High-toughness zirconium oxide toughened aluminum oxide ceramic material and preparation method thereof

Abstract

The invention discloses a high-toughness zirconium oxide toughened aluminum oxide ceramic material and a preparation method thereof.The preparation method of the high-toughness zirconium oxide toughened aluminum oxide ceramic material comprises the following steps that mixed slurry is prepared and comprises aluminum oxide powder, zirconium oxide powder, a stabilizer, a sintering aid and a dispersing agent; the sintering aid comprises a strontium source and a chromium source; the mixed slurry is dried and then pre-sintered, a primary material is obtained, the pre-sintering temperature ranges from 1000 DEG C to 1250 DEG C, and the primary material comprises long-strip-shaped crystal grains; grinding and screening the primary mixed material to obtain a secondary material; granulating the second-stage material to obtain a third-stage material; and carrying out cold isostatic pressing on the third-stage material, and then carrying out normal-pressure sintering at 1500-1600 DEG C to obtain the high-toughness zirconium oxide toughened aluminum oxide ceramic material. The high-toughness zirconium oxide toughened aluminum oxide ceramic material has the advantages of high toughness, high strength and excellent biological activity.

Description

Technical Field

[0001] This invention relates to the field of zirconia-toughened alumina ceramic materials, and more specifically to a high-toughness zirconia-toughened alumina ceramic material and its preparation method. Background Technology

[0002] Zirconia-toughened alumina (ZTA) ceramic material is a multiphase fine ceramic material formed by introducing a certain amount of zirconia, a phase change material, into an alumina matrix. Due to the high hardness of alumina and the good toughness of zirconia, these two materials form an excellent composite with high strength and high toughness. It exhibits higher flexural strength and fracture toughness at room temperature, thus demonstrating excellent wear resistance. Furthermore, due to the good bioactivity of zirconia, it is suitable for applications in bioactive materials.

[0003] In traditional zirconia, an excessive amount of monoclinic phase can affect the proportion of tetragonal phase, thus significantly reducing the toughening effect. Furthermore, while zirconia-toughened alumina materials increase strength, they also increase density, which reduces the porosity of the material surface and consequently decreases the material's bioactivity.

[0004] Therefore, how to improve the toughness and strength of zirconia-toughened alumina materials without reducing their bioactivity has become a pressing problem in this field. Summary of the Invention

[0005] The purpose of this invention is to provide a high-toughness zirconia-toughened alumina ceramic material and its preparation method, so that the high-toughness zirconia-toughened alumina ceramic material has high toughness, high strength, and excellent bioactivity.

[0006] In one aspect, the present invention provides a method for preparing a high-toughness zirconia-toughened alumina ceramic material, comprising preparing a mixed slurry, the mixed slurry comprising alumina powder, zirconia powder, stabilizer, sintering aid, and dispersant; wherein the sintering aid comprises a strontium source and a chromium source;

[0007] After the mixture slurry is dried, it is pre-sintered to obtain primary material. The pre-sintering temperature is 1000-1250℃, and the primary material includes elongated grains.

[0008] The primary mixture is ground and sieved to obtain secondary material;

[0009] The secondary material is granulated to obtain the tertiary material;

[0010] The three-stage material is cold isostatically pressed and then sintered at 1500-1600℃ under normal pressure to obtain the high-toughness zirconia toughened alumina ceramic material.

[0011] The advantages of this invention over the prior art are that it achieves the preparation of a high-toughness zirconia toughened alumina ceramic material, comprising zirconia and alumina, by mixing a slurry including alumina powder, zirconia powder, and sintering aids.

[0012] The sintering aids, including strontium and chromium sources, facilitate the combination of aluminum with the strontium and chromium sources to obtain elongated grains.

[0013] After drying the mixed slurry, it is pre-sintered to obtain the primary material. The pre-sintering temperature is 1000-1250℃, which allows the alumina powder to react with strontium and chromium sources during the pre-sintering process to obtain elongated grains. At this temperature, there are many elongated grains, and the grains are not large. This avoids the transformation of tetragonal grains into monoclinic grains during cooling after pre-sintering and subsequent cooling after sintering. That is, during the cooling process, the tetragonal grains expand in volume to the periphery. The presence of elongated grains around the tetragonal grains inhibits the expansion of zirconia grains, thus preventing the tetragonal grains of zirconia from transforming into monoclinic grains during cooling. This results in a high content of tetragonal grains in the obtained high-toughness zirconia-toughened alumina ceramic material, which significantly improves the toughness of the high-toughness zirconia-toughened alumina ceramic material. At the same time, it helps to avoid the reduction in strength caused by the uneven internal structure of the material due to excessively large elongated grains or uneven grain size.

[0014] Secondary materials are obtained by grinding and sieving the primary mixture, which reduces the size of a small number of large elongated grains and facilitates the uniform dispersion of elongated grains and zirconium oxide. This further helps to control the transformation of more zirconium oxide crystal phases into monoclinic crystal phases during the subsequent sintering and cooling process.

[0015] Meanwhile, the energy absorbed during the growth of elongated grains during sintering can effectively suppress the formation of cubic phase in zirconia.

[0016] Tertiary material is obtained by granulating the secondary material, which achieves uniform distribution of elongated grains and zirconia. At the same time, the increase of some particles in the tertiary material can be controlled, thereby controlling the gradation. Most importantly, the granulated tertiary material contains a certain amount of small pores. Then, the tertiary material is cold isostatically pressed to control the low porosity and high density between the particles, thereby improving the strength of the high-toughness zirconia-toughened alumina ceramic material and also improving the bioactivity of the tough zirconia-toughened alumina ceramic material.

[0017] By sintering at atmospheric pressure at 1500-1600℃ and controlling the heating rate and heating time of each stage of the sintering process, it is beneficial to achieve high internal density and relatively small elongated grains in the high-toughness zirconia-toughened alumina ceramic material, while the surface of the finished material has high porosity and relatively large elongated grains. This results in high bioactivity of the finished material and improved surface wear resistance through the large elongated grains, as well as dense internal particles and high strength.

[0018] Furthermore, the method for preparing the mixed slurry includes the following steps: [The steps are described in the original text, but the provided text is incomplete and cannot be accurately translated.]

[0019] Alumina powder, zirconium oxide powder, stabilizer, sintering aid, dispersant and solvent are mixed and ground in a mass ratio of (70-80):(15-25):(1-1.5):(1.6-8.8):(0.5-3):(100-120) to obtain the mixed slurry.

[0020] The beneficial effect of the previous step is that the proportion of the sintering aid helps to obtain a suitable elongated grain, avoiding the problem that the elongated grain is too small, which leads to a low control effect of the elongated grain on the control of the zirconia crystal phase, and avoiding the problem that the internal pores of the high-toughness zirconia toughened alumina ceramic material are too large and the strength is reduced when the elongated grain is too large.

[0021] Furthermore, the inhibitor content is reduced by the suppressive effect of the elongated grains, which helps to avoid the formation of cubic zirconia phase during sintering.

[0022] Furthermore, the sintering aid includes sintering aid A and sintering aid B; sintering aid A includes a strontium source and a chromium source; both the strontium source and the chromium source are salt compounds;

[0023] The mass ratio of the strontium source to the chromium source is (1-5):(0.1-3);

[0024] The strontium source includes one or more of strontium carbonate, strontium acetate, strontium oxalate, and strontium chloride;

[0025] The chromium source includes one or more of chromium oxide, chromium acetate, and chromium trichloride.

[0026] The mass ratio of sintering aid A to sintering aid B is 1:(0.5-0.8);

[0027] The sintering aid B includes one or both of magnesium oxide and calcium oxide;

[0028] and / or

[0029] The dispersant includes sodium polyacrylate 5000, a polymeric dispersant containing acidic groups, a polyethylene and acid salt polymeric dispersant; the solvent is water or ethanol.

[0030] The beneficial effect of the previous step is that, by using the strontium source, which includes one or more of strontium carbonate, strontium acetate, strontium oxalate, and strontium chloride; and the chromium source, which includes one or more of chromium oxide, chromium acetate, and chromium trichloride; the added strontium source and chromium source are salts, thereby improving the formation rate of long grains;

[0031] The sintering aid B includes one or both of magnesium oxide and calcium oxide, which helps to reduce the sintering temperature.

[0032] Meanwhile, by using a mass ratio of sintering aid A to sintering aid B of 1:(0.5-0.8), the amount of sintering aid B added is reduced, which helps to avoid the formation of cubic zirconia phase.

[0033] Furthermore, the preparation method of the mixed slurry also includes the following steps: surface treatment of the alumina powder, that is, adding the alumina powder to a sintering aid solution, mixing and stirring, and then drying to obtain alumina with strontium and chromium elements attached to the surface; the sintering aid solution preparation process involves dissolving the sintering aid in a solvent;

[0034] Alumina material with strontium and chromium adhering to its surface is mixed with zirconium oxide powder, sintering aid, and dispersant in a solvent, and then ball-milled to obtain the mixed slurry.

[0035] The beneficial effect of the previous step is that the alumina powder is surface treated by adding the alumina powder to the sintering aid solution, mixing and stirring, and then drying it to obtain alumina with strontium and chromium elements attached to the surface. This achieves uniform mixing of alumina with strontium and chromium elements, and then uniform mixing with zirconium oxide. This results in uniformly sized elongated grains generated during pre-sintering, and the elongated grains are evenly dispersed with zirconium oxide. Therefore, it effectively suppresses the formation of monoclinic radial zirconium oxide during sintering.

[0036] Further, the slurry mixture is dried and sieved to obtain a dried mixture; the dried mixture is then mixed with carbon black of different particle sizes, and pre-sintered to obtain the primary material; and / or,

[0037] The pre-sintering process is as follows: from room temperature to 100-120℃, the heating rate is 9-10℃ / min; from 100-120℃ to 400-430℃, the heating rate is 4-6℃; from 400-430℃ to 800-820℃, the heating rate is 1-2℃; and from 800-820℃ to 1000-1250℃, the heating rate is 3-4℃.

[0038] The beneficial effect of the previous step is that by mixing the dried mixture with carbon black of different particle sizes and then pre-sintering it, it is beneficial to ensure that the alumina reacts with strontium and chromium in the dried mixture evenly during the reaction, resulting in uniform elongated grains. This avoids the problem of some areas being overheated, causing the elongated grains to grow too large, while other areas do not form elongated grains at all; and the added carbon black is volatilized after pre-sintering.

[0039] Heating from room temperature to 100-120℃ at a rate of 9-10℃ / min facilitates the rapid volatilization of small molecule volatiles and forms channels within the dry mixture, which is beneficial for uniform heat conduction. Heating from 100-120℃ to 400-430℃ at a rate of 4-6℃, and from 400-430℃ to 800-820℃ at a rate of 1-2℃, with the heating rate decreasing step by step, helps to ensure the complete volatilization of larger molecular weight volatiles. Heating from 800-820℃ to 1000-1250℃ at a rate of 3-4℃ helps to avoid the formation of excessively large elongated crystals.

[0040] Furthermore, the dried mixture is sieved, and the particle size of the mixture is less than or equal to 150 mesh;

[0041] The carbon black has a specific surface area of ​​120-145 m². 2 / g of particles, with a specific surface area of ​​73-91m² 2 / g of particles, with a specific surface area of ​​40-50m 2 The particle mass ratio per g is (4.5-5.5):(2.5-3.5):(1.5-2.5).

[0042] The advantage of the previous step is that by using a particle size of less than or equal to 150 mesh, the small particle size of the mixture is conducive to obtaining a material with long grains and zirconium oxide uniformly dispersed.

[0043] By mixing the carbon black, which comprises particles with different specific surface areas, with the mixture, it is further beneficial to ensure uniform heating inside the dried mixture.

[0044] Furthermore, the secondary material preparation process includes the following steps: ball milling the primary material for 8-12 hours, drying it after ball milling, and then sieving it through a 120-mesh sieve to obtain the secondary material.

[0045] The beneficial effect of the previous step is that, through secondary ball milling of the primary material, it is beneficial to achieve uniform mixing of the elongated grains obtained from pre-sintering and the zirconium oxide before granulation. At the same time, it is beneficial to reduce the small amount or trace amount of larger elongated grains by ball milling, thereby achieving uniform size of elongated grains in the secondary material.

[0046] Furthermore, the preparation process of the tertiary material includes the following steps: mixing the secondary material with polyethylene glycol, granulating the mixture, and then sieving the granulated material to obtain the tertiary material.

[0047] The beneficial effect of the previous step is that granulation can increase the number of particles in the tertiary material, forming a particle size distribution. At the same time, it can achieve a slightly higher internal porosity of the particles. However, the density between particles in the subsequent cold isostatic pressing green body is high. Thus, the finished high-toughness zirconia toughened alumina ceramic material obtained by sintering has high strength, but the internal porosity is beneficial to improving biological activity.

[0048] Furthermore, the particle size of the tertiary material is 90-110 mesh particles to 110-160 mesh particles in a mass ratio of (1-2):(8-9);

[0049] After the three-stage material is filled into the mold, it is centrifugally rotated, and then the material in the mold is cold isostatically pressed.

[0050] The sintering process is as follows: heating from room temperature to 100-120℃ at a rate of 7-8℃ / min; heating from 100-120℃ to 600-620℃ at a rate of 3-4℃; holding at 600-620℃ for 1.8-2.2 hours; heating from 600-620℃ to 1100-1250℃ at a rate of 1.5-2.5℃ / min; and holding at 1100℃... Hold at -1250℃ for 1 hour; raise the temperature from 1100-1250℃ to 1400-1500℃ at a rate of 1-1.5℃ / min, and hold at 1400-1500℃ for 3-7 hours; raise the temperature from 1400-1500℃ to 1500-1600℃ at a rate of 8-10℃ / min, and heat at 1500-1600℃ for 20-40 minutes.

[0051] Then, the material is cooled to obtain the high-toughness zirconia-toughened alumina ceramic material.

[0052] The beneficial effect of the previous step is that the particle size of the three-stage material is 90-110 mesh particles to 110-160 mesh particles in a mass ratio of (1-2):(8-9); after the three-stage material is filled into the mold, it is centrifugally rotated, and then the material in the mold is cold isostatically pressed; the surface of the formed green body contains a large amount of 90-110 mesh material with relatively large particles, and the interior of the green body contains 110-160 mesh material, thereby achieving high density and high strength between particles in the sintered high-toughness zirconia toughened alumina ceramic material. The surface of the high-toughness zirconia toughened alumina ceramic material has high porosity due to being mainly composed of large particles, which is beneficial to improving the bioactivity of the high-toughness zirconia toughened alumina ceramic material.

[0053] Heating from room temperature to 100-120℃ at a rate of 7-8℃ / min facilitates the rapid volatilization of small-molecule volatiles in the green body, forming small-pore channels. Heating from 100-120℃ to 600-620℃ at a rate of 3-4℃, and holding at 600-620℃ for 1.8-2.2 hours, with slow heating, promotes the volatilization of larger molecules and macromolecules within these channels, thus preventing cracks or damage. Heating from 600-620℃ to 1100-1250℃ at a rate of 1.5-2.5℃ / min, and holding at 1100-1250℃ for 1 hour, promotes the formation of tetragonal zirconia grains. Heating from 1100-1250℃ to 1400-1500℃... At a temperature of 1-1.5℃ / min, the temperature is raised to 1400-1500℃ and held for 3-7 hours, which is conducive to the synchronous growth of tetragonal and elongated zirconia grains. The temperature is then raised from 1400-1500℃ to 1500-1600℃ at a rate of 8-10℃ / min, and held for 20-40 minutes. At this temperature, the rapid heating rate and short heating time result in minimal temperature increase in the elongated grains inside the high-toughness zirconia-toughened alumina ceramic material, preventing significant grain enlargement. Meanwhile, the elongated grains on the surface of the high-toughness zirconia-toughened alumina ceramic material grow larger and coarser, thus improving the wear resistance of the surface layer.

[0054] Another aspect of the present invention provides a high-toughness zirconia-toughened alumina ceramic material, which is prepared by a method for preparing high-toughness zirconia-toughened alumina ceramic material;

[0055] The high-toughness zirconia-toughened alumina ceramic material includes zirconia grains and elongated grains, wherein the elongated grains are dispersed around the zirconia grains.

[0056] The content of tetragonal and monoclinic phases in the zirconia grains reaches more than 95%, and the content of tetragonal phase in the zirconia grains reaches more than 73%.

[0057] The fracture toughness of the high-toughness zirconia-toughened alumina ceramic material is ≥8.71 MPa·m. 1 / 2 Vickers hardness ≥ 17.3 GPa; preferably, fracture toughness ≥ 9.6 MPa·m 1 / 2 Vickers hardness ≥17.5GPa.

[0058] The beneficial effects of this invention compared to the prior art are as follows: the high-toughness zirconia-toughened alumina ceramic material includes zirconia grains and elongated grains, with the elongated grains dispersed around the zirconia grains. This allows the tetragonal grains to transform into monoclinic grains during cooling after pre-sintering and subsequent cooling after sintering. Specifically, during the cooling process, the tetragonal grains expand outwards as they transform into monoclinic grains. The presence of elongated grains around the tetragonal grains inhibits the expansion of the zirconia grains, thus preventing the tetragonal grains from transforming into monoclinic grains during cooling. This results in a high tetragonal grain content in the obtained high-toughness zirconia-toughened alumina ceramic material, significantly improving its toughness. Simultaneously, the uniform size of the elongated grains leads to high internal strength.

[0059] Meanwhile, the energy absorbed during the growth of elongated grains during sintering can effectively suppress the formation of cubic phase in zirconia.

[0060] High-toughness zirconia-toughened alumina ceramic material has high strength, and at the same time, the surface porosity of high-toughness zirconia-toughened alumina ceramic material has high porosity and certain pores inside the internal particles, which improves the bioactivity of high-toughness zirconia-toughened alumina ceramic material.

[0061] Ultimately, the content of tetragonal and monoclinic phases in the zirconia grains reaches over 95%, with the tetragonal phase content exceeding 73%; the fracture toughness of the high-toughness zirconia-toughened alumina ceramic material is ≥8.71 MPa·m. 1 / 2 Vickers hardness ≥ 17.3 GPa; preferably, fracture toughness ≥ 9.6 MPa·m 1 / 2 Vickers hardness ≥17.5GPa. Attached Figure Description

[0062] Figure 1 The image is a scanning electron microscope backscattering image of the high-toughness zirconia-toughened alumina ceramic material of Embodiment 1 of the invention, where the arrows indicate elongated grains.

[0063] Figure 2 This is a composition analysis diagram of the high-toughness zirconia-toughened alumina ceramic material of Embodiment 1 of the present invention. Detailed Implementation

[0064] To better understand the technical solution of the present invention, the present invention will be further described below in conjunction with specific embodiments and accompanying drawings.

[0065] Example 1:

[0066] This embodiment provides a method for preparing a high-toughness zirconia-toughened alumina ceramic material, comprising preparing a mixed slurry, the mixed slurry including alumina powder, zirconia powder, stabilizer, sintering aid, and dispersant; the sintering aid includes a strontium source and a chromium source; the method for preparing the mixed slurry includes the following steps: mixing and grinding the alumina powder, zirconia powder, stabilizer, sintering aid, dispersant, and solvent in a mass ratio of 75:20:1.3:5.2:1.8:110 to obtain the mixed slurry;

[0067] The sintering aids include sintering aid A and sintering aid B; sintering aid A includes a strontium source and a chromium source; both the strontium source and the chromium source are salt compounds;

[0068] The mass ratio of the strontium source to the chromium source is 3:1.6;

[0069] The strontium source includes strontium carbonate and strontium acetate;

[0070] The chromium source includes chromium oxide and chromium acetate;

[0071] The mass ratio of sintering aid A to sintering aid B is 1:0.65;

[0072] The sintering aid B includes magnesium oxide; the dispersant includes sodium polyacrylate 5000; and the solvent is ethanol.

[0073] After drying the mixed slurry, it is pre-sintered to obtain a primary material. The pre-sintering temperature is 1125℃. The primary material includes elongated crystals. The specific process is as follows: after drying the mixed slurry, it is sieved to obtain a dried mixed material.

[0074] The pre-sintering process is as follows: from room temperature to 110°C, the heating rate is 9.5°C / min; from 110°C to 415°C, the heating rate is 5°C; from 415°C to 810°C, the heating rate is 1.5°C; and from 810°C to 1125°C, the heating rate is 3.5°C.

[0075] The primary mixture is ground and sieved to obtain secondary material; the preparation process of the secondary material includes the following steps: the primary material is ball-milled for 10 hours, and then dried and sieved through a 120-mesh sieve to obtain secondary material.

[0076] The secondary material is granulated to obtain the tertiary material; the preparation process of the tertiary material includes the following steps: the secondary material is mixed with polyethylene glycol and then granulated; the granulated material is then sieved to obtain the tertiary material.

[0077] The three-stage material is cold isostatically pressed and then sintered at 1550℃ under normal pressure to obtain the high-toughness zirconia toughened alumina ceramic material; the particle size of the three-stage material is 90-110 mesh particles to 110-160 mesh particles in a mass ratio of 1.5:8.5.

[0078] After the three-stage material is filled into the mold, it is centrifugally rotated, and then the material in the mold is cold isostatically pressed.

[0079] The sintering process is as follows: heating from room temperature to 110°C at a rate of 7.5°C / min; heating from 110°C to 610°C at a rate of 3.5°C / min, and holding at 610°C for 2 hours; heating from 610°C to 1175°C at a rate of 2°C / min, and holding at 1175°C for 1 hour; heating from 1175°C to 1450°C at a rate of 1.25°C / min, and holding at 1450°C for 5 hours; heating from 1450°C to 1550°C at a rate of 9°C / min, and heating at 1550°C for 30 minutes.

[0080] Then, the material is cooled to obtain the high-toughness zirconia-toughened alumina ceramic material.

[0081] Another aspect of this embodiment provides a high-toughness zirconia-toughened alumina ceramic material, which is prepared by a method for preparing high-toughness zirconia-toughened alumina ceramic materials.

[0082] The high-toughness zirconia-toughened alumina ceramic material includes zirconia grains and elongated grains, wherein the elongated grains are dispersed around the zirconia grains.

[0083] The content of tetragonal and monoclinic phases in the zirconia grains reaches 95.6%, and the content of tetragonal phase in the zirconia grains reaches 73.9%.

[0084] The fracture toughness of the high-toughness zirconia-toughened alumina ceramic material is 9.7 MPa·m. 1 / 2 Its Vickers hardness is 17.8 GPa.

[0085] Example 2:

[0086] The contents that are the same as in Example 1 will not be repeated here; the different aspects of this embodiment compared to Example 1 are as follows:

[0087] One aspect of this embodiment provides a method for preparing a medical silicon nitride metal composite material, comprising the following steps:

[0088] The preparation method of the mixed slurry further includes the following steps: surface treatment of the alumina powder, that is, adding the alumina powder to a sintering aid solution, mixing and stirring, and then drying to obtain alumina with strontium and chromium elements attached to the surface; the sintering aid solution preparation process involves dissolving the sintering aid in a solvent;

[0089] Alumina material with strontium and chromium adhering to its surface is mixed with zirconium oxide powder, sintering aid, and dispersant in a solvent, and then ball-milled to obtain the mixed slurry.

[0090] The dried mixture is mixed with carbon black of different particle sizes and then pre-sintered to obtain the primary material; the dried mixture is sieved and the particle size of the mixture is less than or equal to 150 mesh.

[0091] The carbon black has a specific surface area of ​​133 m². 2 / g of particles, with a specific surface area of ​​82m² 2 / g of particles, with a specific surface area of ​​45m 2 The particle mass ratio is 5:3:2.

[0092] The alumina powder, zirconium oxide powder, stabilizer, sintering aid, dispersant and solvent are mixed and ground in a mass ratio of 78:23:1.3:8.5:2.8:118 to obtain the mixed slurry;

[0093] The mass ratio of the strontium source to the chromium source is 4:1;

[0094] The strontium source includes strontium carbonate; the chromium source includes chromium oxide;

[0095] The mass ratio of sintering aid A to sintering aid B is 1:0.7;

[0096] The sintering aid B includes magnesium oxide and calcium oxide; the dispersant includes sodium polyacrylate 5000 and a polymeric dispersant containing acidic groups.

[0097] After drying the mixed slurry, it is pre-sintered to obtain a primary material. The pre-sintering temperature is 1220℃. The primary material includes elongated crystals. The specific process is to dry the mixed slurry and then sieve it to obtain a dried mixed material.

[0098] The pre-sintering process is as follows: from room temperature to 118°C, the heating rate is 9.8°C / min; from 118°C to 420°C, the heating rate is 5.8°C; from 420°C to 818°C, the heating rate is 1.8°C; and from 818°C to 1230°C, the heating rate is 3.8°C.

[0099] The primary mixture is ground and sieved to obtain secondary material; the preparation process of the secondary material includes the following steps: the primary material is ball-milled for 11 hours, and then dried and sieved through a 120-mesh sieve to obtain secondary material.

[0100] The tertiary material is cold isostatically pressed and then sintered at 1580℃ under normal pressure to obtain the high-toughness zirconia toughened alumina ceramic material; the particle size of the tertiary material is 90-110 mesh particles to 110-160 mesh particles in a mass ratio of 1.8:8.2.

[0101] After the three-stage material is filled into the mold, it is centrifugally rotated, and then the material in the mold is cold isostatically pressed.

[0102] The sintering process is as follows: heating from room temperature to 118°C at a rate of 7.8°C / min; heating from 118°C to 618°C at a rate of 3.8°C, and holding at 610°C for 2.1 hours; heating from 618°C to 1230°C at a rate of 2.3°C / min, and holding at 1230°C for 1 hour; heating from 1230°C to 1480°C at a rate of 1.3°C / min, and holding at 1480°C for 4 hours; heating from 1480°C to 1580°C at a rate of 9.8°C / min, and heating at 1580°C for 25 minutes.

[0103] Another aspect of this embodiment provides a high-toughness zirconia-toughened alumina ceramic material, which is prepared by a method for preparing high-toughness zirconia-toughened alumina ceramic materials.

[0104] The high-toughness zirconia-toughened alumina ceramic material includes zirconia grains and elongated grains, wherein the elongated grains are dispersed around the zirconia grains.

[0105] The content of tetragonal and monoclinic phases in the zirconia grains reaches 96%, and the content of tetragonal phase in the zirconia grains reaches more than 74%.

[0106] The fracture toughness of the high-toughness zirconia-toughened alumina ceramic material is ≥9.9 MPa·m. 1 / 2 Vickers hardness ≥18.2GPa.

[0107] Example 3:

[0108] The contents that are the same as in Example 1 will not be repeated here; the different aspects of this embodiment compared to Example 1 are as follows:

[0109] One aspect of this embodiment provides a method for preparing a medical silicon nitride metal composite material, comprising the following steps:

[0110] The preparation method of the mixed slurry further includes the following steps: surface treatment of the alumina powder, that is, adding the alumina powder to a sintering aid solution, mixing and stirring, and then drying to obtain alumina with strontium and chromium elements attached to the surface; the sintering aid solution preparation process involves dissolving the sintering aid in a solvent;

[0111] Alumina material with strontium and chromium adhering to its surface is mixed with zirconium oxide powder, sintering aid, and dispersant in a solvent, and then ball-milled to obtain the mixed slurry.

[0112] The dried mixture is mixed with carbon black of different particle sizes and then pre-sintered to obtain the primary material; the dried mixture is sieved and the particle size of the mixture is less than or equal to 150 mesh.

[0113] The carbon black has a specific surface area of ​​133 m². 2 / g of particles, with a specific surface area of ​​82m² 2 / g of particles, with a specific surface area of ​​45m 2 The particle mass ratio is 5:3:2.

[0114] The alumina powder, zirconium oxide powder, stabilizer, sintering aid, dispersant and solvent are mixed and ground in a mass ratio of 72:18:1.1:5.8:0.9:108 to obtain the mixed slurry;

[0115] The mass ratio of the strontium source to the chromium source is 1.2:0.5;

[0116] The strontium source includes strontium acetate and strontium oxalate; the chromium source includes chromium acetate and chromium trichloride.

[0117] The mass ratio of sintering aid A to sintering aid B is 1:0.6;

[0118] The sintering aid B includes calcium oxide; the dispersant includes polyethylene and acid salt polymer dispersants; and the solvent is water.

[0119] After drying the mixed slurry, it is pre-sintered to obtain a primary material. The pre-sintering temperature is 1050℃. The primary material includes elongated crystals. The specific process is to dry the mixed slurry and then sieve it to obtain a dried mixed material.

[0120] The pre-sintering process is as follows: from room temperature to 108°C, the heating rate is 9.2°C / min; from 108°C to 408°C, the heating rate is 4.3°C; from 408°C to 808°C, the heating rate is 1.2°C; and from 808°C to 1080°C, the heating rate is 3.2°C.

[0121] The primary mixture is ground and sieved to obtain secondary material; the preparation process of the secondary material includes the following steps: the primary material is ball-milled for 9 hours, and then dried and sieved through a 120-mesh sieve to obtain secondary material.

[0122] The three-stage materials are cold isostatically pressed and then sintered at 1520℃ under normal pressure to obtain the high-toughness zirconia toughened alumina ceramic material; the particle size of the three-stage materials is 90-110 mesh particles to 110-160 mesh particles in a mass ratio of 1.2:8.8.

[0123] After the three-stage material is filled into the mold, it is centrifugally rotated, and then the material in the mold is cold isostatically pressed.

[0124] The sintering process is as follows: heating from room temperature to 108°C at a rate of 7.2°C / min; heating from 108°C to 608°C at a rate of 3.2°C, and holding at 608°C for 1.9 hours; heating from 608°C to 1120°C at a rate of 1.6°C / min, and holding at 1120°C for 1 hour; heating from 1120°C to 1430°C at a rate of 1.1°C / min, and holding at 1430°C for 6 hours; heating from 1430°C to 1520°C at a rate of 8.3°C / min, and heating at 1520°C for 35 minutes.

[0125] Another aspect of this embodiment provides a high-toughness zirconia-toughened alumina ceramic material, which is prepared by a method for preparing high-toughness zirconia-toughened alumina ceramic materials.

[0126] The high-toughness zirconia-toughened alumina ceramic material includes zirconia grains and elongated grains, wherein the elongated grains are dispersed around the zirconia grains.

[0127] The content of tetragonal and monoclinic phases in the zirconia grains reaches more than 96.5%, and the content of tetragonal phase in the zirconia grains reaches more than 75%.

[0128] The fracture toughness of the high-toughness zirconia-toughened alumina ceramic material is 10.5 MPa·m. 1 / 2 Its Vickers hardness is 18.6 GPa.

[0129] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to the technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, the above-described features have similar functions to (but are not limited to) those disclosed in this application.

Claims

1. A method for preparing a high-toughness zirconia-toughened alumina ceramic material, characterized in that, Includes the following steps: A mixed slurry is prepared, comprising alumina powder, zirconium oxide powder, stabilizer, sintering aid, and dispersant; the sintering aid includes a strontium source and a chromium source. After the mixture slurry is dried, it is pre-sintered to obtain primary material. The pre-sintering temperature is 1000-1250℃, and the primary material includes elongated grains. The primary mixture is ground and sieved to obtain secondary material; The secondary material is granulated to obtain the tertiary material; The three-stage material is cold isostatically pressed and then sintered at 1500-1600℃ under normal pressure to obtain the high-toughness zirconia toughened alumina ceramic material.

2. The method for preparing high-toughness zirconia-toughened alumina ceramic material according to claim 1, characterized in that, The preparation method of the mixed slurry includes the following steps: mixing and grinding the alumina powder, zirconium oxide powder, stabilizer, sintering aid, dispersant and solvent in a mass ratio of (70-80):(15-25):(1-1.5):(1.6-8.8):(0.5-3):(100-120) to obtain the mixed slurry.

3. The method for preparing high-toughness zirconia-toughened alumina ceramic material according to claim 2, characterized in that, The sintering aids include sintering aid A and sintering aid B; sintering aid A includes a strontium source and a chromium source; both the strontium source and the chromium source are salt compounds; The mass ratio of the strontium source to the chromium source is (1-5):(0.1-3); The strontium source includes one or more of strontium carbonate, strontium acetate, strontium oxalate, and strontium chloride; The chromium source includes one or more of chromium oxide, chromium acetate, and chromium trichloride. The mass ratio of sintering aid A to sintering aid B is 1:(0.5-0.8); The sintering aid B includes one or both of magnesium oxide and calcium oxide; and / or The dispersant includes one or more of sodium polyacrylate 5000, a polymeric dispersant containing acidic groups, polyethylene, and acid salt polymeric dispersants; The solvent is water or ethanol.

4. The method for preparing high-toughness zirconia-toughened alumina ceramic material according to claim 3, characterized in that, The method for preparing the mixed slurry also includes The process includes the following steps: surface treatment of the alumina powder, namely, adding the alumina powder to a sintering aid solution, mixing and stirring, and then drying to obtain alumina with strontium and chromium elements attached to the surface; Alumina material with strontium and chromium adhering to its surface is mixed with zirconium oxide powder, sintering aid, and dispersant in a solvent, and then ball-milled to obtain the mixed slurry.

5. The method for preparing high-toughness zirconia-toughened alumina ceramic material according to claim 1, characterized in that, The mixture slurry is dried and then sieved to obtain a dried mixture; the dried mixture is mixed with carbon black of different particle sizes and then pre-sintered to obtain the primary material. and / or The pre-sintering process is as follows: from room temperature to 100-120℃, the heating rate is 9-10℃ / min; from 100-120℃ to 400-430℃, the heating rate is 4-6℃; from 400-430℃ to 800-820℃, the heating rate is 1-2℃; and from 800-820℃ to 1000-1250℃, the heating rate is 3-4℃.

6. The method for preparing high-toughness zirconia-toughened alumina ceramic material according to claim 5, characterized in that, The dried mixture is sieved, and the particle size of the mixture is less than or equal to 150 mesh. The carbon black has a specific surface area of ​​120-145 m². 2 / g of particles, with a specific surface area of ​​73-91m² 2 / g of particles, with a specific surface area of ​​40-50m 2 The particle mass ratio per g is (4.5-5.5):(2.5-3.5):(1.5-2.5).

7. The method for preparing high-toughness zirconia-toughened alumina ceramic material according to claim 1, characterized in that, The secondary material preparation process includes the following steps: the primary material is ball-milled for 8-12 hours, and then dried and sieved through a 120-mesh sieve to obtain the secondary material.

8. The method for preparing high-toughness zirconia-toughened alumina ceramic material according to claim 1, characterized in that, The preparation process of the tertiary material includes the following steps: mixing the secondary material with polyethylene glycol, granulating the mixture, and then sieving the granulated material to obtain the tertiary material.

9. The method for preparing high-toughness zirconia-toughened alumina ceramic material according to claim 1, characterized in that, The particle size of the third-level material is 90-110 mesh particles to 110-160 mesh particles in a mass ratio of (1-2):(8-9); After the three-stage material is filled into the mold, it is centrifugally rotated, and then the material in the mold is cold isostatically pressed. The sintering process is as follows: heating from room temperature to 100-120℃ at a rate of 7-8℃ / min; heating from 100-120℃ to 600-620℃ at a rate of 3-4℃; holding at 600-620℃ for 1.8-2.2 hours; heating from 600-620℃ to 1100-1250℃ at a rate of 1.5-2.5℃ / min; and holding at 1100℃... Hold at -1250℃ for 1 hour; raise the temperature from 1100-1250℃ to 1400-1500℃ at a rate of 1-1.5℃ / min, and hold at 1400-1500℃ for 3-7 hours; raise the temperature from 1400-1500℃ to 1500-1600℃ at a rate of 8-10℃ / min, and heat at 1500-1600℃ for 20-40 minutes. Then, the material is cooled to obtain the high-toughness zirconia-toughened alumina ceramic material.

10. A high-toughness zirconia-toughened alumina ceramic material, characterized in that, It was prepared by any one of the methods for preparing high-toughness zirconia toughened alumina ceramic materials according to claims 1-9; The high-toughness zirconia-toughened alumina ceramic material includes zirconia grains and elongated grains, wherein the elongated grains are dispersed around the zirconia grains. The content of tetragonal and monoclinic phases in the zirconia grains reaches more than 95%, and the content of tetragonal phase in the zirconia grains reaches more than 73%. The fracture toughness of the high-toughness zirconia-toughened alumina ceramic material is ≥8.71 MPa·m. 1 / 2 Vickers hardness ≥ 17.3 GPa; preferably, fracture toughness ≥ 9.6 MPa·m 1 / 2 Vickers hardness ≥17.5GPa.

Images