A grain boundary and surface doped rare earth zirconium-based ceramic material, its preparation method and application

Abstract

This invention relates to a grain boundary and surface-doped rare-earth zirconium-based ceramic material, its preparation method, and its applications. By employing a stepwise doping method, some dopant elements are located at the grain boundaries and surfaces of the rare-earth zirconium-based ceramic material. Adjusting the type and content of dopant elements at the grain boundaries and surfaces alters the sintering activity of the rare-earth zirconium-based ceramic material, thereby regulating the grain size, number, and characteristics of the grain boundaries, ultimately optimizing the material's electrical and mechanical properties. The doping method employed is simple, low-cost, and highly versatile, meeting the doping element requirements of various rare-earth zirconium-based ceramics and suitable for large-scale applications. The rare-earth zirconium-based ceramic material obtained using the technical solution of this invention can be used in various fields such as grinding media, fiber optic connectors, mobile phone backplanes, dental materials, bioceramics, thermal barrier coatings, oxygen or nitrogen-oxygen sensors, and solid oxide fuel cells.

Description

Technical Field

[0001] This invention relates to the field of ceramic materials technology, and in particular to a rare earth zirconium-based ceramic material doped at grain boundaries and surfaces, its preparation method, and its application. Background Technology

[0002] Rare earth zirconium-based ceramic materials possess excellent physical and chemical properties and are currently widely used in high-end fields such as national defense, biomedicine, new energy, electronics, and automobiles. For example, in the biomedical field, their excellent biocompatibility and mechanical properties make them the most ideal material for dental restorations. In the information and communication field, their high strength, high toughness, and lack of signal shielding make them the preferred casing material for 5G mobile phones. In the aerospace field, their excellent thermal insulation and high-temperature stability make them a crucial material in the thermal barrier coating of aircraft engines. In environmental protection, their corrosion resistance and oxygen ion conductivity make them a key material for automotive oxygen or nitrogen-oxygen sensors. In the energy field, their high oxygen ion conductivity makes them the most ideal electrolyte material for solid oxide fuel cells.

[0003] In summary, improving the mechanical and electrical properties of rare-earth zirconium-based ceramics is key to enhancing their performance. Doping modification is a common method for improving the properties of rare-earth zirconium-based ceramics. Previous studies have shown that doping with Ce can significantly improve the toughness of rare-earth zirconium-based ceramics, and this material has already been applied in special structural components and grinding media in specialized industries. Ni, Er, and Yb doping elements can significantly reduce the thermal diffusivity and thermal conductivity of rare-earth zirconium-based ceramics, making them potential novel thermal barrier coating materials. Doping with Yb, Gd, or Ce can improve the ionic conductivity of rare-earth zirconium-based ceramics and help prevent high-temperature phase transitions, thus improving the material's thermal stability. These doped rare-earth zirconium-based ceramics have attracted widespread attention in fields such as gas sensors and solid oxide fuel cells. However, improving the performance of rare-earth zirconium-based ceramics through simple element doping has significant limitations, while the latest application areas place increasingly higher demands on the performance of rare-earth zirconium-based ceramic materials. Therefore, there is an urgent need to further improve the mechanical and electrical properties of rare-earth zirconium-based ceramic materials. Summary of the Invention

[0004] Based on the above-mentioned situation of the prior art, the purpose of the present invention is to provide a rare earth zirconium-based ceramic material with grain boundary and surface doping, its preparation method and application. By doping specific elements at the grain boundaries and surface of rare earth zirconium-based ceramic powder materials, the sintering activity of rare earth zirconium-based ceramic materials can be changed based on the different types and contents of doping elements, thereby adjusting the grain size, number of grain boundaries and grain boundary characteristics, so as to improve the physical and chemical properties of the material such as strength, thermal shock resistance, and ionic conductivity, so as to meet the requirements of different application fields such as bioceramics, thermal barrier coatings, oxygen sensors or nitrogen-oxygen sensors, and solid oxide fuel cells.

[0005] To achieve the above objectives, a first aspect of the present invention provides a rare-earth zirconium-based ceramic material doped at grain boundaries and surfaces, wherein the chemical formula of the rare-earth zirconium-based ceramic material is RE. x Zr 1-x-y M y O 2-z ;in,

[0006] RE represents rare earth elements;

[0007] M is a cation-doped element;

[0008] 0.03≤x≤0.5, 0≤y≤0.15, 0.01≤z<0.3.

[0009] Furthermore, the RE is one or more of Sc, Y, La, Gd and Ce.

[0010] Furthermore, M includes one or more of the following: cationic transition metal elements, alkaline earth metal elements, Al, Ga, In, Ge, Sn, Sb, Bi, Si, and rare earth elements.

[0011] Furthermore, M is one or more of Mg, Ca, Sr, Al, Ga, V, Fe, Mn, Ni, Zn, Nb, In, Bi and rare earth elements; preferably one or more of Mg, Sr, Al, V, Ni, Bi, La, Ce, Pr, Nd, Sm, Eu, Gd, Er, Yb, Lu, Y and Sc.

[0012] Furthermore, the molar content of M in the rare earth zirconium-based ceramic material does not exceed 15%, preferably not more than 10%.

[0013] Furthermore, the rare earth zirconium-based ceramic material contains oxides of M at its grain boundaries and surface.

[0014] Furthermore, the rare earth zirconium-based ceramic material is one or more of cubic fluorite structure, tetragonal phase, monoclinic phase and rhombohedral phase, preferably one or two of cubic fluorite structure and tetragonal phase.

[0015] A second aspect of the present invention provides a method for preparing rare-earth zirconium-based ceramic materials with grain boundary and surface doping as described in the first aspect of the present invention, comprising the steps of:

[0016] S1. Mix the aqueous solutions of RE and Zr compounds in the required stoichiometric ratio to obtain a mixed solution; add the mixed solution and alkaline substance to a reactor to carry out a precipitation reaction; filter, wash, dry and calcine the obtained precipitate to obtain rare earth zirconium-based oxide powder.

[0017] S2. Mix the rare earth zirconium-based oxide powder material obtained in step S1 with the liquid salt of doping element M, dry it, and then perform one or two heat treatments, followed by one or two calcinations to obtain rare earth zirconium-based ceramic materials with grain boundary and surface doping.

[0018] A third aspect of the present invention provides a method for preparing rare-earth zirconium-based ceramic materials with grain boundary and surface doping as described in the first aspect of the present invention, comprising the steps of:

[0019] S1. Mix the aqueous solutions of RE, Zr and part of M in the required stoichiometric ratio to obtain a mixed liquid; add the mixed liquid and alkaline substance to a reactor to carry out a precipitation reaction; filter, wash, dry and calcine the obtained precipitate to obtain rare earth zirconium-based oxide powder containing element M.

[0020] S2. Mix the rare earth zirconium-based oxide powder containing element M obtained in step S1 with the liquid salt of the remaining dopant element M, dry it, and then perform one or two heat treatments, followed by one or two calcinations to obtain rare earth zirconium-based ceramic materials doped at grain boundaries and surfaces.

[0021] Furthermore, the Zr-containing aqueous solution in step S1 includes one or more aqueous solutions of zirconium oxychloride, zirconium oxynitrate, zirconium oxysulfate, zirconium acetate, and zirconium citrate.

[0022] Furthermore, the aqueous solution containing RE in step S1 includes one or more aqueous solutions of rare earth chlorides, nitrates, sulfates, acetates, and citrates.

[0023] Furthermore, the liquid salt of the dopant element M includes one or more of the following: molten salts or aqueous solutions of chlorides, nitrates, sulfates, acetates, citrates, and amino acid salts.

[0024] Furthermore, the alkaline substance includes magnesium bicarbonate, urea, and at least one of hydroxides, carbonates, or bicarbonates of at least one element selected from ammonium, sodium, and potassium, preferably at least one of sodium hydroxide, urea, ammonia, and ammonium bicarbonate.

[0025] Furthermore, in step S1, the pH value during the precipitation process is controlled at 4.5–14, preferably 5–11, and the pH value at the precipitation endpoint is controlled at 8–13, preferably 9–11; the temperature during the precipitation process is 0–120℃, preferably 10–80℃.

[0026] Furthermore, the roasting temperature in step S1 is 600–1100°C, preferably 650–950°C, and the roasting time is 1–24 h, preferably 3–15 h.

[0027] Furthermore, the heat treatment temperature in step S2 is 200–750°C, preferably 400–600°C, and the heat treatment time is 1–24 h, preferably 1–12 h.

[0028] Furthermore, the calcination temperature in step S2 is 700–1200°C, preferably 800–1100°C, and the time is 1–24 h, preferably 3–15 h.

[0029] A fourth aspect of the present invention provides the application of grain boundary and surface doped rare earth zirconium-based ceramic powder materials as described in the first aspect of the present invention in the fields of grinding media, fiber optic connectors, mobile phone back panels, dental materials, bioceramics, thermal barrier coatings, oxygen sensors or nitrogen-oxygen sensors, and solid oxide fuel cells.

[0030] In summary, this invention provides a grain boundary and surface-doped rare-earth zirconium-based ceramic material, its preparation method, and its applications. The grain boundary doping method positions the dopant element at the grain boundaries and surface of the rare-earth zirconium-based ceramic material. Based on the differences in valence state, atomic radius, and content of different dopant elements, grain boundary and surface doping can alter the sintering activity of the rare-earth zirconium-based ceramic material, thereby adjusting the grain size, number of grain boundaries, and grain boundary characteristics. When the dopant element increases the sintering activity and reduces the number of grain boundaries, the grain boundary resistivity of the rare-earth zirconium-based ceramic material decreases, thus improving its ionic conductivity. When the dopant element decreases the sintering activity and increases the number of grain boundaries, the grains of the rare-earth zirconium-based ceramic material are refined, thereby improving its mechanical properties and high-temperature stability. The grain boundary and surface doping method provided by this invention has universality, achieving efficient and low-cost improvement of the mechanical, electrical, and thermal properties of rare-earth zirconium-based ceramic materials to meet the requirements of different rare-earth zirconium-based ceramic materials for dopant elements. Attached Figure Description

[0031] Figure 1 This is a flowchart of the preparation method of the grain boundary doped rare earth zirconium-based ceramic of the present invention. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0033] In a first aspect, the present invention provides a rare-earth zirconium-based ceramic material doped at grain boundaries and surfaces, the rare-earth zirconium-based ceramic material having the chemical formula RE. x Zr 1-x-y M y O2-z RE represents rare earth elements; M represents cation dopant elements; 0.03≤x≤0.5, 0≤y≤0.15, 0.01≤z<0.3.

[0034] Wherein, RE can be one or more of Sc, Y, La, Gd, and Ce; the cation dopant M can be one or more of a cation transition metal element, an alkaline earth metal element, Al, Ga, In, Ge, Sn, Sb, Bi, Si, and a rare earth element; preferably, M is one or more of Mg, Ca, Sr, Al, Ga, V, Fe, Mn, Ni, Zn, Nb, In, Bi, and a rare earth element; more preferably, M is one or more of Mg, Sr, Al, V, Ni, Bi, La, Ce, Pr, Nd, Sm, Eu, Gd, Er, Yb, Lu, Y, and Sc. The molar content of the cation dopant M in the rare earth zirconium-based ceramic material does not exceed 15%, preferably not more than 10%. The cation dopant M is located at the grain boundaries and surface of the rare earth zirconium-based ceramic material, or at the grain boundaries, surface, and within the grains. The cation dopant element M is transformed into one or more of oxides, nitrogen-containing compounds, and their complexes at the grain boundaries and surface of the rare-earth zirconium-based ceramic, or within the grain boundaries, surface, and grains. The rare-earth zirconium-based ceramic material can be one or more of cubic fluorite structure, tetragonal phase, monoclinic phase, and rhombohedral phase, preferably one or two of cubic fluorite structure and tetragonal phase.

[0035] The rare-earth zirconium-based ceramic materials provided in this invention can yield different rare-earth zirconium-based ceramic powders for various applications by changing the doping elements and adjusting the doping process. By doping the grain boundaries and surfaces with the cation element M, the rare-earth zirconium-based ceramic materials contain oxides of M at the grain boundaries and surfaces. Different types and contents of doping elements can alter the grain boundary characteristics of the rare-earth zirconium-based ceramic materials, thereby adjusting the grain size, number, and characteristics of the grain boundaries, ultimately optimizing the electrical, mechanical, and thermal properties of the material. Doping specific types of cation elements M at the grain boundaries and surfaces can improve sintering activity, reduce grain boundaries, facilitate the migration of oxygen ions at the grain boundaries, and reduce the grain boundary resistance of the rare-earth zirconium-based ceramic materials, thus effectively improving their ionic conductivity. Doping other types of cation elements M at the grain boundaries and surfaces can reduce the sintering activity of the rare-earth zirconium-based ceramic materials, thereby refining the grains, pinning grain boundaries, and improving the fracture toughness, flexural strength, and other mechanical properties, as well as high-temperature stability of the rare-earth zirconium-based ceramic materials. Meanwhile, considering that doping with cation doping element M exceeding 15 mol% would increase the degree of lattice distortion and affect the ion conduction and mechanical properties of the material, the present invention also limits the molar content of cation doping element M in rare earth zirconium-based ceramic materials.

[0036] A second aspect of the present invention provides a method for preparing rare-earth zirconium-based ceramic materials with grain boundary and surface doping as described in the first aspect of the present invention, the flowchart of which is shown below. Figure 1 As shown, it includes the following steps:

[0037] S1. Mix the aqueous solutions of RE and Zr compounds in the required stoichiometric ratio to obtain a mixed solution; add the mixed solution and alkaline substance to a reactor to carry out a precipitation reaction; filter, wash, dry and calcine the obtained precipitate to obtain rare earth zirconium-based oxide powder.

[0038] S2. Mix the rare earth zirconium-based oxide powder obtained in step S1 with the liquid salt of doping element M, dry it, and then perform one or two heat treatments, followed by one or two calcinations to obtain rare earth zirconium-based ceramic powder with grain boundary and surface doping.

[0039] A third aspect of the present invention provides a method for preparing rare-earth zirconium-based ceramic materials with grain boundary and surface doping as described in the first aspect of the present invention, comprising the following steps:

[0040] S1. Mix the aqueous solutions of RE, Zr and part of M in the required stoichiometric ratio to obtain a mixed solution; add the mixed solution and alkaline substance to a reactor to carry out a precipitation reaction; filter, wash, dry and calcine the obtained precipitate to obtain rare earth zirconium-based oxide powder containing element M.

[0041] S2. Mix the rare earth zirconium-based oxide powder containing element M obtained in step S1 with the liquid salt of the remaining dopant element M, dry it, and then perform one or two heat treatments, followed by one or two calcinations to obtain rare earth zirconium-based ceramic materials doped at grain boundaries and surfaces.

[0042] In the above two preparation methods, the Zr-containing solution in step S1 includes a combination of one or more aqueous solutions of zirconium oxychloride, zirconium oxynitrate, zirconium oxysulfate, zirconium acetate, and zirconium citrate; the RE-containing solution in step S1 includes a combination of one or more aqueous solutions of rare earth chlorides, nitrates, sulfates, acetates, and citrates. The alkaline substance includes magnesium bicarbonate, urea, and at least one hydroxide, carbonate, or bicarbonate of at least one element selected from ammonium, sodium, and potassium, preferably at least one of sodium hydroxide, urea, ammonia, and ammonium bicarbonate. The pH value during the precipitation process in step S1 is controlled at 4.5–14, preferably 5–11, and the pH value at the precipitation endpoint is controlled at 8–13, preferably 9–11; the temperature during the precipitation process is 0–120℃, preferably 10–80℃. The liquid salt of the dopant element M includes one or more combinations of molten salts or aqueous solutions of nitrates, acetates, citrates, and amino acid salts. The molar percentage of M at grain boundaries and surfaces is 10–70%. The morphology and proportion of M at grain boundaries and surfaces can be controlled by adjusting precipitation conditions, heat treatment of the product, and calcination temperature, time, and atmosphere.

[0043] In step S1, the calcination temperature is 600–1100℃, preferably 650–950℃, and the calcination time is 1–24h, preferably 3–15h.

[0044] In step S2, the heat treatment temperature is 200–750℃, preferably 400–600℃, and the heat treatment time is 1–24h, preferably 1–12h; the calcination temperature is 700–1200℃, preferably 800–1100℃. The rare earth zirconium-based ceramic powder obtained above undergoes 1–2 calcinations to effectively control its strength and dispersibility. After the first calcination, ball milling and surface treatment can be performed to avoid secondary sintering and agglomeration. Within this temperature range, dopant elements can preferentially enter the grain boundaries. Below this temperature range, it becomes difficult for dopant elements to enter the grain boundaries; above this temperature range, dopant elements enter the bulk phase, causing over-sintering and reducing grain boundaries. The calcination time is 1–24h, preferably 3–15h. The morphology and proportion of M at the grain boundaries and surface are controlled by adjusting precipitation parameters, heat treatment and calcination temperature, time, and atmosphere. To meet the specific requirements of different applications for ceramic performance, it is necessary to adjust or change the type of doping elements and the microstructure of ceramics. This requires different heat treatment regimes, such as step-by-step heat treatment, to allow more doping elements to enter the grain boundaries and surfaces more uniformly and stably. Water washing, water quenching, and other treatments can also be performed between the two heat treatment steps.

[0045] A fourth aspect of the present invention provides applications of grain boundary and surface-doped rare-earth zirconium-based ceramic materials as described in the first aspect of the invention in grinding media, fiber optic connectors, mobile phone back panels, dental materials, bioceramics, thermal barrier coatings, oxygen sensors or nitrogen-oxygen sensors, and solid oxide fuel cells. The grain boundary and surface-doped rare-earth zirconium-based ceramic powders provided in the embodiments of the present invention can be prepared into ceramics by molding methods such as casting and hot pressing. They can also be further structurally designed to prepare ceramic materials for applications in grinding media, fiber optic connectors, mobile phone back panels, dental materials, bioceramics, thermal barrier coatings, oxygen sensors or nitrogen-oxygen sensors, and solid oxide fuel cells.

[0046] The present invention will be further described below through specific embodiments.

[0047] Example 1

[0048] Yttrium chloride and zirconium oxychloride were dissolved in water according to stoichiometric ratios to prepare a Yttrium chloride solution with a total cation concentration of 1.0 M. 3+ and Zr 4+ A mixed solution was prepared by adding the mixed solution and a 2.0M sodium hydroxide solution to the reactor at a uniform rate under stirring conditions. The pH value was controlled at 10.7±0.2 during the precipitation process, with a final pH value of 10.5. The temperature was controlled at 30℃ to ensure complete cation precipitation. The precipitate was then filtered, washed, and dried. The dried product was calcined at 600℃ for 24 hours to obtain YSZ powder. YSZ was mixed with a liquid salt of lanthanum nitrate doped with La in stoichiometric ratio, dried at 100℃ for 5 hours, heat-treated at 250℃ for 24 hours, and then calcined at 1200℃ for 2 hours to obtain rare earth zirconium-based ceramic powder YS with grain boundary and surface doping. 0.05 La 0.01 Zr 0.94 O 1.97 After being sintered into ceramic, its bending strength was measured to be 1378.28 MPa in a three-point bending test.

[0049] Example 2

[0050] Yttrium nitrate and zirconium oxynitrate were dissolved in water according to stoichiometric ratios to prepare a 1.0 M solution of Yttrium nitrate. 3+ and Zr 4+A mixed solution was prepared by uniformly adding the mixed solution and a 3.0M ammonia solution to the reactor under stirring conditions. The pH value was controlled at 7±0.2 during the precipitation process, with a final pH value of 10.5. The temperature was controlled at 20℃ to ensure complete cation precipitation. The precipitate was then filtered, washed, and dried. The dried product was calcined at 1000℃ for 2 hours to obtain YSZ powder. YSZ was mixed with a liquid salt of cerium acetate doped with Ce in stoichiometric ratio, dried at 100℃ for 5 hours, heat-treated at 300℃ for 20 hours, and then calcined at 700℃ for 24 hours to obtain rare earth zirconium-based ceramic powder YS with grain boundary and surface doping. 0.04 Ce 0.02 Zr 0.94 O 1.97 After being sintered into ceramic, its bending strength was measured to be 1298.02 MPa in a three-point bending test.

[0051] Example 3

[0052] Yttrium chloride and zirconium oxychloride were dissolved in water according to the stoichiometric ratio to prepare a 1.0 M solution of Yttrium chloride. 3+ and Zr 4+ A mixed solution was prepared by adding the mixed solution and a 2.0M sodium hydroxide solution to the reactor at a uniform rate under stirring conditions. The pH value was controlled at 5±0.2 during the precipitation process, with a final pH value of 10, and the temperature was controlled at 10℃ to ensure complete cation precipitation. The precipitate was then filtered, washed, and dried. The dried product was calcined at 800℃ for 6 hours to obtain YSZ powder. YSZ was mixed with liquid salts of lanthanum nitrate and lutetium nitrate doped with La and Lu in stoichiometric ratios. After drying at 100℃ for 5 hours, the mixture was heat-treated at 300℃ for 20 hours and then calcined at 1100℃ for 4 hours to obtain rare earth zirconium-based ceramic powder YS with grain boundary and surface doping. 0.02 La 0.02 Lu 0.02 Zr 0.94 O 1.97 After being sintered into ceramic, its bending strength was measured to be 1350.33 MPa in a three-point bending test.

[0053] Example 4

[0054] Yttrium chloride and zirconium oxychloride were dissolved in water according to the stoichiometric ratio to prepare a 1.0 M solution of Yttrium chloride. 3+ and Zr 4+A mixed solution was prepared by adding the mixed solution and a 2.0M sodium hydroxide solution to the reactor at a uniform rate under stirring conditions. The pH value was controlled at 4.7–11 during the precipitation process, with a final pH value of 9.5. The temperature was controlled at 30℃ to ensure complete cation precipitation. The precipitate was then filtered, washed, and dried. The dried product was calcined at 950℃ for 4 hours to obtain YSZ powder. YSZ was mixed with liquid salts of europium nitrate and ytterbium nitrate doped with Eu and Yb in stoichiometric ratios. After drying at 100℃ for 5 hours, the mixture was heat-treated at 500℃ for 6 hours and then calcined at 1000℃ for 8 hours to obtain rare earth zirconium-based ceramic powder YN with grain boundary and surface doping. 0.04 Eu 0.01 Yb 0.01 Zr 0.94 O 1.97 After being sintered into ceramic, its bending strength was measured to be 1310.43 MPa in a three-point bending test.

[0055] Example 5

[0056] Yttrium chloride and zirconium oxychloride were dissolved in water according to the stoichiometric ratio to prepare a 1.0 M solution of Yttrium chloride. 3+ and Zr 4+ A mixed solution was prepared by adding the mixed solution and a 2.0M sodium hydroxide solution to the reactor at a uniform rate under stirring conditions. The pH value was controlled at 10.7±0.2 during the precipitation process, with a final pH value of 12. The temperature was controlled at 30℃ to ensure complete cation precipitation. The precipitate was then filtered, washed, and dried. The dried product was calcined at 1000℃ for 2 hours to obtain YSZ powder. YSZ was mixed with a liquid salt of aluminum nitrate doped with Al in stoichiometric ratio, dried at 100℃ for 5 hours, heat-treated at 750℃ for 2 hours, and then calcined at 900℃ for 15 hours to obtain rare earth zirconium-based ceramic powder YS with grain boundary and surface doping. 0.05 Al 0.01 Zr 0.94 O 1.97 After being sintered into ceramic, its bending strength was measured to be 1390.02 MPa in a three-point bending test.

[0057] Example 6

[0058] Yttrium nitrate and zirconium oxynitrate were dissolved in water according to stoichiometric ratios to prepare a 1.0 M solution of Yttrium nitrate. 3+ and Zr 4+A mixed solution was prepared by adding the mixed solution and a 3.0M ammonia solution to the reactor at a uniform rate under stirring conditions. The pH value was controlled at 9±0.2 during the precipitation process, with a final pH value of 10, and the temperature was controlled at 20℃ to ensure complete cation precipitation. The precipitate was then filtered, washed, and dried. The dried product was calcined at 600℃ for 24 hours to obtain YSZ powder. YSZ was mixed with liquid salt of erbium nitrate doped with Er, dried at 100℃ for 5 hours, heat-treated at 400℃ for 12 hours, and then calcined at 1200℃ for 2 hours to obtain rare earth zirconium-based ceramic powder YS with grain boundary and surface doping. 0.09 Er 0.01 Zr 0.9 O 1.95 After being sintered into ceramic, its bending strength was measured to be 570.45 MPa in a three-point bending test, and its electrical conductivity at 850℃ was measured to be 32.78 mS / cm using the DC four-probe method.

[0059] Example 7

[0060] Yttrium nitrate and zirconium oxynitrate were dissolved in water according to stoichiometric ratios to prepare a 1.0 M solution of Yttrium nitrate. 3+ and Zr 4+ A mixed solution was prepared by adding the mixed solution and ammonia solution to the reactor at a uniform rate under stirring conditions. The pH value was controlled at 8 ± 0.2 during the precipitation process, with a final pH value of 9, and the temperature was controlled at 10℃ to ensure complete cation precipitation. The precipitate was then filtered, washed, and dried. The dried product was calcined at 1000℃ for 2 hours to obtain YSZ powder. YSZ was mixed with a liquid salt of scandium nitrate doped with Sc in stoichiometric ratio, dried at 100℃ for 5 hours, heat-treated at 500℃ for 6 hours, and then calcined at 900℃ for 15 hours to obtain rare earth zirconium-based ceramic powder YS with grain boundary and surface doping. 0.05 Sc 0.05 Zr 0.9 O 1.95 After being sintered into ceramic, its bending strength was measured to be 615.22 MPa in a three-point bending test, and its conductivity at 850℃ was measured to be 40.67 mS / cm using the DC four-probe method.

[0061] Example 8

[0062] Yttrium nitrate and zirconium oxynitrate were dissolved in water according to stoichiometric ratios to prepare a 1.0 M solution of Yttrium nitrate. 3+ and Zr 4+A mixed solution was prepared by adding the mixed solution and ammonia solution to the reactor at a uniform rate under stirring conditions. The pH value was controlled at 8.5 ± 0.2 during the precipitation process, with a final pH value of 9, and the temperature was controlled at 20℃ to ensure complete cation precipitation. The precipitate was then filtered, washed, and dried. The dried product was calcined at 650℃ for 15 hours to obtain YSZ powder. YSZ was mixed with liquid salts of ytterbium nitrate and lutetium nitrate doped with Yb and Lu in stoichiometric ratios. After drying at 100℃ for 5 hours, the mixture was heat-treated at 500℃ for 6 hours and then calcined at 750℃ for 20 hours to obtain rare earth zirconium-based ceramic powder YB with grain boundaries and surface doping. 0.07 Yb 0.02 Lu 0.01 Zr 0.9 O 1.95 After being sintered into ceramic, its bending strength was measured to be 600.24 MPa in a three-point bending test, and its electrical conductivity at 850℃ was measured to be 34.83 mS / cm using the DC four-probe method.

[0063] Example 9

[0064] Yttrium nitrate and zirconium oxynitrate were dissolved in water according to stoichiometric ratios to prepare a 1.0 M solution of Yttrium nitrate. 3+ and Zr 4+ A mixed solution was prepared by adding the mixed solution and ammonia solution to the reactor at a uniform rate under stirring conditions. The pH value was controlled at 9±0.2 during the precipitation process, with a final pH value of 9.5, and the temperature was controlled at 20℃ to ensure complete cation precipitation. The precipitate was then filtered, washed, and dried. The dried product was calcined at 1000℃ for 2 hours to obtain YSZ powder. YSZ was mixed with a liquid salt of lutetium nitrate doped with Lu in stoichiometric ratio, dried at 100℃ for 5 hours, heat-treated at 600℃ for 3 hours, and then calcined at 1000℃ for 8 hours to obtain rare earth zirconium-based ceramic powder YS with grain boundary and surface doping. 0.09 Lu 0.01 Zr 0.9 O 1.95 After being sintered into ceramic, its bending strength was measured to be 590.62 MPa in a three-point bending test, and its conductivity at 850℃ was measured to be 33.01 mS / cm using the DC four-probe method.

[0065] Example 10

[0066] Yttrium nitrate and zirconium oxynitrate were dissolved in water according to stoichiometric ratios to prepare a 1.0 M solution of Yttrium nitrate. 3+ and Zr 4+A mixed solution was prepared by adding the mixed solution and ammonia solution to the reactor at a uniform rate under stirring conditions. The pH value was controlled at 6±0.2 during the precipitation process, with a final pH value of 9.5. The temperature was controlled at 20℃ to ensure complete cation precipitation. The precipitate was then filtered, washed, and dried. The dried product was calcined at 1000℃ for 2 hours to obtain YSZ powder. YSZ was mixed with a liquid salt of scandium nitrate doped with Sc in stoichiometric ratio, dried at 100℃ for 5 hours, heat-treated at 400℃ for 12 hours, calcined at 900℃ for 10 hours, and then calcined at 1000℃ for 5 hours to obtain rare earth zirconium-based ceramic powder YS with grain boundary and surface doping. 0.08 Sc 0.02 Zr 0.9 O 1.95 After being sintered into ceramic, its bending strength was measured to be 610.54 MPa in a three-point bending test, and its electrical conductivity at 850℃ was measured to be 35.70 mS / cm using the DC four-probe method.

[0067] Example 11

[0068] Yttrium nitrate and zirconium oxynitrate were dissolved in water according to stoichiometric ratios to prepare a 1.0 M solution of Yttrium nitrate. 3+ and Zr 4+ A mixed solution was prepared by adding the mixed solution and ammonia solution to the reactor at a uniform rate under stirring conditions. The pH value was controlled at 8 ± 0.2 during the precipitation process, with a final pH value of 9, and the temperature was controlled at 20℃ to ensure complete cation precipitation. The precipitate was then filtered, washed, and dried. The dried product was calcined at 700℃ for 8 hours to obtain YSZ powder. YSZ was mixed with liquid salts of scandium nitrate and gadolinium nitrate doped with Sc and Gd in stoichiometric ratios. After drying at 100℃ for 5 hours, the mixture was heat-treated at 300℃ for 15 hours, then heat-treated at 500℃ for 3 hours, and finally calcined at 1000℃ for 8 hours to obtain rare earth zirconium-based ceramic powder YS with grain boundary and surface doping. 0.05 Sc 0.03 Gd 0.02 Zr 0.9 O 1.95 After being sintered into ceramic, its bending strength was measured to be 605.22 MPa in a three-point bending test, and its conductivity at 850℃ was measured to be 38.67 mS / cm using the DC four-probe method.

[0069] Example 12

[0070] Yttrium nitrate and zirconium oxynitrate were dissolved in water according to stoichiometric ratios to prepare a 1.0 M solution of Yttrium nitrate. 3+ and Zr 4+A mixed solution was prepared by adding the mixed solution and ammonia solution to the reactor at a uniform rate under stirring conditions. The pH value was controlled at 9-12 during the precipitation process, with a final pH value of 9, and the temperature was controlled at 10℃ to ensure complete cation precipitation. The precipitate was then filtered, washed, and dried. The dried product was calcined at 1000℃ for 2 hours to obtain YSZ powder. YSZ was mixed with liquid salts of scandium nitrate and samarium nitrate doped with Sc and Sm in stoichiometric ratios. After drying at 100℃ for 5 hours, the mixture was heat-treated at 300℃ for 10 hours, then heat-treated at 500℃ for 4 hours, calcined at 800℃ for 15 hours, and finally calcined at 1100℃ for 3 hours to obtain rare earth zirconium-based ceramic powder YS with grain boundary and surface doping. 0.06 Sc 0.03 Sm 0.01 Zr 0.9 O 1.95 After being sintered into ceramic, its bending strength was measured to be 625.24 MPa in a three-point bending test, and its conductivity at 850℃ was measured to be 36.83 mS / cm using the DC four-probe method.

[0071] Example 13

[0072] Yttrium chloride and zirconium oxychloride were dissolved in water according to the stoichiometric ratio to prepare a 1.0 M solution of Yttrium chloride. 3+ and Zr 4+ A mixed solution was prepared by adding the mixed solution and sodium carbonate solution to the reactor at a uniform rate under stirring conditions. The pH value was controlled at 8.5 ± 0.2 during the precipitation process, with a final pH value of 9, and the temperature was controlled at 30℃ to ensure complete cation precipitation. The precipitate was then filtered, washed, and dried. The dried product was calcined at 700℃ for 8 hours to obtain YSZ powder. YSZ was mixed with a liquid salt of strontium nitrate doped with Sr in stoichiometric ratio, dried at 100℃ for 5 hours, heat-treated at 600℃ for 3 hours, and then calcined at 1000℃ for 8 hours to obtain rare earth zirconium-based ceramic powder YS with grain boundary and surface doping. 0.13 Sr 0.03 Zr 0.85 O 1.925 After being sintered into ceramic, its bending strength was measured to be 389.93 MPa in a three-point bending test, and its conductivity at 850℃ was measured to be 81.34 mS / cm using the DC four-probe method.

[0073] Example 14

[0074] Yttrium chloride and zirconium oxychloride were dissolved in water according to the stoichiometric ratio to prepare a 1.0 M solution of Yttrium chloride. 3+ and Zr 4+A mixed solution was prepared by adding the mixed solution and a 2.0M sodium hydroxide solution to the reactor at a uniform rate under stirring conditions. The pH value was controlled at 5.5±0.2 during the precipitation process, with a final pH value of 13. The temperature was controlled at 60℃ to ensure complete cation precipitation. The precipitate was then filtered, washed, and dried. The dried product was calcined at 1000℃ for 2 hours to obtain YSZ powder. YSZ was mixed with a liquid salt of bismuth nitrate doped with Bi in stoichiometric proportions, dried at 100℃ for 5 hours, heat-treated at 500℃ for 6 hours, and then calcined at 1000℃ for 8 hours to obtain rare earth zirconium-based ceramic powder YS with grain boundary and surface doping. 0.1 Bi 0.03 Zr 0.85 O 1.925 After being sintered into ceramic, its bending strength was measured to be 400.17 MPa in a three-point bending test, and its conductivity at 850℃ was measured to be 97.09 mS / cm using the DC four-probe method.

[0075] Example 15

[0076] Yttrium chloride and zirconium oxychloride were dissolved in water according to the stoichiometric ratio to prepare a 1.0 M solution of Yttrium chloride. 3+ and Zr 4+ A mixed solution was prepared by adding the mixed solution and a 2.0M sodium hydroxide solution to the reactor at a uniform rate under stirring conditions. The pH value was controlled at 4.7–11 during the precipitation process, with a final pH value of 9.5. The temperature was controlled at 80℃ to ensure complete cation precipitation. The precipitate was then filtered, washed, and dried. The dried product was calcined at 800℃ for 6 hours to obtain YSZ powder. YSZ was mixed with a liquid salt of ytterbium nitrate and aluminum nitrate doped with Yb and Al in stoichiometric ratios. After drying at 100℃ for 5 hours, the mixture was heat-treated at 500℃ for 6 hours and then calcined at 1100℃ for 4 hours to obtain rare earth zirconium-based ceramic powder YB with grain boundaries and surface doping. 0.12 Yb 0.02 Al 0.01 Zr 0.85 O 1.925 After being sintered into ceramic, its bending strength was measured to be 420.82 MPa in a three-point bending test, and its conductivity at 850℃ was measured to be 85.98 mS / cm using the DC four-probe method.

[0077] Example 16

[0078] Yttrium nitrate and zirconium oxynitrate were dissolved in water according to stoichiometric ratios to prepare a 1.0 M solution of Yttrium nitrate. 3+ and Zr 4+A mixed solution was prepared by uniformly adding the mixed solution and a 3.0M ammonia solution to the reactor under stirring conditions. The pH value was controlled at 7±0.2 during the precipitation process, with a final pH value of 11, and the temperature was controlled at 10℃ to ensure complete cation precipitation. The precipitate was then filtered, washed, and dried. The dried product was calcined at 800℃ for 6 hours to obtain YSZ powder. YSZ was mixed with liquid salts of bismuth nitrate, ytterbium nitrate, and aluminum nitrate in stoichiometric ratios of Bi, Yb, and Al. After drying at 100℃ for 5 hours, the mixture was heat-treated at 500℃ for 6 hours and then calcined at 1000℃ for 8 hours to obtain rare earth zirconium-based ceramic powder YS with grain boundary and surface doping. 0.07 Bi 0.03 Yb 0.02 Al 0.01 Zr 0.85 O 1.925 After being sintered into ceramic, its bending strength was measured to be 415.05 MPa in a three-point bending test, and its conductivity at 850℃ was measured to be 90.00 mS / cm using the DC four-probe method.

[0079] Example 17

[0080] Yttrium nitrate and zirconium oxynitrate were dissolved in water according to stoichiometric ratios to prepare a 1.0 M solution of Yttrium nitrate. 3+ and Zr 4+ A mixed solution was prepared by uniformly adding the mixed solution and a 3.0M ammonia solution to the reactor under stirring conditions. The pH value was controlled at 7±0.2 during the precipitation process, with a final pH value of 9.5, and the temperature was controlled at 30℃ to ensure complete cation precipitation. The precipitate was then filtered, washed, and dried. The dried product was calcined at 600℃ for 24 hours to obtain YSZ powder. YSZ was mixed with a liquid salt of vanadium nitrate doped with a V stoichiometric ratio, dried at 100℃ for 5 hours, heat-treated at 600℃ for 3 hours, and then calcined at 1100℃ for 4 hours to obtain rare earth zirconium-based ceramic powder YS with grain boundary and surface doping. 0.1 V 0.03 Zr 0.85 O 1.925 After being sintered into ceramic, its bending strength was measured to be 400.79 MPa in a three-point bending test, and its conductivity at 850℃ was measured to be 73.65 mS / cm using the DC four-probe method.

[0081] Example 18

[0082] Scandium nitrate and zirconium oxynitrate were dissolved in water according to stoichiometric ratios to prepare a 1.0 M solution of Sc. 3+ and Zr 4+A mixed solution was prepared by uniformly adding the mixed solution and a 3.0M ammonia solution to the reactor under stirring conditions. The pH value during precipitation was controlled at 5.5±0.2, with a final pH value of 9, and the temperature was controlled at 30℃ to ensure complete cation precipitation. The precipitate was then filtered, washed, and dried. The dried product was calcined at 1000℃ for 2 hours to obtain ScSZ powder. ScSZ was mixed with a liquid salt of ytterbium nitrate doped with Yb in stoichiometric ratio, dried at 100℃ for 5 hours, heat-treated at 500℃ for 6 hours, and then calcined at 900℃ for 15 hours to obtain rare earth zirconium-based ceramic powder Sc with grain boundary and surface doping. 0.14 Yb 0.04 Zr 0.82 O 1.91 After being sintered into ceramic, its conductivity at 850℃ was measured to be 190.88 mS / cm using the DC four-probe method.

[0083] Example 19

[0084] Scandium nitrate and zirconium oxynitrate were dissolved in water according to stoichiometric ratios to prepare a 1.0 M solution of Sc. 3+ and Zr 4+ A mixed solution was prepared by uniformly adding the mixed solution and a 3.0M ammonia solution to the reactor under stirring conditions. The pH value during precipitation was controlled at 5.5±0.2, with a final pH value of 9, and the temperature was controlled at 30℃ to ensure complete cation precipitation. The precipitate was then filtered, washed, and dried. The dried product was calcined at 1000℃ for 2 hours to obtain ScSZ powder. ScSZ was mixed with a liquid salt of cerium nitrate doped with Ce in stoichiometric ratio, dried at 100℃ for 5 hours, heat-treated at 500℃ for 6 hours, and then calcined at 900℃ for 15 hours to obtain rare earth zirconium-based ceramic powder Sc with grain boundary and surface doping. 0.14 Ce 0.03 Zr 0.82 O 1.91 After being sintered into ceramic, its conductivity at 850℃ was measured to be 185.72 mS / cm using the DC four-probe method.

[0085] Example 20

[0086] Yttrium chloride and zirconium oxychloride were dissolved in water according to the stoichiometric ratio to prepare a 1.0 M solution of Yttrium chloride. 3+ and Zr 4+A mixed solution was prepared by adding the mixed solution and a 2.0M sodium hydroxide solution to the reactor at a uniform rate under stirring conditions. The pH value was controlled at 10–14 during the precipitation process, with a final pH value of 9.5. The temperature was controlled at 60℃ to ensure complete cation precipitation. The precipitate was then filtered, washed, and dried. The dried product was calcined at 650℃ for 15 hours to obtain YSZ powder. YSZ was mixed with a liquid salt of ferric citrate doped with Fe stoichiometry, dried at 100℃ for 5 hours, heat-treated at 400℃ for 12 hours, and then calcined at 900℃ for 15 hours to obtain rare earth zirconium-based ceramic powder YS with grain boundary and surface doping. 0.05 Fe 0.03 Zr 0.92 O 1.96 After sintering into ceramic, phase analysis showed that it could maintain phase structure stability below 1200℃, and its fracture toughness was measured to be 2.94 MPa·m by indentation method. 1 / 2 After thermal spraying, a thermal shock cycle test was conducted, with 248 cycles. (The thermal shock cycle test involved heating and holding the coating at 1150℃ in a box furnace for 50 minutes, then removing it and cooling it in room temperature air for 10 minutes. This process was repeated multiple times until 10% of the coating peeled off from the substrate, at which point it was considered a failure. The following thermal shock cycle test is the same as this example.)

[0087] Example 21

[0088] Yttrium chloride and zirconium oxychloride were dissolved in water according to the stoichiometric ratio to prepare a 1.0 M solution of Yttrium chloride. 3+ and Zr 4+ A mixed solution was prepared by adding the mixed solution and a 2.0M sodium hydroxide solution to the reactor at a uniform rate under stirring conditions. The pH value was controlled at 10±0.2 during the precipitation process, with a final pH value of 10.5. The temperature was controlled at 20℃ to ensure complete cation precipitation. The precipitate was then filtered, washed, and dried. The dried product was calcined at 1000℃ for 2 hours to obtain YSZ powder. YSZ was mixed with a liquid salt of zinc acetate with a Zn-doped ratio, dried at 100℃ for 5 hours, heat-treated at 400℃ for 12 hours, and then calcined at 900℃ for 15 hours to obtain rare earth zirconium-based ceramic powder YS with grain boundary and surface doping. 0.05 Zn 0.03 Zr 0.92 O 1.96 After sintering into ceramic, phase analysis showed that it could maintain phase structure stability below 1200℃, and its fracture toughness was measured to be 2.88 MPa·m by indentation method. 1 / 2 After thermal spraying, a thermal shock cycle test was conducted, with 256 thermal shock cycles.

[0089] Example 22

[0090] Yttrium chloride and zirconium oxychloride were dissolved in water according to the stoichiometric ratio to prepare a 1.0 M solution of Yttrium chloride. 3+ and Zr 4+ A mixed solution was prepared by adding the mixed solution and magnesium bicarbonate solution to the reactor at a uniform rate under stirring conditions. The pH value was controlled at 4.7 ± 0.2 during the precipitation process, with a final pH value of 8.5. The temperature was controlled at 20℃ to ensure complete cation precipitation. The precipitate was then filtered, washed, and dried. The dried product was calcined at 1000℃ for 2 hours to obtain YSZ powder. YSZ was mixed with liquid salt of magnesium nitrate with a stoichiometric ratio of Mg, dried at 100℃ for 5 hours, heat-treated at 300℃ for 20 hours, and then calcined at 800℃ for 17 hours to obtain rare earth zirconium-based ceramic powder YS with grain boundary and surface doping. 0.05 Mg 0.03 Zr 0.92 O 1.96 After sintering into ceramic, phase analysis showed that it could maintain phase structure stability below 1200℃, and its fracture toughness measured by indentation method was 3.03 MPa·m. 1 / 2 After thermal spraying, a thermal shock cycle test was conducted, with 320 thermal shock cycles.

[0091] Example 23

[0092] Yttrium nitrate and zirconium oxynitrate were dissolved in water according to stoichiometric ratios to prepare a 1.0 M solution of Yttrium nitrate. 3+ and Zr 4+ A mixed solution was prepared by adding the mixed solution and a 3.0M ammonia solution to the reactor at a uniform rate under stirring conditions. The pH value was controlled at 7±0.2 during the precipitation process, with a final pH value of 10, and the temperature was controlled at 10℃ to ensure complete cation precipitation. The precipitate was then filtered, washed, and dried. The dried product was calcined at 800℃ for 6 hours to obtain YSZ powder. YSZ was mixed with liquid salts of aluminum nitrate and samarium nitrate doped with Al and Sm in stoichiometric ratios. After drying at 100℃ for 5 hours, the mixture was heat-treated at 400℃ for 12 hours and then calcined at 1200℃ for 2 hours to obtain rare earth zirconium-based ceramic powder YS with grain boundary and surface doping. 0.05 Sm 0.02 Al 0.01 Zr 0.92 O 1.96 After sintering into ceramic, phase analysis showed that it could maintain phase structure stability below 1200℃, and its fracture toughness was measured to be 2.12 MPa·m by indentation method. 1 / 2 After thermal spraying, a thermal shock cycle test was conducted, with 417 thermal shock cycles.

[0093] Example 24

[0094] Yttrium nitrate and zirconium oxynitrate were dissolved in water according to stoichiometric ratios to prepare a 1.0 M solution of Yttrium nitrate.3+ and Zr 4+ A mixed solution was prepared by adding the mixed solution and a 3.0M ammonia solution to the reactor at a uniform rate under stirring conditions. The pH value was controlled at 6±0.2 during the precipitation process, with a final pH value of 11. The temperature was controlled at 30℃ to ensure complete cation precipitation. The precipitate was then filtered, washed, and dried. The dried product was calcined at 950℃ for 4 hours to obtain YSZ powder. YSZ was mixed with a liquid salt of europium nitrate doped with Eu in stoichiometric ratio, dried at 100℃ for 5 hours, heat-treated at 400℃ for 12 hours, and then calcined at 1200℃ for 2 hours to obtain rare earth zirconium-based ceramic powder YS with grain boundary and surface doping. 0.04 Eu 0.04 Zr 0.92 O 1.96 After sintering into ceramic, phase analysis showed that it could maintain phase structure stability below 1200℃, and its fracture toughness, measured by indentation method, was 2.50 MPa·m. 1 / 2 After thermal spraying, a thermal shock cycle test was conducted, with 301 thermal shock cycles.

[0095] Example 25

[0096] Yttrium nitrate and zirconium oxynitrate were dissolved in water according to stoichiometric ratios to prepare a 1.0 M solution of Yttrium nitrate. 3+ and Zr 4+ A mixed solution was prepared by uniformly adding the mixed solution and a 3.0M ammonia solution to the reactor under stirring conditions. The pH value during precipitation was controlled at 8.5±0.2, with a final pH value of 11.5. The temperature was controlled at 30℃ to ensure complete cation precipitation. The precipitate was then filtered, washed, and dried. The dried product was calcined at 600℃ for 24 hours to obtain YSZ powder. YSZ was mixed with liquid salts of lanthanum nitrate and gadolinium nitrate doped with La and Gd in stoichiometric ratios. After drying at 100℃ for 5 hours, the mixture was heat-treated at 400℃ for 12 hours and then calcined at 1200℃ for 2 hours to obtain rare earth zirconium-based ceramic powder YS with grain boundary and surface doping. 0.06 La 0.01 Gd 0.01 Zr 0.92 O 1.96 After sintering into ceramic, phase analysis showed that it could maintain phase structure stability below 1200℃, and its fracture toughness was measured to be 2.86 MPa·m by indentation method. 1 / 2 After thermal spraying, a thermal shock cycle test was conducted, with 450 thermal shock cycles.

[0097] Example 26

[0098] Lanthanum nitrate and zirconium oxynitrate were dissolved in water according to stoichiometric ratios to prepare a 0.5M solution of La. 3+ and Zr 4+A mixed solution was prepared by adding the mixed solution and ammonia solution to the reactor at a uniform rate under stirring conditions. The pH value was controlled at 6 ± 0.2 during the precipitation process, with a final pH value of 9.5, and the temperature was controlled at 50℃ to ensure complete cation precipitation. The precipitate was then filtered, washed, and dried. The dried product was calcined at 1000℃ for 2 hours to obtain LaZO powder. The LaZO powder was mixed with a liquid salt of scandium nitrate doped with Sc in stoichiometric ratio, dried at 100℃ for 5 hours, heat-treated at 400℃ for 12 hours, and calcined at 950℃ for 10 hours to obtain rare earth zirconium-based ceramic powder La with grain boundary and surface doping. 0.4 Sc 0.1 Zr 0.5 O 1.75 After sintering into ceramic, phase analysis showed that it could maintain a stable phase structure below 1500℃, and its fracture toughness, measured by indentation method, was 1.39 MPa·m. 1 / 2 After thermal spraying, a thermal shock cycle test was conducted, with 39 thermal shock cycles.

[0099] Example 27

[0100] Gd nitrate and zirconium oxynitrate were dissolved in water according to stoichiometric ratios to prepare a 1.5M solution of Gd nitrate. 3+ and Zr 4+ A mixed solution was prepared by adding the mixed solution and ammonia solution to the reactor at a uniform rate under stirring. The pH value was controlled at 6 ± 0.2 during the precipitation process, with a final pH value of 9.5. The temperature was controlled at 50℃ to ensure complete cation precipitation. The precipitate was then filtered, washed, and dried. The dried product was calcined at 900℃ for 5 hours to obtain GdZO powder. GdZO was mixed with a liquid salt of lanthanum nitrate doped with La in stoichiometric ratio, dried at 100℃ for 5 hours, heat-treated at 400℃ for 5 hours, and calcined at 950℃ for 10 hours to obtain rare earth zirconium-based ceramic powder Gd with grain boundary and surface doping. 0.3 La 0.2 Zr 0.5 O 1.75 After sintering into ceramic, phase analysis showed that it could maintain phase structure stability below 1500℃, and its fracture toughness, measured by indentation method, was 2.56 MPa·m. 1 / 2 After thermal spraying, a thermal shock cycle test was conducted, with 109 thermal shock cycles.

[0101] Example 28

[0102] Gd nitrate and zirconium oxynitrate were dissolved in water according to stoichiometric ratios to prepare a 2.0 M solution of Gd nitrate. 3+ and Zr 4+A mixed solution was prepared by adding the mixed solution and ammonia solution to the reactor at a uniform rate under stirring conditions. The pH value was controlled at 6 ± 0.2 during the precipitation process, with a final pH value of 9.5. The temperature was controlled at 50℃ to ensure complete cation precipitation. The precipitate was then filtered, washed, and dried. The dried product was calcined at 900℃ for 5 hours to obtain GdZO powder. GdZO was mixed with a liquid salt of scandium nitrate doped with Sc in stoichiometric ratio. After drying at 100℃ for 5 hours, the mixture was heat-treated at 400℃ for 12 hours and calcined at 950℃ for 10 hours to obtain rare earth zirconium-based ceramic powder Gd with grain boundary and surface doping. 0.06 Sc 0.02 Zr 0.92 O 1.96 After sintering into ceramic, phase analysis showed that it could maintain a stable phase structure below 1500℃, and its fracture toughness, measured by indentation method, was 1.59 MPa·m. 1 / 2 After thermal spraying, a thermal shock cycle test was conducted, with 41 thermal shock cycles.

[0103] Comparative Example 1

[0104] Yttrium chloride, lanthanum nitrate, and zirconium oxychloride were dissolved in water according to the stoichiometric ratio to prepare a 1.0 M solution of Yttrium chloride. 3+ La 3+ and Zr 4+ A mixed solution was prepared; under stirring conditions, the mixed solution and 2.0M sodium hydroxide solution were added to the reactor at a uniform rate. The pH value during the precipitation process was controlled at 10.7±0.2, with a final pH value of 10.5, and the temperature was controlled at 30℃ to ensure complete cation precipitation. The precipitate was then filtered, washed, and dried. The dried product was calcined at 600℃ for 24 hours to obtain YSZ powder. This powder was then calcined at 1200℃ for 2 hours to obtain rare earth zirconium-based ceramic powder YSZ. 0.05 La 0.01 Zr 0.94 O 1.97 After being sintered into ceramic, its bending strength was measured to be 1235.71 MPa in a three-point bending test.

[0105] Comparative Example 2

[0106] Yttrium chloride, scandium nitrate, and zirconium oxychloride were dissolved in water according to the stoichiometric ratio to prepare a 1.0 M solution of Yttrium chloride. 3+ ,Sc 3+ and Zr 4+A mixed solution was prepared; under stirring conditions, the mixed solution and a 3.0M ammonia solution were added to the reactor at a uniform rate. The pH value during the precipitation process was controlled at 5±0.2, with a final pH value of 10, and the temperature was controlled at 10℃ to ensure complete cation precipitation. The precipitate was then filtered, washed, and dried. The dried product was calcined at 800℃ for 6 hours to obtain YSZ powder. This powder was then calcined at 1100℃ for 4 hours to obtain rare earth zirconium-based ceramic powder YSZ. 0.05 Sc 0.05 Zr 0.9 O 1.95 After being sintered into ceramic, its bending strength was measured to be 520.23 MPa in a three-point bending test, and its conductivity at 850℃ was measured to be 30.45 mS / cm using the DC four-probe method.

[0107] Comparative Example 3

[0108] Yttrium chloride, bismuth nitrate, and zirconium oxychloride were dissolved in water according to the stoichiometric ratio to prepare a 1.0 M solution of Yttrium chloride. 3+ Bi 3+ and Zr 4+ A mixed solution was prepared; under stirring conditions, the mixed solution and 2.0M sodium hydroxide solution were added to the reactor at a uniform rate. The pH value during precipitation was controlled at 5.5±0.2, with a final pH value of 13. The temperature was controlled at 60℃ to ensure complete cation precipitation. The precipitate was then filtered, washed, and dried. The dried product was calcined at 1000℃ for 2 hours to obtain YSZ powder. Further calcination at 1000℃ for 8 hours yielded rare earth zirconium-based ceramic powder YSZ. 0.1 Bi 0.03 Zr 0.85 O 1.925 After being sintered into ceramic, its bending strength was measured to be 353.49 MPa in a three-point bending test, and its electrical conductivity at 850℃ was measured to be 71.20 mS / cm using the DC four-probe method.

[0109] Comparative Example 4

[0110] Scandium nitrate, ytterbium nitrate, and zirconium oxynitrate were dissolved in water according to stoichiometric ratios to prepare a 1.10 M solution of Sc. 3+ Yb 3+ and Zr 4+ A mixed solution was prepared; under stirring conditions, the mixed solution and a 3.0M ammonia solution were added to the reactor at a uniform rate. The pH value during precipitation was controlled at 5.5±0.2, with a final pH value of 9, and the temperature was controlled at 30℃ to ensure complete cation precipitation. The precipitate was then filtered, washed, and dried. The dried product was calcined at 1000℃ for 2 hours to obtain ScSZ powder. This powder was then calcined at 900℃ for 15 hours to obtain rare earth zirconium-based ceramic powder Sc. 0.14 Yb 0.04 Zr0.82 O 1.91 After being sintered into ceramic, its conductivity at 850℃ was measured to be 165.23 mS / cm using the DC four-probe method.

[0111] Comparative Example 5

[0112] Yttrium chloride, magnesium nitrate, and zirconium oxychloride were dissolved in water according to the stoichiometric ratio to prepare a 1.0 M solution of Yttrium chloride. 3+ Mg 2+ and Zr 4+ A mixed solution was prepared; under stirring conditions, the mixed solution and magnesium bicarbonate solution were added to the reactor at a uniform rate. The pH value during the precipitation process was controlled at 4.7±0.2, with a final pH value of 8.5, and the temperature was controlled at 20℃ to ensure complete cation precipitation. The precipitate was then filtered, washed, and dried. The dried product was calcined at 1000℃ for 2 hours to obtain YSZ powder. This powder was then calcined at 800℃ for 17 hours to obtain rare earth zirconium-based ceramic powder YSZ. 0.05 Mg 0.03 Zr 0.92 O 1.96 After sintering into ceramic, phase analysis showed that it could maintain phase structure stability below 1200℃, and its fracture toughness was measured to be 2.76 MPa·m by indentation method. 1 / 2 After thermal spraying, a thermal shock cycle test was conducted, and the number of thermal shock cycles was measured to be 250.

[0113] Comparative Example 6

[0114] Lanthanum nitrate, scandium nitrate, and zirconium oxynitrate were dissolved in water according to stoichiometric ratios to prepare a 0.5M solution of La. 3+ ,Sc 3 + and Zr 4+ A mixed solution was prepared; under stirring conditions, the mixed solution and ammonia solution were added to the reactor at a uniform rate. The pH value during the precipitation process was controlled at 6±0.2, with a final pH value of 9.5, and the temperature was controlled at 50℃ to ensure complete cation precipitation. The precipitate was then filtered, washed, and dried. The dried product was calcined at 1000℃ for 2 hours to obtain LaZO powder. This powder was then calcined at 950℃ for 10 hours to obtain rare earth zirconium-based ceramic powder La. 0.4 Sc 0.1 Zr 0.5 O 1.75 After sintering into ceramic, phase analysis showed that it could maintain phase structure stability below 1500℃, and its fracture toughness measured by indentation method was 1.12 MPa·m. 1 / 2 After thermal spraying, a thermal shock cycle test was conducted, with 30 thermal shock cycles.

[0115] As can be seen from the above embodiments, the rare earth zirconium-based ceramic powder prepared by the embodiments of the present invention has significantly improved flexural strength, electrical conductivity, fracture toughness and thermal shock cycle count compared with the comparative example, and can achieve significant and beneficial technical effects.

[0116] In summary, this invention provides a grain boundary and surface-doped rare-earth zirconium-based ceramic material, its preparation method, and its applications. By employing grain boundary doping, the grain boundaries and surfaces of the rare-earth zirconium-based ceramic material contain oxides of M. Based on the different types and contents of doping elements, the sintering activity of the rare-earth zirconium-based ceramic material can be altered, thereby adjusting the grain size, number, and characteristics of the grain boundaries, ultimately optimizing the electrical, mechanical, and thermal properties of the material. The grain boundary and surface doping method provided by this invention is universal, achieving efficient and low-cost adjustment of the grain boundary characteristics of rare-earth zirconium-based ceramic materials, thereby improving their performance and meeting the requirements of different rare-earth zirconium-based ceramic materials for doping elements.

[0117] It should be understood that the specific embodiments described above are merely illustrative or explanatory of the principles of the invention and do not constitute a limitation thereof. Therefore, any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and scope of the invention should be included within the protection scope of the invention. Furthermore, the appended claims are intended to cover all variations and modifications falling within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.

Claims

1. A rare-earth zirconium-based ceramic material doped at grain boundaries and surfaces, characterized in that, The chemical formula of the rare earth zirconium-based ceramic material is RE x Zr 1-x-y M y O 2-z ;in, RE represents rare earth elements; M is a cation-doped element; M includes one or more of the following: cation transition metal elements, alkaline earth metal elements, Al, Ga, In, Ge, Sn, Sb, Bi, Si, and non-RE rare earth elements. 0.03≤x≤0.5, 0<y≤0.15, 0.01≤z<0.3; the grain boundaries and surface of the rare earth zirconium-based ceramic material contain oxides of doped element M.

2. The rare-earth zirconium-based ceramic material with grain boundary and surface doping according to claim 1, characterized in that, The RE is one or more of Sc, Y, La, Gd and Ce.

3. The rare-earth zirconium-based ceramic material with grain boundary and surface doping according to claim 1, characterized in that, M is one or more of Mg, Ca, Sr, Al, Ga, V, Fe, Mn, Ni, Zn, Nb, In, and Bi.

4. The rare-earth zirconium-based ceramic material with grain boundary and surface doping according to claim 3, characterized in that, M is one or more of Mg, Sr, Al, V, Ni, and Bi.

5. The rare-earth zirconium-based ceramic material with grain boundary and surface doping according to claim 3 or 4, characterized in that, The molar content of M in the rare earth zirconium-based ceramic material does not exceed 15%.

6. The rare-earth zirconium-based ceramic material with grain boundary and surface doping according to claim 5, characterized in that, The molar content of M in the rare earth zirconium-based ceramic material does not exceed 10%.

7. The rare-earth zirconium-based ceramic material with grain boundary and surface doping according to claim 1, characterized in that, The rare earth zirconium-based ceramic material is one or more of the following: cubic fluorite structure, tetragonal phase, monoclinic phase, and rhombohedral phase.

8. The rare-earth zirconium-based ceramic material with grain boundary and surface doping according to claim 7, characterized in that, The rare earth zirconium-based ceramic material is one or both of cubic fluorite structure and tetragonal phase.

9. A method for preparing a rare-earth zirconium-based ceramic material with grain boundary and surface doping as described in any one of claims 1-8, characterized in that, Including the following steps: S1. Mix the aqueous solutions of RE and Zr compounds in the required stoichiometric ratio to obtain a mixed solution; add the mixed solution and an alkaline substance to a reactor to carry out a precipitation reaction; filter, wash, dry and calcine the obtained precipitate to obtain rare earth zirconium-based oxide powder. S2. Mix the rare earth zirconium-based oxide powder material obtained in step S1 with the liquid salt of doping element M, dry it, and then perform one or two heat treatments, followed by one or two calcinations to obtain rare earth zirconium-based ceramic materials with grain boundary and surface doping.

10. A method for preparing a rare-earth zirconium-based ceramic material with grain boundary and surface doping as described in any one of claims 1-8, characterized in that, Including the following steps: S1. Mix RE, Zr and a portion of M liquid salt in the required stoichiometric ratio to obtain a mixed liquid; add the mixed liquid and alkaline substance to a reactor to carry out a precipitation reaction; filter, wash, dry and calcine the obtained precipitate to obtain rare earth zirconium-based oxide powder containing M element. S2. Mix the rare earth zirconium-based oxide powder containing element M obtained in step S1 with the liquid salt of the remaining dopant element M, dry it, and then perform one or two heat treatments, followed by one or two calcinations to obtain rare earth zirconium-based ceramic materials doped at grain boundaries and surfaces.

11. The method according to claim 9 or 10, characterized in that, The Zr-containing aqueous solution in step S1 includes one or more of the following aqueous solutions: zirconium oxychloride, zirconium oxynitrate, zirconium oxysulfate, zirconium acetate, and zirconium citrate.

12. The method according to claim 9 or 10, characterized in that, The aqueous solution containing RE in step S1 includes one or more of rare earth chlorides, nitrates, sulfates, acetates, and citrates.

13. The method according to claim 9 or 10, characterized in that, The liquid salt of the dopant element M includes one or more of the liquid salts of chlorides, nitrates, sulfates, acetates, citrates, and amino acid salts.

14. The method according to claim 9 or 10, characterized in that, The alkaline substance includes magnesium bicarbonate, urea, and at least one of the hydroxides, carbonates, or bicarbonates of at least one of the elements selected from ammonium, sodium, and potassium.

15. The method according to claim 14, characterized in that, The alkaline substance is at least one of sodium hydroxide, urea, ammonia, and ammonium bicarbonate.

16. The method according to claim 9 or 10, characterized in that, In step S1, the pH value during the precipitation process is controlled at 4.5~14, and the pH value at the precipitation endpoint is controlled at 8~13; the temperature during the precipitation process is 0~120℃.

17. The method according to claim 16, characterized in that, The pH value during the precipitation process in step S1 is controlled at 5~11, and the pH value at the precipitation endpoint is controlled at 9~11; the temperature during the precipitation process is 10~80℃.

18. The method according to claim 9 or 10, characterized in that, The roasting temperature in step S1 is 600~1100℃, and the roasting time is 1~24h.

19. The method according to claim 18, characterized in that, The roasting temperature in step S1 is 650~950℃, and the roasting time is 3~15h.

20. The method according to claim 9 or 10, characterized in that, The heat treatment temperature in step S2 is 200~750℃, and the heat treatment time is 1~24h.

21. The method according to claim 20, characterized in that, The heat treatment temperature in step S2 is 400~600℃, and the heat treatment time is 1~12h.

22. The method according to claim 9 or 10, characterized in that, The calcination temperature in step S2 is 700~1200℃, and the time is 1~24h.

23. The method according to claim 22, characterized in that, The calcination temperature in step S2 is 800~1100℃, and the time is 3~15h.

24. Applications of grain boundary and surface doped rare earth zirconium-based ceramic materials as described in any one of claims 1-8 in grinding media, fiber optic connectors, mobile phone back panels, bioceramics, thermal barrier coatings, oxygen sensors or nitrogen-oxygen sensors, and solid oxide fuel cells.

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