CN107986777B

CN107986777B - Zirconia ceramic matrix composite and preparation method thereof

Info

Publication number: CN107986777B
Application number: CN201711092738.5A
Authority: CN
Inventors: 李专; 肖鹏; 刘鹏飞; 程艳蒙
Original assignee: Central South University
Current assignee: Central South University
Priority date: 2017-11-08
Filing date: 2017-11-08
Publication date: 2021-05-18
Anticipated expiration: 2037-11-08
Also published as: CN107986777A

Abstract

The invention relates to a zirconia ceramic matrix composite and a preparation method thereof, belonging to the technical field of design and preparation of ceramic matrix composites. The raw materials of the zirconia ceramic matrix composite material comprise the following components in percentage by mass: 40-60% of zirconium oxide; 4-10% of yttrium oxide; 5.1 to 25.5 percent of alumina; 2-10% of silicon dioxide; 1-4% of acrylamide; 0.1 to 0.4 percent of N, N-methylene bisacrylamide; 0.2 to 1 percent of sodium hexametaphosphate; 1-4% of ammonium persulfate; 0.5 to 2 percent of tetramethyl ethylene diamine; the balance being water. The preparation method comprises the steps of preparing slurry, obtaining a wet blank by adopting a gel casting method, drying under special conditions, and finally calcining to obtain a finished product. The invention has reasonable component design, simple and controllable preparation process, and excellent performance of the obtained product, can be used for biological materials, electronic materials, friction wear-resistant materials and the like, and is convenient for large-scale industrial application.

Description

Zirconia ceramic matrix composite and preparation method thereof

Technical Field

The invention relates to a zirconia ceramic matrix composite and a preparation method thereof, and the ceramic matrix composite is mainly applied to biological materials, electronic materials, friction wear-resistant materials and the like, and belongs to the technical field of design and preparation of ceramic matrix composites.

Background

Zirconia powder is a natural byproduct of copper ore, phosphate ore, magnetite, and baddeleyite ores. Or obtained by chemical pyrolysis of zircon. Adding a stabilizer, such as Y₂O₃CaO, MgO and CeO₂ZrO is formed by sintering₂A ceramic. ZrO since 1975₂Ceramics are gradually gaining importance in many countries. The 'ceramic heat' of the whole world was covered by ZrO during the 80 s₂The ceramic was the subject of investigation. ZrO has had various properties for almost 20 years₂Ceramics and ZrO₂The composite ceramic which is a phase change toughening substance is rapidly developed and is increasingly widely applied in many fields of industry and science and technology.

ZrO due to excellent mechanical properties, low thermal conductivity and good thermal shock resistance₂Ceramics are known as 'ceramic steel', and have very wide application. Because it has high hardness, good wear resistance and very low thermal conductivity at room temperature, and is an insulator at room temperature, it is an ideal structural ceramic, in the electronic materials of fuel cell, oxygen sensor and oxygen pump, etc. and friction wear-resistant materialHas good application in material aspect. As a novel fine ceramic, the zirconia ceramic has the characteristics of good mechanical property, biocompatibility, stability, aesthetic property, thermal conductivity, formability and the like. Therefore, particular attention has been paid in recent years to the field of oral restoration. Although ZrO₂Ceramics have excellent physical and chemical properties, but the brittleness, which is a fatal disadvantage of ceramics, limits their applications. Therefore, to improve ZrO₂The application performance of the ceramic material needs to be toughened to prepare ZrO₂A ceramic matrix composite. The prior zirconia ceramic toughening effective modes are as follows: zirconium oxide phase transformation toughening and second phase toughening. The main mechanism of the toughening method is that zirconia particles are subjected to crystal transformation from tetragonal phase to monoclinic phase to cause volume expansion, so that the toughening effect is achieved. The main toughening mechanisms of the second phase are load transfer, crack deflection and the like, and the existence of the second phase can increase the energy consumption of crack propagation, thereby achieving the aim of toughening.

Second phase toughening can be divided into external introduction and in situ autogenesis. The external introduction method is to introduce the existing second phase into the matrix directly, and the toughening and reinforcing effects are remarkable, so that the external introduction method is widely applied. However, the method has problems that the second phase particles are difficult to disperse, the uniformity is poor, and the sintering is affected. The in-situ autogenesis method is to mix the reactants and add the raw materials for generating the second phase, and the composition phase generates the required second phase in situ in the sintering process, thus not only avoiding the defects of mutual incompatibility and uneven particle distribution, but also ensuring that the strength and toughness of the toughened material are higher than those of the toughened material by adding the second phase alone. And the in-situ generation method does not need to prepare or treat the second phase in advance, thereby greatly simplifying the preparation process and reducing the production cost. The method is a new process capable of effectively improving the fracture toughness of the ceramic, has a plurality of excellences, but the development is not yet mature at present, and is only rarely recorded in related documents, so that the research on the preparation process is very necessary.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a zirconia ceramic matrix composite and a preparation method thereof, which effectively solve the problems of insufficient strength and toughness, short service life and poor stability of the existing zirconia ceramic material.

The invention relates to a zirconia ceramic matrix composite, which comprises the following raw materials in percentage by mass:

40 to 60% of zirconia, preferably 42 to 50%, more preferably 44 to 46%, and still more preferably 45%;

yttrium oxide 4-10%, preferably 4-8%, more preferably 4-6%, and still more preferably 5-5.5%;

5.1 to 25.5% of alumina, preferably 10 to 20%, more preferably 10 to 16%, and still more preferably 12.75 to 15.3%;

2 to 10% of silica, preferably 4 to 8%, more preferably 4 to 6%, and still more preferably 5 to 6%;

1 to 4% of acrylamide, preferably 1.5 to 3%, and more preferably 2%;

0.1 to 0.4% of N, N-methylenebisacrylamide, preferably 0.15 to 0.3% of N, N-methylenebisacrylamide, and more preferably 0.2% of N, N-methylenebisacrylamide;

sodium hexametaphosphate 0.2-1%, preferably 0.5-0.8%, more preferably 0.6-0.7%, and still more preferably 0.7%;

1-4% of ammonium persulfate solution, preferably 1.5-3%, and more preferably 2%; the ammonium persulfate solution is preferably an ammonium persulfate aqueous solution; the concentration of the ammonium persulfate aqueous solution is 9-11 wt%;

tetramethylethylenediamine 0.5 to 2%, preferably 0.75 to 1.5%, and more preferably 1%.

If the balance is water, the balance is water. The water is preferably deionized water, excluding water contained in the aqueous ammonium persulfate solution.

As a preferred scheme, the invention relates to a zirconia ceramic matrix composite; the molar ratio of alumina to silica in the raw materials used is 3:1.5 to 2.5, more preferably 3: 2.

As a preferred scheme, the invention relates to a zirconia ceramic matrix composite; among the raw materials used, alumina is preferably 10 to 20%, more preferably 10 to 16%, and still more preferably 12.75 to 15.3%.

As a preferred scheme, the invention relates to a zirconia ceramic matrix composite; among the raw materials used, silica is preferably 2 to 8%, more preferably 2 to 6%, and still more preferably 5 to 6%.

The invention relates to a preparation method of a zirconia ceramic matrix composite, which comprises the following steps:

step one

Taking zirconium oxide powder, yttrium oxide powder, aluminum oxide powder, silicon dioxide powder, acrylamide, N-methylene bisacrylamide, sodium hexametaphosphate, ammonium persulfate, tetramethylethylenediamine and water as raw materials according to the design group distribution,

uniformly mixing the prepared acrylamide, N-methylene bisacrylamide, sodium hexametaphosphate and water, and adjusting the pH value to 9-11 to obtain a premixed solution;

step two

Adding the prepared zirconium oxide powder, yttrium oxide powder, aluminum oxide powder and silicon dioxide powder into the premixed liquid obtained in the step one, and uniformly mixing to obtain slurry;

step three

After the slurry obtained in the second step is degassed, under the protective atmosphere, adding the prepared tetramethylethylenediamine into the degassed slurry, stirring and mixing uniformly, then increasing the stirring speed to 500-1000r/min, adding the prepared ammonium persulfate solution within 5-10 seconds, stirring for 5-10 seconds, and then pouring into a mold to polymerize and crosslink the organic monomer in the suspension to form a three-dimensional network structure; demolding to obtain a wet blank;

step four

Putting the wet blank obtained in the step three into 40-60 wt% of polyethylene glycol solution and/or ethanol for drying, preferably polyethylene glycol solution, taking out and naturally drying in the air, and finally putting into an oven for drying at 40-90 ℃ to obtain a dried blank;

step five

Heating the dried blank to 500-plus-one temperature of 600 ℃, preserving heat, then heating to 950-1200 ℃, preserving heat, finally heating to 1450-plus-one temperature of 1650 ℃, preserving heat for at least 1h, and cooling to obtain the zirconia ceramic matrix composite.

In a first step, the prepared acrylamide, N-methylene bisacrylamide, sodium hexametaphosphate and deionized water are stirred at 30-45 ℃ for 10-20 min, and then the pH value is adjusted to 10-11 to obtain a premixed solution.

As a preferable scheme, in the first step of the preparation method of the zirconia ceramic matrix composite material, the particle size of the zirconia powder is 1-2 microns.

Preferably, in the first step of the preparation method of the zirconia ceramic matrix composite, the particle size of the yttria powder is 1-5 microns.

Preferably, in the first step of the preparation method of the zirconia ceramic matrix composite material, the grain size of the alumina powder is 1-5 microns.

Preferably, in the first step of the preparation method of the zirconia ceramic matrix composite, the particle size of the silica powder is 1 to 5 microns.

Preferably, in the first step of the method for preparing the zirconia ceramic matrix composite material, the purity of the zirconia powder, the purity of the yttria powder, the purity of the alumina powder and the purity of the silica powder are all greater than or equal to 99.9%.

As a preferred scheme, in the second step, the prepared zirconia powder, yttria powder, alumina powder and silica powder are added into the premixed liquid obtained in the first step, and are uniformly mixed by ball milling to obtain slurry; during ball milling, the ball milling rotation speed is controlled to be 150-.

As a preferred scheme, the preparation method of the zirconia ceramic matrix composite material comprises the third step of degassing for 15-30min under a vacuum condition; the relative vacuum degree of the vacuum condition is less than 0.095 MPa.

In the third step of the invention, tetramethylethylenediamine is added firstly, then ammonium persulfate solution is added rapidly, and stirring is carried out for 5-10 seconds under the condition of high-speed stirring, so as to ensure the fluidity of the slurry, otherwise, the sizing of a wet blank is not facilitated. And the properties of the resulting product are also degraded. In industrial application, the mass ratio of the ammonium persulfate aqueous solution to the tetramethylethylenediamine aqueous solution is controlled. The mass ratio is preferably 1 to 3:1, and more preferably 2: 1.

As a preferable scheme, the preparation method of the zirconia ceramic matrix composite material comprises the fourth step of placing the wet blank in 50 wt% polyethylene glycol solution for drying for 2-8h, then taking out and naturally drying in the air for 20-30h, and finally placing in an oven for drying for 15-20h at 80 ℃.

As a preferred scheme, the preparation method of the zirconia ceramic-based composite material comprises the fourth step of enabling the molecular weight of polyethylene glycol to be 200-2000; preferably 400-; more preferably 600. When the conditions are determined, the molecular weight of the polyethylene glycol has certain influence on the product performance, especially the mechanical property.

The preparation method of the zirconia ceramic matrix composite material adopts the combination of three drying modes in the fourth step, and reduces the probability of generating cracks and the probability of uneven shrinkage to the lowest in the process of converting a wet blank into a dry blank; this provides the necessary conditions for obtaining high quality finished products. In particular provides favorable technical support for obtaining high-quality products by sintering under normal pressure.

As a preferred scheme, in the fifth step, the temperature of the dried blank is raised from room temperature to 500-600 ℃ at the heating rate of 1-5 ℃/min, and the temperature is kept for 0.5-1.5 h; then raising the temperature to 950-1200 ℃ at the heating rate of 5-10 ℃/min, and preserving the temperature for 0.5-2 h; then heating to 1450-1650 ℃ at the heating rate of 2-5 ℃/min, and preserving the heat for 1-3 h; and then cooling along with the furnace to obtain the zirconia ceramic matrix composite.

According to the invention, the ceramic is molded by gel injection molding, the density of the blank body is low after the rubber is discharged, and the pores formed by lapping the internal frameworks provide a passage for gas phase flow, thereby being beneficial to the generation of mullite phase. After the sintering temperature reaches 960 ℃, the mullite and the densification of the blank are carried out simultaneously.

The bending strength of the zirconia biological ceramic obtained by the invention is 600-900MPa, preferably 762-900 MPa, more preferably 890-900MPa, and the fracture toughness is 7.1-11 MPa.m¹/₂Preferably 12.7 to 13.5MPa · m¹/₂More preferably 13.2 to 13.5MPa · m¹/₂(ii) a The microhardness is 10.9 to 13.5GPa, preferably 12.7 to 13.5GPa, and more preferably 13.2 to 13.5 GPa.

The invention obtains the zirconia ceramic-based composite material with high stability, long service life, high strength and high toughness by regulating and controlling the dosage and proportion of the aluminum trioxide and the silicon dioxide and by the synergistic effect of other components and the preparation process. The ceramic matrix composite can be used as biological materials, electronic materials, friction wear-resistant materials and the like.

Drawings

FIG. 1 is a material morphology diagram of a product prepared in example 1.

FIG. 2 is a material morphology diagram of a product prepared in comparative example 1.

In fig. 1, the black area is the mullite toughening phase generated in situ; the grey white area is a zirconia ceramic matrix.

From fig. 2 the microscopic morphology of the material of the product can be seen, clearly without the presence of the reinforcing phase.

Detailed Description

The purities of the zirconium oxide, the yttrium oxide, the aluminum oxide and the silicon dioxide in the embodiment and the comparative example are more than or equal to 99.9 percent

Example 1:

designing a material comprising the following components in percentage by mass:

45% of zirconium oxide; the particle size is 1-2 microns;

5% of yttrium oxide; the particle size is 1-5 microns;

15.3 percent of alumina; the particle size is 1-5 microns;

6% of silicon oxide; the particle size is 1-5 microns;

2% of acrylamide;

0.2 percent of N, N-methylene bisacrylamide;

0.7 percent of sodium hexametaphosphate;

2% of ammonium persulfate aqueous solution; the concentration of ammonium persulfate in the ammonium persulfate aqueous solution is 10 wt%;

1% of tetramethyl ethylene diamine;

22.8 percent of deionized water.

The first step is as follows: dissolving acrylamide, N-methylene bisacrylamide and sodium hexametaphosphate in deionized water in sequence according to the proportion, then heating in a water bath at 45 ℃, stirring for 15min, cooling the solution to room temperature, and then adding ammonia water and hydrochloric acid to adjust the pH value to 10.4.

The second step is that: sequentially adding the solution obtained in the step one, zirconia, yttria, alumina and silica powder into a ball milling tank according to a preset proportion, wherein Al is₂O₃∶SiO₂Ball milling at 200r/min speed of 3:2 (mol ratio) for 4 hr, controlling the temperature in ball milling tank at 40 deg.C, and ball milling to obtain slurry with high solid content

The third step: vacuumizing the slurry with high solid content obtained in the step two for 15min, degassing to remove bubbles in the slurry, adding tetramethylethylenediamine into the degassed slurry in a nitrogen atmosphere, uniformly stirring and mixing, then increasing the stirring speed to 800r/min, adding an ammonium persulfate aqueous solution within 5-10 seconds, stirring for 5-10 seconds, and pouring into a mold to polymerize and crosslink organic monomers in the suspension to form a three-dimensional network structure; demolding to obtain a wet blank;

the fourth step: in order to avoid cracking and uneven shrinkage caused by too high drying speed in the drying process of the green body prepared in the fourth step, liquid phase drying and air drying are adopted, the wet green body is firstly placed in polyethylene glycol (with the molecular weight of 600) with the volume fraction of 50% for drying for 6 hours, then the green body is taken out for natural drying for 25 hours, and finally the green body is placed in a drying oven for drying at the temperature of 80 ℃ for 18 hours to obtain a ceramic dried blank.

The fifth step: heating the dried blank obtained in the fourth step from room temperature to 500-600 ℃ at the heating rate of 1 ℃/min, and preserving the heat for 1 h; then raising the temperature to 1200 ℃ at the heating rate of 6 ℃/min, and preserving the heat for 1 h; then heating to 1450 ℃ at the heating rate of 3 ℃/min, and preserving heat for 3 h; and then cooling along with the furnace to obtain the finished product of the mullite toughened zirconia ceramic.

The results of scanning electron microscope analysis show that the toughening phase synthesized in situ by the process is well dispersed in the zirconia ceramic matrix, and the appearance of the mullite synthesized in situ is shown in figure 1. The properties of the finished product were measured and are shown in Table 1.

Example 2:

designing a material comprising the following components in percentage by mass:

45% of zirconium oxide; the particle size is 1-2 microns;

5% of yttrium oxide; the particle size is 1-5 microns;

10% of aluminum oxide; the particle size is 1-5 microns;

2% of silicon oxide; the particle size is 1-5 microns;

2% of acrylamide;

0.2 percent of N, N-methylene bisacrylamide;

0.6 percent of sodium hexametaphosphate;

2% of ammonium persulfate aqueous solution; the concentration of ammonium persulfate in the ammonium persulfate aqueous solution is 11 wt%;

1% of tetramethyl ethylene diamine;

32.2 percent of deionized water.

The first step is as follows: dissolving acrylamide, N-methylene bisacrylamide and sodium hexametaphosphate in deionized water in sequence according to the proportion, then heating in a water bath at 45 ℃, stirring for 15min, cooling the solution to room temperature, and then adding ammonia water and hydrochloric acid to adjust the pH value to 10.1.

The second step is that: and (3) sequentially adding the solution obtained in the step one, zirconia, yttria, alumina and silica powder into a ball milling tank according to a preset ratio, carrying out ball milling for 4 hours at a rotating speed of 200r/min, controlling the temperature of the ball milling tank at 40 ℃, and carrying out ball milling to obtain the slurry with high solid content.

The third step: vacuumizing the slurry with high solid content obtained in the step two for 15min, degassing to remove bubbles in the slurry, adding tetramethylethylenediamine into the degassed slurry in a nitrogen atmosphere, uniformly stirring and mixing, then increasing the stirring speed to 1000r/min, adding an ammonium persulfate aqueous solution within 5-10 seconds, stirring for 5-10 seconds, and pouring into a mold to polymerize and crosslink organic monomers in the suspension to form a three-dimensional network structure; demolding to obtain a wet blank;

the fourth step: in order to avoid cracking and uneven shrinkage caused by too high drying speed in the drying process of the green body prepared in the fourth step, liquid phase drying and air drying are adopted, the wet green body is firstly placed in polyethylene glycol (with the molecular weight of 600) with the volume fraction of 50% for drying for 8 hours, then the green body is taken out for natural drying for 30 hours, and finally the green body is placed in a drying oven for drying at the temperature of 80 ℃ for 20 hours to obtain a ceramic dried blank.

The fifth step: heating the dried blank obtained in the fourth step from room temperature to 500-600 ℃ at the heating rate of 2 ℃/min, and preserving heat for 1 h; then raising the temperature to 1200 ℃ at the heating rate of 5 ℃/min, and preserving the heat for 1.5 h; then heating to 1600 ℃ at the heating rate of 3 ℃/min, and preserving heat for 3 h; and then cooling along with the furnace to obtain the finished product of the mullite toughened zirconia ceramic. The properties of the finished product were measured and are shown in Table 1.

Example 3

Designing a material comprising the following components in percentage by mass:

45% of zirconium oxide; the particle size is 1-2 microns;

5% of yttrium oxide; the particle size is 1-5 microns;

15.3 percent of alumina; the particle size is 1-5 microns;

6% of silicon oxide; the particle size is 1-5 microns;

2% of acrylamide;

0.2 percent of N, N-methylene bisacrylamide;

0.7 percent of sodium hexametaphosphate;

1% of tetramethyl ethylene diamine;

22.8 percent of deionized water.

The operations of the first step, the second step and the third step are uniform, and the operation in the example 1 is consistent, and finally, the ceramic wet blank is obtained.

The fourth step: in order to avoid cracking and uneven shrinkage caused by too high drying speed in the drying process of the green body prepared in the fourth step, liquid phase drying and air drying are adopted, the wet green body is firstly placed in 50% volume fraction alcohol solution for drying for 20 hours, then is taken out for natural drying for 25 hours, and finally is placed in a drying oven for drying at 80 ℃ for 18 hours, and finally, a ceramic dried blank is obtained.

The fifth step: heating the dried blank obtained in the fourth step from room temperature to 500-600 ℃ at the heating rate of 1 ℃/min, and preserving the heat for 1 h; then raising the temperature to 1200 ℃ at the heating rate of 6 ℃/min, and preserving the heat for 1 h; then heating to 1450 ℃ at the heating rate of 3 ℃/min, and preserving heat for 3 h; and then cooling along with the furnace to obtain the finished product of the mullite toughened zirconia ceramic. The properties of the finished product were measured and are shown in Table 1.

Example 4:

designing a material comprising the following components in percentage by mass:

40% of zirconium oxide; the particle size is 1-2 microns;

10% of yttrium oxide; the particle size is 1-5 microns;

20% of alumina; the particle size is 1-5 microns;

2% of silicon oxide; the particle size is 1-5 microns;

1% of acrylamide;

0.4 percent of N, N-methylene bisacrylamide;

1% of sodium hexametaphosphate;

4% of ammonium persulfate aqueous solution; the concentration of ammonium persulfate in the ammonium persulfate aqueous solution is 10 wt%;

2% of tetramethyl ethylene diamine;

and 19.6% of deionized water.

The second step is that: sequentially adding the solution obtained in the step one, zirconia, yttria, alumina and silica powder into a ball milling tank according to a preset proportion, carrying out ball milling for 4 hours at a rotating speed of 200r/min, controlling the temperature of the ball milling tank at 40 ℃, and obtaining slurry with high solid-phase content after ball milling

the fourth step: in order to avoid cracking and uneven shrinkage caused by too high drying speed in the drying process of the green body prepared in the fourth step, liquid phase drying and air drying are adopted, the wet green body is firstly placed in polyethylene glycol (molecular weight is 400) with 50% volume fraction for drying for 6 hours, then the green body is taken out for natural drying for 25 hours, and finally the green body is placed in a drying oven for drying at 80 ℃ for 18 hours to obtain a ceramic dried blank.

The fifth step: heating the dried blank obtained in the fourth step from room temperature to 500-600 ℃ at the heating rate of 1 ℃/min, and preserving the heat for 1 h; then raising the temperature to 1200 ℃ at the heating rate of 6 ℃/min, and preserving the heat for 1 h; then, the temperature is raised to 1550 ℃ at the heating rate of 3 ℃/min, and the temperature is kept for 3 hours; and then cooling along with the furnace to obtain the finished product of the mullite toughened zirconia ceramic. The properties of the finished product were measured and are shown in Table 1.

Example 5:

designing a material comprising the following components in percentage by mass:

60% of zirconium oxide; the particle size is 1-2 microns;

5% of yttrium oxide; the particle size is 1-5 microns;

5% of alumina; the particle size is 1-5 microns;

3% of silicon oxide; the particle size is 1-5 microns;

2% of acrylamide;

0.2 percent of N, N-methylene bisacrylamide;

0.8 percent of sodium hexametaphosphate;

3% of ammonium persulfate aqueous solution; the concentration of ammonium persulfate in the ammonium persulfate aqueous solution is 11 wt%;

1.5 percent of tetramethyl ethylene diamine;

and 19.5% of deionized water.

The fifth step: heating the dried blank obtained in the fourth step from room temperature to 500-600 ℃ at the heating rate of 2 ℃/min, and preserving heat for 1 h; then raising the temperature to 1200 ℃ at the heating rate of 5 ℃/min, and preserving the heat for 1.5 h; then heating to 1650 ℃ at the heating rate of 3 ℃/min, and preserving the heat for 3 h; and then cooling along with the furnace to obtain the finished product of the mullite toughened zirconia ceramic. The properties of the finished product were measured and are shown in Table 1.

Example 6:

designing a material comprising the following components in percentage by mass:

45% of zirconium oxide; the particle size is 1-2 microns;

5% of yttrium oxide; the particle size is 1-5 microns;

14% of alumina; the particle size is 1-5 microns;

4% of silicon oxide; the particle size is 1-5 microns;

2% of acrylamide;

0.2 percent of N, N-methylene bisacrylamide;

0.7 percent of sodium hexametaphosphate;

1% of tetramethyl ethylene diamine;

26.1 percent of deionized water.

The fourth step: in order to avoid cracking and uneven shrinkage caused by too high drying speed in the drying process of the green body prepared in the fourth step, liquid phase drying and air drying are adopted, the wet green body is firstly placed in polyethylene glycol (molecular weight is 400) with 50% volume fraction for drying for 8 hours, then the green body is taken out for natural drying for 25 hours, and finally the green body is placed in a drying oven for drying at 80 ℃ for 18 hours to obtain a ceramic dried blank.

The fifth step: heating the dried blank obtained in the fourth step from room temperature to 500-600 ℃ at the heating rate of 1 ℃/min, and preserving the heat for 1 h; then raising the temperature to 1200 ℃ at the heating rate of 6 ℃/min, and preserving the heat for 1 h; then heating to 1500 ℃ at the heating rate of 3 ℃/min, and preserving heat for 3 h; and then cooling along with the furnace to obtain the finished product of the mullite toughened zirconia ceramic. The properties of the finished product were measured and are shown in Table 1.

Comparative example 1:

designing a material comprising the following components in percentage by mass:

45% of zirconium oxide; the particle size is 1-2 microns;

5% of yttrium oxide; the particle size is 1-5 microns;

2% of acrylamide;

0.2 percent of N, N-methylene bisacrylamide;

0.5 percent of sodium hexametaphosphate;

1% of tetramethyl ethylene diamine;

44.3 percent of deionized water.

The operations of the first step, the second step and the third step are uniform and consistent in the example 1, and the ceramic wet blank is obtained.

The fourth step: the method adopts liquid phase drying and air drying, the wet blank body is firstly placed in 50% volume fraction polyethylene glycol (molecular weight 2000) for drying for 6h, then is taken out for natural drying for 25h, and finally is placed in a drying oven for drying at 80 ℃ for 18h, and finally the ceramic dried blank is obtained.

The fifth step: heating the dried blank obtained in the fourth step from room temperature to 500-600 ℃ at the heating rate of 1 ℃/min, and preserving the heat for 1 h; then raising the temperature to 1200 ℃ at the heating rate of 6 ℃/min, and preserving the heat for 1 h; then heating to 1650 ℃ at the heating rate of 3 ℃/min, and preserving the heat for 3 h; and then cooling along with the furnace to obtain the finished product of the mullite toughened zirconia ceramic. The properties of the finished product were measured and are shown in Table 1.

TABLE 1

Table 1 shows the flexural strength, fracture toughness, microhardness, friction coefficient and wear rate of the test pieces obtained in examples 1, 2, 3, 4, 5, 6 and comparative example 1. The test was carried out on an Instron336 universal material testing machine, where the flexural strength was determined with reference to ISO14704-2000 standard, the specimen size was 3mm × 4mm × 35mm, the span was 30mm, the loading rate was 0.5mm/min, the fracture toughness was determined by the one-sided straight-through notched beam method (SENB method), the specimen size was 5mm × 5mm × 25mm, the notch depth was 2.5mm, the span was 20mm, and the loading rate was 0.05 mm/min. The dry friction test was performed on a ball-disk friction wear tester, the mating part being a 52100 steel ball. The test parameters are: the amplitude and frequency used were 1mm and 30Hz respectively (corresponding to a linear speed of 0.12m/s), the load used was 60N, the running time was 20min and the total stroke was 140 m. All samples were ultrasonically cleaned in acetone and absolute ethanol for 15min before testing, and then blown dry with hot air. The dry rub test was performed at room temperature in an environment with a relative humidity between 34% and 41%.

As can be seen from table 1, the process designed by the present invention achieves significant performance improvement under the synergistic effect of the components and the preparation process. Comparing example 1 with examples 2, 3, 4, 5, 6, it was found that the optimized version achieved unexpected results.

Claims

1. The zirconia ceramic matrix composite is characterized by comprising the following components in percentage by mass:

45% of zirconium oxide; the particle size is 1-2 microns;

5% of yttrium oxide; the particle size is 1-5 microns;

15.3 percent of alumina; the particle size is 1-5 microns;

6% of silicon oxide; the particle size is 1-5 microns;

2% of acrylamide;

0.2 percent of N, N-methylene bisacrylamide;

0.7 percent of sodium hexametaphosphate;

1% of tetramethyl ethylene diamine;

22.8% of deionized water;

the first step is as follows: sequentially dissolving acrylamide, N-methylene bisacrylamide and sodium hexametaphosphate in deionized water according to the proportion, then heating in a water bath at 45 ℃, stirring for 15min, cooling the solution to room temperature, and then adding ammonia water and hydrochloric acid to adjust the pH value to 10.4;

the second step is that: sequentially adding the solution of the first step, zirconia, yttria, alumina and silica powder into a ball milling tank according to a preset proportion, wherein the molar ratio of Al is₂O₃∶SiO₂Ball milling at the rotation speed of 200r/min for 4 hours, controlling the temperature of a ball milling tank at 40 ℃, and obtaining slurry with high solid content after ball milling;

the third step: vacuumizing the slurry with high solid content obtained in the second step for 15min, degassing to remove bubbles in the slurry, adding tetramethylethylenediamine into the degassed slurry in a nitrogen atmosphere, uniformly stirring and mixing, then increasing the stirring speed to 800r/min, adding an ammonium persulfate aqueous solution within 5-10 seconds, stirring for 5-10 seconds, and pouring into a mold to polymerize and crosslink organic monomers in the suspension to form a three-dimensional network structure; demolding to obtain a wet blank;

the fourth step: in order to avoid cracking and uneven shrinkage caused by too high drying speed in the drying process of the green body prepared in the fourth step, liquid phase drying and air drying are adopted, the wet green body is firstly placed in polyethylene glycol with the volume fraction of 50% for drying for 6 hours, then is taken out for natural drying for 25 hours, and finally is placed in a drying oven for drying at 80 ℃ for 18 hours, and finally a ceramic dried green body is obtained; the molecular weight of the polyethylene glycol is 600;

the fifth step: heating the dried blank obtained in the fourth step from room temperature to 500-; then raising the temperature to 1200 ℃ at the heating rate of 6 ℃/min, and preserving the heat for 1 h; then heating to 1450 ℃ at the heating rate of 3 ℃/min, and preserving heat for 3 h; and then cooling along with the furnace to obtain the finished product of the mullite toughened zirconia ceramic.