Hafnium-zirconium-titanium oxide-based thermal barrier / environmental barrier coating material with low thermal expansion, low thermal conductivity and high fracture toughness, preparation method of thermal barrier / environmental barrier coating material, thermal barrier / environmental barrier coating and engine

Abstract

The invention belongs to the technical field of thermal protection coating materials, and discloses a hafnium-zirconium-titanium-oxide-based low-thermal-expansion low-thermal-conductivity high-fracture-toughness material and a preparation method thereof, a thermal barrier / environmental barrier coating and an engine. The hafnium zirconium titanium oxide-based low thermal expansion, low thermal conductivity and high fracture toughness comprise xHfO2yZrO2zTiO2, wherein x is equal to 0%-65%; y is equal to 0-65%, and x + y is greater than 0%; z is equal to 35 percent to 55 percent; x + y + z = 1. The hafnium-zirconium-titanium oxide base provided by the invention is low in thermal expansion, low in thermal conductivity and high in fracture toughness, the use temperature of the base can be increased, and meanwhile, the hafnium-zirconium-titanium oxide base has the advantages of high melting point, low thermal expansion coefficient, low thermal conductivity and high fracture toughness.

Description

Technical Field

[0001] This invention belongs to the technical field of thermal protective coating materials, specifically relating to a hafnium zirconium titanium oxide-based thermal barrier / environmental barrier coating material with low thermal expansion, low thermal conductivity, and high fracture toughness, its preparation method, thermal barrier / environmental barrier coating, and engine. Background Technology

[0002] With the increasing service temperatures of aero-engines, ceramic matrix composites (CMCs) have become important substrate materials for hot-end components. CMCs possess advantages such as low density, higher temperature resistance, and superior high-temperature mechanical properties, which can significantly increase the turbine inlet gas temperature, improve gas efficiency and thrust-to-weight ratio, making them an important development direction for future aero-engines. The mainstream CMC is silicon carbide-silicon carbide microceramic matrix material (SiC / SiC). f -CMCs), during the service of aero engines, the high-temperature combustion gases containing water vapor cause SiC to undergo an oxidation reaction to generate SiO2. The surface SiO2 further reacts with water vapor to generate Si(OH)4, which escapes, resulting in SiC / SiC... f -CMCs components are corroded and damaged. Therefore, SiC / SiC f - A coating resistant to high-temperature water vapor corrosion, i.e., a thermal barrier / environmental barrier coating, needs to be prepared on the surface of CMCs to ensure that the CMC materials are not directly exposed to high-temperature water vapor / oxygen environments and are protected from the corrosive effects of high-temperature water vapor. Typical thermal barrier / environmental barrier coating materials are rare earth silicate ceramic materials, which are widely studied and applied due to their excellent thermal properties and resistance to water vapor corrosion.

[0003] The disadvantages of rare-earth silicate ceramic materials are their low melting point and poor fracture toughness, making them prone to failure at higher temperatures such as 1500℃. With the further increase in turbine inlet temperature, in order to meet the requirements of 1500℃~1600℃... o The use of SiC-CMCs in C environment requires that the outer coating protect against water vapor corrosion as well as high temperature erosion.

[0004] Common high-melting-point materials, such as rare-earth stabilized zirconium oxide / hafnium materials and rare-earth zirconium / hafnium salt materials, have higher melting points but high coefficients of thermal expansion, making them unsuitable for use with ceramic matrix composite substrates that have low coefficients of thermal expansion. Summary of the Invention

[0005] This invention aims to at least partially solve one of the technical problems in related technologies. Therefore, one objective of this invention is to provide a hafnium-zirconium titanium oxide-based thermal barrier / environmental barrier coating material with low thermal expansion, low thermal conductivity, and high fracture toughness, as well as its preparation method, thermal barrier / environmental barrier coating, and engine. The thermal barrier / environmental barrier coating material provided by this invention can increase the operating temperature of the substrate, while possessing the advantages of high melting point, low coefficient of thermal expansion, low thermal conductivity, and high fracture toughness.

[0006] In a first aspect, the present invention provides a hafnium zirconium titanium oxide-based thermal barrier / environmental barrier coating material with low thermal expansion, low thermal conductivity, and high fracture toughness, comprising: xHfO2•yZrO2•zTiO2; wherein, x=0%~65%; y=0%~65%, and x+y>0%; z=35%~55%; and x+y+z=1.

[0007] The hafnium zirconium titanium oxide-based thermal barrier / environmental barrier coating material of the present invention, based on HfO2, ZrO2, and TiO2, is made by controlling the relative content of HfO2, ZrO2 and TiO2, and the total amount and type of rare earth dopants, so that the thermal barrier / environmental barrier coating material has an orthorhombic phase and a small amount (<10 vol%) of monoclinic or cubic phase. While achieving low thermal expansion coefficient and low thermal conductivity, the thermal barrier / environmental barrier coating material has high fracture toughness.

[0008] In addition, the hafnium zirconium titanium oxide-based thermal barrier / environmental barrier coating material with low thermal expansion, low thermal conductivity, and high fracture toughness according to the above embodiments of the present invention may also have the following additional technical features: In some embodiments of the present invention, the hafnium zirconium titanium oxide-based low thermal expansion, low thermal conductivity, and high fracture toughness thermal barrier / environmental barrier coating material has a coefficient of thermal expansion α ≤ 9 × 10⁻⁶ at 1300 °C. -6 / K. Therefore, this thermal barrier / environmental barrier coating material has a low coefficient of thermal expansion, which allows it to be well-matched with ceramic matrix composite substrates.

[0009] In some embodiments of the present invention, the thermal conductivity κ of the hafnium zirconium titanium oxide-based material, characterized by low thermal expansion, low thermal conductivity, and high fracture toughness, is ≤2.5 W·m. -1 ·K -1 Therefore, it can act as a good thermal barrier, protecting the inner ceramic layer and the CMC substrate.

[0010] In some embodiments of the present invention, the hafnium zirconium titanium oxide-based low thermal expansion, low thermal conductivity, and high fracture toughness thermal barrier / environmental barrier coating material comprises an orthorhombic phase structure, wherein the volume content of the orthorhombic phase structure is 90%-100% based on the total volume of the phase structure of the hafnium zirconium titanium oxide-based low thermal expansion, low thermal conductivity, and high fracture toughness thermal barrier / environmental barrier coating material being 100%. Therefore, while achieving a low coefficient of thermal expansion and low thermal conductivity, the thermal barrier / environmental barrier coating material can be guaranteed to possess high fracture toughness.

[0011] In some embodiments of the present invention, the hafnium zirconium titanium oxide-based low thermal expansion, low thermal conductivity, and high fracture toughness thermal barrier / environmental barrier coating material comprises a monoclinic or cubic phase structure. With the total volume of the phase structure of the hafnium zirconium titanium oxide-based low thermal expansion, low thermal conductivity, and high fracture toughness thermal barrier / environmental barrier coating material being 100%, the content of the monoclinic or cubic phase is less than 10%. Therefore, while achieving a low coefficient of thermal expansion and low thermal conductivity, the thermal barrier / environmental barrier coating material can be guaranteed to have high fracture toughness.

[0012] In some embodiments of the present invention, the hafnium zirconium titanium oxide-based low thermal expansion, low thermal conductivity, and high fracture toughness thermal barrier / environmental barrier coating material comprises: mA₂O₃•xHfO₂•yZrO₂•zTiO₂; wherein A includes Yb 3+ Lu 3+ ,Sc 3+ 、Nd 3+ Eu 3+ 、Sm 3+ Gd 3+ Ho 3+ Dy 3+ Y 3+ Tm 3+ Er 3+ La 3+ At least one of the following: m = 0%~2.5%; x = 0%~65%; y = 0%~65%, and x+y>0%; z = 35%~55%; 2m+x+y+z=1. Therefore, while achieving a low coefficient of thermal expansion and low thermal conductivity, high fracture toughness can be ensured in the thermal barrier / environmental barrier coating material.

[0013] In some embodiments of the present invention, the hafnium zirconium titanium oxide-based low thermal expansion, low thermal conductivity, and high fracture toughness thermal barrier / environmental barrier coating material comprises: mA₂O₃•nB₂O₅•xHfO₂•yZrO₂•zTiO₂; wherein A comprises at least one trivalent rare earth metal ion; B comprises Nb 5+ Ta 5+At least one of the following: m = 0%~2.5%; n = 0%~2.5%; x = 0%~65%; y = 0%~65%, and x+y>0%; z = 35%~55%; 2m+2n+x+y+z=1. Therefore, while achieving a low coefficient of thermal expansion and low thermal conductivity, high fracture toughness can be ensured in the thermal barrier / environmental barrier coating material.

[0014] In some embodiments of the present invention, x = 15%~65%; and / or y = 15%~65%; and / or z = 35%~55%. Thus, while achieving a low coefficient of thermal expansion and low thermal conductivity, high fracture toughness can be ensured in the thermal barrier / environmental barrier coating material.

[0015] In a second aspect of the present invention, a method for preparing the hafnium zirconium titanium oxide-based thermal barrier / environmental barrier coating material with low thermal expansion, low thermal conductivity, and high fracture toughness as described in the first aspect is proposed, comprising: mixing HfO2, ZrO2, TiO2, optionally A2O3, and optionally B2O5 in a molar ratio to obtain a precursor mixture; ball milling the precursor mixture with a solvent to obtain a mixed slurry; performing solid-liquid separation on the mixed slurry to obtain a block material; sieving the block material and pre-pressing it; and calcining it at 1450℃-1700℃ for 5h-10h to obtain the hafnium zirconium titanium oxide-based thermal barrier / environmental barrier coating material with low thermal expansion, low thermal conductivity, and high fracture toughness.

[0016] Therefore, the method for preparing hafnium zirconium titanium oxide-based thermal barrier / environmental barrier coating materials with low thermal expansion, low thermal conductivity, and high fracture toughness proposed in this invention results in thermal barrier / environmental barrier coating materials with stable structures and excellent thermodynamic properties.

[0017] In a third aspect, the present invention provides a thermal barrier / environmental barrier coating comprising the hafnium zirconium titanium oxide-based thermal barrier / environmental barrier coating material with low thermal expansion, low thermal conductivity, and high fracture toughness described in the first aspect of this application. Thus, this thermal barrier / environmental barrier coating simultaneously possesses the advantages of high melting point, low coefficient of thermal expansion, low thermal conductivity, and high fracture toughness, making it compatible with ceramic matrix composite substrates with low coefficients of thermal expansion.

[0018] In a fourth aspect, the present invention provides an engine comprising the thermal barrier / environmental barrier coating described in the third aspect of the invention. Consequently, the engine has a longer service life.

[0019] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0020] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 The XRD patterns of the hafnium zirconium titanium oxide-based thermal barrier / environmental barrier coating materials with low thermal expansion, low thermal conductivity and high fracture toughness prepared in Examples 1-3 and Comparative Examples 1-2 of the present invention are shown.

[0021] Figure 2 Backscattered SEM images of the hafnium zirconium titanium oxide-based thermal barrier / environmental barrier coating materials with low thermal expansion, low thermal conductivity and high fracture toughness prepared in Examples 1-3 of the present invention are shown. Detailed Implementation

[0022] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0023] In a first aspect, the present invention proposes a hafnium zirconium titanium oxide-based thermal barrier / environmental barrier coating material with low thermal expansion, low thermal conductivity and high fracture toughness, comprising: xHfO2•yZrO2•zTiO2; wherein, x=0%~65%; y=0%~65%, and x+y>0%; z=35%~55%; and x+y+z=1.

[0024] As an example, the value of x can be 0%, 5%, 10%, 15%, 20%, 25%, 30%, 40%, 50%, 60%, 65%, or any range between two of these values; the value of y can be 0%, 5%, 10%, 15%, 20%, 25%, 30%, 40%, 50%, 60%, 65%, or any range between two of these values; and the value of z can be 35%, 40%, 45%, 50%, 55%, or any range between two of these values. According to other embodiments of the invention, x = 15%~65%; and / or y = 15%~65%; and / or z = 35%~55%.

[0025] The hafnium zirconium titanium oxide-based thermal barrier / environmental barrier coating material of the present invention, based on HfO2, ZrO2, and TiO2, is made by controlling the relative content of HfO2, ZrO2 and TiO2, and the total amount and type of rare earth dopants, so that the thermal barrier / environmental barrier coating material has an orthorhombic phase and a small amount (<10 vol%) of monoclinic or cubic phase. While achieving low thermal expansion coefficient and low thermal conductivity, the thermal barrier / environmental barrier coating material has high fracture toughness.

[0026] In this embodiment, rare earth-doped hafnium zirconium titanium oxide material with excellent thermodynamic properties and high melting point is used as the target material. By controlling the relative content of hafnium zirconium titanium oxide and the total content of rare earth oxides, the target material is guaranteed to be dominated by orthorhombic phase, with a small amount of monoclinic or cubic phase.

[0027] According to an embodiment of the present invention, the hafnium zirconium titanium oxide-based low thermal expansion, low thermal conductivity, and high fracture toughness thermal barrier / environmental barrier coating material has a coefficient of thermal expansion α ≤ 9 × 10⁻⁶ at 1300 °C. -6 / K, for example, could be 9×10 -6 / K, 8×10 -6 / K, 7×10 -6 / K, 6×10 -6 / K, 5×10 -6 / K, 4×10 -6 / K, 3×10 -6 / K, 2×10 -6 / K, 1×10 -6 / K, 10 -7 / K or any value between the two, the coefficient of thermal expansion of the thermal barrier / environmental barrier coating material at 1300℃ is controlled within the above range. The thermal barrier / environmental barrier coating material has a low coefficient of thermal expansion, which can be well matched with the ceramic matrix composite substrate and effectively protect the ceramic matrix composite substrate.

[0028] The coefficient of thermal expansion α of hafnium zirconium titanium oxide-based thermal barrier / environmental barrier coating materials with low thermal expansion, low thermal conductivity, and high fracture toughness at 1300℃ can be determined using the following methods: According to the national standard GB / T 16535-2008-Test Method for Linear Thermal Expansion Coefficient of Fine Ceramics - Push Rod Method, the thermal expansion coefficient of the sample is tested using the push rod method, wherein the sample size is 25mm×5mm×5mm.

[0029] According to an embodiment of the present invention, the thermal conductivity κ of the hafnium zirconium titanium oxide-based low thermal expansion, low thermal conductivity, and high fracture toughness thermal barrier / environmental barrier coating material is ≤2.5 W·m. -1 ·K -1 For example, it could be 2.5 W·m -1 ·K -1 2.0 W·m -1 ·K -1 1.5 W·m -1 ·K -1 1.0 W·m -1 ·K -1 0.5 W·m -1 ·K -1The thermal conductivity of the thermal barrier / environmental barrier coating material is within the range of the above values, or any value between the two. The thermal barrier / environmental barrier coating material has a low thermal conductivity and can play a good thermal barrier role, protecting the inner ceramic layer and the CMC substrate.

[0030] The thermal conductivity κ of hafnium zirconium titanium oxide-based thermal barrier / environmental barrier coating materials with low thermal expansion, low thermal conductivity, and high fracture toughness can be determined using the following methods: The thermal diffusivity was determined by laser flare method, the specific heat capacity was calculated by Nemann-Kopp theorem, and the sample density was measured by Archimedes method. The thermal conductivity was then calculated from the thermal diffusivity, heat capacity, and density.

[0031] According to an embodiment of the present invention, the hafnium zirconium titanium oxide-based low thermal expansion, low thermal conductivity, and high fracture toughness thermal barrier / environmental barrier coating material includes an orthorhombic phase structure, wherein the volume content of the orthorhombic phase structure is 90%-100% based on the total volume of the phase structure of the hafnium zirconium titanium oxide-based low thermal expansion, low thermal conductivity, and high fracture toughness thermal barrier / environmental barrier coating material being 100%. For example, the values ​​could be 90%, 92%, 94%, 96%, 98%, 100%, or any range between two. As a result, the orthorhombic phase content in the thermal barrier / environmental barrier coating material is relatively high. The orthorhombic phase crystal structure has stronger anisotropy, and some crystal axes have negative thermal expansion, resulting in a lower overall coefficient of thermal expansion. In the orthorhombic phase lattice, each metal ion occupies the same site, exhibiting disorder and causing lattice distortion, which can achieve low thermal conductivity. The orthorhombic phase itself has good fracture toughness. After doping with trivalent and pentavalent ions, the grains are further refined to achieve high fracture toughness. This can ensure that the thermal barrier / environmental barrier coating material has high fracture toughness while achieving low coefficient of thermal expansion and low thermal conductivity.

[0032] According to embodiments of the present invention, the hafnium zirconium titanium oxide-based low thermal expansion, low thermal conductivity, and high fracture toughness thermal barrier / environmental barrier coating material comprises a monoclinic or cubic phase structure. Taking the total volume of the phase structure of the hafnium zirconium titanium oxide-based low thermal expansion, low thermal conductivity, and high fracture toughness thermal barrier / environmental barrier coating material as 100%, the content of the monoclinic or cubic phase is less than 10%. For example, it can be 9.9%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0%, or any value range between the two. The high coefficient of thermal expansion and relatively high thermal conductivity inherent in the monoclinic and cubic phases are detrimental to TEBC materials. The higher their content, the greater the tendency for the coefficient of thermal expansion and thermal conductivity to be higher, following the average law. Therefore, the content of the monoclinic and cubic phases should be limited. The monoclinic and cubic phases do not have a significant toughening mechanism, and their fracture toughness is not superior to that of orthorhombic crystals. Therefore, the low content of monoclinic or cubic phase in thermal barrier / environmental barrier coating materials can ensure high fracture toughness while achieving low coefficient of thermal expansion and low thermal conductivity.

[0033] It can be understood that the monoclinic or cubic phase content refers to the sum of the monoclinic and cubic phase contents in hafnium zirconium titanium oxide-based thermal barrier / environmental barrier coating materials with low thermal expansion, low thermal conductivity, and high fracture toughness.

[0034] It is understood that in the embodiments of the present invention, the content of orthorhombic phase, monoclinic phase or cubic phase is first determined by XRD analysis of phase composition, and then by backscattered electron mode (BSE) in SEM. In this mode, phases with different compositions exhibit different gray levels. Through image analysis, the volume ratio of the main phase and the volume ratio of the second phase, monoclinic phase to cubic phase, can be obtained.

[0035] According to an embodiment of the present invention, the hafnium zirconium titanium oxide-based low thermal expansion, low thermal conductivity, and high fracture toughness thermal barrier / environmental barrier coating material comprises: mA₂O₃•xHfO₂•yZrO₂•zTiO₂; wherein, A includes Yb 3+ Lu 3+ ,Sc 3+ 、Nd 3+ Eu 3+ 、Sm 3+ Gd 3+ Ho 3+ Dy 3+ Y 3+ Tm 3+ Er 3+ La 3+ At least one of the following: m = 0%~2.5%; x = 0%~65%; y = 0%~65%, and x+y>0%; z = 35%~55%; 2m+x+y+z=1.

[0036] As an example, m can be 0%, 0.5%, 1%, 1.5%, 2%, 2.5%, or any value between two of these; x can be 0%, 5%, 10%, 15%, 20%, 25%, 30%, 40%, 50%, 60%, 65%, or any value between two of these; y can be 0%, 5%, 10%, 15%, 20%, 25%, 30%, 40%, 50%, 60%, 65%, or any value between two of these; z can be 35%, 40%, 45%, 50%, 55%, or any value between two of these. According to other embodiments of the invention, it is further preferred that x = 15%~65%; and / or y = 15%~65%; and / or z = 35%~55%.

[0037] Therefore, trivalent rare earth metal ions A in hafnium zirconium titanium oxide-based thermal barrier / environmental barrier coating materials with low thermal expansion, low thermal conductivity, and high fracture toughness can refine grains and improve fracture toughness. By coordinating and controlling the amounts of A2O3, HfO2, ZrO2, and TiO2, it is possible to achieve low thermal expansion coefficient and low thermal conductivity while ensuring high fracture toughness in the thermal barrier / environmental barrier coating materials.

[0038] According to an embodiment of the present invention, the hafnium zirconium titanium oxide-based low thermal expansion, low thermal conductivity, and high fracture toughness thermal barrier / environmental barrier coating material comprises: mA₂O₃•nB₂O₅•xHfO₂•yZrO₂•zTiO₂; wherein, A comprises at least one trivalent rare earth metal ion; B comprises Nb 5+ Ta 5+ At least one of the following: m = 0%~2.5%; n = 0%~2.5%; x = 0%~65%; y = 0%~65%, and x+y>0%; z = 35%~55%; 2m+2n+x+y+z=1.

[0039] As an example, m can be 0%, 0.5%, 1%, 1.5%, 2%, 2.5%, or any value between two of these; n can be 0%, 0.5%, 1%, 1.5%, 2%, 2.5%, or any value between two of these; x can be 0%, 5%, 10%, 15%, 20%, 25%, 30%, 40%, 50%, 60%, 65%, or any value between two of these; y can be 0%, 5%, 10%, 15%, 20%, 25%, 30%, 40%, 50%, 60%, 65%, or any value between two of these; z can be 35%, 40%, 45%, 50%, 55%, or any value between two of these. According to other embodiments of the invention, it is further preferred that x = 15%~65%; and / or y = 15%~65%; and / or z = 35%~55%.

[0040] It can be understood that in the above chemical formula, m, n, x, y, z can represent the molar proportion of each component in the hafnium zirconium titanium oxide-based thermal barrier / environmental barrier coating material with low thermal expansion, low thermal conductivity, and high fracture toughness.

[0041] Therefore, the combined action of trivalent rare earth metal ions A and pentavalent metal ions B can refine the grains and improve fracture toughness. By coordinating and controlling the amounts of A2O3, B2O5, HfO2, ZrO2, and TiO2, it is possible to achieve low thermal expansion coefficient and low thermal conductivity while ensuring high fracture toughness in thermal barrier / environmental barrier coating materials.

[0042] In a second aspect of the invention, a method for preparing the hafnium zirconium titanium oxide-based thermal barrier / environmental barrier coating material with low thermal expansion, low thermal conductivity, and high fracture toughness as described in the first aspect is proposed, the method comprising: S1. Mix HfO2, ZrO2, and TiO2 in a certain molar ratio to obtain a precursor mixture.

[0043] It is understandable that when the hafnium zirconium titanium oxide-based thermal barrier / environmental barrier coating material contains A2O3 and / or B2O5, the precursor mixture also contains A2O3 and / or B2O5.

[0044] It is understandable that when the hafnium zirconium titanium oxide-based thermal barrier / environmental barrier coating material does not contain either HfO2 or ZrO2, the corresponding raw materials are not added.

[0045] According to some embodiments of the present invention, before the step of mixing the raw material components to obtain the precursor mixture, the raw material components may be calcined to remove impurities such as water and carbon dioxide adsorbed by the raw material components. For example, the raw material components are calcined at 1100°C for 1-3 hours. The calcination time can be 1 hour, 2 hours, 3 hours, or any value range between the two.

[0046] S2. The precursor mixture and solvent are ball-milled to obtain a mixed slurry.

[0047] According to some embodiments of the present invention, ball milling can be performed using zirconia balls and a precursor mixture. Exemplarily, the mass ratio of the precursor mixture to the zirconia balls is between 1:10 and 1:20, and the ball milling speed is between 200 rpm and 300 rpm. The solvent can be alcohol or deionized water. As an example, the mass ratio can be 1:10, 1:12, 1:15, 1:18, 1:20, or any value range between the two; the ball milling speed can be 200 rpm, 250 rpm, 300 rpm, or any value range between the two.

[0048] S3. After solid-liquid separation of the mixed slurry, block material is obtained. After sieving the block material, it is pre-pressed and then calcined at 1450℃-1700℃ for 5h-10h to obtain hafnium zirconium titanium oxide-based thermal barrier / environmental barrier coating material with low thermal expansion, low thermal conductivity and high fracture toughness.

[0049] As an example, the calcination temperature can be 1450℃, 1500℃, 1550℃, 1600℃, 1700℃ or any range between the two, and the calcination time can be 5h, 6h, 7h, 8h, 9h, 10h or any range between the two.

[0050] High-density thermal barrier / environmental barrier ceramic coating materials can be obtained by calcining at 1450℃-1700℃ for 5-10 hours. These materials can be used as EB-PVD targets (electron beam physical vapor deposition targets) or as high-temperature structural materials.

[0051] According to some embodiments of the present invention, the step of pre-compressing the obtained block material includes: sieving the ball-milled powder, granulating it by spraying, and then calcining it at 1350-1500℃ for 1-3 hours (for example, the calcination temperature can be 1350℃, 1400℃, 1450℃, 1500℃ or any range between two), and the calcination time can be 1 hour, 2 hours, 3 hours or any range between two). Subsequently, the powder is sieved to select particles with a size of 30-110 micrometers (the size can be 30 micrometers, 50 micrometers, 70 micrometers, 90 micrometers, 100 micrometers, 110 micrometers or any range between two), at which point the 30-110 micrometer particles can be used for atmospheric plasma spraying. The pre-compressing can be performed using cold isostatic pressing.

[0052] In summary, the method for preparing hafnium zirconium titanium oxide-based thermal barrier / environmental barrier coating materials with low thermal expansion, low thermal conductivity, and high fracture toughness proposed in this invention can synthesize thermal barrier / environmental barrier coating materials through a simple solid-state reaction. By controlling the relative content of hafnium zirconium titanium oxide and the total content of rare earth oxides, the target material is ensured to be dominated by orthorhombic phase, containing a small amount of monoclinic or cubic phase, which can improve the service temperature of the substrate and has the advantages of high melting point, low coefficient of thermal expansion, low thermal conductivity, and high fracture toughness.

[0053] In a third aspect, the present invention provides a thermal barrier / environmental barrier coating comprising the hafnium zirconium titanium oxide-based thermal barrier / environmental barrier coating material with low thermal expansion, low thermal conductivity, and high fracture toughness described in the first aspect of this application. Thus, this thermal barrier / environmental barrier coating simultaneously possesses the advantages of high melting point, low coefficient of thermal expansion, low thermal conductivity, and high fracture toughness, making it compatible with ceramic matrix composite substrates with low coefficients of thermal expansion.

[0054] According to some embodiments of the present invention, this application provides a thermal barrier / environmental barrier coating, which is formed by granulation and deposition of the thermal barrier / environmental barrier coating material of the first aspect of the present application.

[0055] Thermal barrier / environmental barrier coating materials can be deposited using several techniques. Deposition methods include, but are not limited to, thermal spraying (plasma spraying, flame spraying, and HVOF spraying), sputtering, and electron beam physical vapor deposition (EBPVD).

[0056] In a fourth aspect, the present invention provides an engine comprising the thermal barrier / environmental barrier coating described in the third aspect. Thus, the thermal barrier / environmental barrier coating, applied to the ceramic matrix composite material of the engine, effectively protects the ceramic matrix composite material from corrosion and damage, thereby extending the engine's lifespan.

[0057] According to some embodiments of the present invention, the engine includes an aircraft engine.

[0058] The present disclosure will be explained below with reference to embodiments. Those skilled in the art will understand that the following embodiments are for illustrative purposes only and should not be construed as limiting the scope of the disclosure. Where specific techniques or conditions are not specified in the embodiments, they are performed in accordance with the techniques or conditions described in the literature in the art or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0059] Example 1 (a) The raw material components A2O3, B2O5, HfO2, ZrO2 and TiO2 are calcined at 1100℃ for 1-3 hours to remove adsorbed water and carbon dioxide and other impurities; (b) Weigh the dried A2O3, B2O5, HfO2, ZrO2 and TiO2 in a specific ratio, and the contents are shown in Table 1; (c) The weighed powder is ball-milled and mixed, wherein the ball-milling media are zirconium oxide balls and alcohol, and the ball-milling time is 8 hours.

[0060] (d) Separate the ball-milled slurry, grind and sieve the obtained blocks, and then calcine them at 1200℃ for 8 hours; (e) The obtained powder is ball-milled again for 7 hours, then sieved and calcined at 1500°C for 7 hours to obtain hafnium zirconium titanium oxide-based powder. (f) The powder after ball milling in step (e) is passed through a 250-mesh sieve, spray granulated, calcined at 1400℃ for 2 hours, and then sieved to select particles with a size of 30-110 micrometers, which can be used for atmospheric plasma spraying. (g) Using a grinding wheel with a diameter of 15 mm, the powder after ball milling in step (e) is pre-pressed into shape with a pressure of 7 kg; the obtained blank is held at 250 MPa for 90 seconds using cold isostatic pressing. (h) Finally, the sample was calcined at 1550 °C for 8 hours to obtain a high-density bulk sample.

[0061] Examples 2-6 Similar to the preparation process in Example 1, the difference lies in the different relative contents of hafnium oxide, zirconium oxide and titanium oxide, and the different doping ratios of rare earth oxides. The composition of the hafnium-zirconium-titanium oxide-based low thermal expansion, low thermal conductivity and high fracture toughness thermal barrier / environmental barrier ceramic materials in Examples 2 to 6 is shown in Table 1.

[0062] Comparative Example 1 The preparation process is similar to that of Example 1, except that the proportion of rare earth ions is different and titanium is not contained, resulting in a typical high-melting-point rare earth stable hafnium oxide / zirconium material. The composition of Comparative Example 1 is shown in Table 1.

[0063] Comparative Example 2 The preparation process is similar to that of Example 1, except that the proportion of rare earth ions is different and titanium is not contained, resulting in a typical high-melting-point rare earth hafnium / zirconate material. The composition of Comparative Example 1 is shown in Table 1.

[0064] Comparative Examples 3-4 The preparation process is similar to that of Comparative Example 1, except that the TiO2 content is different, as shown in Table 1.

[0065] Table 1

[0066] The XRD patterns of the hafnium zirconium titanium oxide-based thermal barrier / environmental barrier coating materials with low thermal expansion, low thermal conductivity, and high fracture toughness prepared in Examples 1-3 and Comparative Examples 1-2 are shown below. Figure 1 As shown, in Examples 1-3 of this application, the volume content of the orthorhombic phase structure is relatively high, while the volume content of the monoclinic or cubic phase structure is relatively low. In Comparative Examples 1-2, the volume content of the orthorhombic phase structure is relatively low.

[0067] Backscattered SEM images of the hafnium zirconium titanium oxide-based thermal barrier / environmental barrier coating materials with low thermal expansion, low thermal conductivity, and high fracture toughness prepared in Examples 1-3 are shown below. Figure 2 As shown, in embodiments 1-3 of this application, the volume content of the orthorhombic phase structure is relatively high, while the volume content of the monoclinic or cubic phase structure is relatively low.

[0068] Testing and Analysis 1. The thermal expansion coefficient of the sample was tested according to the national standard GB / T 16535-2008-Test Method for Linear Thermal Expansion Coefficient of Fine Ceramics - Push Rod Method. The sample size was 25mm×5mm×5mm. The test results are shown in Table 2.

[0069] 2. The volume ratios of orthorhombic, monoclinic, and cubic phases were obtained by analyzing the backscattered SEM images of the test samples.

[0070] 3. Determination of thermal conductivity: The thermal diffusivity was determined by laser flare method, the specific heat capacity was calculated by Nemann-Kopp theorem, and the sample density was measured by Archimedes method. The thermal conductivity was then calculated from the thermal diffusivity, heat capacity, and density.

[0071] 4. Determination of fracture toughness: Fracture toughness was tested using the single-sided notched beam method, with a three-point bending loading method.

[0072] Table 2

[0073] Table 3

[0074] As can be seen from the results in Tables 1-3, the hafnium zirconium titanium oxide-based thermal barrier / environmental barrier coating material with low thermal expansion, low thermal conductivity and high fracture toughness prepared by the embodiments of the present invention has the advantages of high melting point, low coefficient of thermal expansion, low thermal conductivity and high fracture toughness.

[0075] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," "some implementations," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0076] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A hafnium zirconium titanium oxide-based thermal barrier / environmental barrier coating material with low thermal expansion, low thermal conductivity, and high fracture toughness, characterized in that, The thermal barrier / environmental barrier coating material includes: xHfO2•yZrO2•zTiO2; wherein, x=0%~65%; y=0%~65%, and x+y>0%; z=35%~55%; x+y+z=1.

2. The hafnium zirconium titanium oxide-based thermal barrier / environmental barrier coating material with low thermal expansion, low thermal conductivity, and high fracture toughness according to claim 1, characterized in that, The hafnium zirconium titanium oxide-based thermal barrier / environmental barrier coating material, characterized by low thermal expansion, low thermal conductivity, and high fracture toughness, exhibits a coefficient of thermal expansion α ≤ 9 × 10⁻⁶ at 1300℃. -6 / K; and / or, The hafnium zirconium titanium oxide-based thermal barrier / environmental barrier coating material exhibits a thermal conductivity κ ≤ 2.5 W·m. -1 ·K -1 .

3. The hafnium zirconium titanium oxide-based thermal barrier / environmental barrier coating material with low thermal expansion, low thermal conductivity, and high fracture toughness according to claim 1, characterized in that, The hafnium zirconium titanium oxide-based low thermal expansion, low thermal conductivity, and high fracture toughness thermal barrier / environmental barrier coating material includes an orthorhombic phase structure. With the total volume of the phase structure of the hafnium zirconium titanium oxide-based low thermal expansion, low thermal conductivity, and high fracture toughness thermal barrier / environmental barrier coating material being 100%, the volume content of the orthorhombic phase structure is 90%-100%.

4. The hafnium zirconium titanium oxide-based thermal barrier / environmental barrier coating material with low thermal expansion, low thermal conductivity, and high fracture toughness according to claim 1, characterized in that, The hafnium zirconium titanium oxide-based low thermal expansion, low thermal conductivity, and high fracture toughness thermal barrier / environmental barrier coating material comprises a monoclinic or cubic phase structure. Based on the total volume of the phase structure of the hafnium zirconium titanium oxide-based low thermal expansion, low thermal conductivity, and high fracture toughness thermal barrier / environmental barrier coating material as 100%, the content of the monoclinic or cubic phase is less than 10%.

5. The hafnium zirconium titanium oxide-based thermal barrier / environmental barrier coating material with low thermal expansion, low thermal conductivity, and high fracture toughness according to claim 1, characterized in that, The hafnium zirconium titanium oxide-based thermal barrier / environmental barrier coating material with low thermal expansion, low thermal conductivity, and high fracture toughness comprises: mA₂O₃•xHfO₂•yZrO₂•zTiO₂; wherein A includes Yb 3+ Lu 3+ ,Sc 3+ 、Nd 3+ Eu 3+ 、Sm 3+ Gd 3+ Ho 3 + Dy 3+ Y 3+ Tm 3+ Er 3+ La 3+ At least one of the following: m = 0%~2.5%; x = 0%~65%; y = 0%~65%, and x+y>0%; z = 35%~55%; 2m+x+y+z=1.

6. The hafnium zirconium titanium oxide-based thermal barrier / environmental barrier coating material with low thermal expansion, low thermal conductivity, and high fracture toughness according to claim 1, characterized in that, The hafnium zirconium titanium oxide-based low thermal expansion, low thermal conductivity, and high fracture toughness thermal barrier / environmental barrier coating material comprises: mA₂O₃•nB₂O₅•xHfO₂•yZrO₂•zTiO₂; wherein A includes at least one trivalent rare earth metal ion; B includes Nb 5+ Ta 5+ At least one of the following: m = 0%~2.5%; n = 0%~2.5%; x = 0%~65%; y = 0%~65%, and x+y>0%; z = 35%~55%; 2m+2n+x+y+z=1.

7. The hafnium zirconium titanium oxide-based thermal barrier / environmental barrier coating material with low thermal expansion, low thermal conductivity, and high fracture toughness according to any one of claims 1-6, characterized in that, x = 15%~65%; and / or, y = 15%~65%; and / or, z=35%~55%。 8. A method for preparing a hafnium zirconium titanium oxide-based thermal barrier / environmental barrier coating material with low thermal expansion, low thermal conductivity, and high fracture toughness as described in any one of claims 1-7, characterized in that, include: HfO2, ZrO2, and TiO2 were mixed in a specific molar ratio to obtain a precursor mixture. The precursor mixture was ball-milled with a solvent to obtain a mixed slurry; After solid-liquid separation of the mixed slurry, block material is obtained. After sieving, the block material is pre-pressed and then calcined at 1450℃-1700℃ for 5h-10h to obtain a hafnium zirconium titanium oxide-based thermal barrier / environmental barrier coating material with low thermal expansion, low thermal conductivity and high fracture toughness.

9. A thermal barrier / environmental barrier coating, characterized in that, The thermal barrier / environmental barrier coating comprises any one of the hafnium zirconium titanium oxide-based thermal barrier / environmental barrier coating materials of claims 1-7, characterized by low thermal expansion, low thermal conductivity, and high fracture toughness.

10. An engine, characterized in that, The engine includes the thermal barrier / environmental barrier coating as described in claim 9.

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