. Typical but non-limiting combinations include: a combination of HfCl4 and Hf(SO4)2, a combination of HfCl4 and HfOCl2, a combination of Hf(SO4)2 and HfOCl2, or a combination of HfCl4, Hf(SO4)2, and HfOCl2.

[0022] Preferably, the RE source includes a Yb source and / or a Lu source.

[0023] Preferably, the Yb source includes any one or a combination of at least two of Yb2O3, YbCl3, Yb(ClO4)3 or Yb(NO3)3. Typical but non-limiting combinations include: a combination of YbCl3 and Yb(ClO4)3, a combination of Yb2O3 and Yb(NO3)3, or a combination of Yb2O3, YbCl3, Yb(ClO4)3 and Yb(NO3)3.

[0024] Preferably, the Lu source includes any one or a combination of at least two of Lu2O3, LuCl3, Lu(ClO4)3 or Lu(NO3)3. Typical but non-limiting combinations include: a combination of LuCl3 and Lu(ClO4)3, a combination of Lu2O3 and Lu(NO3)3, or a combination of Lu2O3, LuCl3, Lu(ClO4)3 and Lu(NO3)3.

[0025] As a preferred technical solution of the present invention, the remixing in step (1) includes stirring and mixing, accompanied by heating.

[0026] Preferably, the stirring speed is 300-800 r / min, for example, it can be 300 r / min, 400 r / min, 500 r / min, 600 r / min, 700 r / min or 800 r / min, but is not limited to the listed values, and other values ​​not listed in the range are also applicable; preferably 500-800 r / min.

[0027] Preferably, the mixing time is 1 to 9 hours, for example, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours or 9 hours, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0028] Preferably, the heating temperature is 60 to 90°C, for example, it can be 60°C, 65°C, 70°C, 75°C, 80°C, 85°C or 90°C, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0029] Further, the remixing in step (1) of the present invention refers to: after the mixture of Zr source, Hf source, RE source and water is clarified, stirring and heating are stopped, and then cooled to room temperature to obtain a mixed solution.

[0030] As a preferred technical solution of the present invention, the precipitant in step (2) includes any one or a combination of at least two of ammonia, ammonium carbonate or ammonium bicarbonate. Typical but non-limiting combinations include a combination of ammonia and ammonium carbonate, a combination of ammonium carbonate and ammonium bicarbonate, a combination of ammonia and ammonium bicarbonate, or a combination of ammonia, ammonium carbonate and ammonium bicarbonate.

[0031] Preferably, when the precipitation stops, the pH value of the precipitant and the mixed solution is 11 to 12, for example, 11, 11.2, 11.4, 11.6, 11.8 or 12, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0032] Preferably, the pretreatment includes washing, filtering, drying, grinding and sieving in sequence.

[0033] Preferably, the detergent used in the washing process includes deionized water and / or anhydrous ethanol.

[0034] Preferably, the number of washing cycles is 2 to 5, for example, 2, 3, 4 or 5 times.

[0035] Preferably, the drying temperature is 85-120°C, for example, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C or 120°C, but not limited to the listed values, and other values ​​not listed within the range are also applicable; the drying time is 4-8 hours, for example, 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours, 6.5 hours, 7 hours, 7.5 hours or 8 hours, but not limited to the listed values, and other values ​​not listed within the range are also applicable.

[0036] Preferably, the grinding includes manual crushing in a mortar and pestle or mechanical dry ball milling.

[0037] Preferably, the particle size of the sieved powder is ≥300 mesh, for example, it can be 300 mesh, 400 mesh, 450 mesh, 500 mesh, 700 mesh, 800 mesh or 1000 mesh, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0038] In this invention, the particle size of the powder before calcination is ≥300 mesh. If the powder particle size is too large, it will lead to poor granulation effect and result in excessively large particle size of the sprayed powder.

[0039] Preferably, the calcination temperature is 1250-1350℃, for example, it can be 1250℃, 1270℃, 1290℃, 1310℃, 1330℃ or 1350℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0040] Preferably, the calcination time is 3 to 5 hours, for example, 3 hours, 3.4 hours, 3.8 hours, 4.2 hours, 4.6 hours or 5 hours, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0041] The calcination temperature described in this invention is 1250-1350℃. If the temperature is too low, impurities will remain in the powder, and if the calcination temperature is too high, the powder will undergo a phase change.

[0042] As a preferred technical solution of the present invention, the granulation in step (3) includes mixing a binder, a dispersant and a thermal barrier coating material, and then performing a drying process.

[0043] Preferably, the adhesive comprises epoxy resin.

[0044] Preferably, the dispersant comprises a mixture of ethyl acetate and n-butanol.

[0045] Preferably, the amount of adhesive used is 4 to 8 wt% of the thermal barrier coating material, for example, it can be 4 wt%, 5 wt%, 6 wt%, 7 wt% or 8 wt%, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0046] Preferably, the amount of dispersant is 3 to 6 wt% of the thermal barrier coating material, for example, 3 wt%, 3.5 wt%, 4 wt%, 5 wt%, 5.5 wt%, or 6 wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0047] Preferably, the particle size range of the sprayed powder is 45 to 150 μm, for example, it can be 45 μm, 50 μm, 70 μm, 90 μm, 110 μm, 130 μm or 150 μm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0048] Preferably, the flowability of the sprayed powder is 20-50s / 50g, for example, it can be 20s / 50g, 30s / 50g, 40s / 50g or 50s / 50g, but is not limited to the listed values. Other values ​​not listed within the value range are also applicable.

[0049] Preferably, the loose packing density of the sprayed powder is 1.8-2.8 g / cm³. 3 For example, it could be 1.8 g / cm³ 3 2g / cm 3 2.2g / cm 3 2.4g / cm 3 2.6g / cm 3 Or 2.8g / cm 3 However, this does not apply to all values ​​listed, but rather to other unlisted values ​​within the range.

[0050] In the preparation process of the coating described in this invention, the physical properties of the sprayed powder will affect the spraying effect of atmospheric plasma spraying. Specifically, if the particle size of the sprayed powder is too large, the powder will not be able to melt completely, and if the particle size is too small, the powder will agglomerate. If the flow rate of the sprayed powder is too fast, the mixed powder will separate, and if it is too slow, the powder will stick or agglomerate. If the loose density of the sprayed powder is too high, it will be difficult to feed the powder, and if it is too low, it will indicate that the powder is loose and will cause defects on the coating surface.

[0051] As a preferred technical solution of the present invention, the spray gun voltage for atmospheric plasma spraying in step (4) is 60-70V, for example, it can be 60V, 62V, 64V, 66V, 68V or 70V, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0052] Preferably, the spray gun current for atmospheric plasma spraying is 500-600A, for example, it can be 500A, 520A, 540A, 560A, 580A or 600A, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0053] Preferably, the argon flow rate for atmospheric plasma spraying is 35-45 L / min, for example, it can be 35 L / min, 37 L / min, 39 L / min, 41 L / min, 43 L / min or 45 L / min, but is not limited to the listed values. Other values ​​not listed within the range are also applicable.

[0054] Preferably, the hydrogen flow rate for atmospheric plasma spraying is 3 to 5 L / min, for example, it can be 3 L / min, 3.4 L / min, 3.8 L / min, 4.2 L / min, 4.6 L / min or 5 L / min, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0055] Preferably, the powder feeding rate of the atmospheric plasma spraying is 20-35 g / min, for example, it can be 20 g / min, 23 g / min, 26 g / min, 29 g / min, 32 g / min or 35 g / min, but is not limited to the listed values. Other values ​​not listed within the range are also applicable.

[0056] Preferably, the spraying distance of the atmospheric plasma spraying is 80-100mm, for example, it can be 80mm, 85mm, 90mm, 95mm or 100mm, but is not limited to the listed values. Other values ​​not listed within the range are also applicable.

[0057] As a preferred embodiment of the present invention, the method for preparing a thermal barrier coating provided in the third aspect of the present invention includes the following steps:

[0058] (1) Mix Zr source, Hf source and RE source according to atomic stoichiometry, and then mix with water to obtain a mixed solution;

[0059] The remixing includes mixing at a stirring rate of 300-800 r / min for 1-9 hours, accompanied by heating; the heating temperature is 60-90℃.

[0060] (2) Mix the precipitant and the mixed solution obtained in step (1). When precipitation stops, the pH value of the precipitant and the mixed solution is 11-12. Then, wash, filter, dry, grind, sieve and calcinate in sequence to obtain the thermal barrier coating material.

[0061] The drying temperature is 85-120℃ and the time is 4-8 hours; the particle size of the powder after sieving is ≥300 mesh; the calcination temperature is 1250-1350℃ and the time is 3-5 hours.

[0062] (3) Granulate the thermal barrier coating material obtained in step (2) to obtain spray powder;

[0063] The granulation process includes mixing a binder, a dispersant, and a thermal barrier coating material, followed by drying. The amount of binder used is 4-8 wt% of the thermal barrier coating material, and the amount of dispersant used is 3-6 wt% of the thermal barrier coating material.

[0064] The powder has a particle size range of 45–150 μm, a flowability of 20–50 s / 50 g, and a bulk density of 1.8–2.8 g / cm³. 3 ;

[0065] (4) The thermal barrier coating is obtained by atmospheric plasma spraying using the spray powder obtained in step (3);

[0066] The atmospheric plasma spraying process uses a spray gun with a voltage of 60–70V, a spray gun current of 500–600A, an argon flow rate of 35–45L / min, a hydrogen flow rate of 3–5L / min, a powder feeding rate of 20–35g / min, and a spraying distance of 80–100mm.

[0067] Fourthly, the present invention provides an application of the thermal barrier coating provided in the second aspect, the thermal barrier coating being used in hot-end components of aero engines and gas turbines.

[0068] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0069] Compared with the prior art, the present invention has the following beneficial effects:

[0070] (1) The thermal barrier coating provided by the present invention has a single non-thermodynamic equilibrium tetragonal t' phase ferroelastic domain structure similar to YSZ, which has both good fracture toughness and excellent thermophysical properties (temperature resistance 1500℃), can avoid cracking during thermal cycling, and has strong anti-stripping ability.

[0071] (2) The thermal barrier coating provided by the present invention has important application value in hot-end components of aero-engines and gas turbines. Attached Figure Description

[0072] Figure 1These are X-ray diffraction (XRD) patterns of the thermal barrier coatings provided in Embodiments 1-3 and Comparative Example 1 of the present invention;

[0073] Figure 2 This is a SEM image of the thermal barrier coating provided in Embodiment 1 of the present invention;

[0074] Figure 3 This is a surface SEM image of the thermal barrier coating provided in Embodiment 1 of the present invention;

[0075] Figure 4 This is a differential scanning thermogravimetric curve of the thermal barrier coating provided in Embodiment 1 of the present invention. Detailed Implementation

[0076] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be considered as specific limitations thereof.

[0077] Example 1

[0078] This embodiment provides a thermal barrier coating, the thermal barrier coating comprising chemical formula 9(Hf) 0.5 Zr 0.5 Thermal barrier coating material of O2·0.5(Yb2O3);

[0079] The method for preparing the thermal barrier coating includes the following steps:

[0080] (1) ZrOCl2, HfCl4 and Yb2O3 were initially mixed according to the atomic stoichiometric ratio of the thermal barrier coating material (4.5:4.5:1), and then water was mixed to obtain a mixed solution;

[0081] The remixing includes mixing at a stirring rate of 300 r / min for 2 hours, accompanied by heating; the heating temperature is 70°C.

[0082] (2) Mix ammonia water and the mixed solution obtained in step (1). When precipitation stops, the pH value of the ammonia water and the mixed solution is 11-12. Then, wash, filter, dry, grind, sieve and calcinate in sequence to obtain thermal barrier coating material.

[0083] The drying temperature is 100℃ and the time is 6 hours; the particle size of the powder after sieving is 300 mesh; the calcination temperature is 1300℃ and the time is 4 hours.

[0084] (3) Granulate the thermal barrier coating material obtained in step (2) to obtain spray powder;

[0085] The granulation process involves mixing a binder, a dispersant, and a thermal barrier coating material, followed by drying. The binder is used at 5 wt% of the thermal barrier coating material, and the dispersant is used at 3 wt% of the thermal barrier coating material.

[0086] The powder has a particle size range of 45–150 μm, a flowability of 32.68 s / 50 g, and a bulk density of 2.2 g / cm³. 3 ;

[0087] (4) The thermal barrier coating is obtained by atmospheric plasma spraying using the spray powder obtained in step (3);

[0088] The atmospheric plasma spraying system has a spray gun voltage of 63V, a spray gun current of 500A, an argon flow rate of 38L / min, a hydrogen flow rate of 4.2L / min, a powder feeding rate of 20-35g / min, and a spraying distance of 85mm.

[0089] Example 2

[0090] This embodiment provides a thermal barrier coating, the thermal barrier coating comprising chemical formula 9(Hf) 0.3 Zr 0.7 Thermal barrier coating material of O2·0.5(Yb2O3);

[0091] The preparation method of the thermal barrier coating is the same as that in Example 1.

[0092] Example 3

[0093] This embodiment provides a thermal barrier coating, the thermal barrier coating comprising chemical formula 9(Hf) 0.1 Zr 0.9 Thermal barrier coating material of O2·0.5(Yb2O3);

[0094] The preparation method of the thermal barrier coating is the same as that in Example 1.

[0095] Example 4

[0096] This embodiment provides a thermal barrier coating, the thermal barrier coating comprising chemical formula 9(Hf) 0.2 Zr 0.8 Thermal barrier coating material of O2·0.5(YbLuO3);

[0097] The method for preparing the thermal barrier coating includes the following steps:

[0098] (1) HfCl4, ZrCl4, YbCl3 and LuCl3 were initially mixed according to atomic stoichiometry, and then water was mixed to obtain a mixed solution;

[0099] The remixing includes mixing at a stirring rate of 800 r / min for 1 hour, accompanied by heating; the heating temperature is 90°C.

[0100] (2) Mix ammonium carbonate and the mixed solution obtained in step (1). When precipitation stops, the pH value of the ammonium carbonate and the mixed solution is 11-12. Then, wash, filter, dry, grind, sieve and calcinate in sequence to obtain the thermal barrier coating material.

[0101] The drying temperature is 85℃ and the time is 8 hours; the particle size of the powder after sieving is 500 mesh; the calcination temperature is 1250℃ and the time is 5 hours.

[0102] (3) Granulate the thermal barrier coating material obtained in step (2) to obtain spray powder;

[0103] The granulation process involves mixing a binder, a dispersant, and a thermal barrier coating material, followed by drying. The binder is used at 4 wt% of the thermal barrier coating material, and the dispersant is used at 3 wt% of the thermal barrier coating material.

[0104] The powder has a particle size range of 60–120 μm, a flowability of 50 s / 50 g, and a bulk density of 1.8 g / cm³. 3 ;

[0105] (4) The thermal barrier coating is obtained by atmospheric plasma spraying using the spray powder obtained in step (3);

[0106] The atmospheric plasma spraying system has a spray gun voltage of 60V, a spray gun current of 550A, an argon flow rate of 35L / min, a hydrogen flow rate of 3L / min, a powder feeding rate of 20g / min, and a spraying distance of 80mm.

[0107] Example 5

[0108] This embodiment provides a thermal barrier coating, the thermal barrier coating comprising chemical formula 9(Hf) 0.1 Zr 0.9 Thermal barrier coating material of O2·0.5(Lu2O3);

[0109] The method for preparing the thermal barrier coating includes the following steps:

[0110] (1) ZrCl4, Hf(SO4)2 source and Lu(NO3)3 were initially mixed according to atomic stoichiometry, and then water was mixed to obtain a mixed solution;

[0111] The remixing includes mixing at a stirring rate of 350 r / min for 9 hours, accompanied by heating; the heating temperature is 60°C.

[0112] (2) Mix ammonium bicarbonate and the mixed solution obtained in step (1). When precipitation stops, the pH value of the ammonium bicarbonate and the mixed solution is 11-12. Then, wash, filter, dry, grind, sieve and calcinate in sequence to obtain thermal barrier coating material.

[0113] The drying temperature is 120℃ and the time is 4 hours; the particle size of the powder after sieving is 600 mesh; the calcination temperature is 1350℃ and the time is 3 hours.

[0114] (3) Granulate the thermal barrier coating material obtained in step (2) to obtain spray powder;

[0115] The granulation process involves mixing a binder, a dispersant, and a thermal barrier coating material, followed by drying. The binder is used at 8 wt% of the thermal barrier coating material, and the dispersant is used at 6 wt% of the thermal barrier coating material.

[0116] The powder has a particle size range of 100–150 μm, a flowability of 20 s / 50 g, and a bulk density of 2.8 g / cm³. 3 ;

[0117] (4) The thermal barrier coating is obtained by atmospheric plasma spraying using the spray powder obtained in step (3);

[0118] The atmospheric plasma spraying system has a spray gun voltage of 70V, a spray gun current of 600A, an argon flow rate of 45L / min, a hydrogen flow rate of 5L / min, a powder feeding rate of 35g / min, and a spraying distance of 100mm.

[0119] Example 6

[0120] This embodiment provides a thermal barrier coating, the thermal barrier coating comprising chemical formula 9(Hf) 0.5 Zr 0.5 Thermal barrier coating material of O2·0.5(Yb2O3);

[0121] The difference between the preparation method of the thermal barrier coating and that of Example 1 is only that:

[0122] In this embodiment, the calcination temperature in step (2) is adjusted to 1100℃.

[0123] Example 7

[0124] This embodiment provides a thermal barrier coating, the thermal barrier coating comprising chemical formula 9(Hf) 0.5 Zr 0.5 Thermal barrier coating material of O2·0.5(Yb2O3);

[0125] The difference between the preparation method of the thermal barrier coating and that of Example 1 is only that:

[0126] In this embodiment, the calcination temperature in step (2) is adjusted to 1400℃.

[0127] Example 8

[0128] This embodiment provides a thermal barrier coating, the thermal barrier coating comprising chemical formula 9(Hf) 0.5 Zr 0.5 Thermal barrier coating material of O2·0.5(Yb2O3);

[0129] The difference between the preparation method of the thermal barrier coating and that of Example 1 is only that:

[0130] In this embodiment, the flowability of the sprayed powder described in step (3) is adjusted to 60s / 50g, and the loose packing density is 3.2g / cm³. 3 .

[0131] Example 9

[0132] This embodiment provides a thermal barrier coating, the thermal barrier coating comprising chemical formula 9(Hf) 0.5 Zr 0.5 Thermal barrier coating material of O2·0.5(Yb2O3);

[0133] The difference between the preparation method of the thermal barrier coating and that of Example 1 is only that:

[0134] In this embodiment, the flowability of the sprayed powder described in step (3) is adjusted to 15s / 50g, and the loose packing density is 1.5g / cm³. 3 .

[0135] Example 10

[0136] This embodiment provides a thermal barrier coating, the thermal barrier coating comprising chemical formula 9(Hf) 0.5 Zr 0.5 Thermal barrier coating material of O2·0.5(Yb2O3);

[0137] The difference between the preparation method of the thermal barrier coating and that of Example 1 is only that:

[0138] In this embodiment, the spray gun voltage in the atmospheric plasma spraying described in step (4) is adjusted to 50V and the spraying current is adjusted to 450A.

[0139] Example 11

[0140] This embodiment provides a thermal barrier coating, the thermal barrier coating comprising chemical formula 9(Hf) 0.5 Zr 0.5 Thermal barrier coating material of O2·0.5(Yb2O3);

[0141] The difference between the preparation method of the thermal barrier coating and that of Example 1 is only that:

[0142] In this embodiment, the spray gun voltage in the atmospheric plasma spraying described in step (4) is adjusted to 80V and the spraying current is adjusted to 650A.

[0143] Example 12

[0144] This embodiment provides a thermal barrier coating, the thermal barrier coating comprising chemical formula 9(Hf) 0.5 Zr 0.5 Thermal barrier coating material of O2·0.5(Yb2O3);

[0145] The difference between the preparation method of the thermal barrier coating and that of Example 1 is only that:

[0146] In this embodiment, the spraying distance in the atmospheric plasma spraying described in step (4) is adjusted to 70mm.

[0147] Example 13

[0148] This embodiment provides a thermal barrier coating, the thermal barrier coating comprising chemical formula 9(Hf) 0.5 Zr 0.5 Thermal barrier coating material of O2·0.5(Yb2O3);

[0149] The difference between the preparation method of the thermal barrier coating and that of Example 1 is only that:

[0150] In this embodiment, the spraying distance in the atmospheric plasma spraying described in step (4) is adjusted to 110mm.

[0151] Comparative Example 1

[0152] This comparative example provides a thermal barrier coating, which comprises a thermal barrier coating material with the chemical formula 9(ZrO2)·0.5(Yb2O3);

[0153] The preparation method of the thermal barrier coating is the same as that in Example 1.

[0154] Comparative Example 2

[0155] This comparative example provides a thermal barrier coating, which comprises a thermal barrier coating material with the chemical formula 9(HfO2)·0.5(Yb2O3);

[0156] The preparation method of the thermal barrier coating is the same as that in Example 1.

[0157] Comparative Example 3

[0158] This comparative example provides a thermal barrier coating, the thermal barrier coating comprising the chemical formula 9(Hf) 0.7Zr 0.3 Thermal barrier coating material of O2·0.5(Yb2O3);

[0159] The preparation method of the thermal barrier coating is the same as that in Example 1.

[0160] Performance testing:

[0161] (1) Phase analysis of the thermal barrier coatings provided in Examples 1-3 and Comparative Example 1 was performed using XRD, with 2θ ranging from 20 to 100°. The results are as follows: Figure 1 As shown;

[0162] The microstructure and ablation surface of the thermal barrier coating provided in Example 1 were observed using scanning electron microscopy (SEM), and the results are as follows: Figure 2 and Figure 3 As shown;

[0163] The thermogravimetric (TG) and differential thermal analysis (DSC) data of the thermal barrier coating were measured using a simultaneous thermal analyzer. The weight change and potential physicochemical processes such as phase transition and decomposition of the thermal barrier coating provided in Example 1 were analyzed at high temperatures. The analysis results are shown in the figure below. Figure 4 As shown;

[0164] (2) 1500℃ thermal cycling test:

[0165] The thermal barrier coatings provided in the above embodiments and comparative examples were placed in a muffle furnace, kept at 1500°C for 10 minutes, and then cooled in room temperature water. When the surface area of ​​the thermal barrier coating of the test sample reached 20%, the coating was deemed to have failed and the test was completed. The number of thermal cycles was recorded, and the results are shown in Table 1.

[0166] (3) Oxidation test at 1500℃:

[0167] The thermal barrier coatings provided in the above embodiments and comparative examples were placed in a muffle furnace and kept at 1500℃ for 100h. The surface condition of the test samples was observed. The fracture toughness of the thermal barrier coatings was calculated by the indentation method, and the results are shown in Table 1.

[0168] Table 1

[0169]

[0170]

[0171] Depend on Figure 1 As shown in Table 1, the thermal barrier coating provided by this invention has a distinct t' pseudo-tetragonal phase ferroelastic domain structure, forming a zirconium oxide-hafnium oxide solid solution type thermal barrier coating. The incorporation of HfO2 causes a slight distortion in the original YSZ lattice, but does not affect the original phase structure of YSZ, maintaining the original t' pseudo-tetragonal phase; Figure 2As can be seen from the SEM images of the thermal barrier coating prepared in the embodiments of the present invention, there is a ferroelastic domain microstructure. The thermal barrier coating has a ferroelastic toughening effect and its fracture toughness is significantly improved compared with YSZ.

[0172] Depend on Figure 4 It can be seen that the thermal barrier coating prepared by the present invention did not show significant weight loss in the TG curve at a high temperature of 1500℃, and no obvious endothermic / exothermic peaks were observed in the DSC curve, indicating that the coating did not undergo phase change or other physicochemical processes at high temperature and has excellent high temperature stability.

[0173] As shown in Table 1, the thermal barrier coatings prepared by the methods provided in Examples 1-5 of the present invention showed no obvious cracks on the surface after 20 cycles of thermal cycling at 1500℃, while the thermal barrier coatings prepared in Comparative Example 1 peeled off after 10 cycles of thermal cycling at 1500℃. The thermal barrier coatings prepared by the methods provided in Examples 1-5 can remain intact under long-term high-temperature (1500℃) oxidation conditions without cracking or peeling, and have good heat resistance.

[0174] In summary, the thermal barrier coating provided by this invention has a single non-thermodynamic equilibrium tetragonal t' phase ferroelastic domain structure similar to YSZ, which combines good fracture toughness and excellent thermophysical properties (temperature resistance up to 1500℃), can avoid cracking during thermal cycling, and has strong anti-stripping ability.

[0175] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A thermal barrier coating, characterized in that, The thermal barrier coating includes a thermal barrier coating material; The thermal barrier coating has a ferroelastic domain structure; The thermal barrier coating material comprises RE-doped zirconium hafnium oxide, wherein the RE is Yb and / or Lu. The general chemical formula of the thermal barrier coating material is: (Hf x Zr 1-x ) 0.9 RE 0.1 O 1.95 Where 0 < x ≤ 0.5; The thermal barrier coating is prepared by the following method, which includes the following steps: (1) Mix Zr source, Hf source and RE source according to atomic stoichiometry, and then mix with water to obtain a mixed solution; (2) Mix the precipitant and the mixed solution obtained in step (1), precipitate, pretreat and calcine to obtain the thermal barrier coating material; (3) Granulate the thermal barrier coating material obtained in step (2) to obtain spray powder; (4) Atmospheric plasma spraying is performed using the spray powder obtained in step (3) to obtain the thermal barrier coating; the calcination temperature in step (2) is 1250~1350℃.

2. The thermal barrier coating according to claim 1, characterized in that, The thickness of the thermal barrier coating is 0.8~1.5mm.

3. A method for preparing a thermal barrier coating as described in claim 1 or 2, characterized in that, The preparation method includes the following steps: (1) Mix Zr source, Hf source and RE source according to atomic stoichiometry, and then mix with water to obtain a mixed solution; (2) Mix the precipitant and the mixed solution obtained in step (1), precipitate, pretreat and calcine to obtain the thermal barrier coating material; (3) Granulate the thermal barrier coating material obtained in step (2) to obtain spray powder; (4) The thermal barrier coating is obtained by atmospheric plasma spraying using the spray powder obtained in step (3); The calcination temperature in step (2) is 1250~1350℃.

4. The preparation method according to claim 3, characterized in that, The remixing in step (1) includes stirring and mixing, accompanied by heating.

5. The preparation method according to claim 4, characterized in that, The stirring speed is 300~800 r / min.

6. The preparation method according to claim 5, characterized in that, The stirring speed is 500~800 r / min.

7. The preparation method according to claim 4, characterized in that, The mixing time is 1 to 9 hours.

8. The preparation method according to claim 4, characterized in that, The heating temperature is 60~90℃.

9. The preparation method according to claim 3, characterized in that, The precipitant in step (2) includes any one or a combination of at least two of ammonia, ammonium carbonate or ammonium bicarbonate.

10. The preparation method according to claim 3, characterized in that, When the precipitation stops, the pH value of the precipitant and the mixed solution is 11-12.

11. The preparation method according to claim 3, characterized in that, The pretreatment includes washing, filtering, drying, grinding and sieving in sequence.

12. The preparation method according to claim 11, characterized in that, The drying temperature is 85~120℃, and the time is 4~8h.

13. The preparation method according to claim 11, characterized in that, The particle size of the sieved powder is ≥300 mesh.

14. The preparation method according to claim 3, characterized in that, The calcination time is 3-5 hours.

15. The preparation method according to claim 3, characterized in that, The granulation in step (3) involves mixing a binder, a dispersant, and a thermal barrier coating material, followed by drying.

16. The preparation method according to claim 15, characterized in that, The amount of adhesive used is 4-8 wt% of the thermal barrier coating material.

17. The preparation method according to claim 15, characterized in that, The amount of dispersant used is 3-6 wt% of the thermal barrier coating material.

18. The preparation method according to claim 3, characterized in that, The particle size range of the sprayed powder is 45~150μm.

19. The preparation method according to claim 3, characterized in that, The fluidity of the sprayed powder is 20~50s / 50g.

20. The preparation method according to claim 3, characterized in that, The loose bulk density of the sprayed powder is 1.8~2.8 g / cm³. 3 .

21. The preparation method according to claim 3, characterized in that, The spray gun voltage for atmospheric plasma spraying in step (4) is 60~70V.

22. The preparation method according to claim 3, characterized in that, The spray gun current for atmospheric plasma spraying is 500~600A.

23. The preparation method according to claim 3, characterized in that, The argon flow rate for atmospheric plasma spraying is 35~45L / min.

24. The preparation method according to claim 3, characterized in that, The hydrogen flow rate for atmospheric plasma spraying is 3~5 L / min.

25. The preparation method according to claim 3, characterized in that, The powder feeding rate for atmospheric plasma spraying is 20~35g / min.

26. The preparation method according to claim 3, characterized in that, The spraying distance for atmospheric plasma spraying is 80~100mm.

27. The preparation method according to claim 3, characterized in that, The preparation method includes the following steps: (1) Mix Zr source, Hf source and RE source according to atomic stoichiometry, and then mix with water to obtain a mixed solution; The remixing includes mixing at a stirring rate of 300~800 r / min for 1~9 h, accompanied by heating; the heating temperature is 60~90℃; (2) Mix the precipitant and the mixed solution obtained in step (1). When precipitation stops, the pH value of the precipitant and the mixed solution after mixing is 11~12. Then, wash, filter, dry, grind, sieve and calcinate in sequence to obtain the thermal barrier coating material. The drying temperature is 85~120℃, and the time is 4~8h; the particle size of the powder after sieving is ≥300 mesh; the calcination temperature is 1250~1350℃, and the time is 3~5h. (3) Granulate the thermal barrier coating material obtained in step (2) to obtain spray powder; The granulation process involves mixing a binder, a dispersant, and a thermal barrier coating material, followed by drying. The binder is used at 4-8 wt% of the thermal barrier coating material, and the dispersant is used at 3-6 wt% of the thermal barrier coating material. The powder has a particle size range of 45~150μm, a flowability of 20~50s / 50g, and a bulk density of 1.8~2.8g / cm³. 3 ; (4) The thermal barrier coating is obtained by atmospheric plasma spraying using the spray powder obtained in step (3); The atmospheric plasma spraying process uses a spray gun with a voltage of 60-70V, a spray gun current of 500-600A, an argon flow rate of 35-45L / min, a hydrogen flow rate of 3-5L / min, a powder feeding rate of 20-35g / min, and a spraying distance of 80-100mm.

28. An application of the thermal barrier coating as described in claim 1 or 2, characterized in that, The thermal barrier coating is used in hot-end components of aero engines and gas turbines.

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