AU2021368918B2

AU2021368918B2 - Ceramic material having crack healing capability and preparation method therefor

Info

Publication number: AU2021368918B2
Application number: AU2021368918A
Authority: AU
Inventors: Zhaoqiang CHEN; Guangchun XIAO; Chonghai XU; Mingdong YI; Jingjie ZHANG; Shuai ZHANG
Original assignee: Qilu University of Technology
Current assignee: Qilu University of Technology
Priority date: 2020-10-29
Filing date: 2021-10-25
Publication date: 2024-02-01
Anticipated expiration: 2041-10-25
Also published as: CN112279653B; WO2022089378A1; AU2021368918A1; CN112279653A

Abstract

A ceramic material having crack healing capability and a preparation method therefor. The ceramic material is prepared from, by volume, 60-80% of α-Si

Description

CERAMIC MATERIAL WITH CRACK HEALING CAPABILITY AND PREPARATION METHOD THEREOF TECHNICAL FIELD

The present disclosure relates to the technical field of ceramic materials, and particularly relates to a ceramic material with a crack healing capability and a preparation method thereof.

BACKGROUND

Information of the Related Art part is merely disclosed to increase the understanding of the overall background of the present invention, but is not necessarily regarded as acknowledging or suggesting, in any form, that the information constitutes the prior art known to a person of ordinary skill in the art. People had paid more and more attention to and applied ceramic materials in the past decades due to their excellent properties, such as high temperature resistance, corrosion resistance, wear resistance and high strength. However, the ceramic materials also have obvious shortcomings such as micro-cracks which are easily generated due to mechanical shock and thermal shock acting force in the high-speed dry cutting process, a high friction coefficient, and sensitivity to defects. Consequently, the ceramic material will reach the failure standard in advance, resulting in a great waste of resources and economy. In view of the above-mentioned problems, researchers have developed ceramic materials with a crack healing capability in recent years. By adding components with specific functions to the ceramic matrix, the cutter material has the function of crack healing. The ceramic material with a crack healing capability refers to adding a suitable healing agent to the ceramic material matrix. When a crack occurs in the ceramic material, self-repairing the ceramic material is achieved by adding a specific healing agent to the ceramic matrix. When a crack occurs in the material, the crack of the ceramic material is healed through the healing agent or the chemical reaction of the healing agent. Studies have shown that after the healing agent heals the crack, the strength of the ceramic material is recovered, and the service life is prolonged. It has been disclosed in the prior art that the self-healing ceramic material is prepared by adding SiC, MoSi 2 , MAX phase materials and the like. The inventor has found that the self-healing ceramic material in the prior art also has certain deficiencies, for example, the heat treatment temperature of SiC materials needs to be 1000-1300°C, the lower the heat treatment temperature, the longer the time required, and when the temperature is lower than 1000°C, tens of hours are needed for crack healing.

SUMMARY

In order to solve the technical problems existing in the prior art, the present disclosure provides a Si 3N 4/TiC/ZrSi2 ceramic material with a crack healing capability and a preparation method thereof, wherein the Si 3N4/TiC ceramic material has a good crack repairing capability and good sintering compactness by adding a healing agent ZrSi 2, which enhances the comprehensive mechanical properties of a ceramic cutter material. Specifically, technical solutions of the present disclosure are as follows. In the first aspect, the present disclosure provides a ceramic material with a crack healing capability, comprising, by volume percentage, 60-80% of a-Si3N4, 5-15% of TiC, 0-20% of ZrSi2 , 3-7% of Al 2 03 and 5-7% ofY 2 0 3 .

a-Si3 N4 is a matrix, TiC is a reinforcing phase, ZrSi 2 is a healing agent, and A1 2 0 3 and Y20 3 are sintering aids. In the second aspect, the present disclosure provides a method for preparing a ceramic material with a crack healing capability in the first aspect, the method comprising: (1) weighing and taking a-Si 3 N 4 , TiC and ZrSi 2 powder in proportion, respectively adding an appropriate amount of absolute ethyl alcohol as a dispersion medium, and performing ultrasonic dispersing and mechanical stirring for 15-25 min to make a a-Si3N4 suspension, a TiC suspension and a ZrSi 2 suspension; (2) mixing the above-mentioned three suspensions to obtain a multi-phase suspension; (3) weighing and taking 1-5 wt% of dispersant based on the weight of Si 3 N4 , and after dissolving with the absolute ethyl alcohol, adding into the multi-phase suspension; and then adding A12 0 3 and Y 2 0 3 powder in proportion, and performing ultrasonic dispersing and mechanical stirring for 20-40 min; (4) pouring a final suspension obtained in step (3) into a ball milling tank, adding ball milling balls according to a ball material weight ratio of 10:1, and performing ball milling under a protective atmosphere for 48 h; (5) drying a ball milling solution obtained in step (4) in a vacuum drying oven at 80-120°C for 12-24 h, then sieving through a 100-120-mesh sieve to obtain mixed powder, and sealing and storing for future use; and (6) loading the mixed powder obtained in step (5) into a graphite mould, and after cold pressing molding, putting into a SPS furnace for sintering.

The specific implementations of the present disclosure have the following beneficial effects: By adding ZrSi 2 into a Si 3N4/TiC ceramic material matrix to realize the function of crack healing of a ceramic cutter material, a healing agent ZrSi2 selected in the present disclosure can react with oxygen at a relatively low temperature to generate ZrO 2 and SiO 2 which can heal cracks so as to effectively heal the cracks in the ceramic cutter material; and the bending strength of the ceramic material can be recovered to 80% or more of that of a smooth sample, which prolongs the service life of the ceramic cutter material. ZrSi2 also acts as a conductive phase to promote SPS of Si 3N 4, and ZrSi 2 can be added to play a role of a sintering aid. A preparation method is simple in process, low in equipment requirement and high in reliability.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings constituting a part of the present disclosure are used to provide a further understanding of the present disclosure. The exemplary embodiments of the present disclosure and descriptions thereof are used to explain the present disclosure, and do not constitute an improper limitation of the present disclosure. FIG. 1 is a cross-sectional SEM diagram of a Si 3N4/TiC/ZrSi 2 ceramic material prepared in Example 1 of the present disclosure; FIG. 2 is crack morphology of the Si 3N 4/TiC/ZrSi 2 ceramic material prepared in Example 1 of the present disclosure; FIG. 3 is morphology of the Si 3N 4/TiC/ZrSi2 ceramic material prepared in Example 1 of the present disclosure after crack healing; FIG. 4 is an EDS detection diagram of a crack healing area of the Si 3N 4/TiC/ZrSi 2 ceramic material prepared in Example 1 of the present disclosure; and FIG. 5 is an XRD detection diagram of the Si 3N4/TiC/ZrSi 2 ceramic material prepared in Example 1 of the present disclosure after crack healing.

DETAILED DESCRIPTION

It should be noted that the following detailed descriptions are all exemplary and are intended to provide a further understanding of this application. Unless otherwise indicated, all technical terms and scientific terms used in this application have the same meaning as commonly understood by a person of ordinary skill in the technical field to which this application belongs. It should be noted that terms used herein are only for describing specific implementations and are not intended to limit exemplary implementations according to this application. As used herein, the singular form is intended to include the plural form, unless the context clearly indicates otherwise. In addition, it should further be understood that terms "comprise" and/or "include" used in this specification indicate that there are features, steps, operations, devices, components, and/or combinations thereof. As described in the background, SiC, MoSi 2 , MAX phase materials and the like have been added in the prior art to prepare self-healing ceramic materials, but the self-healing ceramic materials prepared in the prior art also have certain deficiencies, such as high heat treatment temperature and long healing time. In view of this, the present disclosure provides a Si3N4/TiC/ZrSi2 ceramic material with a crack healing capability and a preparation method thereof. In one implementation of the present disclosure, a ceramic material with a crack healing capability is provided, takes a-Si 3N 4 as a matrix, TiC as a reinforcing phase, ZrSi 2 as a healing agent, and A1 2 0 3 and Y 2 0 3 as sintering aids, and comprises, by volume percentage, 60-80% of a-Si3N4, 5-15% of TiC, 0-20% of ZrSi2, 3-7% of Al203 and 5-7% ofY 2 0 3 .

In the implementations of the present disclosure, by adding ZrSi 2 into a Si 3N4/TiC ceramic cutter material matrix to realize the function of crack healing of the ceramic cutter material, the healing agent ZrSi2 can react with oxygen at a relatively low temperature of 600°C to generate ZrO2 and SiO2 which can heal cracks so as to effectively heal cracks in the ceramic cutter

material; and the bending strength of the ceramic material can be recovered to 80% or more of that of a smooth sample, which prolongs the service life of cutters and other devices prepared from the ceramic material. In a specific implementation, the ceramic material comprises, by volume percentage, 65 % of a-Si 3N 4 , 10% of TiC, 5-15% of ZrSi2, 4% of A12 0 3 and 6% of Y 2 0 3 ; and the sum of various components is 100%. Preferably, the average particle size of a-Si 3 N 4 powder is 0.5-1 pm; the average particle size of TiC powder is 0.5-1 pm; the average particle size of ZrSi 2 powder is 1-3 m; the average particle size of Al 2 03 powder is 0.5-2 pm; and the average particle size ofY 2 0 3 powder is 0.1 0.5 pm. In one implementation of the present disclosure, a method for preparing the above mentioned ceramic material with a crack healing capability is provided, the method comprising:

(1) weighing and taking a-Si 3 N 4 , TiC and ZrSi 2 powder in proportion, respectively adding an appropriate amount of absolute ethyl alcohol as a dispersion medium, and performing ultrasonic dispersing and mechanical stirring for 15-25 min to make a a-Si 3 N4 suspension, a TiC suspension and a ZrSi2 suspension; (2) mixing the above-mentioned three suspensions to obtain a multi-phase suspension; (3) weighing and taking 1-5 wt% of dispersant based on the weight of Si 3 N4 , and after dissolving with the absolute ethyl alcohol, adding into the multi-phase suspension; and then adding A12 0 3 and Y 2 0 3 powder in proportion, and performing ultrasonic dispersing and mechanical stirring for 20-40 min; (4) pouring a final suspension obtained in step (3) into a ball milling tank, adding ball milling balls according to a ball material weight ratio of 10:1, and performing ball milling under a protective atmosphere for 48 h; (5) drying a ball milling solution obtained in step (4) in a vacuum drying oven at 80-120°C for 12-24 h, then sieving through a 100-120-mesh sieve to obtain mixed powder, and sealing and storing for future use; and (6) loading the mixed powder obtained in step (5) into a graphite mould, and after cold pressing molding, putting into a spark plasma sintering furnace for sintering. In a specific implementation, the dispersant in step (3) is polyethylene glycol 6000. In a specific implementation, ball milling balls in step (5) are cemented carbide small balls YG6 or YG8, and the protective atmosphere is nitrogen. In a specific example, parameters of the spark plasma sintering in step (6) are as follows: a temperature rise rate: 90-110°C/min before 1300°C, and 30-50°C/min above 1300°C; sintering temperature of 1700-1750°C; heat preserving time of 20-35 min, and preserving heat at 1600°C and preserving heat after reaching the sintering temperature respectively for 10-17 min; and axial pressure of 25-35 MPa. Spark plasma sintering can greatly improve the sinterability of most materials and allow them to be sintered rapidly at a relatively low temperature for a short period of time, thereby expanding the possibility of developing new advanced materials. The essential difference between spark plasma sintering and a traditional sintering method (hot pressing) is the way of heating, since a hot pressing sintered material is heated only by heat conduction from a vessel, whereas spark plasma sintering is a form of heating by both a current and a vessel. If rapid sintering of the ceramic material is carried out by using spark plasma sintering, it is possible to have better mechanical properties on the basis ofkeeping the ceramic material having the crack healing capability.

ZrSi2 can also act as a conductive phase, the addition of ZrSi 2 also promotes spark plasma sintering of Si3 N 4 , and the addition of ZrSi2 can play a role of a sintering aid. The ceramic material prepared in the present disclosure has good sintering compactness, which enhances the comprehensive mechanical properties of the ceramic material. The present disclosure will be further explained with reference to specific examples, but the present disclosure is not limited to the following examples. The methods are conventional method unless otherwise specified. In the raw material components of each example, the average particle size ofa-Si 3 N4 powder is 0.5-1 pm; the average particle size of TiC powder is 0.5-1 pm; the average particle size of ZrSi 2 powder is 1-3 m; the average particle size of A1 2 0 3 powder is 0.5-2 pm; and the average particle size ofY 2 0 3 powder is 0.1-0.5 pm. Example 1 It was a method for preparing a Si 3N 4/TiC/ZrSi 2 ceramic material with a crack healing capability based on SPS, and raw material components comprised, by volume percentage, 75% of a-Si3N4, 10% of TiC, 5% of ZrSi2, 4% of Al203 and 6% ofY 2 0 3 . a-Si3 N4 , TiC and ZrSi2 powder were weighed and taken in proportion, an appropriate amount of absolute ethyl alcohol was added respectively as a dispersion medium, and ultrasonic dispersing and mechanical stirring were performed for 20 min to make a a-Si3N4 suspension, a TiC suspension and a ZrSi 2 suspension; and the above-mentioned three suspensions were mixed to obtain a multi-phase suspension. 3 wt% of dispersant was weighed and taken based on the weight of the Si 3 N4 powder, after dissolving with absolute ethyl alcohol, the solution was added into the multi-phase suspension, then A1 2 0 3 and Y 2 0 3 powder were added in proportion, and ultrasonic dispersing and mechanical stirring were performed for 30 min; and an obtained final suspension was poured into a ball milling tank, ball milling balls were added according to a ball material weight ratio of 10:1, and ball milling was performed under a nitrogen atmosphere for 48 h. An obtained ball milling solution was dried in a vacuum drying oven at 110°C for 12 h, and then sieved through a 100-mesh sieve to obtain mixed powder, and the obtained mixed powder was loaded into a graphite mould, and after cold pressing molding, put into a SPS furnace for hot pressing sintering; and SPS parameters were as follows: 100°C/min before 1300°C; 50°C/min at 1300°C-1450°C; 30°C/min at 1450°C-1600°C; heat preserving for 15 min at 1600°C; 30°C/min at 1600°C-1700°C; heat preserving for 10 min at 1700°C; and axial pressure of 30 MPa. The ceramic material prepared in this example was cut into standard bar-shaped samples of 3 mm x 4 mm x 35 mm, and then sample bars were subjected to rough grinding, grinding, chamfering and polishing treatment. Mechanical properties thereof were tested, and the results showed that the material had the bending strength of 751 MPa, hardness of 15.91 GPa and fracture toughness of 6.96 MPaM1 12 . A 350-450 pm crack was prefabricated on the cutter surface using a Vickers hardness tester. The cracked sample was heat-treated in a high temperature air furnace at a heat treatment temperature of 600°C, and heat was preserved for min; and room temperature bending strength testing was performed on the cracked sample after heat treatment, the sample strength was increased from 298 MPa at which the crack was generated to 677 Mpa, and the strength was recovered to 90.14% of that of a smooth sample. Compared to a ceramic material without being subjected to heat treatment (FIG. 2), FIG. 3 showed the crack surface morphology after heat treatment, and it was found that the crack was basically healed. After EDS analysis, as shown in FIG. 4, it can be seen from the distribution of Zr, Si and0 elements at the crack that TiO 2 and SiO 2 generated by ZrSi 2 oxidation repaired the crack. An XRD detection diagram in FIG. 5 also proved the presence of ZrO 2 and SiO 2

. Example 2 Raw material components comprised, by volume percentage, 70% ofa-Si 3 N4 , 10% of TiC, % of ZrSi 2 , 4% of A1 2 0 3 and 6% ofY 2 0 3 .

a-Si3N4, TiC and ZrSi2 powder were weighed and taken in proportion, an appropriate amount of absolute ethyl alcohol was added respectively as a dispersion medium, and ultrasonic dispersing and mechanical stirring were performed for 20 min to make a a-Si 3 N4 suspension, a TiC suspension and a ZrSi 2 suspension; and the above-mentioned three suspensions were mixed to obtain a multi-phase suspension. 5 wt% of dispersant was weighed and taken based on the weight of thea-Si 3 N 4 powder, and after dissolving with absolute ethyl alcohol, added into the multi-phase suspension, then A1 2 0 3 and Y 2 0 3 powder were added in proportion, and ultrasonic dispersing and mechanical stirring were performed for 20 min; and an obtained final suspension was poured into a ball milling tank, ball milling balls were added according to a ball material weight ratio of 10:1, and ball milling was performed under a nitrogen atmosphere for 48 h. An obtained ball milling solution was dried in a vacuum drying oven at 120°C for 24 h, and then sieved through a 100-mesh sieve to obtain mixed powder, and the obtained mixed powder was loaded into a graphite mould, and after cold pressing molding, putt into a SPS furnace for hot pressing sintering; and hot pressing sintering parameters were as follows: 100°C/min before 1300°C; 50°C/min at 1300°C-1450°C; 30°C/min at 1450°C-1600°C; heat preserving for 15 min at 1600°C; 30°C/min at 1600°C-1700°C; heat preserving for 10 min at

1700°C; and axial pressure of 30 MPa. The ceramic material prepared in this example was cut into standard bar-shaped samples of 3 mm x 4 mm x 35 mm, and then sample bars were subjected to rough grinding, grinding, chamfering and polishing treatment. Mechanical properties thereof were tested, and the results showed that the material had the bending strength of 802 MPa, hardness of 15.36 GPa and fracture toughness of 8.02 MPa-Mu 2. As shown in FIG. 1 which was an SEM diagram of the cracked surface of a ceramic material, it can be found that ZrSi2 was uniformly distributed in a ceramic matrix, and p-Si3 N 4 grains were uniform and had good compactness, which was beneficial to the mechanical properties of the ceramic material. A 350-450 pm crack was prefabricated on the cutter surface using a Vickers hardness tester. The cracked sample was heat-treated in a high temperature air furnace at a heat treatment temperature of 600°C, and heat was preserved for 30 min; and room temperature bending strength testing was performed on the cracked sample after heat treatment, the sample strength was increased from 301 MPa at which the crack was generated to 712 Mpa, and the strength was recovered to 88.78% of that of a smooth sample. Example 3 Raw material components comprised, by volume percentage, 60% ofa-Si 3 N4 , 15% of TiC, % of ZrSi2, 4% of A1 2 0 3 and 6% ofY 2 0 3 .

a-Si3N4, TiC and ZrSi 2 powder were weighed and taken in proportion, an appropriate amount of absolute ethyl alcohol was added respectively as a dispersion medium, and ultrasonic dispersing and mechanical stirring were performed for 20 min to make a a-Si 3 N4 suspension, a TiC suspension and a ZrSi 2 suspension; and the above-mentioned three suspensions were mixed to obtain a multi-phase suspension. 5 wt% of dispersant was weighed and taken based on the weight of thea-Si 3 N 4 powder, and after dissolving with absolute ethyl alcohol, added into the multi-phase suspension, then A1 2 0 3 and Y 2 0 3 powder were added in proportion, and ultrasonic dispersing and mechanical stirring were performed for 20 min; and an obtained final suspension was poured into a ball milling tank, ball milling balls were added according to a ball material weight ratio of 10:1, and ball milling was performed under a nitrogen atmosphere for 48 h. An obtained ball milling solution was dried in a vacuum drying oven at 120°C for 24 h, and then sieved through a 100-mesh sieve to obtain mixed powder, and the obtained mixed powder was loaded into a graphite mould, and after cold pressing molding, put into a SPS furnace for hot pressing sintering; and hot pressing sintering parameters were as follows: 100°C/min before 1300°C; 50°C/min at 1300°C-1450°C; and 30°C/min at 1450°C-1600°C; heat preserving for 15 min at 1600°C; 30°C/min at 1600°C-1750°C; heat preserving for 15 min at 1750°C; and axial pressure of 30 MPa. The ceramic material prepared in this example was cut into standard bar-shaped samples of 3 mm x 4 mm x 35 mm, and then sample bars were subjected to rough grinding, grinding, chamfering and polishing treatment. Mechanical properties thereof were tested, and the results showed that the material had the bending strength of 685 MPa, hardness of 14.82 GPa and fracture toughness of 7.53 MPa-M1 2 . A 350-450 pm crack was prefabricated on the cutter surface using a Vickers hardness tester. The cracked sample was heat-treated in a high temperature air furnace at a heat treatment temperature of 6000 C, and heat was preserved for min; and room temperature bending strength testing was performed on the cracked sample after heat treatment, the sample strength was increased from 221 MPa at which the crack was generated to 551 Mpa, and the strength was recovered to 80.43% of that of a smooth sample. Comparative Example 1 Raw material components comprised, by volume percentage, 75% ofa-Si 3 N4 , 10% of TiC, % of ZrSi2, 4% of A1 2 0 3 and 6% ofY 2 0 3 .

a-Si3 N4 , TiC and ZrSi2 powder were weighed and taken in proportion, an appropriate amount of absolute ethyl alcohol was respectively as a dispersion medium, and ultrasonic dispersing and mechanical stirring were performed for 20 min to make aa-Si3N4 suspension, a TiC suspension and a ZrSi 2 suspension; and the above-mentioned three suspensions were mixed to obtain a multi-phase suspension. 5 wt% of dispersant was weighed and taken based on the weight of thea-Si 3 N4 powder, and after dissolving with absolute ethyl alcohol, added into the multi-phase suspension, then A12 0 3 and Y 2 0 3 powder were added in proportion, and ultrasonic dispersing and mechanical stirring were performed for 20 min; and an obtained final suspension was poured into a ball milling tank, ball milling balls were added according to a ball material weight ratio of 10:1, and ball milling was performed under a nitrogen atmosphere for 48 h. An obtained ball milling solution was dried in a vacuum drying oven at 120 0 C for 24 h, and then sieved through a 100-mesh sieve to obtain mixed powder, and the obtained mixed powder was loaded into a graphite mould, and after cold pressing molding, put into a SPS furnace for hot pressing sintering; and hot pressing sintering parameters were as follows: 100 0C/min before 1300°C; 50°C/min at 1300°C-1450°C; 30°C/min at 1450°C-1600°C; heat preserving for 15 min at 1600°C; 30°C/min at 1600°C-1750°C; heat preserving for 15 min at 1750°C; axial pressure of 30 MPa. The ceramic material prepared in this example was cut into standard bar-shaped samples of 3 mm x 4 mm x 35 mm, and then sample bars were subjected to rough grinding, grinding, chamfering and polishing treatment. Mechanical properties thereof were tested, and the results showed that the material had the bending strength of 802 MPa, hardness of 15.36 GPa and 12 fracture toughness of 8.02 MPaM . A 350-450 pm crack was prefabricated on the cutter surface using a Vickers hardness tester. The cracked sample was heat-treated under a high temperature vacuum condition at a heat treatment temperature of 600°C, and heat was preserved for 30 min; and room temperature bending strength testing was performed on the cracked sample after heat treatment, the sample strength was increased from 298 MPa at which the crack was generated to 381 Mpa, and the strength was recovered to 47.51% of that of a smooth sample. The lower recovery rate of the bending strength of the ceramic material was mainly due to the fact that no oxidation reactions occurred to generate oxides to repair cracks. However, the strength of the material was partially recovered, because partial strength thereof was recovered due to the release of residual stresses inside a cutter at a high temperature. The foregoing descriptions are merely preferred embodiments of the present disclosure and are not intended to limit the present disclosure. A person skilled in the art may make various alterations and variations to the present disclosure. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present disclosure shall fall within the protection scope of the present disclosure.

Claims

What is claimed is: 1. A ceramic material with a crack healing capability, comprising, by volume percentage, 65-75% of a-Si3N4, 10% of TiC, 5-15% of ZrSi 2, 4% of Al2 03 and 6% ofY 2 0 3 ; and the sum of various components is 100%; wherein the method for the ceramic material to heal cracks comprises subjecting the ceramic material to a heat treatment at 600 °C for 30 min.
2. The ceramic material with a crack healing capability according to claim 1, wherein the average particle size of a-Si3N4 powder is 0.5-1 [m.
3. The ceramic material with a crack healing capability according to claim 1, wherein the average particle size of TiC powder is 0.5-1 [m.
4. The ceramic material with a crack healing capability according to claim 1, wherein the average particle size of ZrSi 2 powder is 1-3 [m.
5. The ceramic material with a crack healing capability according to claim 1, wherein the average particle size of A1 2 0 3 powder is 0.5-2 [m; and the average particle size of Y 2 0 3 powder is 0.1-0.5 [m.
6. A method for preparing the ceramic material with a crack healing capability according to claim 1, the method comprising: (1) weighing and taking a-Si3N4, TiC and ZrSi 2 powder in proportion, respectively adding an appropriate amount of absolute ethyl alcohol as a dispersion medium, and performing ultrasonic dispersing and mechanical stirring for 15-25 min to make a a-Si3N4 suspension, a TiC suspension and a ZrSi 2 suspension; (2) mixing the above-mentioned three suspensions to obtain a multi-phase suspension; (3) weighing and taking 1-4 wt% of dispersant based on the weight of Si3 N 4 , and after dissolving with absolute ethyl alcohol, adding into the multi-phase suspension; and then adding A12 0 3 and Y 2 0 3 powder in proportion, and performing ultrasonic dispersing and mechanical stirring for 20-40 min; (4) pouring a final suspension obtained in step (3) into a ball milling tank, adding ball milling balls according to a ball material weight ratio of 10:1, and performing ball milling under a protective atmosphere for 48 h; (5) drying a ball milling solution obtained in step (4) in a vacuum drying oven at -120°C for 12-24 h, then sieving through a 100-120-mesh sieve to obtain mixed powder, and sealing and storing for future use; and (6) loading the mixed powder obtained in step (5) into a graphite mould, and after cold pressing molding, putting into a spark plasma sintering furnace for spark plasma sintering.
7. The method for preparing a ceramic material with a crack healing capability according to claim 6, wherein the dispersant in step (3) is polyethylene glycol 6000.
8. The method for preparing a ceramic material with a crack healing capability according to claim 6, wherein the ball milling balls in step (5) are cemented carbide small balls YG6 or YG8, and the protective atmosphere is nitrogen.
9. The method for preparing a ceramic material with a crack healing capability according to claim 6, wherein parameters of the spark plasma sintering in step (6) are as follows: a temperature rise rate: 90-110°C/min before 1300°C, and 30-50°C/min above 1300°C; sintering temperature of 1700-1750°C; heat preserving time of 20-35 min, and preserving heat at 1600°C and preserving heat after reaching the sintering temperature respectively for 10-17 min; and axial pressure of 25-35 MPa.