阅读说明：本技术 一种ZrN-镧硅酸盐复相陶瓷及其热压反应烧结制备方法 (ZrN-lanthanum silicate complex phase ceramic and hot pressing reaction sintering preparation method thereof ) 是由 陆有军 刘洋 李彦瑞 袁振侠 刘乡 于 2021-01-29 设计创作，主要内容包括：本申请提供一种ZrN-镧硅酸盐复相陶瓷及制备方法,主相包括ZrN、La-(4.67)Si-3O-(13),ZrN晶粒尺寸20-60μm,ZrN晶粒分散在La-(4.67)Si-3O-(13)中；其体积密度90％-95％,硬度6.5-9.5GPa,抗弯强度180-205MPa,断裂韧性1.6-2.8MPa.m～(1/2)；制备方法包括：取摩尔比为(1-4):3:2的α-Si-3N-4、La-2Zr-2O-7、Zr粉,加助剂后,依次球磨、烘干、研磨处理；而后压制成型,再热压烧结处理。通过在Si-3N-4-La-2Zr-2O-7二元原料系统引入Zr,避免气体对ZrN基复相陶瓷性能的影响,通过原料配比及合理的热压反应烧结制度获得了性能优异的陶瓷。(The application provides a ZrN-lanthanum silicate complex phase ceramic and a preparation method thereof, wherein a main phase comprises ZrN and La 4.67 Si 3 O 13 ZrN crystal grains with the size of 20-60 mu m are dispersed in La 4.67 Si 3 O 13 Performing the following steps; the volume density is 90-95%, the hardness is 6.5-9.5GPa, the bending strength is 180-205MPa, and the fracture toughness is 1.6-2.8MPa.m 1/2 (ii) a The preparation method comprises the following steps: taking alpha-Si with the molar ratio of (1-4) to 3:2 3 N 4 、La 2 Zr 2 O 7 Adding an auxiliary agent into Zr powder, and then performing ball milling, drying and grinding treatment in sequence; then pressing and forming, and hot pressing and sintering. By reaction at Si 3 N 4 ‑La 2 Zr 2 O 7 Zr is introduced into the binary raw material system, so that the influence of gas on the performance of the ZrN-based complex phase ceramic is avoided, and the ceramic with excellent performance is obtained through the raw material proportion and a reasonable hot-pressing reaction sintering system.)

1. The ZrN-lanthanum silicate composite ceramic is characterized in that the main phase comprises ZrN and La_4.67Si₃O₁₃The ZrN crystal grain size is 20-60 mu mThe ZrN crystal grains are dispersed in the La_4.67Si₃O₁₃Performing the following steps; the volume density of the ZrN-lanthanum silicate complex phase ceramic is 90-95 percent, the hardness is 6.5-9.5GPa, the bending strength is 180-205MPa, and the fracture toughness is 1.6-2.8MPa.m^1/2。

2. A hot-pressing reaction sintering preparation method of ZrN-lanthanum silicate complex phase ceramic is characterized by comprising the following steps:

the method comprises the following steps of: weighing appropriate amount of alpha-Si₃N₄、La₂Zr₂O₇Adding a proper amount of auxiliary agent into Zr powder, performing ball milling treatment, and then performing drying treatment and grinding treatment to obtain mixture powder;

a molding treatment step: placing the mixture powder in a forming die, and applying pressure to perform forming treatment to obtain a forming blank;

the hot-pressing reaction sintering treatment step: carrying out hot-pressing sintering treatment on the formed blank to obtain the ZrN-lanthanum silicate complex phase ceramic;

wherein, in the raw material pretreatment step, the alpha-Si is₃N₄Is expressed by m, and the La₂Zr₂O₇The mol number of the Zr powder is represented by n, and the mol number of the Zr powder is represented by p, the mixture ratio of the reaction raw materials is as follows: m: n: p ═ (1-4) 3: 2.

3. The hot-pressing reaction sintering production method according to claim 2, wherein in the raw material pretreatment step, the α -Si is used as the raw material₃N₄The purity of the product is more than 99.9 percent, and the granularity is less than 0.7 mu m; the La₂Zr₂O₇The purity of the product is more than 99.5 percent, and the granularity is less than 1.8 mm; the Zr powder has a purity of 99.5% or more and a particle size of 75 μm or less.

4. The hot-pressing reactive sintering production method according to claim 2 or 3, wherein in the raw material pretreatment step, the auxiliary agent is ethanol.

5. The hot-pressing reactive sintering preparation method as claimed in any one of claims 2 to 4, wherein in the raw material pretreatment step, the time of the ball milling treatment is 30 to 180min, and the rotation speed of the ball mill is set to 500-.

6. The hot-pressing reaction sintering production method according to any one of claims 2 to 5, wherein in the raw material pretreatment step, the temperature of the baking treatment is 90 to 110 ℃.

7. The hot-pressing reactive sintering production method according to any one of claims 2 to 6, wherein in the molding treatment step, the pressure is 2MPa to 5MPa.

8. The hot-pressing reaction sintering preparation method according to any one of claims 2 to 7, wherein in the hot-pressing reaction sintering treatment step, the temperature is raised to 1400 ℃ at a constant speed within 0 to 70min, and simultaneously the pressure is increased to 24KN at a constant speed within 0 to 70min, and the sintering is carried out for 60 to 80min while maintaining 1400 ℃ and 24 KN.

Technical Field

The invention belongs to the field of inorganic ceramic materials, and particularly relates to a ZrN-lanthanum silicate complex phase ceramic and a hot-pressing sintering preparation method thereof.

Background

Ultra High Temperature Ceramics (UHTCs) refer to ceramic materials that provide mechanical stability and heat dissipation when operated in extreme environments (e.g., extreme heat flux, chemically reactive plasma, or harsh environments with extremely high oxygen content), and have stable physicochemical properties, such as high thermal and electrical conductivity, good thermal shock resistance, excellent corrosion resistance, and the like. UHTCs materials are mainly borides, carbides and nitrides of transition metals (Ti, Zr, Hf, Nb, Ta, etc.) and ceramic materials compounded with them, including zirconium diboride (ZrB)₂) Hafnium diboride (HfB)₂) Zirconium carbide (ZrC), hafnium carbide (HfC), zirconium nitride (ZrN), hafnium nitride (HfN), and the like. ZrN has high melting point, high hardness, high wear resistance and good corrosion resistance as an ultra-high temperature ceramic (UHTCs), and the sintering difficulty is very high due to the strong covalent bond, high melting point and low diffusion coefficient of ZrN, so that the preparation of the ultra-high temperature ZrN ceramic by in-situ reaction sintering is considered to be a low-consumption preparation method. Si₃N₄-ZrO₂The binary system can react to synthesize ZrN, but the reaction can generate a large amount of volatile gases (SiO and N2), the sintering has a large loss rate, and the sintering cannot be dense.

In order to eliminate volatile gases during the reaction, in Si₃N₄-ZrO₂Introducing rare earth metal oxide La into binary system₂O₃Solidifying volatile gas SiO and promoting Si₃N₄-ZrO₂By substitution reaction to form ZrN, by Si₃N₄-ZrO₂-La₂O₃The ternary system can generate ZrN phase and various silicate phases through one-step in-situ reaction, and the silicate phases are commonly La_4.67Si₃O₁₃、La₅Si₃NO₁₂、La₄Si₂N₂O₇、LaSiNO₂、La₂Zr₂O₇Etc. according to previous studies by the applicant, La has been found₂Zr₂O₇Is generated in lanthanum silicate at lower temperature, and because the structure of the lanthanum silicate contains certain oxygen vacancy, a channel is provided for the diffusion of oxygen ions and nitrogen ions, and Si can be improved through the vacancy diffusion of a point defect structure₃N₄-ZrO₂-La₂O₃Reaction rate of ternary system (see Liyanrui, Lujun, etc.. Si)₃N₄-ZrO₂-La₂O₃Systematic reaction for ZrN synthesis and phase diagram construction inorganic materials bulletin, Vol.35, No. 7, pp.823-826), but La₂O₃And ZrO₂Reaction to form La₂Zr₂O₇Pyrochlore phase, pyrochlore phase possibly being combined with Si₃N₄Reaction to form ZrN and silicate on Si₃N₄-La₂Zr₂O₇La in binary reaction system₂Zr₂O₇Since Zr4+ is reduced to Zr3+ during the nitridation to ZrN, accompanied by the evolution of gas, the formulation of the raw material is optimized to avoid the gas from reacting with Si₃N₄-La₂Zr₂O₇The influence of the mechanical property of the ZrN-based complex phase ceramic prepared by the binary system reaction becomes a main technical problem.

Aiming at the technical problems, the invention provides an improved ceramic formula system and prepares the ZrN-lanthanum silicate complex phase ceramic by utilizing a hot pressing reaction sintering process.

Disclosure of Invention

One of the purposes of the application is to provide a ZrN-lanthanum silicate complex phase ceramic which has good comprehensive performance.

Another objective of the application is to provide a hot-pressing reaction sintering preparation method of ZrN-lanthanum silicate complex phase ceramic, by introducing La₂Zr₂O₇The metal Zr simple substance forms Si₃N₄-La₂Zr₂O₇And a Zr-Zr ternary system is used for optimizing the raw material formula to reduce gas generation, so that the ZrN-lanthanum silicate complex phase ceramic with low shrinkage, high density and excellent mechanical property is prepared.

In order to achieve the purpose, the following technical scheme is adopted in the application:

the ZrN-lanthanum silicate complex phase ceramic has main phase comprising ZrN and La_4.67Si₃O₁₃ZrN grains having a size of 20 to 60 μm (e.g., 25 μm, 30 μm, 40 μm, 50 μm, 55 μm, etc.) dispersed in La_4.67Si₃O₁₃Performing the following steps; the volume density of the ZrN-lanthanum silicate complex phase ceramic is 90-95 percent (such as 90.5 percent, 91 percent, 92 percent, 93 percent, 94 percent, 94.5 percent and the like), the hardness is 6.5-9.5GPa (such as 7GPa, 7.5GPa, 8GPa, 8.5GPa and the like), the bending strength is 180-205MPa (such as 182MPa, 185MPa, 190MPa, 195MPa, 200MPa, 203MPa and the like), and the fracture toughness is 1.6-2.8MPa.m^1/2(e.g., 1.8MPa. m)^1/2、2.0MPa.m^1/2、2.2MPa.m^1/2、2.4MPa.m^1/2、2.6MPa.m^1/2Etc.).

A hot-pressing reaction sintering preparation method of ZrN-lanthanum silicate complex phase ceramic comprises the following steps:

the method comprises the following steps of: weighing appropriate amount of alpha-Si₃N₄、La₂Zr₂O₇Adding a proper amount of auxiliary agent into Zr powder, performing ball milling treatment, and then performing drying treatment and grinding treatment to obtain mixture powder;

a molding treatment step: placing the mixture powder in a forming die, and applying pressure to perform forming treatment to obtain a forming blank;

the hot-pressing reaction sintering treatment step: carrying out hot-pressing sintering treatment on the formed blank to obtain the ZrN-lanthanum silicate complex phase ceramic;

wherein, in the raw material pretreatment step, the alpha-Si is₃N₄Is expressed by m, and the La₂Zr₂O₇The mol number of the Zr powder is represented by n, and the mol number of the Zr powder is represented by p, the mixture ratio of the reaction raw materials is as follows: m: n: p ═ (1-4) 3: 2.

In the above-mentioned method for preparing ZrN-lanthanum silicate complex phase ceramic by hot pressing reaction sintering, as a preferred embodiment, in the step of pretreating the raw material, the alpha-Si is added₃N₄The purity of the product is more than 99.9 percent, and the granularity is less than 0.7 mu m; the La₂Zr₂O₇Has a purity of 99.5% or more and a particle size of 11 mesh (i.e., about 1.8mm or less); the Zr powder has a purity of 99.5% or more and a particle size of 200 mesh (i.e., about 75 μm or less).

In the above-mentioned preparation method of the ZrN-lanthanum silicate complex phase ceramic by hot pressing reaction sintering, as a preferred embodiment, in the step of pretreating the raw material, the auxiliary agent is ethanol.

In the preparation method of the ZrN-lanthanum silicate multiphase ceramic by hot-pressing reaction sintering, as a preferred embodiment, in the raw material pretreatment step, the ball milling time is 30-180min (e.g., 40min, 50min, 60min, 70min, 80min, 90min, 100min, 110min, 120min, 130min, 140min, 150min, 160min, 170min, etc.), and the ball mill rotation speed is set to 500-.

In the above-mentioned method for preparing ZrN-lanthanum silicate multiphase ceramic by hot-pressing reaction sintering, as a preferred embodiment, in the step of pretreating the raw material, the temperature of the drying treatment is 90-110 ℃ (for example, 92 ℃, 95 ℃, 100 ℃, 105 ℃, 108 ℃ and the like), and the time is 3-12h (for example, 4h, 5h, 6h, 7h, 8h, 9h, 10h, 11h and the like).

In the above-mentioned method for preparing ZrN-lanthanum silicate multiphase ceramic by hot-pressing reaction sintering, as a preferred embodiment, in the step of forming treatment, the pressure is 2MPa to 5MPa (such as 2.5MPa, 3MPa, 3.5MPa, 4MPa, 4.5MPa, etc.).

In the hot-pressing reaction sintering preparation method of the ZrN-lanthanum silicate complex phase ceramic, as a preferred embodiment, in the hot-pressing reaction sintering treatment step, the temperature is increased to 1400 ℃ at a constant speed within 0-70min, and simultaneously the pressure is increased to 24KN at a constant speed within 0-70min, and the temperature is maintained at 1400 ℃ and the pressure of 24KN for sintering for 60-80 min.

The ZrN-lanthanum silicate complex phase ceramic prepared by the hot pressing reaction sintering preparation method of the ZrN-lanthanum silicate complex phase ceramic comprises the main phase of ZrN and La_4.67Si₃O₁₃ZrN grains having a size of 20 to 60 μm (e.g., 25 μm, 30 μm, 40 μm, 50 μm, 55 μm, etc.) are dispersed in La_4.67Si₃O₁₃Performing the following steps; the volume density of the ZrN-lanthanum silicate complex phase ceramic is 90-95 percent (such as 90.5 percent, 91 percent, 92 percent, 93 percent, 94 percent, 94.5 percent and the like), the hardness is 6.5-9.5GPa (such as 7GPa, 7.5GPa, 8GPa, 8.5GPa and the like), the bending strength is 180-205MPa (such as 182MPa, 185MPa, 190MPa, 195MPa, 200MPa, 203MPa and the like), and the fracture toughness is 1.6-2.8MPa.m^1/2(e.g., 1.8MPa. m)^1/2、2.0MPa.m^1/2、2.2MPa.m^{1 /2}、2.4MPa.m^1/2、2.6MPa.m^1/2Etc.).

To avoid gas to Si₃N₄-ZrO₂-La₂O₃Influence of the Properties of ZrN-based Complex phase ceramic prepared by ternary System reaction the raw Material System of this application is in Si₃N₄-La₂Zr₂O₇The binary system is introduced with a metal Zr simple substance, the metal Zr has strong chemical affinity with oxidants such as nitrogen, oxygen and the like, and can respectively form ZrN and ZrO at high temperature₂. Further to reduce La₂Zr₂O₇Pyrochlore phase with Si₃N₄Reacting the process gas to increase the silicon nitride content to suppress Si₃N₄-La₂Zr₂O₇The sintering of the ZrN-lanthanum silicate complex phase ceramic can be promoted, the mechanical comprehensive performance of the complex phase ceramic obtained in the raw material proportioning range of the invention is superior to other formula systems, and the invention has direct relation with the complex phase composition of the ZrN-lanthanum silicate.

Compared with the prior art, the beneficial effects of the application include but are not limited to:

1) the ZrN-lanthanum silicate complex phase ceramic provided by the application has good comprehensive performance, the volume density reaches 90-95%, the hardness can reach 6.5-9.5GPa, the bending strength can reach 180-205MPa, and the fracture toughness can reach 1.6-2.8MPa.m^{1 /2}；

2) The application provides a hot-pressing reaction sintering preparation method of ZrN-lanthanum silicate complex phase ceramic, which is implemented by a raw material system (Si)₃N₄-La₂Zr₂O₇Binary system) to avoid gas to Si by introducing metal Zr simple substance₃N₄-ZrO₂-La₂O₃Ternary system, and Si₃N₄-La₂Zr₂O₇The influence of the performance of the ZrN-based complex phase ceramic prepared by the binary system reaction can regulate the appearance of silicate phase in the product and further properly increase Si₃N₄Content of La is reduced₂Zr₂O₇Pyrochlore phase with Si₃N₄Reacting the process gas to suppress Si₃N₄-La₂Zr₂O₇Thereby enabling to promote ZrN-La_4.67Si₃O₁₃The sintering of the complex phase ceramic improves the comprehensive performance of the ZrN-lanthanum silicate complex phase ceramic.

Drawings

FIG. 1 is a schematic view of a hot press reaction sintering treatment system according to examples 1 to 4 and comparative example 1 of the present application;

FIG. 2 is an XRD pattern of ZrN-lanthanum silicate complex phase ceramics prepared in examples 1-4 and comparative example 1;

FIG. 3 is SEM photographs (scale bar 10 μm) of the sintered bodies prepared in examples 1 and 3, wherein (a) shows the SEM morphology of the sintered body prepared in example 2 and (b) shows the SEM morphology of the sintered body prepared in example 3;

FIG. 4 shows the results of bulk density tests on ZrN-lanthanum silicate complex phase ceramics prepared in examples 1 to 4 and comparative example 1 and on ceramic bodies prepared in comparative example 1;

FIG. 5 shows hardness test results of ZrN-lanthanum silicate complex phase ceramics prepared in examples 1 to 4 and comparative example 1 and ceramic bodies prepared in comparative example 1;

FIG. 6 shows the results of flexural strength tests on ZrN-lanthanum silicate complex phase ceramics prepared in examples 1 to 4 and comparative example 1 and on ceramic bodies prepared in comparative example 1;

FIG. 7 shows the results of fracture toughness tests for ZrN-lanthanum silicate complex phase ceramics prepared in examples 1-4 and comparative example 1 and ceramic bodies prepared in comparative example 1.

Detailed Description

The following examples are presented to facilitate a better understanding of the present application and are not intended to limit the present application.

The experimental procedures in the following examples are conventional unless otherwise specified.

The test materials used in the following examples were purchased from a conventional biochemical reagent store unless otherwise specified.

Example 1

1) Selecting alpha-Si₃N₄The purity is 99.9 percent, and the granularity is less than or equal to 0.7 mu m; la₂Zr₂O₇: the purity is 99.5 percent, and the mixture is sieved by a 11-mesh sieve; zr powder: the purity is 99.5 percent, and the particle size is sieved by a 200-mesh sieve; wherein alpha-Si₃N₄、La₂Zr₂O₇The mol ratio of Zr powder is: 1:3:2 (marked 1S3LZ2Zr), from which a starting powder was prepared;

2) weighing the raw material powder in the proportion, then using ethanol as a medium, putting the raw material powder into a ball milling tank, carrying out ball milling for 40min, setting the rotating speed of the ball milling tank to be 500r/min, drying the mixed raw material after ball milling, controlling the drying temperature to be within 90 ℃, setting the drying time to be 12 hours, and grinding the mixture after drying;

3) placing the ground mixture powder into a forming die, and applying pressure in a press machine for forming, wherein the pressure range is set to be 5 MPa;

4) and (3) placing the pressed and formed blank into a hot-pressing sintering furnace for sintering: heating to 1400 deg.C at constant speed within 0-70min, pressurizing to 24KN at constant speed within 0-70min, sintering at 1400 deg.C and 24KN for 60min, stopping heating, and cooling to room temperature, as shown in FIG. 1, to obtain ZrN-lanthanum silicate complex phase ceramic.

The ZrN-lanthanum silicate complex phase ceramic prepared in the embodiment is marked as a sample 1S3LZ2Zr, the XRD pattern of the ceramic is shown in figure 2, and the main phases ZrN and La can be seen from the figure_4.67Si₃O₁₃And with a small amount of La₂Zr₂O₇Not completely reacted and a small amount of ZrO is also formed₂. The samples were subjected to the performance test, and the results are shown in FIGS. 4 to 7, respectively, in which the density was 92%, the hardness was 9.1GPa, the bending strength was 185.0MPa, and the fracture toughness was 1.75MPa.m^1/2。

Example 2

1) Selecting alpha-Si₃N₄The purity is 99.9 percent, and the granularity is less than or equal to 0.7 mu m; la₂Zr₂O₇: the purity is 99.5 percent, and the mixture is sieved by a 11-mesh sieve; zr powder: the purity is 99.5 percent, and the particle size is sieved by a 200-mesh sieve; wherein alpha-Si₃N₄、La₂Zr₂O₇The mol ratio of Zr powder is: 2:3:2 (labeled 2S3LZ2Zr), from which a raw material powder was prepared;

2) weighing the raw material powder in the proportion, then using ethanol as a medium, putting the raw material powder into a ball milling tank, carrying out ball milling for 40min, setting the rotating speed of the ball milling tank to be 500r/min, drying the mixed raw material after ball milling, controlling the drying temperature to be within 90 ℃, setting the drying time to be 12 hours, and grinding the mixture after drying;

3) placing the ground mixture powder into a forming die, and applying pressure in a press machine for forming, wherein the pressure range is set to be 5 MPa;

4) and (2) sintering the pressed and formed blank in a hot-pressing sintering furnace, heating to 1400 ℃ at a constant temperature rising speed within 0-70min, simultaneously pressurizing to 24KN at a constant temperature within 0-70min, sintering for 60min under the conditions of 1400 ℃ and 24KN, stopping heating, and cooling to room temperature, wherein the ZrN-lanthanum silicate complex phase ceramic is prepared as shown in figure 1.

The ZrN-lanthanum silicate complex phase ceramic prepared in the embodiment is marked as a sample 2S3LZ2Zr, the XRD pattern of the ceramic is shown in figure 2, and the main phases ZrN and La can be seen from the figure_4.67Si₃O₁₃And also a small amount of ZrO₂. FIG. 3(a) shows the SEM microscopic profile of the ceramic sample preparedIn light gray La_4.67Si₃O₁₃Phase, the dark gray is ZrN, the black is micro-pores, it can be seen that the size of ZrN crystal grains is 20-60 μm in the micro morphology, the ZrN crystal grains are dispersed in La_4.67Si₃O₁₃In (1). The samples were subjected to the performance test, and the results are shown in FIGS. 4 to 7, respectively, in which the density was 95%, the hardness was 8.6GPa, the bending strength was 185.5MPa, and the fracture toughness was 2.68MPa.m^{1 /2}。

Example 3

1) Selecting alpha-Si₃N₄The purity is 99.9 percent, and the granularity is less than or equal to 0.7 mu m; la₂Zr₂O₇: the purity is 99.5 percent, and the mixture is sieved by a 11-mesh sieve; zr powder: the purity is 99.5 percent, and the particle size is sieved by a 200-mesh sieve; wherein alpha-Si₃N₄、La₂Zr₂O₇The mol ratio of Zr powder is: 3:3:2 (labeled 3S3LZ2Zr), from which a raw material powder was prepared;

2) weighing the raw material powder in the proportion, then using ethanol as a medium, putting the raw material powder into a ball milling tank, carrying out ball milling for 40min, setting the rotating speed of the ball milling tank to be 500r/min, drying the mixed raw material after ball milling, controlling the drying temperature to be within 90 ℃, setting the drying time to be 12 hours, and grinding the mixture after drying;

3) placing the ground mixture powder into a forming die, and applying pressure in a press machine for forming, wherein the pressure range is set to be 5 MPa;

4) and (2) sintering the pressed and formed blank in a hot-pressing sintering furnace, heating to 1400 ℃ at a constant temperature rising speed within 0-70min, simultaneously pressurizing to 24KN at a constant temperature within 0-70min, sintering for 60min under the conditions of 1400 ℃ and 24KN, stopping heating, and cooling to room temperature, wherein the ZrN-lanthanum silicate complex phase ceramic is prepared as shown in figure 1.

The XRD pattern of the ZrN-lanthanum silicate complex phase ceramic prepared in the example is shown as a sample 3S3LZ2Zr, and the figure 2 shows that the main phases ZrN and La can be seen from the XRD pattern_4.67Si₃O₁₃And also a small amount of ZrO₂. FIG. 3 shows the SEM microstructure of the prepared ceramic sample, light gray La_4.67Si₃O₁₃Phase, dark gray is ZrN, blackThe color is micro-pores, and it can be seen that in the micro-morphology, the ZrN crystal grains have the size of 20-60 μm, and are dispersed in La_4.67Si₃O₁₃In (1). The samples were subjected to the performance test, and the results are shown in FIGS. 4 to 7, respectively, in which the density was 93%, the hardness was 8.0GPa, the bending strength was 203.6MPa, and the fracture toughness was 2.32MPa.m^1/2。

Example 4

1) Selecting alpha-Si₃N₄The purity is 99.9 percent, and the granularity is less than or equal to 0.7 mu m; la₂Zr₂O₇: the purity is 99.5 percent, and the mixture is sieved by a 11-mesh sieve; zr powder: the purity is 99.5 percent, and the particle size is sieved by a 200-mesh sieve; wherein alpha-Si₃N₄、La₂Zr₂O₇The mol ratio of Zr powder is: 4:3:2 (marked 4S3LZ2Zr), from which a raw material powder was prepared;

2) weighing the raw material powder in the proportion, then using ethanol as a medium, putting the raw material powder into a ball milling tank, carrying out ball milling for 40min, setting the rotating speed of the ball milling tank to be 500r/min, drying the mixed raw material after ball milling, controlling the drying temperature to be within 90 ℃, setting the drying time to be 12 hours, and grinding the mixture after drying;

3) placing the ground mixture powder into a forming die, and applying pressure in a press machine for forming, wherein the pressure range is set to be 5 MPa;

4) and (2) sintering the pressed and formed blank in a hot-pressing sintering furnace, heating to 1400 ℃ at a constant temperature rising speed within 0-70min, simultaneously pressurizing to 24KN at a constant temperature within 0-70min, sintering for 60min under the conditions of 1400 ℃ and 24KN, stopping heating, and cooling to room temperature, wherein the ZrN-lanthanum silicate complex phase ceramic is prepared as shown in figure 1.

The ZrN-lanthanum silicate complex phase ceramic prepared in the embodiment is marked as a sample 4S3LZ2Zr, the XRD pattern of the ceramic is shown in figure 2, and the main phases ZrN and La can be seen from the figure_4.67Si₃O₁₃And also a small amount of ZrO₂. FIG. 3(b) shows the SEM microstructure of the ceramic sample prepared, light gray La_4.67Si₃O₁₃Phase, the dark gray is ZrN, the black is micro-pores, it can be seen that in the micro-morphology, the size of ZrN grains is 20-60 μm, and the ZrN grains are dispersed inLa_4.67Si₃O₁₃In (b) with Si₃N₄The addition amount of (A) is increased, and the micro pores of the prepared ceramic sample are obviously increased. The samples were subjected to the performance test, and the results are shown in FIGS. 4 to 7, respectively, in which the density was 94%, the hardness was 6.5GPa, the bending strength was 195.3MPa, and the fracture toughness was 1.76MPa.m^1/2。

Comparative example 1

1) Selecting La₂Zr₂O₇: the purity is 99.5 percent, and the mixture is sieved by a 11-mesh sieve; zr powder: the purity is 99.5 percent, and the particle size is sieved by a 200-mesh sieve; la₂Zr₂O₇And a molar ratio of Zr powder was 3:2 (designated as 0S3LZ2Zr), thereby preparing a raw material powder;

2) weighing the raw material powder in the proportion, then using ethanol as a medium, putting the raw material powder into a ball milling tank, carrying out ball milling for 40min, setting the rotating speed of the ball milling tank to be 500r/min, drying the mixed raw material after ball milling, controlling the drying temperature to be within 90 ℃, setting the drying time to be 12 hours, and grinding the mixture after drying;

3) placing the ground mixture powder into a forming die, and applying pressure in a press machine for forming, wherein the pressure range is set to be 5 MPa;

4) and (3) sintering the pressed and formed blank in a hot-pressing sintering furnace, heating to 1400 ℃ at a constant temperature rising speed within 0-70min, simultaneously pressurizing to 24KN at a constant temperature within 0-70min, sintering for 60min by keeping 1400 ℃ and 24KN, stopping heating, and cooling to room temperature, wherein the reference is made in figure 1, so as to obtain the ceramic block.

The ceramic produced in this comparative example, designated as sample 0S3LZ2Zr, had an XRD pattern as shown in FIG. 2, from which only La was seen₂Zr₂O₇Diffraction peaks. The samples were subjected to the performance test, and the results are shown in FIGS. 4 to 7, respectively, in which the density was 87%, the hardness was 4.1GPa, the bending strength was 115.2MPa, and the fracture toughness was 0.48MPa.m^1/2。

TABLE 1 comparison of the parameters of the examples and comparative examples

As shown in Table 1 above, with Si₃N₄The content is increased, the relative density and the bending strength of the ZrN-based complex phase ceramic are improved, and the sample prepared in the example 2 has good mechanical property, the relative density is 95 percent, the hardness reaches 8.6GPa, the bending strength is 188.18MPa, and the fracture toughness is 2.68MPa.m^1/2(ii) a When Si is present₃N₄At higher contents, Si₃N₄-La₂Zr₂O₇Excess of Si in binary system₃N₄Does not participate in the reaction, and the prepared ceramic sample has high bending strength and low fracture toughness.

Finally, it should be further noted that, in the present application, relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

While the application has been disclosed by the description of specific embodiments thereof, it should be understood that various modifications, adaptations, and equivalents may occur to one skilled in the art and are within the spirit and scope of the appended claims. Such modifications, improvements and equivalents are intended to be included within the scope of the claims.