A zirconia ceramic with both biological activity and anti-low-temperature aging and a preparation method thereof

Abstract

The present invention discloses a zirconia ceramic with both biological activity and resistance to low-temperature aging and a preparation method thereof. The method includes: preparing a calcium magnesium silicon or calcium silicon phosphorus sol; preparing a pre-sintered zirconia ceramic matrix; preparing a zirconia transition layer ceramic green film with resistance to low-temperature aging; preparing a zirconia ceramic with a porous surface layer; and by means of a negative pressure infiltration method, enabling the calcium magnesium silicon or calcium silicon phosphorus sol to infiltrate into the porous surface layer, followed by drying and then heat treatment to obtain the ceramic. By loading biological active substances in the structure of the zirconia porous surface layer, the present invention improves the biological activity of the zirconia ceramic; by constructing a transition layer resistant to low-temperature aging, the low-temperature aging resistance of the zirconia ceramic is improved, ensuring the long-term stability of the material; the porous surface layer, the transition layer resistant to low-temperature aging and the zirconia matrix are sintered in one step after combination, solving the problems of low interfacial bonding strength and easy cracking and peeling between the traditional coating and the matrix.

Description

Technical Field

[0001] The present invention relates to the field of dental restoration medical materials, and particularly relates to a zirconia ceramic with both bioactivity and resistance to low-temperature aging and a preparation method thereof. Background Art

[0002] Dental implants, especially titanium alloy implants, have been widely used in the clinical field of replacing damaged teeth or repairing tooth loss. However, titanium alloy implants will corrode and release ions in the complex oral environment, leading to allergic and inflammatory reactions. Zirconia ceramics, especially tetragonal zirconia ceramics, as an ideal ceramic material, have extremely high mechanical strength, chemical stability and good biocompatibility, and their color and appearance are also closer to natural teeth, showing great potential to become dental implants. However, most of the zirconia implants on the market at present have defects such as poor bioactivity and poor resistance to low-temperature aging, which greatly limit their clinical application.

[0003] Zirconia ceramics are bio-inert ceramics. Poor bioactivity means that zirconia cannot induce the mineralization of calcium and phosphorus ions in body fluids on its surface, nor can it promote the adhesion, proliferation and osteogenic differentiation of stem cells on its surface. After being implanted into the body, the human body will recognize it as a foreign body and form a fibrous capsule to isolate it from the surrounding tissues, seriously affecting its integration effect with the surrounding bone tissue and gingival tissue. Existing studies have increased the surface roughness of zirconia ceramics by methods such as sandblasting, acid etching, and laser micro-texturing to improve the adhesion and growth effect of stem cells on its surface. However, such methods damage the mechanical strength of zirconia ceramics; there are also studies on modification by adding bioactive substances, such as silk fibroin, hydroxyapatite, etc. Although the bioactivity of the zirconia ceramic implant material is improved, the thermal expansion coefficients and elastic moduli of these bioactive substances are quite different from those of zirconia, resulting in difficulty in long-term binding, and excessive addition may significantly affect the mechanical properties of zirconia implants; if coated on the surface of zirconia implants by the coating method, the bonding strength is generally weak, and the coating is also prone to cracking and peeling. CN112274692A discloses a method for preparing a bio-coating for a zirconia implant and a zirconia implant. Surface sandblasting treatment results in the generation of microcracks and surface defects, damaging the mechanical strength of the zirconia implant. CN112441842A discloses a method for preparing a porous bioceramic coating with controllable porosity. Since the bioactive substance affects the density of the zirconia ceramic, the mechanical strength and stability of the zirconia ceramic are reduced. CN112028626A discloses a method for preparing a zirconia bioactive ceramic. Due to the mismatched thermodynamic properties between the coating and the substrate, residual stress exists at the interface, and the interfacial bonding force is weak. Long-term service may lead to cracking and peeling of the coating.

[0004] The low-temperature aging phenomenon of zirconia refers to the spontaneous transformation of tetragonal zirconia to monoclinic zirconia after long-term exposure in a humid environment at low temperatures (30 - 300 °C), where water molecules enter the grain boundaries. This transformation is accompanied by volume expansion, which can generate cracks in the ceramic, significantly reducing its mechanical properties and affecting its service life. Regarding the poor low-temperature aging resistance of zirconia implants, researchers have also conducted extensive studies. They have tried adding stabilizers to improve the low-temperature aging resistance of zirconia implants. However, this method has problems such as excessive and miscellaneous addition of stabilizers, which not only affects the mechanical properties of the implants but may also damage their biocompatibility, and leads to chaotic processing procedures and excessively high production costs. CN113321505A discloses a zirconia-based ceramic material and its preparation method, where yttrium oxide, alumina, and cerium oxide stabilizers are added simultaneously to tetragonal zirconia ceramics, resulting in a significant decrease in the mechanical strength of the zirconia ceramics. The dissolution of aluminum ions in the body may also cause hazards such as cytotoxicity. CN113072378A discloses tetragonal nanocomposite zirconia powder, its preparation method, and sintered body, using cerium salts, erbium salts, and praseodymium salts as stabilizers, along with coprecipitation, water washing, spray drying, and reduction gas calcination. The use of stabilizers is complex, the processes are numerous, and the requirements for equipment are higher. CN113548890A discloses a modified zirconia ceramic with high bioactivity and high mechanical strength and its preparation method. Although the porous zirconia surface layer increases the surface roughness and the ability to accommodate bioactive substances, the introduction of bioactive substances not only directly affects the mechanical stability of the zirconia matrix, but the increased specific surface area caused by the porous layer is more vulnerable to the influence of moisture in the humid environment, resulting in severe low-temperature aging phenomena and serious damage to the mechanical strength.

[0005] Calcium magnesium silicon or calcium silicon phosphorus bioactive substances can slowly release calcium, silicon, magnesium, or phosphorus ions in body fluids, which have a significant promoting effect on the proliferation and osteogenic differentiation of stem cells and can significantly promote the bone integration effect in clinical applications. Currently, the coating method is usually used to coat it on the surface of the zirconia matrix, but there is a huge gap in the physical and chemical properties between it and the internal matrix of the zirconia ceramic, and cracking and peeling are likely to occur; although methods such as sandblasting, acid etching, and laser treatment increase the roughness of the zirconia ceramic, they produce microcracks that affect its mechanical stability; the method of manufacturing a surface porous layer can accommodate bioactive substances, but the increased specific surface area also means a greatly increased contact opportunity with moisture in the humid environment, making it extremely prone to low-temperature aging phenomena, resulting in the destruction of the surface layer and further affecting the internal zirconia matrix. Therefore, it is of great significance to develop a zirconia ceramic dental implant material with high bioactivity, high mechanical strength, high low-temperature aging resistance, and a surface modification layer that has both high bonding strength with the internal matrix and does not have a negative impact on the internal matrix. Summary of the Invention

[0006] In order to overcome the disadvantages and deficiencies of conventional modified zirconia ceramic dental implants in the prior art, which cannot simultaneously possess high mechanical strength, resistance to low-temperature aging, and bioactivity, the purpose of the present invention is to provide a zirconia ceramic with both bioactivity and resistance to low-temperature aging and a preparation method thereof. This zirconia ceramic material has the characteristics of high mechanical strength, strong resistance to low-temperature aging, and good bioactivity.

[0007] The purpose of the present invention is achieved by at least one of the following technical solutions.

[0008] The preparation method provided by the present invention creatively utilizes the performance differences of tetragonal zirconia with different yttrium oxide addition amounts, gives full play to the advantages of high mechanical strength of 3mol% yttrium-stabilized tetragonal zirconia, while avoiding its disadvantage of poor resistance to low-temperature aging, and uses it as the matrix material of the zirconia ceramic; while using 5mol% yttrium-stabilized tetragonal zirconia with stronger resistance to low-temperature aging as the porous surface layer and the anti-low-temperature aging transition layer material that directly contacts the moisture in the humid environment, and protects the 3mol% yttrium-stabilized tetragonal zirconia matrix with higher internal mechanical strength. The present invention constructs a 5mol% yttrium-stabilized tetragonal zirconia porous surface layer and a 5mol% yttrium-stabilized tetragonal zirconia anti-low-temperature aging transition layer on the 3mol% yttrium-stabilized tetragonal zirconia matrix, penetrates and retains the calcium magnesium silicon or calcium silicon phosphorus bioactive sol in the pore structure of the porous surface layer, and improves the bioactivity of the zirconia ceramic. After the porous surface layer and the transition layer are combined, they are sintered at high temperature synchronously, solving the problems of low bonding efficiency and easy cracking and peeling between the traditional bioactive coating and the zirconia matrix. The bioactive substance only remains in the pore structure of the 5mol% yttrium-stabilized tetragonal zirconia porous surface layer, and the water molecules in the environment only contact the porous surface layer and the transition layer without affecting the internal 3mol% yttrium-stabilized tetragonal zirconia matrix, showing good resistance to low-temperature aging while not reducing the overall mechanical strength and stability of the material.

[0009] A preparation method of a zirconia ceramic with both bioactivity and resistance to low-temperature aging provided by the present invention includes the following steps:

[0010] (1) Add a silicon-containing compound to a solvent, mix evenly, adjust the pH value to 1.0 - 2.0 to hydrolyze it; then add a calcium salt, a magnesium salt, or a phosphate salt, and adjust the pH value of the mixed solution to 6.0 - 8.0 to obtain a calcium magnesium silicon bioactive sol or a calcium silicon phosphorus bioactive sol;

[0011] (2) Dry-press and form the zirconia powder, perform cold isostatic pressing treatment, and pre-sintering treatment to obtain a pre-sintered zirconia ceramic matrix;

[0012] (3) Add the binder, stabilizer, dispersant and zirconia powder into a solvent, mix them evenly to obtain Slurry A; atomize and spray Slurry A onto the surface of the pre-sintered zirconia ceramic substrate in step (2), and dry it to obtain a pre-sintered zirconia ceramic substrate with a film of an anti-low-temperature aging transition layer.

[0013] (4) Add the pore former, stabilizer, dispersant and zirconia powder into a solvent, mix them evenly to obtain Slurry B; atomize and spray Slurry B onto the surface of the pre-sintered zirconia ceramic substrate with the anti-low-temperature aging transition film in step (3), dry it, and perform high-temperature sintering treatment to obtain a zirconia ceramic with a porous surface layer and an anti-low-temperature aging transition layer.

[0014] (5) Immerse the zirconia ceramic with the porous surface layer and the anti-low-temperature aging transition layer in step (4) into the calcium-magnesium-silicon bioactive sol or calcium-silicon-phosphorus bioactive sol prepared in step (1) for negative pressure infiltration treatment, so that the calcium-magnesium-silicon bioactive sol or calcium-silicon-phosphorus bioactive sol enters and remains in the porous surface layer, take it out, stand for aging, dry, and perform heat treatment to obtain a zirconia ceramic with a surface layer composite bioactive substance and an anti-low-temperature aging transition layer.

[0015] Further, the silicon-containing compound in step (1) is at least one of tetraethyl orthosilicate, tetramethyldisiloxane, and methyl silicate.

[0016] Further, the solvent in step (1) is ultrapure water.

[0017] Further, for the hydrolysis in step (1), the hydrolysis time is 2 - 24 h.

[0018] Further, the calcium salt in step (1) is at least one of calcium nitrate, calcium acetate, calcium bicarbonate, and calcium citrate.

[0019] Further, the magnesium salt in step (1) is at least one of magnesium nitrate, magnesium acetate, and magnesium citrate.

[0020] Further, the phosphorus salt in step (1) is at least one of ammonium phosphate, ammonium hydrogen phosphate, diammonium hydrogen phosphate, ammonium hydrogen phosphate, potassium phosphate, and triethyl phosphate.

[0021] Further, for the mixed solution in step (1), the mixing time is 2 - 24 h.

[0022] Further, the mixed solution in step (1), by mass fraction, includes:

[0023]

[0024] Or:

[0025]

[0026] Further, the zirconia powder described in step (2) is 3 mol% yttria-stabilized tetragonal zirconia powder.

[0027] Further, the pressure for dry pressing in step (2) is 45 - 80 MPa, and the time for dry pressing is 0.5 - 3 min.

[0028] Further, the pressure for cold isostatic pressing in step (2) is 150 - 250 MPa, and the time for cold isostatic pressing is 2 - 30 min.

[0029] Further, the sintering temperature for pre-sintering treatment in step (2) is 500 - 1000 °C, the time for pre-sintering treatment is 1 - 4 h, and the heating rate for pre-sintering treatment is 2 - 15 °C / min.

[0030] Further, the binder described in step (3) is at least one of polyvinyl alcohol, polyvinyl acetal, polyvinyl butyral, and polymethacrylate.

[0031] Further, the stabilizer described in step (3) is at least one of polyvinylpyrrolidone, polyvinyl butyral, and glycerol.

[0032] Further, the dispersant described in step (3) is at least one of polyethylene glycol, sodium polyacrylate, and sodium dodecylbenzenesulfonate.

[0033] Further, the zirconia powder described in step (3) is 5 mol% yttria-stabilized tetragonal zirconia powder.

[0034] Further, the solvent described in step (3) is at least one of ultrapure water and absolute ethanol.

[0035] Further, the slurry A described in step (3), by mass, includes:

[0036]

[0037] Further, the pressure for atomized spraying in step (3) is 0.2 - 0.5 MPa, and the time for atomized spraying is 2 - 15 s.

[0038] Preferably, the pressure for atomized spraying described in step (3) is 0.2 - 0.3 Mpa.

[0039] Further, the thickness of the anti-low-temperature aging transition layer described in step (3) is 10 - 50 μm.

[0040] Preferably, the thickness of the anti-low-temperature aging transition layer described in step (3) is 10 - 30 μm.

[0041] Further, the temperature of the drying in step (3) is 30 - 80 °C, and the drying time is 2 - 24 h.

[0042] Further, the pore-forming agent in step (4) is at least one of polyvinyl alcohol microspheres, poly(lactic-co-glycolic acid) microspheres, sodium polyphosphate microspheres, hydroxypropyl methylcellulose microspheres, and activated carbon microspheres, and the particle size of the pore-forming agent is 1 - 50 μm.

[0043] Further, the stabilizer in step (4) is at least one of polyvinylpyrrolidone, polyvinyl butyral, and glycerol.

[0044] Further, the dispersant in step (4) is at least one of polyethylene glycol, sodium polyacrylate, and sodium dodecylbenzenesulfonate.

[0045] Further, the zirconia powder in step (4) is 5 mol% yttria-stabilized tetragonal zirconia powder.

[0046] Further, the solvent in step (4) is at least one of ultrapure water and absolute ethanol.

[0047] Further, the slurry B in step (4), by mass, comprises:

[0048]

[0049] Further, the spraying pressure in step (4) is 0.2 - 0.5 MPa.

[0050] Preferably, the spraying time in step (4) is 2 - 20 s.

[0051] Further, the thickness of the porous surface layer in step (4) is 20 - 100 μm.

[0052] Preferably, the thickness of the porous surface layer in step (4) is 20 - 60 μm.

[0053] Further, the temperature of the drying in step (4) is 30 - 80 °C, and the drying time is 2 - 24 h.

[0054] Further, the temperature of the high-temperature sintering treatment in step (4) is 1350 - 1600 °C, the sintering time is 2 - 5 h, and the heating rate of the high-temperature sintering treatment is 2 - 15 °C / min.

[0055] Further, the osmotic pressure of the negative-pressure infiltration treatment in step (5) is -0.10 to 0 MPa, and the time of the negative-pressure infiltration treatment is 0.5 - 60 min.

[0056] Preferably, the time of the negative-pressure infiltration treatment in step (5) is 5 - 25 min.

[0057] Further, the standing and aging time in step (5) is 4 - 48 h.

[0058] Further, the drying temperature in step (5) is 30 - 150 °C, and the drying time is 6 - 72 h.

[0059] Further, the heat treatment temperature in step (5) is 600 - 1350 °C, the heat treatment time is 0.5 - 4 h, and the heating rate of the heat treatment is 2 - 10 °C / min.

[0060] The present invention provides a zirconia ceramic with both biological activity and resistance to low - temperature aging prepared by the above - mentioned preparation method.

[0061] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0062] (1) In the preparation method provided by the present invention, for the first time, tetragonal zirconia with different yttrium oxide addition amounts is comprehensively considered, giving full play to the advantages of yttrium - stabilized tetragonal zirconia with different yttrium oxide addition amounts. 3 mol% yttrium - stabilized tetragonal zirconia has extremely high mechanical strength but extremely poor low - temperature aging resistance; 5 mol% yttrium - stabilized tetragonal zirconia has slightly lower mechanical strength but significantly enhanced low - temperature aging resistance. Therefore, the present invention proposes that the porous surface layer with a pore structure is composed of 5 mol% yttrium - stabilized tetragonal zirconia with stronger low - temperature aging resistance; the dense internal matrix is composed of 3 mol% yttrium - stabilized tetragonal zirconia with higher mechanical strength; and a transition layer composed of 5 mol% yttrium - stabilized tetragonal zirconia is creatively designed between the internal matrix and the porous surface. Its porosity is lower. On the one hand, it prevents water molecules in the humid environment from passing through the internal matrix and contacting the 3 mol% yttrium - stabilized tetragonal zirconia internal matrix, causing low - temperature aging of the internal matrix; on the other hand, it prevents the diffusion of the bioactive substances loaded in the porous surface layer and the influence on the stable structure of the internal matrix, resulting in a decrease in the mechanical strength of the internal matrix.

[0063] (2) In the preparation method provided by the present invention, the phase compositions of the 5 mol% yttrium - stabilized tetragonal zirconia porous layer and the low - temperature aging - resistant transition layer are basically the same as those of the 3 mol% yttrium - stabilized tetragonal zirconia ceramic matrix. After high - temperature synchronous sintering, firm bonding between layers can be achieved, far superior to the extremely weak interfacial bonding strength between the traditional coating and the zirconia matrix, solving the problems of easy cracking and peeling of the traditional coating.

[0064] (3) The zirconia ceramic with both biological activity and resistance to low - temperature aging prepared by the present invention shows significantly stronger low - temperature aging resistance than the unmodified zirconia ceramic in the in vitro simulated low - temperature aging experiment. After low - temperature aging, its mechanical strength is not significantly damaged, and there are no situations such as peeling and cracking of the surface modification layer.

[0065] (4) The zirconia ceramics with both bioactivity and resistance to low-temperature aging prepared by the present invention can significantly promote the adhesion, proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells after co-culture, and the bioactivity is significantly improved, which can promote the integration of zirconia dental implants with bone tissue.

[0066] (5) The 5mol% yttria-stabilized tetragonal zirconia porous surface layer prepared by the present invention can penetrate various bioactive substance sols, and is not limited by the composition and type of bioactive substances. By adjusting the addition amount of the pore-forming agent, the atomization spraying pressure and the atomization spraying time, the thickness and porosity of the porous surface layer can be controlled; by adjusting the pressure and time of negative pressure infiltration of the bioactive substance sol, the content of the bioactive substance composite in the porous surface layer can be controlled, and the process is controllable, the finished product rate is high, and the cost is low. Brief Description of the Drawings

[0067] Figure 1 Schematic structural diagrams of the matrix, low-temperature aging-resistant transition layer and porous surface layer of the zirconia ceramics with both bioactivity and resistance to low-temperature aging in Examples 1-4.

[0068] Figure 2 Surface microtopography diagrams of the zirconia ceramics with both bioactivity and resistance to low-temperature aging in Examples 1-2.

[0069] Figure 3 Surface microtopography diagrams of the zirconia ceramics with both bioactivity and resistance to low-temperature aging in Examples 1-2 after being immersed in 1-fold modified simulated body fluid for 14 days.

[0070] Figure 4 Variation of the volume fraction of monoclinic zirconia on the surface of the 3mol% yttria-stabilized tetragonal zirconia ceramic samples without any modification treatment and the zirconia ceramics with both bioactivity and resistance to low-temperature aging prepared in Examples 1-4 after 0h, 20h, 40h, 60h, 80h in the in vitro simulated low-temperature aging experiment.

[0071] Figure 5 Variation of the flexural strength of the 3mol% yttria-stabilized tetragonal zirconia ceramic samples without any modification treatment and the zirconia ceramics with both bioactivity and resistance to low-temperature aging prepared in Examples 1-4 after 0h, 20h, 40h, 60h, 80h in the in vitro simulated low-temperature aging experiment.

[0072] Figure 6 Results of the cell proliferation of the 3mol% yttria-stabilized tetragonal zirconia ceramics without any modification treatment and the zirconia ceramics with both bioactivity and resistance to low-temperature aging prepared in Examples 1-3 after co-culture with mouse bone marrow mesenchymal stem cells for 1 day and 3 days.

[0073] Figure 7 The results of the activities of osteogenic differentiation alkaline phosphatase after co-culturing 3mol% yttria-stabilized tetragonal zirconia ceramics without any modification treatment, and the zirconia ceramics with both bioactivity and anti-low-temperature aging prepared in Examples 1-3 with mouse bone marrow mesenchymal stem cells for 7 days and 14 days. Detailed implementation mode

[0074] The following further illustrates the specific implementation of the present invention in combination with examples, but the implementation and protection of the present invention are not limited thereto. It should be noted that for the processes not specifically described in detail below, those skilled in the art can implement or understand them with reference to the prior art. The reagents or instruments used without indicating the manufacturer are regarded as conventional products that can be obtained through commercial purchase.

[0075] Example 1

[0076] (1) Preparation of calcium-silicon-phosphorus bioactive sol: Add 50 g of tetraethyl orthosilicate to 34 g of deionized water, mix evenly, adjust the pH value to 1.0, and hydrolyze it for 3 h. Then add 21 g of calcium nitrate and 5 g of triethyl phosphate, mix evenly to obtain a mixed solution, and adjust the pH value of the mixed solution to 7.0 (the reaction time is 12 h) to form a calcium-silicon-phosphorus bioactive sol;

[0077] (2) Dry-press 3mol% yttria-stabilized tetragonal zirconia powder into a shape. The pressure for dry pressing is 50 MPa, and the time for dry pressing is 45 s. After dry pressing, perform cold isostatic pressing. The pressure for cold isostatic pressing is 200 MPa, and the time for cold isostatic pressing is 2.5 min to prepare a zirconia ceramic green body. Carry out pre-sintering treatment at a temperature of 850 °C for 2 h, and the heating rate is 3 °C / min to obtain a pre-sintered zirconia ceramic matrix;

[0078] (3) Mix polyvinyl alcohol, polyvinylpyrrolidone, polyethylene glycol, ultrapure water and 5mol% yttria-stabilized tetragonal zirconia powder in a mass ratio of 7:2:1:80:10, mix evenly and stir to prepare zirconia slurry A; Spray zirconia slurry A on the surface of the pre-sintered zirconia ceramic matrix through an atomization spraying process, spray atomization at a pressure of 0.2 MPa for 5 s, and dry at 80 °C for 2 h to form an anti-low-temperature aging transition layer (thickness: 12.5 μm) to obtain a pre-sintered zirconia ceramic matrix with an anti-low-temperature aging transition layer film;

[0079] (4) Mix polyvinyl alcohol microspheres (particle size 40 μm), polyvinylpyrrolidone, polyethylene glycol, ultrapure water and 5 mol% yttria-stabilized tetragonal zirconia powder in a mass ratio of 14:5:0.3:55.7:25, stir evenly to prepare zirconia slurry B; spray zirconia slurry B on the pre-sintered zirconia ceramic substrate with an anti-low-temperature aging transition layer film prepared in step (3) through an atomization spraying process, the spraying pressure is 0.3 MPa, the spraying time is 20 s, dry at 60 °C for 12 h to form a porous surface layer (thickness 45 μm), and then heat the whole to 1500 °C and sinter for 3 h, with a heating rate of 3 °C / min, to obtain a zirconia ceramic with a porous surface layer and an anti-low-temperature aging transition layer;

[0080] (5) Immerse the zirconia ceramic with a porous surface layer and an anti-low-temperature aging transition layer prepared in step (4) in the calcium silicate phosphorus bioactive sol prepared in step (1), through a negative pressure infiltration process, the infiltration pressure is -0.1 MPa, the infiltration time is 10 min, so that the calcium silicate phosphorus bioactive sol suspension infiltrates into the porous surface layer of the zirconia ceramic, take it out, stand for aging for 24 h, dry at 60 °C for 72 h, heat up to 600 °C and heat-treat for 3 h, with a heating rate of 3 °C / min, to obtain an anti-low-temperature aging modified zirconia ceramic with calcium silicate phosphorus bioactive substances compounded on the surface (a zirconia ceramic with both bioactivity and anti-low-temperature aging).

[0081] Figure 1 It is a schematic diagram of the structure of the matrix, anti-low-temperature aging transition layer and porous surface layer of the zirconia ceramic with both bioactivity and anti-low-temperature aging in Example 1. The anti-low-temperature aging transition layer is located between the porous surface layer and the zirconia ceramic matrix.

[0082] Figure 2 Part a of is the surface microscopic result diagram of the zirconia ceramic with a porous surface layer and an anti-low-temperature aging transition layer in Example 1. From Figure 2 Part a, it can be seen that a porous surface layer has been successfully prepared, and the pore distribution is relatively uniform.

[0083] Figure 2 Part b of is the surface microscopic structure result diagram of the zirconia ceramic with both bioactivity and anti-low-temperature aging and calcium silicate phosphorus bioactive substances compounded on the surface in Example 1. From Figure 2 Part b, it can be seen that the calcium silicate phosphorus bioactive substances have successfully entered the pore structure of the porous surface layer and are successfully retained.

[0084] Through a three-point bending test (refer to the international standard ISO 6872:2015 "Dental ceramic materials"), it is obtained that the bending strength of the zirconia ceramic with both bioactivity and anti-low-temperature aging and calcium silicate phosphorus bioactive substances compounded on the surface is 982 MPa, showing excellent mechanical properties.

[0085] The surface composite calcium-silicon-phosphorus bioactive substance-prepared anti-low-temperature-aging modified zirconia ceramic in this embodiment has good bioactivity. As shown in part a of Figure 3 After soaking this ceramic in 1-fold modified simulated body fluid for 14 days, rich cluster-like crystalline products were mineralized from the calcium-silicon-phosphorus bioactive substance deep in the porous surface layer, indicating that the zirconia ceramic with both bioactivity and anti-low-temperature aging of the surface composite calcium-silicon-phosphorus bioactive substance has excellent bioactivity.

[0086] Example 2:

[0087] (1) Prepare calcium-silicon-phosphorus bioactive sol: Add 35 g of tetraethyl orthosilicate to 40 g of deionized water, mix evenly, adjust the pH value to 1.5, and hydrolyze it for 3 h. Then add 20 g of calcium nitrate and 5 g of triethyl phosphate, mix evenly to obtain a mixed solution, and adjust the pH value of the mixed solution to 7.4 (reaction time is 12 h) to form calcium-silicon-phosphorus bioactive sol;

[0088] (2) Dry-press 3 mol% yttrium-stabilized tetragonal zirconia powder. The dry-pressing pressure is 45 MPa, and the dry-pressing time is 30 s. After dry-pressing, perform cold isostatic pressing. The cold isostatic pressing pressure is 250 MPa, and the cold isostatic pressing time is 10 min to prepare a zirconia ceramic green body. Perform pre-sintering treatment at a temperature rising to 900 °C for 1 h, and the heating rate is 6 °C / min to obtain a pre-sintered zirconia ceramic matrix;

[0089] (3) Mix polymethyl methacrylate, polyvinylpyrrolidone, sodium dodecylbenzenesulfonate, ultrapure water and 5 mol% yttrium-stabilized tetragonal zirconia powder in a mass ratio of 10:2.5:1:74.5:12, mix evenly and stir to prepare zirconia slurry A; Spray zirconia slurry A on the surface of the pre-sintered zirconia ceramic matrix prepared in step (2) by atomization spraying process, atomize and spray for 10 s under a pressure of 0.2 MPa, and dry at 80 °C for 2 h to form an anti-low-temperature-aging transition layer (thickness is 30 μm) to obtain a pre-sintered zirconia ceramic matrix with an anti-low-temperature-aging transition layer;

[0090] (4) Mix polyvinyl alcohol microspheres (particle size 50 μm), polyvinylpyrrolidone, sodium dodecylbenzenesulfonate, ultrapure water and 5 mol% yttrium-stabilized tetragonal zirconia powder in a mass ratio of 16:10:3:45:26, stir evenly, and prepare zirconia slurry B; spray zirconia slurry B on the surface of the pre-sintered zirconia ceramic substrate with an anti-aging transition layer film prepared in step (3) through an atomization spraying process, spray atomize for 10 s under a pressure of 0.2 MPa, dry at 80 °C for 2 h to form a porous surface layer (thickness 50 μm), and then heat the whole to 1450 °C and sinter for 5 h, the heating rate is 5 °C / min, to obtain a zirconia ceramic with a porous surface layer and an anti-low-temperature aging transition layer;

[0091] (5) Immerse the zirconia ceramic with a porous surface layer and an anti-low-temperature aging transition layer prepared in step (4) in the calcium silicate phosphorus bioactive sol prepared in step (1), through a negative pressure infiltration process, the infiltration pressure is -0.1 MPa, and the infiltration time is 25 min, so that the calcium silicate phosphorus bioactive sol suspension infiltrates into the porous surface layer of the zirconia ceramic, take it out, stand and age for 24 h, dry at 80 °C for 12 h, heat up to 1100 °C and heat-treat for 3 h, the heating rate is 3 °C / min, to obtain an anti-low-temperature aging modified zirconia ceramic with calcium silicate phosphorus bioactive substances compounded on the surface (a zirconia ceramic with both bioactivity and anti-low-temperature aging).

[0092] Figure 2 Part c is the surface microscopic result diagram of the zirconia ceramic with a porous surface layer and an anti-low-temperature aging transition layer of Example 2. From Figure 2 Part c, it can be seen that a porous surface layer has been successfully prepared, and the pore distribution is relatively uniform.

[0093] Figure 2 Part d is the surface microscopic structure result diagram of the zirconia ceramic with both bioactivity and anti-low-temperature aging and calcium silicate phosphorus bioactive substances compounded on the surface of Example 2. From Figure 2 Part d, it can be seen that the calcium silicate phosphorus bioactive substances have successfully entered the pores of the porous surface layer and successfully remained.

[0094] Through mechanical property testing (refer to the national standard GB 30367-2013 "Dental Ceramic Materials"), it is obtained that the flexural strength of the anti-low-temperature aging modified zirconia ceramic with calcium silicate phosphorus bioactive substances compounded on the surface is 978 MPa.

[0095] The anti-low-temperature aging modified zirconia ceramic with calcium silicate phosphorus bioactive substances compounded on the surface prepared in this example has good bioactivity, such as Figure 3As shown in part b), after the ceramic was immersed in the 1-fold modified simulated body fluid for 14 days, rich cluster-like crystalline products were mineralized from the calcium-silicon-phosphorus bioactive substances that penetrated deep into the porous surface layer, indicating that the anti-low-temperature aging modified zirconia ceramic with surface composite calcium-silicon-phosphorus bioactive substances has excellent bioactivity.

[0096] Example 3:

[0097] (1) Prepare a calcium-magnesium-silicon bioactive sol: Add 30 g of tetraethyl orthosilicate to 41 g of deionized water, mix evenly, adjust the pH value to 1.0, and hydrolyze it for 3 h. Then add 13 g of calcium nitrate and 16 g of magnesium nitrate, mix evenly to obtain a mixed solution, and adjust the pH value of the mixed solution to 6.0 (reaction time is 8 h) to form a calcium-magnesium-silicon bioactive sol;

[0098] (2) Dry-press 3 mol% yttria-stabilized tetragonal zirconia powder. The pressure for dry pressing is 50 MPa, and the time for dry pressing is 50 s. After dry pressing, perform cold isostatic pressing. The pressure for cold isostatic pressing is 180 MPa, and the time for cold isostatic pressing is 3 min to prepare a zirconia ceramic green body. Carry out pre-sintering treatment at a temperature of 1000 °C for 4 h, and the heating rate is 8 °C / min to obtain a pre-sintered zirconia ceramic matrix;

[0099] (3) Mix polyvinyl acetal, glycerol, sodium polyacrylate, ultrapure water and 5 mol% yttria-stabilized tetragonal zirconia powder in a mass ratio of 11:4:0.5:74.5:10, mix evenly and stir to prepare zirconia slurry A; Spray zirconia slurry A on the surface of the pre-sintered zirconia ceramic matrix prepared in step (2) by atomized spraying process, atomized spraying for 15 s under a pressure of 0.2 MPa, and drying at 40 °C for 20 h to form an anti-low-temperature aging transition layer (thickness is 20 μm) to obtain a pre-sintered zirconia ceramic matrix with an anti-low-temperature aging transition layer film;

[0100] (4) Mix poly(lactic-co-glycolic acid) microspheres (particle size 25 μm), polyvinyl butyral, sodium dodecyl benzene sulfonate, ultrapure water and 5 mol% yttria-stabilized tetragonal zirconia powder in a mass ratio of 14:15:3:40:28, mix evenly and stir to prepare zirconia slurry B; Spray zirconia slurry B on the surface of the pre-sintered zirconia ceramic matrix with an anti-aging transition layer film prepared in step (3) by atomized spraying process, atomized spraying for 15 s under a pressure of 0.25 MPa, and drying at 80 °C for 2 h to form a porous surface layer (thickness is 60 μm), and then heat the whole to 1500 °C and sinter for 3 h, and the heating rate is 4 °C / min to obtain a zirconia ceramic with a porous surface layer and an anti-low-temperature aging transition layer;

[0101] (5) Immerse the zirconia ceramic with a porous surface layer and an anti-low-temperature-aging transition layer prepared in step (4) into the calcium-magnesium-silicon bioactive sol prepared in step (1). Through a negative-pressure infiltration process, the infiltration pressure is -0.1 MPa and the infiltration time is 25 min, so that the calcium-magnesium-silicon bioactive sol suspension infiltrates into the porous surface layer of the zirconia ceramic. Take it out, let it stand and age for 24 h, dry it at 80 °C for 24 h, heat-treat it at 1100 °C for 3 h, and the heating rate is 3 °C / min to obtain a low-temperature-aging-resistant modified zirconia ceramic with calcium-magnesium-silicon bioactive substances compounded on the surface (a zirconia ceramic with both bioactivity and low-temperature-aging resistance).

[0102] Through mechanical property testing (referring to the international standard ISO 6872:2015 "Dental ceramic materials"), it is obtained that the flexural strength of the low-temperature-aging-resistant modified zirconia ceramic with calcium-magnesium-silicon bioactive substances compounded on the surface is 919 MPa.

[0103] Example 4:

[0104] (1) Prepare a calcium-magnesium-silicon bioactive sol: Add 24 g of tetraethyl orthosilicate to 46 g of deionized water, mix evenly, adjust the pH value to 2.0, and hydrolyze it for 2 h. Then add 13 g of calcium nitrate and 17 g of magnesium nitrate, mix evenly to obtain a mixed solution, and adjust the pH value of the mixed solution to 6.5 (the reaction time is 24 h) to form a calcium-magnesium-silicon bioactive sol;

[0105] (2) Dry-press 3 mol% yttria-stabilized tetragonal zirconia powder. The dry-pressing pressure is 50 MPa and the dry-pressing time is 30 s. After dry-pressing, perform cold isostatic pressing. The cold isostatic pressing pressure is 150 MPa and the cold isostatic pressing time is 15 min to prepare a green zirconia ceramic body. Heat it to 900 °C for pre-sintering treatment. The pre-sintering treatment time is 4 h and the heating rate is 5 °C / min to obtain a pre-sintered zirconia ceramic matrix;

[0106] (3) Mix polyvinyl butyral, polyvinylpyrrolidone, polyethylene glycol, ultrapure water and 5 mol% yttria-stabilized tetragonal zirconia powder in a mass ratio of 10:4:3:75:8, mix evenly and stir to prepare zirconia slurry A; Spray zirconia slurry B on the surface of the pre-sintered zirconia ceramic matrix prepared in step (2) through an atomization spraying process, spray it at 0.4 MPa for 25 s, and dry it at 50 °C for 10 h to form an anti-low-temperature-aging transition layer (with a thickness of 25 μm) to obtain a pre-sintered zirconia ceramic matrix with an anti-low-temperature-aging transition layer film;

[0107] (4) Mix hydroxypropyl methylcellulose microspheres (particle size 35 μm), polyvinylpyrrolidone, polyethylene glycol, ultrapure water and 5 mol% yttria-stabilized tetragonal zirconia powder in a mass ratio of 15:12:1:45:27, stir evenly to prepare zirconia slurry B; spray zirconia slurry B on the surface of the pre-sintered zirconia ceramic substrate with an anti-aging transition layer formed film prepared in step (3) through an atomization spraying process, spray for 10 s under a pressure of 0.4 MPa, dry at 80 °C for 2 h to form a porous surface layer (thickness 60 μm), and then heat the whole to 1450 °C and sinter for 4 h, the heating rate is 6 °C / min, to obtain a zirconia ceramic with a porous surface layer and an anti-low-temperature aging transition layer;

[0108] (5) Immerse the zirconia ceramic with a porous surface layer and an anti-low-temperature aging transition layer prepared in step (4) in the calcium magnesium silicon bioactive sol prepared in step (1), through a negative pressure infiltration process, the infiltration pressure is -0.05 MPa, and the infiltration time is 60 min, so that the calcium magnesium silicon bioactive sol suspension infiltrates into the porous surface layer of the zirconia ceramic, take it out, stand and age for 48 h, dry at 150 °C for 6 h, heat up to 1350 °C and heat-treat for 3 h, the heating rate is 5 °C / min, to obtain an anti-low-temperature aging modified zirconia ceramic with a surface composite calcium magnesium silicon bioactive substance (a zirconia ceramic with both bioactivity and anti-low-temperature aging).

[0109] Through mechanical property testing (refer to the international standard ISO 6872:2015 "Dental Ceramics"), it is obtained that the flexural strength of the anti-low-temperature aging modified zirconia ceramic with a surface composite calcium magnesium silicon bioactive substance is 945 MPa.

[0110] In vitro simulated low-temperature aging experiment

[0111] Samples of 3mol% yttria-stabilized tetragonal zirconia ceramics without any modification treatment and samples of zirconia ceramics with both bioactivity and anti-low-temperature aging prepared in Examples 1-4 were respectively labeled as "blank group", "Example 1", "Example 2", "Example 3", and "Example 4". Referring to the international standard "ISO 13356:2015 Surgical implants - Yttria-stabilized tetragonal zirconia-based ceramic materials", the high-pressure steam accelerated hydrothermal aging method was used, with water vapor generated by ultrapure water as the aging medium and 134 °C / 0.2 MPa provided by a high-pressure hydrothermal autoclave as the aging environment to simulate the process of low-temperature aging of zirconia ceramic samples in vitro. After 0 h, 20 h, 40 h, 60 h, and 80 h of in vitro simulated low-temperature aging experiments, each sample was taken out and dried at 37 °C for 2 h. An X-ray diffractometer was used to analyze the change in the content of monoclinic zirconia on the surface of each sample after different durations of in vitro simulated low-temperature aging, and the aging degree of the sample was described in the form of the monoclinic phase volume fraction on the sample surface; referring to the international standard ISO 6872:2015 "Dental ceramic materials", a three-point bending test was carried out to test the change in the bending strength of each sample after different durations of in vitro simulated low-temperature aging, and the aging degree of the sample was described by the retention of the bending strength.

[0112] The preparation of the above 3mol% yttria-stabilized tetragonal zirconia ceramics without any modification treatment includes: pre-sintering treatment and high-temperature sintering treatment. Among them, the pre-sintering treatment can be carried out with reference to step (2) of Example 1 to obtain a pre-sintered zirconia ceramic matrix, and then the pre-sintered zirconia ceramic matrix is subjected to high-temperature sintering treatment. The calcination treatment is: heat treatment at 1400 °C for 2 h, and the heating rate is 6 °C / min.

[0113] Figure 4 Volume fraction changes of monoclinic zirconia on the surfaces of samples of 3mol% yttria-stabilized tetragonal zirconia ceramics without any modification treatment and samples of zirconia ceramics with both bioactivity and anti-low-temperature aging prepared in Examples 1-4 after 0 h, 20 h, 40 h, 60 h, and 80 h of in vitro simulated low-temperature aging experiments.

[0114] From Figure 4It can be seen that significant low-temperature aging occurred in the 3mol% yttria-stabilized tetragonal zirconia ceramic sample without any modification during the in vitro simulated low-temperature aging experiment. After 80h of aging, the monoclinic zirconia content on the surface exceeded 50vol%, showing poor low-temperature aging resistance. The zirconia ceramics with both bioactivity and low-temperature aging resistance prepared in Examples 1-4 underwent a certain degree of low-temperature aging during the in vitro simulated low-temperature aging experiment. However, after 80h of aging, the monoclinic zirconia content on the surface was generally in the range of 15-20vol%. Compared with the 3mol% yttria-stabilized tetragonal zirconia ceramic without any modification, it showed better low-temperature aging resistance.

[0115] Figure 5 Parts a to e of [Figure] show the changes in flexural strength of the 3mol% yttria-stabilized tetragonal zirconia ceramic sample without any modification and the zirconia ceramics with both bioactivity and low-temperature aging resistance prepared in Examples 1-4 after 0h, 20h, 40h, 60h, and 80h of the in vitro simulated low-temperature aging experiment.

[0116] As can be seen from Figure 5 part a of [Figure], although the initial flexural strength of the 3mol% yttria-stabilized tetragonal zirconia ceramic sample without any modification reached 1020MPa, with the extension of the low-temperature aging test time, the flexural strength decreased significantly. After 80h of aging, the mechanical strength was only 672MPa. As can be seen from Figure 5 parts b, c, d, and e of [Figure], the initial flexural strengths of the zirconia ceramics with both bioactivity and low-temperature aging resistance prepared in Examples 1-4 were in the range of 900-1000. However, with the extension of the low-temperature aging test time, there was only a slight decrease in flexural strength. After 80h of aging, the flexural strength of the sample in Example 1 reached 940MPa, the flexural strength of the sample in Example 2 reached 934MPa, the flexural strength of the sample in Example 3 reached 882MPa, and the flexural strength of the sample in Example 4 reached 843MPa, all still maintaining extremely high flexural strengths, indicating that the 5mol% yttria-stabilized tetragonal zirconia porous surface layer and the low-temperature aging-resistant transition layer protected the internal matrix of the 3mol% yttria-stabilized tetragonal zirconia from the severe impact of low-temperature aging.

[0117] Cell experiment

[0118] Determination of cell proliferation: Samples of 3mol% yttria-stabilized tetragonal zirconia ceramics without any modification treatment and samples of zirconia ceramics with both bioactivity and anti-low-temperature aging prepared in Examples 1-3 were respectively labeled as "blank group", "Example 1", "Example 2", and "Example 3". Under a sterile environment, samples of each group sterilized by gamma-ray irradiation were placed into 48-well plates, soaked with basal medium for 24 h, then the basal medium was aspirated out, and a suspension of mouse bone marrow mesenchymal stem cells at passage 5 was added into the plates, with 10,000 cells in each well. During the culture process, the complete medium was changed every other day. After the cells were cultured for 1 d and 3 d, a CCK-8 cell counting kit and a microplate reader were used to determine the cell proliferation, and the cell proliferation was characterized in the form of absorbance.

[0119] Determination of the activity of alkaline phosphatase for cell osteogenic differentiation: Samples of 3mol% yttria-stabilized tetragonal zirconia ceramics without any modification treatment and samples of zirconia ceramics with both bioactivity and anti-low-temperature aging prepared in Examples 1-3 were respectively labeled as "blank group", "Example 1", "Example 2", and "Example 3". Under a sterile environment, samples of each group sterilized by gamma-ray irradiation were placed into 48-well plates, soaked with basal medium for 24 h, then the basal medium was aspirated out, and a suspension of mouse bone marrow mesenchymal stem cells at passage 6 was added into the plates, with 20,000 cells in each well. During the culture process, the osteogenic induction medium was changed every other day. After the cells were cultured for 7 d and 14 d, an alkaline phosphatase quantitative analysis kit and a microplate reader were used to determine the activity of alkaline phosphatase for cell osteogenic differentiation, and the activity of alkaline phosphatase for cell osteogenic differentiation was characterized in the form of relative alkaline phosphatase activity.

[0120] The preparation of the above 3mol% yttria-stabilized tetragonal zirconia ceramics without any modification treatment includes: pre-sintering treatment and high-temperature sintering treatment. Among them, the pre-sintering treatment can be carried out with reference to the step (2) of Example 1 to obtain a pre-sintered zirconia ceramic matrix, and then the pre-sintered zirconia ceramic matrix is subjected to high-temperature sintering treatment. The calcination treatment is: heat treatment at 1400 °C for 2 h, and the heating rate is 6 °C / min.

[0121] Figure 6 Results of cell proliferation after co-culturing 3mol% yttria-stabilized tetragonal zirconia ceramics without any modification treatment and zirconia ceramics with both bioactivity and anti-low-temperature aging prepared in Examples 1-3 with mouse bone marrow mesenchymal stem cells for 1 day and 3 days.

[0122] by Figure 6It can be seen that, compared with the 3mol% yttria-stabilized tetragonal zirconia ceramic samples without any modification treatment, the zirconia ceramics with both bioactivity and anti-low-temperature aging prepared in Examples 1-3 showed significantly better cell proliferation after co-culturing with mouse bone marrow mesenchymal stem cells for 1 day and 3 days, indicating that the zirconia ceramics with both bioactivity and anti-low-temperature aging have excellent cell proliferation promotion ability.

[0123] Figure 7 The results of the activities of osteogenic differentiation alkaline phosphatase after co-culturing the 3mol% yttria-stabilized tetragonal zirconia ceramics without any modification treatment and the zirconia ceramics with both bioactivity and anti-low-temperature aging prepared in Examples 1-3 with mouse bone marrow mesenchymal stem cells for 7 days and 14 days.

[0124] It can be seen from Figure 7 that, compared with the 3mol% yttria-stabilized tetragonal zirconia ceramic samples without any modification treatment, the zirconia ceramics with both bioactivity and anti-low-temperature aging prepared in Examples 1-3 showed better osteogenic differentiation alkaline phosphatase effects after co-culturing with mouse bone marrow mesenchymal stem cells for 7 days and 14 days, indicating that the zirconia ceramics with both bioactivity and anti-low-temperature aging have excellent cell osteogenic differentiation promotion ability.

[0125] The above embodiments are only the preferred embodiments of the present invention, which are only used to explain the present invention, rather than limiting the present invention. Any changes, substitutions, modifications, etc. made by those skilled in the art without departing from the spirit of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for preparing zirconia ceramics having both biological activity and low-temperature aging resistance, It is characterized in that The steps include: (1) adding a silicon-containing compound to a solvent, mixing uniformly, and adjusting the pH to hydrolyze the compound; then adding a calcium salt, a magnesium salt, or a phosphate salt, and adjusting the pH value of the mixed solution to obtain a calcium-magnesium-silicon bioactive sol or a calcium-silicon-phosphorus bioactive sol; (2) dry-pressing the zirconium oxide powder, cold isostatic pressing, and pre-sintering to obtain a pre-sintered zirconium oxide ceramic matrix; (3) adding a binder, a stabilizer, a dispersant and zirconium oxide powder into a solvent and mixing them evenly to obtain slurry A; spraying the slurry A onto the surface of the pre-sintered zirconium oxide ceramic substrate in step (2), and drying to obtain a pre-sintered zirconium oxide ceramic substrate having a low-temperature aging resistant transition layer film; (4) adding a pore-forming agent, a stabilizer, a dispersant and zirconium oxide powder into a solvent and mixing them evenly to obtain a slurry B; spraying the slurry B onto the surface of the pre-sintered zirconium oxide ceramic substrate having a low-temperature aging resistant transition layer film in step (3), drying, and sintering at a high temperature to obtain a zirconium oxide ceramic having a porous surface layer and a low-temperature aging resistant transition layer; (5) immersing the zirconia ceramic with a porous surface layer and a low-temperature aging resistant transition layer described in step (4) into the calcium magnesium silicon bioactive sol or calcium silicon phosphorus bioactive sol prepared in step (1) for negative pressure infiltration treatment, taking it out and letting it stand for aging, drying, and heat treatment to obtain a zirconia ceramic with a surface layer composited with bioactive substances and a low-temperature aging resistant transition layer; The zirconium oxide powder in step (2) is 3 mol% yttria-stabilized tetragonal zirconium oxide powder; the pressure of the dry pressing in step (2) is 45-80 MPa, and the time of the dry pressing is 0.5-3 min; the pressure of the cold isostatic pressing is 150-250 MPa, and the time of the cold isostatic pressing is 2-30 min; the temperature of the pre-sintering in step (2) is 500-1000° C., the time of the pre-sintering is 1-4 h, and the heating rate of the pre-sintering is 2-15° C. / min; The binder in step (3) is at least one of polyvinyl alcohol, polyvinyl acetal, polyvinyl butyral ester, and polymethacrylate; the stabilizer in step (3) is at least one of polyvinyl pyrrolidone, polyvinyl butyral, and glycerol; the dispersant in step (3) is at least one of polyethylene glycol, sodium polyacrylate, and sodium dodecylbenzene sulfonate; the zirconium oxide powder in step (3) is 5 mol% yttria-stabilized tetragonal zirconium oxide powder; the solvent in step (3) is at least one of ultrapure water and anhydrous ethanol; the slurry A in step (3), in terms of mass fractions, comprises:

2. A method for preparing a zirconia ceramic having both biological activity and low-temperature aging resistance according to claim 1, It is characterized in that In step (1), the pH value of the silicon compound solution is adjusted to 1.0-2.0; and the pH value of the mixed solution is adjusted to 6.0-8.

0.

3. A method for preparing a zirconia ceramic having both biological activity and low-temperature aging resistance according to claim 1, It is characterized in that The silicon-containing compound described in step (1) is at least one of tetraethyl orthosilicate, tetramethyldisiloxane, and methyl silicate; the solvent described in step (1) is ultrapure water; for the hydrolysis in step (1), the hydrolysis time is 2 - 24 h; the calcium salt described in step (1) is at least one of calcium nitrate, calcium acetate, calcium bicarbonate, and calcium citrate; the magnesium salt described in step (1) is at least one of magnesium nitrate, magnesium acetate, and magnesium citrate; the phosphate salt described in step (1) is at least one of ammonium phosphate, ammonium hydrogen phosphate, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, potassium phosphate, and triethyl phosphate; for the mixed solution in step (1), the mixing time is 2 - 24 h, and by mass fraction, the mixed solution includes: Or:

4. For the preparation method of a zirconia ceramic with both biological activity and anti-low-temperature aging as described in claim 1, the pressure of the atomized spraying in step (3) is 0.2 - 0.5 MPa, and the time of the atomized spraying is 2 - 15 s; the thickness of the anti-low-temperature aging transition layer in step (3) is 10 - 50 μm; the temperature of the drying in step (3) is 30 - 80 °C, and the time of the drying is 2 - 24 h.

5. For the preparation method of a zirconia ceramic with both biological activity and anti-low-temperature aging as described in claim 1, It is characterized in that The pore-forming agent described in step (4) is at least one of polyvinyl alcohol microspheres, poly(lactic-co-glycolic acid) microspheres, sodium polyphosphate microspheres, hydroxypropyl methylcellulose microspheres, and activated carbon microspheres, and the particle size of the pore-forming agent is 1 - 50 μm; the stabilizer described in step (4) is at least one of polyvinylpyrrolidone, polyvinyl butyral, and glycerol; the dispersant described in step (4) is at least one of polyethylene glycol, sodium polyacrylate, and sodium dodecylbenzenesulfonate; the zirconia powder described in step (4) is 5 mol% yttria-stabilized tetragonal zirconia powder; the solvent described in step (4) is at least one of ultrapure water and absolute ethanol; the slurry B in step (4), by mass fraction, includes:

6. For the preparation method of a zirconia ceramic with both biological activity and anti-low-temperature aging as described in claim 1, It is characterized in that The pressure of the atomized spraying in step (4) is 0.2 - 0.5 MPa, and the time of the atomized spraying is 2 - 20 s; the thickness of the porous surface layer in step (4) is 20 - 100 μm; the temperature of the drying in step (4) is 30 - 80 °C, and the time of the drying is 2 - 24 h; the temperature of the high-temperature sintering treatment in step (4) is 1350 - 1600 °C, the sintering time is 2 - 5 h, and the heating rate of the high-temperature sintering treatment is 2 - 15 °C / min.

7. For the preparation method of a zirconia ceramic with both biological activity and anti-low-temperature aging as described in claim 1, It is characterized in that The osmotic pressure of the negative pressure infiltration treatment described in step (5) is -0.10 to 0 MPa, and the time of the negative pressure infiltration treatment is 0.5 - 60 min; the standing aging time described in step (5) is 4 - 48 h; the drying temperature described in step (5) is 30 - 150 °C, and the drying time is 6 - 72 h; the heat treatment temperature described in step (5) is 600 - 1350 °C, the heat treatment time is 0.5 - 4 h, and the heating rate of the heat treatment is 2 - 10 °C / min.

8. A zirconia ceramic with both biological activity and anti-low temperature aging prepared by the preparation method according to any one of claims 1 - 7.

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