Composite ceramic material as well as preparation method and application thereof

Abstract

The invention discloses a composite ceramic material as well as a preparation method and application thereof. The composite ceramic material comprises an inner core and a shell layer, the shell layer coats at least part of the surface of the inner core; the inner core is prepared from raw materials including aluminum oxide, first YSZ ceramic and second YSZ ceramic; the shell layer is prepared from raw materials including a zirconium compound and a first binder. The first YSZ ceramic with the high yttrium content and the second YSZ ceramic with the low yttrium content are matched, a toughening synergistic mechanism combining a metastable region with non-uniform grain boundary Y enrichment is constructed, and compared with a traditional uniform doping method, the forming effect of the composite ceramic material can be remarkably improved; the fracture toughness and the bending strength are effectively improved on the premise that the sintering density and the hardness are not obviously influenced; and moreover, by forming the core-shell structure, the microstructure can be optimized, and synergistic improvement of strength and toughness is macroscopically realized.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of ceramic materials, and particularly relates to a composite ceramic material and a preparation method and application thereof. BACKGROUND

[0002] In the human bone joint ceramic material ZTA (zirconia reinforced alumina ceramic, the fourth generation of ceramic) system, zirconia (ZrO2) as a key toughening component, its stress-induced phase transition toughening mode significantly improves the toughness and strength of pure alumina ceramic. However, the tetragonal zirconia is in a metastable state at room temperature and can spontaneously undergo a full-size T (tetragonal zirconia)-M (cubic zirconia) phase transition. Therefore, it is necessary to precisely control the phase transition of tetragonal zirconia in ZTA ceramic.

[0003] In yttria-stabilized tetragonal zirconia, yttria is doped into the zirconia lattice by solid solution, replaces the original position of Zr 4+ ion, forms oxygen vacancies, realizes stability, and Y2O3 doping effectively reduces the critical temperature of tetragonal phase to monoclinic phase transition, stabilizes the existence of tetragonal zirconia at room temperature. In addition, Y2O3 doping stabilizes the crystal structure of zirconia, so that the ZTA material matrix obtains higher strength and toughness.

[0004] Most of the YSZ (yttria-stabilized zirconia) powder on the market is co-sintering solid solution formula powder. The yttria in the formula powder formed by co-sintering solid solution is uniformly doped in zirconia, and is used as a basic raw material in the synthesis process of ZTA, which is difficult to change and control. It is worth noting that even if ZTA has the same Y2O3 content, due to the inhibition of adjacent lattices in the matrix material, not all T-ZrO2 has the ability to be stress-induced phase transition into M-ZrO2, and the material forming has a big problem: for example, T-ZrO2 is wrapped inside the Al2O3 lattice, which is more difficult to phase transition than the grains exposed at the grain boundary junction; for example, the uneven distribution of Y2O3, or the intensive distribution of ZrO2 grain surface is more prone to phase transition of zirconia than the dispersion distribution in the lattice. SUMMARY

[0005] In order to overcome at least one problem existing in the prior art, one of the purposes of the present application is to provide a composite ceramic material which has good mechanical stability and anti-aging ability, and can occur stress-induced phase transition under external load, thereby releasing phase transition energy and forming crack blunting effect, and playing a significant toughening effect.

[0006] The second purpose of the present application is to provide a preparation method of the above-mentioned composite ceramic material.

[0007] The third object of the present application is to provide an application of the composite ceramic material.

[0008] To achieve the above object, the technical solution adopted by the present application is: The first aspect of the present application provides a composite ceramic material, comprising a core and a shell layer; the shell layer is coated on at least part of the surface of the core; the core is made of raw materials comprising alumina, a first YSZ ceramic and a second YSZ ceramic; the yttrium content in the first YSZ ceramic is 2.75-2.9 mol%; the yttrium content in the second YSZ ceramic is 0.1-0.25 mol%; the shell layer is made of raw materials comprising a zirconium compound and a first binder; the mass ratio of the zirconium compound to the first binder is 1: (1-2).

[0009] In the present application, YSZ ceramic refers to yttria-stabilized zirconia ceramic, which is formed by yttria (Y2O3) and zirconia (ZrO2).

[0010] The present application innovatively proposes the influence mechanism of "different addition methods under the same doping concentration" on the microstructure, breaking the traditional idea of directly mixing powders according to the mole ratio for uniform doping. Specifically, in the composite ceramic system of the present application, the content of Y2O3 directly determines the phase stability and phase transformation toughening ability of ZrO2, and ZrO2 particles doped with high content of yttrium (Y) can maintain tetragonal phase stability at room temperature, thereby giving the material high mechanical stability and anti-aging ability; ZrO2 particles doped with low content of Y are in a metastable state and are more likely to undergo stress-induced tetragonal-monoclinic phase transition under external load, thereby releasing phase transition energy and forming a crack blunting effect, thereby playing a significant toughening role. Unlike zirconia reinforced alumina ceramic (ZTA) powder obtained by uniform doping of Y, the present application uses the first YSZ ceramic and the second YSZ ceramic to mix powders in the high-Y region and the low-Y region, so that there is uneven doping of Y in the material. During the subsequent sintering process, Y elements in the high-Y region always accumulate at the grain boundaries of ZTA in a diffusion manner. This grain boundary enrichment effect triggers a deeper toughening mechanism: the distribution of Y enrichment at the grain boundaries makes it easier for local stress to trigger phase transition from the surface of the grain, and the volume expansion and compressive stress generated effectively hinder crack propagation. This is because the crack propagation process first contacts the outer region of the grain, and the lattice near the outer region preferentially undergoes phase transition. If the phase transition consumes enough energy or produces enough volume expansion to achieve crack deflection, the Y-stabilized zirconia lattice deep inside the grain is effectively "shielded". This grain boundary strengthening can maintain the structural integrity of the stable region inside the grain, thereby achieving a balance between crack retardation and overall stability.

[0011] In addition, the present application also constructs a shell layer on the surface of the inner core of the powder particles. The layered structure makes the surface of each granulated ball coated with a shell-shaped and easily crushed zirconium layer that does not contain Y. After the subsequent dry pressing process, the area around each crushed granulated ball is distributed with a Y-free region, which provides a high diffusion energy for the diffusion of Y during the sintering process and induces the generation of grain boundary enrichment effect. This can further improve the probability of phase transition of the peripheral ZrO2 grains by stress induction after the formation of porcelain, thereby preferentially forming a transition zone near the crack tip and significantly improving the crack propagation resistance and fracture toughness. At the same time, the high-Y region in the interior ensures the thermal stability and anti-phase change aging performance of the matrix during long-term service. The core-shell layered structure not only optimizes the microstructure, but also achieves a synergistic improvement of high strength and high toughness on the macro level.

[0012] Controlling the yttrium content in the first YSZ ceramic and the second YSZ ceramic within a certain range is to make the two form a relatively obvious diffusion gradient after sintering, thereby being beneficial to the subsequent sintering diffusion of Y; at the same time, it avoids the Y content being too high, which may still exist in a high-Y content area after sintering. The high Y in this part of the area will significantly inhibit spontaneous phase transition, increase the possibility of local cubic phase generation, make T-ZrO2 too stable, and make it difficult to trigger an effective phase transition toughening mechanism during crack propagation, so that the fracture toughness is limitedly improved.

[0013] Controlling the mass ratio of the zirconium compound and the first binder can avoid the discontinuity of the surface coating caused by insufficient first binder, which makes it difficult to form a complete low-Y area, resulting in insufficient surface layer phase transition toughening effect; it also avoids the excessive first binder, which leads to a high content of organic matter during the preparation process, which is easy to decompose and form pores, affecting the integrity of the surface layer structure, thereby reducing the bending strength.

[0014] Preferably, the yttrium content in the first YSZ ceramic is 2.8-2.85 mol%.

[0015] Preferably, the yttrium content in the second YSZ ceramic is 0.15-0.2 mol%.

[0016] Preferably, the mass ratio of the zirconium compound to the first binder is 1: (1.3-1.7).

[0017] Preferably, the molar ratio of the alumina, the first YSZ ceramic and the second YSZ ceramic is (73-75):(10-12):(10-12).

[0018] Preferably, the alumina is selected from a-Al2O3.

[0019] Preferably, the purity of the alumina is 3N-5N; further preferably, 4N.

[0020] Preferably, the specific surface area of the aluminum oxide is 7.3-10.3 m 2 / g.

[0021] Preferably, the specific surface area of the first YSZ ceramic and the specific surface area of the second YSZ ceramic are each independently 10-13 m 2 / g.

[0022] Preferably, the yttrium content in the composite ceramic material is 1.35-1.65 mol%; further preferably 1.4-1.6 mol%.

[0023] Since the tetragonal phase in ZrO2 is difficult to exist stably, it is prone to spontaneously undergo tetragonal-monoclinic phase transition, leading to an increase in microcrack density during sintering and service of the material, reducing the overall strength and accelerating aging, while the addition of Y2O3 can effectively stabilize ZrO2, control the yttrium content in the overall composite ceramic material within a certain range, and ensure that ZrO2 has a suitable stability degree, thereby promoting the stress-induced phase transition ability of the composite ceramic material and improving its toughening effect to obtain higher fracture toughness.

[0024] Preferably, the zirconium compound includes at least one of tetrakis(dimethylamino)zirconium (TDMA-Zr), zirconium cyclopentadienide (ZrCp4), or tetrakis(diethylamino)zirconium (Zr(NEt2)4); in some embodiments of the present application, the zirconium compound is selected from tetrakis(dimethylamino)zirconium (TDMA-Zr).

[0025] Preferably, the first binder includes at least one of polyvinyl alcohol (PVA), methyl cellulose, or isocyanate; in some embodiments of the present application, the first binder is selected from polyvinyl alcohol (PVA).

[0026] Preferably, the shell layer is prepared by atomic layer deposition (ALD) from raw materials including a zirconium compound and a first binder; more specifically, in-situ atomic layer deposition.

[0027] Preferably, the shell layer is free of yttrium.

[0028] Preferably, the raw materials of the inner core further include a dispersant, a second binder, and a solvent.

[0029] Preferably, the dispersant includes at least one of ammonium polyacrylate, sodium citrate, sodium stearate, sodium hexametaphosphate, or sodium tripolyphosphate; in some embodiments of the present application, the dispersant is selected from ammonium polyacrylate.

[0030] Preferably, the second binder includes at least one of acrylate, polyacrylic acid, or polyethylene glycol; in some embodiments of the present application, the binder is selected from acrylate.

[0031] Preferably, the solvent comprises water, ammonia water or a combination thereof; in some embodiments of the present application, the solvent is selected from water.

[0032] Preferably, the mass ratio of the total mass of the alumina, the first YSZ ceramic and the second YSZ ceramic to the mass of the dispersant is 100: (0.3-0.6).

[0033] The use of a certain amount of dispersant is beneficial to reduce the aggregation of ceramic powder, improve the dispersibility of the powder slurry, improve the uniformity of the particle size distribution in the subsequent preparation process, reduce the local defects of the final sintered body, and obtain higher strength; and can reduce the pores generated by the decomposition of the residual dispersant at high temperature, thereby improving the sintering density and obtaining higher hardness and bending strength.

[0034] Preferably, the mass ratio of the total mass of the alumina, the first YSZ ceramic and the second YSZ ceramic to the mass of the second binder is 100: (3-3.5).

[0035] The use of a certain amount of second binder is beneficial to improve the particle bonding force between the ceramic powders, reduce the particle breakage caused by the subsequent preparation process, improve the forming strength, and reduce the cracking of the sintered body; and can reduce the pores generated by the decomposition of the residual organic matter during sintering, thereby improving the density and mechanical properties.

[0036] Preferably, the mass ratio of the total mass of the alumina, the first YSZ ceramic and the second YSZ ceramic to the mass of the solvent is 100: (33-38).

[0037] Preferably, the composite ceramic material is a composite ceramic material for preparing a skeletal joint material.

[0038] The second aspect of the present application provides a preparation method of the composite ceramic material as described in the first aspect of the present application, comprising the following steps: mixing raw materials of the inner core, granulating to obtain the inner core; using raw materials of the shell layer as a precursor, performing atomic layer deposition on the surface of the inner core to form the shell layer, thereby obtaining the composite ceramic material.

[0039] In some embodiments of the present application, the granulation method is selected from wet granulation; further, after mixing the raw materials of the inner core, a slurry is prepared, the slurry is ground, and after drying, the inner core is obtained.

[0040] In some embodiments of the present application, the grinding method comprises at least one of ball milling, sand milling, planetary milling or jet milling.

[0041] In some embodiments of the present application, the drying method comprises at least one of spray drying, freeze drying or drum drying; in some preferred embodiments of the present application, the drying method is selected from spray drying.

[0042] In some embodiments of the present application, the preparation of the inner core comprises: mixing alumina, a first YSZ ceramic and a second YSZ ceramic to form a mixed powder; mixing the mixed powder, a dispersant and a solvent, grinding, then adding a second binder, and drying to obtain the inner core.

[0043] In some embodiments of the present application, the second binder is added for 0.5-1 h. By mixing for a certain period of time, the pores generated after adding the binder can be eliminated.

[0044] Preferably, the nitrogen flow rate used in the atomic layer deposition is 4-6 L / min; further preferably, 4.5-5.5 L / min.

[0045] By using a certain nitrogen flow rate, the residual precursors can be effectively removed, the agglomerates or particles generated by the reaction of the residual precursors with the subsequent precursors can be reduced, the probability of these agglomerates or particles falling on the surface of the substrate to form defects can be reduced, and the situation that the precursors block the inlet to affect the deposition can be reduced. In addition, since the surface reaction of ALD is sensitive to temperature, a slight fluctuation in temperature will affect the adsorption / desorption equilibrium constant and the surface reaction rate of the precursors, therefore, controlling a certain nitrogen flow rate can ensure that the growth rate is within the ideal value range; and controlling a certain nitrogen flow rate can reduce the slight vibration or deformation of the substrate, and improve the uniformity of the deposition in the microcosmic view.

[0046] Preferably, the fluidization time used in the atomic layer deposition is 30-60 min.

[0047] Preferably, the pulse time used in the atomic layer deposition is 0.11-0.15 s.

[0048] Preferably, the pressure maintaining time used in the atomic layer deposition is 8-12 s.

[0049] Preferably, the nitrogen purge time used in the atomic layer deposition is 0.04-0.06 s.

[0050] Preferably, the cycle number used in the atomic layer deposition is 100-200 times.

[0051] Preferably, the atomic layer deposition is followed by drying; the temperature of the drying is 115-135℃; further preferably, 120-130℃.

[0052] The drying after the atomic layer deposition can completely remove the physically adsorbed water remaining in the material surface and voids, and improve the stability of subsequent processes; and the drying at a certain temperature can reduce the destruction of the core-shell structure, reduce the atomic interfacial diffusion caused by high temperature, thereby reducing the generation of interface defect layer and doping layer, and ensure a clear bonding interface; at the same time, high temperature can induce the shell structure on the surface to form a bridge sintering neck in advance under the action of organic matter, and by controlling the drying temperature, the phenomenon can be effectively reduced, and the stability of the subsequent forming process can be improved.

[0053] Preferably, the drying time after the atomic layer deposition is 1-2h.

[0054] Preferably, the atomic layer deposition is in-situ atomic layer deposition.

[0055] Preferably, the ratio of the amount of the shell layer raw material to the amount of the core is (20-50) μL:1g; and further preferably (30-40) μL:1g.

[0056] The third aspect of the present application provides a use of the composite ceramic material as described in the first aspect of the present application, or the composite ceramic material prepared by the preparation method as described in the second aspect of the present application, in the preparation of a bone joint material.

[0057] Under the bone joint load environment, the implanted material needs to have high hardness (resistance to wear), high toughness (avoiding brittle fracture) and excellent aging stability. Traditional ZTA materials or YSZ materials uniformly doped with Y usually have advantages in certain properties, but it is difficult to balance. For example, materials uniformly doped with high Y content have good stability but insufficient toughness, and materials uniformly doped with low Y content have better toughness but poor anti-aging performance. The present application realizes the overall optimization of hardness, toughness and anti-aging performance by constructing a composite microstructure of "high Y stable zone + low Y toughening zone". In practical applications, the material not only can withstand long-term friction and wear, but also can maintain structural integrity under sudden impact or cyclic load, greatly improving the service life and safety of artificial joints, and is significantly superior to traditional ZTA or YSZ materials prepared by directly mixing powders.

[0058] In some embodiments of the present application, the bone joint material includes a human bone joint material.

[0059] The present application has the beneficial effects that: the present application cooperates the first YSZ ceramic with high yttrium content and the second YSZ ceramic with low yttrium content, constructs the toughening synergistic mechanism of "metastable region" combined with "non-uniform grain boundary Y enrichment", compared with the traditional uniform doping method, can significantly improve the forming effect of the composite ceramic material, and effectively improve the fracture toughness and bending strength without significantly affecting the sintering density and hardness; and by forming the core-shell structure, the microstructure can be optimized, and the synergistic improvement of strength and toughness is realized in the macroscopic. DETAILED DESCRIPTION

[0060] The content of the present application is further described in detail through specific examples. It should also be understood that the following examples are only used to further illustrate the present application and cannot be understood as limiting the protection scope of the present application. Some non-essential improvements and adjustments made by those skilled in the art according to the principles set forth in the present application all belong to the protection scope of the present application. The following example specific process parameters are only one example in the appropriate range, i.e. those skilled in the art can make appropriate selection within the range through the description herein, and not limited to the specific data of the following examples. The raw materials, reagents or devices used in the following examples and comparative examples are commercially available or can be obtained by known methods unless otherwise specified.

[0061] In the following examples and comparative examples, high Y-ZrO2 refers to YSZ ceramic with high yttrium content, and low Y-ZrO2 refers to YSZ ceramic with low yttrium content.

[0062] Example 1 The present example provides a composite ceramic material, and the preparation steps are as follows: S1: uniformly mix α-Al2O3, high Y-ZrO2 and low Y-ZrO2 in proportion to obtain a mixed powder; The purity of α-Al2O3 is 4N, and the specific surface range is 8.8m 2 / g; The Y content in high Y-ZrO2 is 2.82mol%, and the Y content in low Y-ZrO2 is 0.18mol%; The specific surface range of high Y-ZrO2 and low Y-ZrO2 is 11.5m 2 / g; The mixing ratio of the above-mentioned is α-Al2O3: high Y-ZrO2: low Y-ZrO2 = 74: 11: 11 in terms of molar ratio, and the mixed powder 1.5Y-ZTA is obtained by mixing; S2: add dispersant ammonium polyacrylate and solvent water to the mixed powder obtained in S1 in proportion, and perform ball milling dispersion, then add adhesive acrylate, slowly stir for 0.8h to remove the pores after adding glue, and then perform spray drying to obtain ZTA granulation balls; wherein the dispersant is used in an amount of 0.5wt%, the solvent is used in an amount of 35wt%, and the binder is used in an amount of 3.2wt%, based on 100wt% of the mixed powder; S3: 0Y zirconium powder tetra(dimethylamino)zirconium (TDMA-Zr) was mixed with the binder PVA in a proportion, and a solution was obtained by filtration; wherein the proportion of 0Y zirconium powder to the binder is 1:1.5 by mass; S4: The ZTA granulated balls obtained in S2 and the solution obtained in S3 were placed in a customized fluidized bed ALD system (vapor deposition equipment) at 35μL of solution per gram of powder, and the gas deposition parameters were set, wherein the N2 flow rate was 5L / min, the fluidization time was 40min, the pulse time was 0.13s, the pressure maintaining time was 10s, the N2 purging time was 0.05s, 150 cycles were performed, a core-shell structure was formed, and the composite ceramic powder was obtained by drying at 125℃ for 1.5h.

[0063] Examples 2-21 Examples 2-21 each provide a composite ceramic material, which differs from Example 1 in that some of the preparation conditions are different, which are specifically recorded in Table 1; other conditions not involved in Table 1 are the same as those of Example 1.

[0064] Comparative Examples 1-10 Comparative Examples 1-10 each provide a composite ceramic material, which differs from Example 1 in that some of the preparation conditions are different, which are specifically recorded in Table 2; other conditions not involved in Table 2 are the same as those of Example 1.

[0065] Table 1 Preparation conditions of Examples 1-21

[0066] Table 2 Preparation conditions of Comparative Examples 1-10

[0067] Performance test 1) Green strength test pieces (size 55x80x7.5mm) were obtained by using cold isostatic pressing at 300MPa, and then the residual organic matter in the strength test pieces was removed by using a 450℃ holding furnace for 70h, and then the green body was sintered in an air atmosphere sintering furnace at a heating rate of 10℃ / min at 1500℃ for 2h to obtain a once-sintered sample.

[0068] Once-sintered non-breakable defect density: Test method: The sample after the first sintering was broken to obtain a cross section, and the flat area was selected for SEM to obtain the cross section morphology. A 2mm x 3mm sample area was fixed, and all non-dense areas were found in the fixed range. The number of defects was counted to obtain the non-crushing defect density: number of defects / actual sample area.

[0069] Passing standard: <0.9 / mm 2 .

[0070] 2) After the first sintering, the sample was treated by hot isostatic pressing (HIP) equipment at 1400°C for 2h in argon atmosphere to obtain a more dense test ZTA sample (density 4.37±0.05g·cm -3 ), and then the size of the strength bar was (3.2±0.1) x (4.2±0.1) x (45.5±0.1) mm by wire cutting. Finally, annealing was completed at 1200°C (300°C lower than the sintering temperature) for 40-60 minutes in air to eliminate processing stress and minimize the error of strength test data. The obtained sample was tested as follows.

[0071] a) Vickers hardness Test method: Vickers hardness test was performed on the surface of smooth and flat sample (Ra<0.1μm) using a Vickers hardness tester with a load of 9.81N (HV1), and the load time was 10-15s. After testing 30 data and removing the extreme value, the average hardness data was obtained.

[0072] Passing standard: ≥16GPa.

[0073] b) Toughness Test method: The sample (Ra<0.1μm) with a V-shaped groove prepared in advance was placed on a three-point bending fixture, and force was applied at a constant loading rate (0.05-0.5mm / min) with a span of 30mm until the sample broke. The maximum load Pmax was recorded to calculate the toughness value. After testing 30 data and removing the extreme value, the average toughness data was obtained.

[0074] Passing standard: ≥4MPa x m 0.5 .

[0075] c) Four-point bending strength Test method: The sample (Ra<0.1μm) prepared in advance was placed on a four-point bending fixture using a universal testing machine, and force was applied at a constant loading rate (0.5mm / min) with a lower span of 30mm and an upper span of 10mm until the sample broke. The maximum load Pmax was recorded to calculate the strength value. After testing 30 data, the average strength data was obtained.

[0076] Pass criteria: ≥ 1300 MPa.

[0077] d) Strength reduction rate after aging Test method: The prepared strength test strip is placed in a high-temperature and high-pressure container for 10 h of treatment in water vapor at 134℃±2℃, then taken out, and the four-point bending strength is tested. The strength reduction rate after aging is obtained by (strength before aging-strength after aging) / strength before aging.

[0078] Pass criteria: ≤ 10%.

[0079] The test results are shown in Tables 3-4.

[0080] Table 3 Performance test results of Examples 1-21

[0081] Table 4 Performance test results of Comparative Examples 1-10

[0082] As can be seen from Tables 3-4, the composite ceramic material prepared by the suitable preparation conditions of Examples 1-21 has low density of compression unbreakable defects, high hardness, high toughness, high bending strength and good aging resistance. The Y content in the high Y-ZrO2 used in Comparative Example 1 is too low, resulting in high density of compression unbreakable defects, low strength; the Y content in the high Y-ZrO2 used in Comparative Example 2 is too high, resulting in limited improvement of fracture toughness; the Y content in the low Y-ZrO2 used in Comparative Example 3 is too low, resulting in poor density of compression unbreakable defects, toughness, strength and aging resistance; the Y content in the low Y-ZrO2 used in Comparative Example 4 is too high, resulting in limited improvement of fracture toughness; the proportion of the binder PVA added in Comparative Examples 5-6 is too low or too high, resulting in decreased toughness and strength; the nitrogen flow rate used in Comparative Examples 7-8 is too small or too large, also resulting in decreased toughness and strength; the drying temperature after ALD in Comparative Example 9 is too low, resulting in poor density of compression unbreakable defects, hardness, strength and aging resistance, while the drying temperature in Comparative Example 10 is too high, resulting in poor density of compression unbreakable defects, toughness, strength and aging resistance.

[0083] In practical applications, the composite ceramic material provided by the embodiments of the present application can be used to prepare a bone joint material with good performance, which not only can withstand long-term friction and wear, but also can maintain structural integrity under sudden impact or cyclic loading, greatly improving the service life and safety of artificial joints, and significantly better than traditional ZTA or YSZ materials prepared by directly mixing powders.

[0084] To sum up, the application constructs the toughening synergistic mechanism of "metastable region" combined with "non-uniform grain boundary Y enrichment" by the cooperation of the first YSZ ceramic with high yttrium content and the second YSZ ceramic with low yttrium content, compared with the traditional uniform doping method, the forming effect of the composite ceramic material can be significantly improved, and the fracture toughness and bending strength can be effectively improved without significantly affecting the sintering density and hardness; and by forming the core-shell structure, the microstructure can be optimized, and the synergistic improvement of strength and toughness is realized in the macroscopic.

Claims

1. A composite ceramic material, characterized by, The composite ceramic material comprises a core and a shell layer; the shell layer is coated on at least part of the surface of the core; the core is prepared from raw materials comprising alumina, a first YSZ ceramic and a second YSZ ceramic; the yttrium content in the first YSZ ceramic is 2.75-2.9 mol%; the yttrium content in the second YSZ ceramic is 0.1-0.25 mol%; the shell layer is prepared from raw materials comprising a zirconium compound and a first binder; the mass ratio of the zirconium compound to the first binder is 1: (1-2).

2. The composite ceramic material of claim 1, wherein, The molar ratio of the alumina, the first YSZ ceramic and the second YSZ ceramic is (73-75):(10-12):(10-12).

3. The composite ceramic material of claim 1, wherein, The specific surface area of the alumina is 7.3 to 10.3 m 2 / g; and / or the specific surface area of the first YSZ ceramic and the specific surface area of the second YSZ ceramic are each independently 10 to 13 m2 / g. 2 / g.

4. The composite ceramic material of claim 1, wherein, The yttrium content in the composite ceramic material is 1.35-1.65 mol%.

5. The composite ceramic material of claim 1, wherein, The zirconium compound comprises at least one of tetrakis(dimethylamino)zirconium, zirconocene or tetrakis(diethylamino)zirconium; The first binder comprises at least one of polyvinyl alcohol, methyl cellulose or isocyanate.

6. The composite ceramic material of claim 1, wherein, The raw materials of the core further comprise a dispersant, a second binder and a solvent.

7. The composite ceramic material of claim 6, wherein, The dispersant comprises at least one of ammonium polyacrylate, sodium citrate, sodium stearate, sodium hexametaphosphate or sodium tripolyphosphate; And / or, the second binder comprises at least one of acrylate, polyacrylic acid or polyethylene glycol; And / or, the solvent comprises water, ammonia or a combination thereof; And / or, the mass ratio of the total mass of the alumina, the first YSZ ceramic and the second YSZ ceramic to the dispersant is 100:(0.3-0.6); And / or, the mass ratio of the total mass of the alumina, the first YSZ ceramic and the second YSZ ceramic to the second binder is 100:(0.3-0.6); And / or, the mass ratio of the total mass of the alumina, the first YSZ ceramic and the second YSZ ceramic to the solvent is 100:(33-38).

8. A method of producing the composite ceramic material according to any one of claims 1 to 7, characterized by, The method comprises the following steps: mixing the raw materials of the core, granulating to obtain the core; using the raw materials of the shell layer as a precursor, performing atomic layer deposition on the surface of the core to form the shell layer, thereby obtaining the composite ceramic material.

9. The production method according to claim 8, characterized by, The nitrogen flow rate used in the atomic layer deposition is 4-6 L / min; And / or, the atomic layer deposition is followed by drying; the drying temperature is 115-135°C.

10. Use of the composite ceramic material according to any one of claims 1-7, or the composite ceramic material prepared by the method according to claim 8 or 9, in the preparation of a skeletal joint material.

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