A ceramic material with high thermal expansion coefficient and sinter resistance, and a preparation method and application of a sintered body

Abstract

This invention relates to the field of ceramic materials, specifically to a high thermal expansion coefficient resistant ceramic material and its preparation method and application in sintered bodies; the high thermal expansion coefficient resistant ceramic material mainly consists of LaYb(Hf) having defective fluorite and pyrochlore structures. 0.3 Ce 0.2 Zr 0.5 )2O7. The ceramic material of this invention has a stable structure and can maintain a high porosity even after high-temperature heat treatment. It can significantly reduce thermal conductivity, exert a heat insulation effect, and improve the upper limit of the material's temperature resistance. The coefficient of thermal expansion of the material is significantly improved, which can alleviate thermal mismatch and local thermal stress concentration during high-temperature service, reduce crack initiation and propagation in the material, reduce cracking and spalling, and extend the service life of rare earth zirconate products.

Description

Technical Field

[0001] This invention relates to the field of ceramic materials, specifically to a ceramic material with a high coefficient of thermal expansion and a method for preparing and applying sintered bodies. Background Technology

[0002] To meet the high-temperature protection requirements of aerospace engines and high-temperature gas turbines, a ceramic coating with excellent thermal insulation and mechanical properties is often used to improve engine operating temperature and efficiency. In this field, yttrium oxide (Y₂O₃) partially stabilized zirconia (YSZ), especially 7wt%~8wt% yttrium oxide partially stabilized zirconia (8YSZ), is currently the most widely used, most thoroughly studied, and best-performing material in terms of overall performance. Studies show that the lifespan of YSZ initially increases with increasing Y₂O₃ content, then decreases. Furthermore, the thermal cycling life of the coating reaches its peak when the Y₂O₃ content reaches 7wt%~8wt%. The coefficient of thermal expansion of the YSZ system decreases sharply with increasing Y₂O₃ content, resulting in poor thermal cycling life for other YSZ compositions. Conversely, when the Y₂O₃ content is too low, the coating may develop an unstable monoclinic phase (M) after thermal cycling, leading to a reduction in coating life. 8YSZ has a metastable tetragonal (T) phase structure and is very stable at temperatures of 1200℃ and below; at the same time, it has a high melting point of 3000 K, very low thermal conductivity (approximately 2.1 W / m·K, 1000℃), and a very high coefficient of thermal expansion (9~11×10⁻⁶). -6 K -1 In addition, YSZ has good chemical compatibility and excellent mechanical properties.

[0003] However, 8YSZ materials can only be used long-term at temperatures below 1200℃. The T' phase of 8YSZ is a metastable structure. When its service temperature exceeds 1200℃, the T' phase will gradually decompose into a T-lean phase with low Y2O3 content and a cubic phase (C) with high Y2O3 content. When the Y2O3 content in the T-lean phase is less than 1.5 mol%, the T-lean phase will transform into the M phase during cooling. This phase transformation is accompanied by a volume expansion of ~3.5%, which leads to the initiation and propagation of cracks in the coating, ultimately causing coating failure. In addition, when 8YSZ is used at higher temperatures, severe sintering occurs, causing changes in the microstructure of the coating and the generation of sintering stress, thereby accelerating coating failure.

[0004] To address this issue, researchers have developed numerous novel materials in recent years, among which rare earth zirconates stand out. These exhibit excellent high-temperature stability, with a sintering temperature resistance of 1400-1500℃, 200-300℃ higher than 8YSZ. However, they possess a low coefficient of thermal expansion. During high-temperature service, coatings made from RE2Zr2O7 materials are prone to thermal mismatch and localized thermal stress concentration. Furthermore, their poor toughness is insufficient to compensate for the losses caused by stress concentration, leading to the initiation and rapid propagation of coating cracks. This severely impacts the service life of the coating and significantly limits its practical engineering applications. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the above-mentioned defects of the prior art and provide a method for preparing and applying rare earth zirconate ceramic materials and sintered bodies with high thermal expansion coefficient.

[0006] The technical solution adopted by this invention to solve its technical problem is as follows: a ceramic material with high thermal expansion coefficient and sintering resistance, the main component of which is LaYb(Hf) having defective fluorite structure and pyrochlore structure. 0.3 Ce 0.2 Zr 0.5 )2O7.

[0007] Based on the same inventive concept, this invention also provides a method for preparing the high thermal expansion coefficient sintering-resistant ceramic material, comprising: according to LaYb(Hf 0.3 Ce 0.2 Zr 0.5 The chemical ratio of raw material powder to 2O7 is weighed and ball-milled to obtain ball milling material A; calcined at 1100~1300℃ for 2~3h to obtain calcined material; the calcined material is ball-milled to obtain ball milling material B; the ball milling material B is ground to a particle size of 30~80um and calcined at 1300~1500℃ for 3~4h to obtain LaYb(Hf) 0.3 Ce 0.2 Zr 0.5 )2O7 ceramic powder.

[0008] Preferably, the raw material powder is an oxide powder.

[0009] Preferably, the ball milling time for the raw material powder is 3 to 6 hours.

[0010] Preferably, the ball milling time for the calcined material is 6-10 hours.

[0011] Preferably, the raw material powders are pre-calcined to remove impurities.

[0012] Based on the same inventive concept, this invention also provides a sintered body of the high thermal expansion coefficient resistant ceramic material or a sintered body of the material obtained by the preparation method of the high thermal expansion coefficient resistant ceramic material, wherein the thermal expansion coefficient is 10.7 × 10⁻⁶. -6 K -1 above.

[0013] The method for preparing the sintered body includes: ... 0.3 Ce 0.2 Zr 0.5 )2O7 powder is pressed into a blank to obtain a green body; the green body is sintered to obtain a sintered body.

[0014] Preferably, the pressing process involves: first pre-pressing the powder under a pressure of 80MPa to 120MPa, and then cold isostatic pressing at 150MPa to 220MPa.

[0015] Preferably, the pre-compression time is 1 min to 2 min, and the holding time for cold isostatic pressing is 2 min to 3 min.

[0016] Preferably, the sintering temperature is 1400~1600℃, and the sintering holding time is 6~10h.

[0017] Based on the same inventive concept, the present invention also provides a coating of the high thermal expansion coefficient anti-sintering ceramic material or a coating of the material obtained by the preparation method of the high thermal expansion coefficient anti-sintering ceramic material, wherein the porosity after treatment at 1400℃ is more than 15%.

[0018] Based on the same inventive concept, the present invention also provides the application of the high thermal expansion coefficient anti-sintering ceramic material or the material obtained by the preparation method of the high thermal expansion coefficient anti-sintering ceramic material or the sintered body or the material obtained by the preparation method of the sintered body or the coating in heat insulation.

[0019] Based on the same inventive concept, the present invention also provides the application of the high thermal expansion coefficient anti-sintering ceramic material or the material obtained by the preparation method of the high thermal expansion coefficient anti-sintering ceramic material or the sintered body or the material obtained by the preparation method of the sintered body or the coating in thermal barrier coatings.

[0020] The present invention has the following beneficial effects: This invention develops LaYb(Hf) whose main components are defective fluorite and pyrochlore structures. 0.3 Ce 0.2 Zr 0.5Rare earth zirconate ceramic material has a high coefficient of thermal expansion and anti-sintering properties; the material has a stable structure and can maintain a high porosity even after high-temperature heat treatment, which can significantly reduce thermal conductivity, exert heat insulation effect, and improve the upper limit of the material's temperature resistance; the material's coefficient of thermal expansion is significantly improved, which can alleviate thermal mismatch and local thermal stress concentration during high-temperature service, reduce crack initiation and propagation in the material, reduce cracking and spalling, and extend the service life of rare earth zirconate products.

[0021] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0022] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is LaYb(Hf) from Embodiment 1 of the present invention. 0.3 Ce 0.2 Zr 0.5 XRD pattern of 2O7 material; Figure 2 These are curves showing the change in the coefficient of thermal expansion of the sintered bodies of Embodiment 1, Comparative Example 1, and Comparative Example 2 of the present invention as a function of temperature. Detailed Implementation

[0023] To make the objectives, solutions, and beneficial technologies of this invention clearer, the invention will be further described in detail below with reference to embodiments and accompanying drawings. It should be noted that the embodiments described in this specification are merely illustrative of the invention and are not intended to limit the invention.

[0024] For simplicity, this paper only explicitly discloses some numerical ranges. However, any lower limit can be combined with any upper limit to form an undefined range; and any lower limit can be combined with other lower limits to form an undefined range, just as any upper limit can be combined with any other upper limit to form an undefined range. Furthermore, although not explicitly stated, every point or individual value between the endpoints of a range is included within that range. Therefore, each point or individual value can serve as its own lower or upper limit and be combined with any other point or individual value, or with other lower or upper limits, to form an undefined range.

[0025] In this description, it should be noted that, unless otherwise stated, "above" and "below" include the stated number, "multiple" in "one or more" means two or more, and "more than" in "one or more" means two or more.

[0026] Embodiments of the present invention provide a high thermal expansion coefficient and sintering-resistant ceramic material, the main component of which is LaYb(Hf) having a defective fluorite structure and a pyrochlore structure. 0.3 Ce 0.2 Zr 0.5 )2O7.

[0027] This invention, LaYb(Hf) 0.3 Ce 0.2 Zr 0.5 Hafnium-zirconium (A2B2O7) ceramic materials belong to high-entropy multi-element rare earth zirconium composite salts: strictly conforming to the general formula A2B2O7 pyrochlore-type / defective fluorite structure and pyrochlore structure; the A site adopts La 3+ Yb 3+ Double rare earth co-doping, with Hf at the B site. 4+ Ce 4+ Zr 4+ This material is a multi-element tetravalent cation high-entropy solid solution system. The Zr content inherits the advantages of rare earth zirconates, such as easy sintering, moderate cost, and good thermal expansion matching. The Hf content inherits the advantages of rare earth hafnium ions, such as ultra-high temperature stability, low thermal conductivity, resistance to CMAS (Chemical Oxide-Resistant System), and resistance to water vapor corrosion. The introduction of Ce further regulates thermal conductivity and thermal expansion, enhancing high-temperature phase transformation stability. This material exhibits a high coefficient of thermal expansion and anti-sintering properties. Its stable structure, after heat treatment at 1400℃, maintains a porosity above 15%, significantly reducing thermal conductivity, providing insulation, and increasing the material's upper temperature resistance limit. The increased coefficient of thermal expansion alleviates thermal mismatch and localized thermal stress concentration during high-temperature service, reducing crack initiation and propagation, minimizing cracking and spalling, and extending the lifespan of rare earth zirconate products.

[0028] This invention also provides a method for preparing the high thermal expansion coefficient sintering-resistant ceramic material, comprising: according to LaYb(Hf 0.3 Ce 0.2 Zr 0.5 The chemical ratio of raw material powder to 2O7 is weighed and ball-milled to obtain ball milling material A; calcined at 1100~1300℃ for 2~3h to obtain calcined material; the calcined material is ball-milled to obtain ball milling material B; the ball milling material B is ground to a particle size of 30~80um and calcined at 1300~1500℃ for 3~4h to obtain LaYb(Hf) 0.3 Ce 0.2 Zr 0.5 )2O7 ceramic powder.

[0029] In some embodiments of the present invention, the raw material powder is an oxide powder.

[0030] In some embodiments of the present invention, the raw material powder includes La2O3, Yb2O3, CeO2, HfO2 and ZrO2.

[0031] In some embodiments of the present invention, the ball milling time for the raw material powder is 3 to 6 hours.

[0032] In some embodiments of the present invention, the calcined material is ball-milled for 6 to 10 hours.

[0033] In some embodiments of the present invention, the raw material powders are pre-calcined to remove impurities.

[0034] In some embodiments of the present invention, the calcination and impurity removal temperature is 1000~1200℃; at this temperature, the raw material will not deteriorate, and the impurity removal effect is good, capable of removing moisture, volatile matter, etc.

[0035] This invention also provides a sintered body of the high thermal expansion coefficient resistant ceramic material or a sintered body of the material obtained by the preparation method of the high thermal expansion coefficient resistant ceramic material, wherein the thermal expansion coefficient is 10.7 × 10⁻⁶. -6 K -1 above.

[0036] The method for preparing the sintered body includes: ... 0.3 Ce 0.2 Zr 0.5 )2O7 powder is pressed into a blank to obtain a green body; the green body is sintered to obtain a sintered body.

[0037] In some embodiments of the present invention, the pressing and molding process is as follows: the powder is first pre-pressed under a pressure of 80MPa to 120MPa, and then cold isostatically pressed at 150MPa to 220MPa.

[0038] In some embodiments of the present invention, the pre-compression time is 1 min to 2 min, and the holding time of cold isostatic pressing is 2 min to 3 min.

[0039] In some embodiments of the present invention, the sintering temperature is 1400~1600℃, and the sintering holding time is 6~10h.

[0040] The present invention also provides a coating of the high thermal expansion coefficient anti-sintering ceramic material or a coating of the material obtained by the preparation method of the high thermal expansion coefficient anti-sintering ceramic material, wherein the porosity after treatment at 1400°C is more than 15%.

[0041] In some embodiments of the present invention, the thickness of the coating is 100~800 μm.

[0042] The present invention also provides the application of the high thermal expansion coefficient anti-sintering ceramic material, or the material obtained by the preparation method of the high thermal expansion coefficient anti-sintering ceramic material, or the sintered body, or the material obtained by the preparation method of the sintered body, or the coating in heat insulation.

[0043] LaYb(Hf 0.3 Ce 0.2 Zr 0.5 2O7 ceramic materials have anti-sintering properties, and after sintering, they have high porosity, which can significantly reduce thermal conductivity, exert heat insulation effect, and improve the upper limit of the material's temperature resistance.

[0044] The present invention also provides the application of the high thermal expansion coefficient anti-sintering ceramic material, or the material obtained by the preparation method of the high thermal expansion coefficient anti-sintering ceramic material, or the sintered body, or the material obtained by the preparation method of the sintered body, or the coating in thermal barrier coatings.

[0045] LaYb(Hf 0.3 Ce 0.2 Zr 0.5 Rare earth zirconate materials have a high coefficient of thermal expansion, which can alleviate thermal mismatch and local thermal stress concentration during high-temperature service, reduce crack initiation and propagation in the material, reduce cracking and spalling, and extend the service life of rare earth zirconate products. They are particularly suitable for thermal barrier coatings.

[0046] Example The following examples describe the disclosure of this invention in more detail. These examples are merely illustrative, as various modifications and variations will be apparent to those skilled in the art within the scope of this disclosure. Unless otherwise stated, all parts, percentages, and ratios reported in the following examples are based on weight. Unless otherwise stated, all reagents used in the examples are available commercially or synthesized using conventional methods and are ready for use without further processing. Unless otherwise stated, all instruments used in the examples are available commercially.

[0047] Example 1 The high thermal expansion coefficient and sintering-resistant ceramic material of this embodiment is mainly composed of LaYb(Hf) with defective fluorite and pyrochlore structures. 0.3 Ce 0.2 Zr 0.5 )2O7.

[0048] The method for preparing the high thermal expansion coefficient sintering-resistant ceramic material described in this embodiment includes: (1) Weigh the raw materials: according to LaYb(Hf) 0.3 Ce 0.2 Zr 0.5The chemical dosage ratio of )2O7 was determined by weighing La2O3, Yb2O3, CeO2, HfO2 and ZrO2 as raw material powders respectively; (2) Impurity removal: The raw material powders are calcined and impurity removed in advance at a temperature of 1100℃ for 1 hour; (3) Ball milling and calcination I: The raw material powder after impurity removal is ball milled and mixed (the ball milling time of the raw material powder is 4h) to obtain ball milling material A; calcined at 1200℃ for 2h to obtain calcined material; (4) Ball milling and calcination II: The calcined material is ball milled (the ball milling time is 8 hours) to obtain ball mill material B; the ball mill material B is ground to a particle size of 30~80 μm, and calcined at 1400℃ for 4 hours to obtain LaYb(Hf) 0.3 Ce 0.2 Zr 0.5 )2O7 ceramic powder.

[0049] LaYb(Hf 0.3 Ce 0.2 Zr 0.5 The XRD pattern of 2O7 ceramic powder is shown below. Figure 1 As shown in the figure, the sintered body in this embodiment has a defective fluorite structure and a pyrochlore structure.

[0050] LaYb(Hf) 0.3 Ce 0.2 Zr 0.5 LaYb(Hf)₂O₇ ceramic powder is used to form a sintered body. The method for preparing the sintered body includes: [The text abruptly ends here, so the translation also ends here.] 0.3 Ce 0.2 Zr 0.5 )2O7 ceramic powder is pressed into shape (the powder is first pre-pressed under a pressure of 100MPa for 1min, and then cold isostatically pressed at 200MPa for 2min) to obtain a green body; the green body is sintered at 1500℃ for 8h to obtain a sintered body.

[0051] LaYb(Hf) was applied using a thermal spraying method. 0.3 Ce 0.2 Zr 0.5 The coating is made of 2O7 ceramic powder with a thickness of 300~400um.

[0052] Example 2 The high thermal expansion coefficient and sintering-resistant ceramic material of this embodiment is mainly composed of LaYb(Hf) with defective fluorite and pyrochlore structures. 0.3 Ce 0.2 Zr 0.5 )2O7.

[0053] The method for preparing the high thermal expansion coefficient resistant sintering ceramic material described in this embodiment includes: (1) Weigh the raw materials: according to LaYb(Hf) 0.3 Ce 0.2 Zr 0.5 The chemical dosage ratio of )2O7 was determined by weighing La2O3, Yb2O3, CeO2, HfO2 and ZrO2 as raw material powders respectively; (2) Impurity removal: The raw material powders are calcined and impurity removed in advance at a temperature of 1000℃ for 1 hour; (3) Ball milling and calcination I: The raw material powder after impurity removal is ball milled and mixed (the ball milling time of the raw material powder is 3h) to obtain ball milling material A; calcined at 1100℃ for 2h to obtain calcined material; (4) Ball milling and calcination II: The calcined material is ball milled (the ball milling time is 6 hours) to obtain ball mill material B; the ball mill material B is ground to a particle size of 30~80 μm, and calcined at 1300℃ for 3 hours to obtain LaYb(Hf) 0.3 Ce 0.2 Zr 0.5 )2O7 ceramic powder.

[0054] LaYb(Hf 0.3 Ce 0.2 Zr 0.5 The 2O7 ceramic powder, as confirmed by XRD analysis, has a defective fluorite structure and a pyrochlore structure.

[0055] LaYb(Hf) 0.3 Ce 0.2 Zr 0.5 LaYb(Hf)₂O₇ ceramic powder is used to form a sintered body. The method for preparing the sintered body includes: [The text abruptly ends here, so the translation also ends here.] 0.3 Ce 0.2 Zr 0.5 )2O7 ceramic powder is pressed into shape (the powder is first pre-pressed under 80MPa pressure for 1min, and then cold isostatic pressing is performed at 180MPa for 2min) to obtain a green body; the green body is sintered at 1400℃ for 6h to obtain a sintered body.

[0056] LaYb(Hf) was applied using a thermal spraying method. 0.3 Ce 0.2 Zr 0.5 The coating is made of 2O7 ceramic powder with a thickness of 300~400um.

[0057] Example 3 The high thermal expansion coefficient and sintering-resistant ceramic material of this embodiment is mainly composed of LaYb(Hf) with defective fluorite and pyrochlore structures. 0.3 Ce0.2 Zr 0.5 )2O7.

[0058] The method for preparing the high thermal expansion coefficient resistant sintering ceramic material described in this embodiment includes: (1) Weigh the raw materials: according to LaYb(Hf) 0.3 Ce 0.2 Zr 0.5 The chemical dosage ratio of )2O7 was determined by weighing La2O3, Yb2O3, CeO2, HfO2 and ZrO2 as raw material powders respectively; (2) Impurity removal: The raw material powders are calcined and impurity removed in advance at a temperature of 1200℃ for 1 hour; (3) Ball milling and calcination I: The raw material powder after impurity removal is ball milled and mixed (the ball milling time of the raw material powder is 6h) to obtain ball milling material A; calcined at 1300℃ for 3h to obtain calcined material; (4) Ball milling and calcination II: The calcined material is ball milled (the ball milling time is 10 h) to obtain ball mill material B; the ball mill material B is ground to a particle size of 30~80 μm, and calcined at 1500℃ for 4 h to obtain LaYb(Hf) 0.3 Ce 0.2 Zr 0.5 )2O7 ceramic powder.

[0059] LaYb(Hf 0.3 Ce 0.2 Zr 0.5 The 2O7 ceramic powder, as confirmed by XRD analysis, has a defective fluorite structure and a pyrochlore structure.

[0060] LaYb(Hf) 0.3 Ce 0.2 Zr 0.5 LaYb(Hf)₂O₇ ceramic powder is used to form a sintered body. The method for preparing the sintered body includes: [The text abruptly ends here, so the translation also ends here.] 0.3 Ce 0.2 Zr 0.5 )2O7 ceramic powder is pressed into shape (the powder is first pre-pressed under a pressure of 120MPa for 2 minutes, and then cold isostatically pressed at 220MPa for 3 minutes) to obtain a green body; the green body is sintered at 1600℃ for 10 hours to obtain a sintered body.

[0061] LaYb(Hf) was applied using a thermal spraying method. 0.3 Ce 0.2 Zr 0.5 The coating is made of 2O7 ceramic powder with a thickness of 300~400um.

[0062] Comparative Example 1 This comparative example uses LaYbZr2O7 as a control.

[0063] The preparation method of this comparative example LaYbZr2O7 powder includes: (1) Weighing raw materials: According to the chemical ratio of LaYbZr2O7, weigh La2O3, Yb2O3 and ZrO2 as raw material powders respectively; (2) Impurity removal: The raw material powders are calcined and impurity removed in advance at a temperature of 1100℃ for 1 hour; (3) Ball milling and calcination I: The raw material powder after impurity removal is ball milled and mixed (the ball milling time of the raw material powder is 4h) to obtain ball milling material A; calcined at 1200℃ for 2h to obtain calcined material; (4) Ball milling and calcination II: The calcined material is ball milled (the ball milling time is 8h) to obtain ball mill material B; the ball mill material B is ground to a particle size of 30~80um and calcined at 1400℃ for 4h to obtain LaYbZr2O7 ceramic powder.

[0064] LaYbZr2O7 ceramic powder was used to prepare a sintered body. The preparation method of the sintered body includes: pressing the LaYbZr2O7 ceramic powder into a green body (first pre-pressing the powder under a pressure of 100MPa for 1 min, and then cold isostatic pressing at 200MPa for 2 min), and sintering the green body at 1500℃ for 8 h to obtain the sintered body.

[0065] LaYbZr2O7 ceramic powder was coated using a thermal spraying method, with a thickness of 300~400 μm.

[0066] Comparative Example 2 This comparative example prepared LaYb(Hf) 0.3 Zr 0.7 )2O7 was used as a control.

[0067] This comparative example is LaYb(Hf) 0.3 Zr 0.7 The preparation method of 2O7 powder includes: (1) Weigh the raw materials: according to LaYb(Hf) 0.3 Zr 0.7 The chemical dosage ratio of )2O7 was determined by weighing La2O3, Yb2O3, HfO2, and ZrO2 as raw material powders, respectively. (2) Impurity removal: The raw material powders are calcined and impurity removed in advance at a temperature of 1100℃ for 1 hour; (3) Ball milling and calcination I: The raw material powder after impurity removal is ball milled and mixed (the ball milling time of the raw material powder is 4h) to obtain ball milling material A; calcined at 1200℃ for 2h to obtain calcined material; (4) Ball milling and calcination II: The calcined material is ball milled (the ball milling time is 8 hours) to obtain ball mill material B; the ball mill material B is ground to a particle size of 30~80 μm, and calcined at 1400℃ for 4 hours to obtain LaYb(Hf) 0.3 Zr 0.7 )2O7 ceramic powder.

[0068] LaYb(Hf) 0.3 Zr 0.7 LaYb(Hf)₂O₇ ceramic powder is used to form a sintered body. The method for preparing the sintered body includes: [The text abruptly ends here, so the translation also ends here.] 0.3 Zr 0.7 )2O7 ceramic powder is pressed into shape (the powder is first pre-pressed under a pressure of 100MPa for 1min, and then cold isostatically pressed at 200MPa for 2min) to obtain a green body; the green body is sintered at 1500℃ for 8h to obtain a sintered body.

[0069] LaYb(Hf) was applied using a thermal spraying method. 0.3 Zr 0.7 The coating is made of 2O7 ceramic powder with a thickness of 300~400um.

[0070] The products of each embodiment and comparative example were tested. The coefficient of thermal expansion of the sintered body was measured using a thermal expansion coefficient tester according to the standard GB / T16535-2008 method. The porosity of the coating after treatment at 1400℃ was measured using metallographic imaging. The results are shown in Table 1. The coefficients of thermal expansion of Example 1, Comparative Example 1, and Comparative Example 2 under different temperature conditions were plotted. Figure 2 .

[0071] Table 1. Coefficients of thermal expansion and porosity of materials in each embodiment and comparative example. From Table 1 and Figure 2 The results show that the LaYb(Hf) implementations of each embodiment... 0.3 Ce 0.2 Zr 0.5 )2O7 ceramic materials all have a high coefficient of thermal expansion, compared to LaYb(Hf) 0.3 Zr 0.7 The coefficient of thermal expansion of 2O7 is increased by more than 5%, which is a significant improvement. LaYb(Hf) 0.3 Ce 0.2 Zr 0.5 The porosity of 2O7 ceramic materials is significantly higher than that of similar materials. High porosity can significantly reduce thermal conductivity, exert a heat insulation effect, and increase the upper limit of the material's temperature resistance.

[0072] The material synthesis methods of each embodiment are simple and the product performance is stable. Further testing of the sample from Example 3 after calcination at 1600℃ for 10 hours revealed that the average grain size remained below 2 micrometers, indicating that it still has a stable composition and structure after high-temperature treatment.

[0073] The above embodiments are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A high thermal expansion coefficient, sintering-resistant ceramic material, characterized in that, The main component is LaYb(Hf) with defective fluorite and pyrochlore structures. 0.3 Ce 0.2 Zr 0.5 )2O7.

2. The method for preparing the high thermal expansion coefficient resistant ceramic material as described in claim 1, characterized in that, include: According to LaYb(Hf) 0.3 Ce 0.2 Zr 0.5 The chemical ratio of raw material powder to 2O7 is weighed and ball-milled to obtain ball milling material A; calcined at 1100~1300℃ for 2~3h to obtain calcined material; the calcined material is ball-milled to obtain ball milling material B; the ball milling material B is ground to a particle size of 30~80um and calcined at 1300~1500℃ for 3~4h to obtain LaYb(Hf) 0.3 Ce 0.2 Zr 0.5 )2O7 ceramic powder.

3. The method for preparing a high thermal expansion coefficient resistant ceramic material according to claim 2, characterized in that, The raw material powder is an oxide powder; the ball milling time for the raw material powder is 3-6 hours; the ball milling time for the calcined material is 6-10 hours.

4. The method for preparing a high thermal expansion coefficient resistant ceramic material according to claim 2, characterized in that, The raw material powders are pre-calcined to remove impurities.

5. The sintered body of the high thermal expansion coefficient resistant ceramic material as described in claim 1, or the sintered body of the material obtained by the preparation method of the high thermal expansion coefficient resistant ceramic material as described in any one of claims 2 to 4, characterized in that, The coefficient of thermal expansion is 10.7 × 10⁻⁶. -6 K -1 above.

6. The method for preparing the sintered body as described in claim 5, characterized in that, include: LaYb(Hf) 0.3 Ce 0.2 Zr 0.5 )2O7 powder is pressed into a blank to obtain a green body; the green body is sintered to obtain a sintered body.

7. The method for preparing the sintered body according to claim 6, characterized in that, The pressing process involves first pre-pressing the powder under a pressure of 80MPa to 120MPa for 1 to 2 minutes, and then cold isostatic pressing at 150MPa to 220MPa for 2 to 3 minutes.

8. The method for preparing the sintered body according to claim 6 or 7, characterized in that, The sintering temperature is 1400~1600℃, and the sintering holding time is 6~10h.

9. A coating comprising the high thermal expansion coefficient sintering-resistant ceramic material as described in claim 1 or the material obtained by the preparation method of the high thermal expansion coefficient sintering-resistant ceramic material as described in any one of claims 2 to 4, characterized in that, The porosity after treatment at 1400℃ is over 15%.

10. The application of the high thermal expansion coefficient anti-sintering ceramic material as described in claim 1, or the material obtained by the preparation method of the high thermal expansion coefficient anti-sintering ceramic material as described in any one of claims 2 to 4, or the sintered body as described in claim 5, or the material obtained by the preparation method of the sintered body as described in any one of claims 6 to 8, or the coating as described in claim 9 in thermal insulation.

11. The application of the high thermal expansion coefficient anti-sintering ceramic material as described in claim 1, or the material obtained by the preparation method of the high thermal expansion coefficient anti-sintering ceramic material as described in any one of claims 2 to 4, or the sintered body as described in claim 5, or the material obtained by the preparation method of the sintered body as described in any one of claims 6 to 8, or the coating as described in claim 9 in a thermal barrier coating.

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