Zirconium oxide powder as well as preparation method and application thereof

Abstract

The invention discloses zirconium oxide powder as well as a preparation method and application thereof, and relates to the technical field of biomedical engineering materials. The average particle size of zirconium oxide primary particles is controlled to be smaller than or equal to 2.0 microns, the particle size D30 of the zirconium oxide primary particles is 0.1-0.3 microns, the particle size D70 of the zirconium oxide primary particles is 0.2-1.5 microns, the particle size D70 / D30 is 1.0-15, and the mass ratio of zirconium oxide, yttrium oxide, a dispersing agent and an organic compound is controlled, so that the final zirconium oxide powder is relatively uniform in particle size and relatively narrow in whole particle size distribution; therefore, the deformation rate difference between different zirconium oxide powders is smaller, and the problem of warping of a compression molding body when different powders are used for preparing multi-layer powders can be obviously improved.

Description

Technical Field

[0001] The present invention relates to the technical field of biomedical engineering materials, and in particular to zirconium oxide powder and a preparation method and application thereof. Background Art

[0002] Zirconia is an ideal dental restoration material, with good biocompatibility and excellent color matching, and its application in the field of oral restoration is becoming more and more widespread, and its demand is increasing year by year. Among them, because natural teeth have transparency and color gradient, based on consumers' demand for aesthetics, multi-layer denture zirconium blocks that are closer to the state of natural teeth and can achieve transparency gradient and color gradient account for an increasing market share.

[0003] Compared with single-layer zirconia denture blocks, layered zirconia denture blocks can produce dentures with transparency and color gradient that are closer to the appearance of natural teeth. This is mainly because when pressing layered denture blocks, 3 to 6 layers are generally pressed according to the differences in process from different manufacturers. The type and proportion of zirconia powder used in each layer are different. By matching powders of different translucency and color, a gradient of translucency and color between different layers can be achieved.

[0004] However, while layered zirconia dentures bring obvious aesthetic effects, the process difficulty of preparing zirconia powder and dentures has also increased a lot because of the different types and proportions of powders used in different layers of the zirconium block, and the differences in performance between different types of powders. This is mainly reflected in the fact that due to the inconsistency of the doping element content, powder particle size, and activity of different types of powders, there are differences in deformation rates between different layers, resulting in warping in the final zirconium block production process, which needs to be corrected through back-end machining. In severe cases, it may even cause the zirconium block to be scrapped, which increases the processing volume and production costs, and also affects the use effect of downstream customers.

[0005] Therefore, there is an urgent need to prepare zirconium oxide powder for multilayer denture zirconium blocks with low warpage and low deformation.

[0006] In view of this, the present invention is proposed. Summary of the invention

[0007] The object of the present invention is to provide a zirconium oxide powder and a preparation method and application thereof, aiming to provide a zirconium oxide powder for multilayer denture zirconium blocks with low warping and low deformation.

[0008] The present invention is achieved in that:

[0009] In a first aspect, the present invention provides a zirconium oxide powder, comprising zirconium oxide, yttrium oxide, a dispersant and an organic compound, wherein the mass ratio of zirconium oxide, yttrium oxide, the dispersant and the organic compound is (85-100):(3-12):(0.01-1.0):(0.05-10);

[0010] The zirconium oxide powder is formed by adding a dispersant and an organic compound to zirconium oxide primary particles containing zirconium oxide and yttrium oxide, and then granulating the particles. The average particle size of the zirconium oxide primary particles is less than or equal to 2.0 μm, the particle size D30 of the zirconium oxide primary particles is 0.1 μm-0.3 μm, D70 is 0.2 μm-1.5 μm, and D70 / D30 is 1.0-15.

[0011] In an optional embodiment, the mass ratio of zirconium oxide, yttrium oxide, dispersant and organic compound is (85-95):(5-10):(0.05-0.5):(0.1-6).

[0012] In an optional embodiment, the dispersant is selected from at least one of polyether acid compounds, polycarboxylic acid compounds, phosphate compounds and polyether amine compounds;

[0013] Preferably, the dispersant is selected from at least one of polycarboxylic acid compounds.

[0014] In an optional embodiment, the organic compound is selected from at least one of a polymeric alcohol compound, a polyacrylate compound, an alcohol ether compound, and an oily compound;

[0015] Preferably, the organic compound is selected from at least one of polymeric alcohol compounds.

[0016] In an optional embodiment, the crystal form of the zirconium oxide primary particles is mainly tetragonal phase, with some monoclinic phases; wherein the tetragonal phase accounts for 50% to 98% and the monoclinic phase accounts for 2 to 50%;

[0017] Preferably, the average particle size D50 of the zirconium oxide granulated powder is 10 μm-200 μm; the specific surface area is 5 m 2 / g-20m 2 / g, bulk density 1.0g / cm 3 -1.6g / cm 3 .

[0018] In a second aspect, the present invention provides a method for preparing zirconium oxide powder according to any one of the aforementioned embodiments, comprising:

[0019] mixing zirconium nitrate and water to obtain an aqueous solution;

[0020] Adding yttrium nitrate into the aqueous solution to perform a synthesis reaction to obtain a reaction slurry;

[0021] filter-pressing, drying and calcining the reaction slurry to obtain a mixed oxide;

[0022] Grinding and dispersing the mixed oxide to obtain a dispersed slurry; controlling the particle size of the particles in the dispersed slurry to meet the requirements of the primary particles of zirconium oxide;

[0023] The dispersion slurry is mixed with a dispersant and an organic compound and dried into a powder.

[0024] In an optional embodiment, the process of preparing the reaction slurry is controlled to be carried out under closed conditions, the reaction temperature is controlled to be 90° C.-250° C., and the synthesis time is 3 h-100 h;

[0025] Preferably, the mass ratio of zirconium oxychloride to water is (10-50):100, more preferably (15-40):100.

[0026] In an optional embodiment, the calcination temperature of the mixed powder is 900° C.-1300° C., and the calcination time is 2 h-50 h.

[0027] In an optional embodiment, the mixed oxide and water are mixed and ground and dispersed, and the mass ratio of the mixed oxide to water is controlled to be 1:(0.2-2.0).

[0028] In a third aspect, the present invention provides use of the zirconium oxide powder of any one of the aforementioned embodiments or the zirconium oxide powder prepared by any one of the preparation methods of the aforementioned embodiments in preparing layered zirconium oxide dentures.

[0029] The present invention has the following beneficial effects: the present invention adjusts the average particle size of the primary zirconia particles to be less than or equal to 2.0 μm, the particle size D30 of the primary zirconia particles is 0.1 μm-0.3 μm, the D70 is 0.2 μm-1.5 μm, and the D70 / D30 is between 1.0 and 15, and coordinately adjusts the mass ratio of zirconia, yttrium oxide, dispersant and organic compound, so that the final zirconia powder particle size is relatively uniform and the overall particle size distribution is relatively narrow, so that the deformation rate difference between different prepared zirconia powders is smaller, and the warping problem of the pressed molded body when multi-layer powders are made of different powders can be significantly improved. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0031] In order to improve the warping problem of multi-layer zirconia denture zirconium blocks, the present invention improves the preparation process of zirconia powder, especially regulates the particle size of zirconia primary particles and the mass ratio of zirconium oxide, yttrium oxide, dispersant and organic compound, and provides zirconia powder with specific particle size distribution and uniform activity. By improving the integrity of grain growth, the concentration of particle size distribution and improving particle activity, the difference in deformation rate between different types of powders is reduced, which is beneficial to improving the warping problem of multi-layer zirconia denture zirconium blocks.

[0032] The present invention provides a method for preparing zirconium oxide powder, comprising the following steps:

[0033] S1. The zirconium nitrate aqueous solution reacts with yttrium nitrate to prepare a reaction slurry

[0034] The zirconium nitrate aqueous solution is mixed with yttrium nitrate, and the mass ratio of zirconium oxide and yttrium oxide generated is controlled to be (85-100): (3-12), preferably (85-95): (5-10). The reaction is carried out at a temperature of 90°C-250°C to obtain a reaction slurry. It is preferable to control the reaction temperature within the above range, so that the particle size of the generated zirconium hydroxide particles can be more uniform.

[0035] Specifically, the reaction temperature of zirconium oxychloride and water can be 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, 150°C, 155°C, 160°C, 165°C, 170°C, 175°C, 180°C, 185°C, 190°C, 195°C, 200°C, 205°C, 210°C, 215°C, 220°C, 225°C, 230°C, 235°C, 240°C, 245°C, 250°C, etc.

[0036] In some embodiments, the process of preparing the reaction slurry is controlled to be carried out under closed conditions, the reaction temperature is controlled to be 90° C.-250° C., and the synthesis time is 3 h-100 h (e.g., 3 h, 10 h, 20 h, 30 h, 40 h, 50 h, 60 h, 70 h, 80 h, 90 h, 100 h, etc.). By optimizing the reaction temperature, time and other parameters, the uniformity of the generated zirconium hydroxide particles can be further improved.

[0037] Specifically, the lining of the container used for the reaction is not particularly limited, and can be made of enamel, stainless steel and other materials. The synthetic heating method is not particularly limited, and can be natural gas heating, electric heating and other methods. The synthetic heating medium is not particularly limited, and can be water, thermal oil and the like. Thermal oil is preferred, which has a high boiling point and high heat conduction efficiency. The synthetic insulation control method is not particularly limited, and can be manual control, DCS control and other methods. DCS control is preferred, which has high control accuracy and low labor intensity.

[0038] In some embodiments, the mass ratio of zirconium nitrate to water is (10-50):100, more preferably (15-40):100, and the amount of water can be controlled within the above range to allow the reaction to proceed fully. Specifically, the mass ratio of zirconium nitrate to water can be 10:100, 15:100, 20:100, 25:100, 30:100, 35:100, 40:100, 45:100, 50:100, etc.

[0039] In actual operation, a hydrothermal reactor can be used to react, dissolve zirconium nitrate in pure water in a certain proportion, and stir evenly to form a clear aqueous solution; add yttrium nitrate to the aqueous solution, transfer the completely dissolved zirconium nitrate and yttrium nitrate solutions to the synthesis reactor, close the valves of the synthesis reactor, seal the synthesis reactor, and heat it to perform a hydrothermal synthesis reaction. In addition to hydrothermal synthesis, other methods such as solid phase method, sol-gel method, vapor deposition method, supercritical synthesis, etc., can prepare powders in this particle size range and achieve anti-warping and low deformation properties.

[0040] S2. Preparation of mixed powder containing yttrium

[0041] The S1 reaction slurry is filtered and dried to obtain a mixed powder. The drying method is not particularly limited, and an oven, a microwave dryer, a spray dryer, etc. can be used. A spray dryer is preferred because it has high drying efficiency and is not easy to introduce impurities.

[0042] S3. Preparation of mixed oxide containing zirconium oxide and yttrium oxide

[0043] The mixed powder is calcined to obtain a mixed oxide.

[0044] In some embodiments, the calcination temperature of the mixed powder is 900°C-1300°C, and the calcination time is controlled to be 2h-50h. By optimizing the calcination temperature, time and other parameters to prevent particle agglomeration, mixed oxide particles with relatively uniform particle size are obtained after calcination.

[0045] Specifically, the calcination temperature can be 900°C, 950°C, 1000°C, 1050°C, 1100°C, 1150°C, 1200°C, 1250°C, 1300°C, etc.; the holding time at the calcination temperature can be 2h, 5h, 10h, 15h, 20h, 25h, 30h, 35h, 40h, 45h, 50h, etc. The calcination equipment is not particularly limited, and can be a box furnace, a push plate furnace, a roller furnace, a rotary furnace, etc. The calcination method is not particularly limited, and can be natural gas heating, resistance wire heating, silicon carbon rod heating, silicon molybdenum rod heating, etc.

[0046] S4, grinding and dispersion

[0047] The mixed oxides are ground and dispersed to remove hard particles and large particles to obtain a dispersed slurry. The particle size of the particles in the dispersed slurry is controlled to meet the requirements of the primary zirconia particles. Specifically, the average particle size of the primary zirconia particles is less than or equal to 2.0 μm, the particle size D30 of the primary zirconia particles is 0.1 μm-0.3 μm, D70 is 0.2 μm-1.5 μm, and D70 / D30 is 1.0-15. It is preferable that the particle size of the primary zirconia particles meets the above requirements, so that the final zirconia powder particle size is relatively uniform and the overall particle size distribution is narrow, so that the deformation rate difference between the prepared different zirconia powders is smaller, and the warping problem of the pressed molded body when different powders are used to make multi-layer powders can be significantly improved.

[0048] Specifically, the average particle size of the zirconia primary particles can be 0.1μm, 0.3μm, 0.5μm, 0.8μm, 1.0μm, 1.3μm, 1.5μm, 1.8μm, 2.0μm, etc.; the particle size D30 of the zirconia primary particles can be 0.10μm, 0.15μm, 0.20μm, 0.25μm, 0.30μm, etc., the particle size D70 of the zirconia primary particles can be 0.2μm, 0.5μm, 0.8μm, 1.0μm, 1.3μm, 1.5μm, etc., and D70 / D30 can be 1.00, 1.67, 1.80, 2.00, 4.00, 6.00, 8.00, 10.00, 12.00, 15.00, etc. The grinding method is not particularly limited, and can be a ball mill, a sand mill, ultrasonic dispersion, high-speed stirring, etc., to grind and disperse the zirconium oxide slurry to test the particle size.

[0049] It should be added that when D30>0.3μm, D70>1.5μm or D30<0.1μm, D70<0.2μm or D70 / D30 is not in the range of 1.0-15, the molded body will warp during the isostatic pressing stage, with a warping degree of >1.0mm, making it impossible to further turn the molded body. In worse cases, interlayer cracks will occur, making the molded body unusable.

[0050] In some embodiments, the mixed oxide and water are mixed and ground and dispersed, and the mass ratio of the mixed oxide and water is controlled to be 1:(0.2-2.0), such as 1:0.2, 1:0.5, 1:0.8, 1:1.0, 1:1.2, 1:1.5, 1:1.8, 1:2.0, etc.

[0051] Furthermore, the crystal form of the zirconium oxide primary particles is mainly tetragonal phase, with partial monoclinic phase; wherein the tetragonal phase accounts for 50% to 98%, such as 50%, 60%, 70%, 80%, 90%, 95%, 98%, etc.; the monoclinic phase accounts for 2% to 50%, such as 2%, 5%, 10%, 20%, 30%, 40%, 50%, etc.

[0052] S5, Granulation

[0053] Zirconia powder is formed by adding a dispersant and an organic compound to primary particles of zirconium oxide containing zirconium oxide and yttrium oxide, and then granulating. The dispersed slurry is mixed with the dispersant and the organic compound and dried into powder. The mass ratio of zirconium oxide, yttrium oxide, dispersant and organic compound is (85-100): (3-12): (0.01-1.0): (0.05-10), preferably (85-95): (5-10): (0.05-0.5): (0.1-6). The dispersant is used to disperse the zirconium oxide powder, and the organic compound is used to adjust the surface characteristics of the zirconium oxide powder particles. By adjusting the amount of each component, the particle size of the zirconium oxide powder obtained after granulation is made more uniform.

[0054] Specifically, the mass ratio of zirconium oxide, yttrium oxide, dispersant and organic compound can be 85:3:0.01:0.05, 90:5:0.05:0.10, 95:8:0.10:1.00, 98:10:0.50:6.00, 100:12:1.00:10.00, etc.

[0055] In some embodiments, the dispersant is selected from at least one of polyether acid compounds, polycarboxylic acid compounds, phosphate compounds and polyether amine compounds, and the dispersant may be any one or more of the above compounds, which can well disperse the zirconium oxide powder. Preferably, the dispersant is selected from at least one of the polycarboxylic acid compounds, and the dispersant is preferably any one or more of the above compounds, which can further improve the uniformity of the particle size of the zirconium oxide powder.

[0056] In some embodiments, the organic compound is selected from at least one of polymeric alcohol compounds, polyacrylate compounds, alcohol ether compounds and oily compounds, and the organic compound can be any one or more of the above. Preferably, the organic compound is selected from at least one of polymeric alcohol compounds, and the organic compound is preferably any one or more of the above, which can make the particle size of the granulated powder more uniform during the granulation process.

[0057] Furthermore, the average particle size of the zirconium oxide granulated powder is 10 μm-200 μm, such as 10 μm, 50 μm, 80 μm, 100 μm, 130 μm, 150 μm, 180 μm, 200 μm, etc.; the specific surface area is 5m 2 / g-20m 2 / g, such as 5m 2 / g, 10m 2 / g, 15m 2 / g, 20m 2 / g, etc.; bulk density 1.0g / cm 3 -1.6g / cm3 , such as 1.0g / cm 3 , 1.1g / cm 3 , 1.2g / cm 3 , 1.3g / cm 3 , 1.4g / cm 3 , 1.5g / cm 3 , 1.6g / cm 3 wait.

[0058] The embodiment of the present invention provides a zirconium oxide powder, comprising zirconium oxide, yttrium oxide, a dispersant and an organic compound, wherein the mass ratio of zirconium oxide, yttrium oxide, dispersant and organic compound is (85-100):(3-12):(0.01-1.0):(0.05-10), (85-95):(5-10):(0.05-0.5):(0.1-6). The zirconium oxide powder is formed by adding a dispersant and an organic compound to zirconium oxide primary particles containing zirconium oxide and yttrium oxide, and granulating the particles. The average particle size of the zirconium oxide primary particles is less than or equal to 2.0 μm, the particle size D30 of the zirconium oxide primary particles is 0.1 μm-0.3 μm, D70 is 0.2 μm-1.5 μm, and D70 / D30 is 1.0-15.

[0059] It should be noted that the zirconia powder provided in the embodiment of the present invention can be prepared by the above-mentioned preparation process, and the deformation rate of the denture zirconium block prepared by the obtained zirconia powder is 4.0-8.0% by optimizing the particle size of the primary zirconia particles and adjusting the mass ratio of zirconia, yttrium oxide, dispersant and organic compound, and the warpage degree of the pre-sintered molded body of the prepared multi-layer zirconia denture zirconium block is 0.1-1.5mm. The advantages of low deformation rate and low warpage degree are particularly suitable for preparing layered zirconia dentures.

[0060] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0061] Example 1

[0062] This embodiment provides a method for preparing zirconium oxide powder, the steps are as follows:

[0063] (1) Mix zirconium nitrate and pure water, control the input amount of zirconium nitrate to 20% of the weight of pure water, stir evenly to form a clear solution, add yttrium nitrate to the completely dissolved zirconium nitrate solution, and perform hydrothermal synthesis after complete dissolution. The hydrothermal synthesis temperature is controlled to 150° C. and the synthesis time is 10 hours. Based on zirconium oxide and yttrium oxide, the mass ratio of zirconium oxide to yttrium oxide is controlled to be 85:3.0.

[0064] (2) adjusting the pH value of the solution after the reaction to above 7.0, allowing it to settle, and performing a filter press operation to obtain a filter cake, and drying the obtained filter cake to obtain a dried mixed powder.

[0065] (3) The dried powder is calcined at 900°C for 50 hours.

[0066] (4) The mixed oxide powder calcined at high temperature is mixed with pure water for slurrying, and then ground and dispersed to obtain a dispersed slurry. The weight of pure water is twice the weight of the zirconium oxide powder (i.e., the mixed oxide powder). The particle size of the particles in the dispersed slurry is controlled to meet the requirements of the zirconium oxide primary particles. The average particle size of the zirconium oxide primary particles is less than or equal to 2.0 μm, the particle size D30 of the zirconium oxide primary particles is 0.12 μm, D70 is 0.63 μm, and D70 / D30 is 5.25.

[0067] (5) Adding a dispersant and an organic compound to the ground and dispersed zirconium oxide slurry, drying the mixed slurry into powder, and testing the loose packing of the dried zirconium oxide powder. The dispersant is sodium polymethacrylate, the organic compound is polyvinyl alcohol, and the mass ratio of zirconium oxide, yttrium oxide, dispersant and organic compound is 85:3.0:0.1:1.00.

[0068] (6) Product performance test:

[0069] ①The mass ratio of zirconium oxide to yttrium oxide is measured by XRF. It is worth mentioning that X-ray fluorescence spectrometer (XRF spectrometer) is a fast, non-destructive material measurement method. X-ray fluorescence (XRF) is the secondary X-rays excited when a material is bombarded with high-energy X-rays or gamma rays, and can be used to determine the composition of ceramic powders.

[0070] ② Particle size test method: After dropping 2 to 3 drops of slurry into the sample pool of the laser particle size detector, start the detector for testing.

[0071] (7) The prepared zirconium oxide powder is used to test the deformation rate of the denture zirconium block and the warpage of the multi-layer denture zirconium block. The specific steps are as follows:

[0072] ① Deformation rate method of denture zirconium block: Pour a certain amount of zirconium oxide powder into the dry pressing machine mold. The dry pressing machine mold has a fixed diameter of 98-108mm and a thickness of 10-25mm depending on the material model. The molded body is in the shape of a cake; after dry pressing, the volume of the dry pressed molded body is measured, and its density, i.e., the dry pressed density, isostatically pressed the dry pressed molded body, and after isostatic pressing, the volume of the isostatic pressed molded body is measured, and its density, i.e., the isostatic pressed density, isostatically pressed the dry pressed molded body is placed in a sintering furnace for pre-sintering, and after sintering, the volume of the pre-sintered molded body is measured, and its density, i.e., the pre-sintered density, isostatically pressed the molded body is placed in a sintering furnace for pre-sintering. After sintering, the volume of the pre-sintered molded body is measured, and its density, i.e., the pre-sintered density, is calculated; based on the above three density values, the deformation rates at different stages are calculated, and the deformation rate calculated by the dry pressing density and the pre-sintering density is the deformation rate of the denture zirconium block.

[0073] Denture zirconium block deformation rate = 1-(dry pressing density / pre-sintering density)^(1 / 3);

[0074] ②Test method for the warping degree of multi-layer denture zirconium blocks: pour the zirconium oxide powder required for each layer of the layered denture zirconium block into the dry pressing machine mold in turn, place the dry pressed body on a horizontal test bench after dry pressing, and use a height gauge to test the height of the center point of the front side as C1, and the height of the center point of the back side as D1; ​​subject the dry pressed body to isostatic pressing, and after isostatic pressing, measure the height of the center point of the front side as C2, and the height of the center point of the back side as D2 according to the above method; place the isostatic pressed body into a sintering furnace for pre-sintering, and test the pre-sintered body according to the above method, the height of the center point of the front side is C3, and the height of the center point of the back side is D3.

[0075] Warpage calculation formula: (|C3-D3|)

[0076] Example 2-22

[0077] The only difference from Example 1 is that some parameters are different, see Table 1-3 for details.

[0078] Comparative Examples 1-14

[0079] The only difference from Example 1 is that some parameters are different, see Table 4-5 for details.

[0080] Table 1 Preparation conditions of Examples 1-8 and deformation rate of the prepared powders

[0081]

[0082]

[0083] Table 2 Preparation conditions of Examples 9-16 and deformation rate of the prepared powders

[0084]

[0085]

[0086] Table 3 Preparation conditions of Examples 17-22 and deformation rate of the prepared powders

[0087]

[0088]

[0089] Table 4 Preparation conditions of comparative examples 1-7 and deformation rate of the prepared powders

[0090]

[0091] Table 5 Preparation conditions of comparative examples 8-14 and deformation rate of the powders obtained

[0092]

[0093] It can be seen that the deformation rate stability of the zirconium oxide powder prepared in the embodiment of the present invention is significantly better than that of the comparative example.

[0094] Application Examples

[0095] The zirconium oxide powder provided in different embodiments of the present invention is used to prepare layered zirconium oxide dentures, and the specific preparation process is as follows:

[0096] The zirconium oxide powder required for each layer of the layered denture zirconium block is poured into the dry pressing machine mold in turn. After dry pressing, the dry pressed body is placed on a horizontal test bench. The height of the center point of the front side is measured with a height gauge as C1, and the height of the center point of the back side is measured as D1; ​​the dry pressed body is isostatically pressed, and after isostatic pressing, the height of the center point of the front side is measured as C2, and the height of the center point of the back side is measured as D2 according to the above method; the isostatic pressed body is placed in a sintering furnace for pre-sintering, and the pre-sintered body is tested according to the above method, and the height of the center point of the front side is measured as C3, and the height of the center point of the back side is measured as D3.

[0097] Warpage calculation formula: (|C3-D3|)

[0098] The warping degree of the denture zirconium block was tested and the results are shown in Table 6.

[0099] Table 6 Warping test results of layered zirconia dentures prepared from zirconia powders obtained in different embodiments

[0100]

[0101] Comparative application examples:

[0102] The zirconium oxide powder combination obtained in the embodiment and the comparative example was used to prepare a layered zirconia denture. The warping degree of the denture zirconium block was tested. The results are shown in Table 7.

[0103] Table 7 Warping test results of layered zirconia dentures prepared with zirconia powder

[0104]

[0105]

[0106] It can be seen from Tables 6 and 7 that if the zirconium oxide powder combination prepared in the embodiment of the present invention is used to prepare a layered zirconia denture, the warping degree of the denture zirconium block is low, and if the zirconium oxide powder prepared in the comparative example is added, the warping degree will be significantly increased.

[0107] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A zirconium oxide powder, characterized in that: It includes zirconium oxide, yttrium oxide, a dispersant and an organic compound, wherein the mass ratio of zirconium oxide, yttrium oxide, the dispersant and the organic compound is (85-100):(3-12):(0.01-1.0):(0.05-10); The zirconium oxide powder is formed by adding the dispersant and the organic compound to the zirconium oxide primary particles containing zirconium oxide and yttrium oxide, and then granulating them. The average particle size of the zirconium oxide primary particles is less than or equal to 2.0 μm, the particle size D30 of the zirconium oxide primary particles is 0.1 μm-0.3 μm, D70 is 0.2 μm-1.5 μm, and D70 / D30 is 1.0-15.

2. The zirconium oxide powder according to claim 1, characterized in that The mass ratio of zirconium oxide, yttrium oxide, dispersant and organic compound is (85-95):(5-10):(0.05-0.5):(0.1-6).

3. The zirconium oxide powder according to claim 1 or 2, characterized in that: The dispersant is selected from at least one of polyether acid compounds, polycarboxylic acid compounds, phosphate compounds and polyether amine compounds; Preferably, the dispersant is selected from at least one of polycarboxylic acid compounds.

4. The zirconium oxide powder according to claim 1 or 2, characterized in that: The organic compound is selected from at least one of polymeric alcohol compounds, polyacrylate compounds, alcohol ether compounds and oily compounds; Preferably, the organic compound is selected from at least one of polymeric alcohol compounds.

5. The zirconium oxide powder according to claim 1, characterized in that: The crystal form of the primary zirconium oxide particles is mainly tetragonal phase, with some monoclinic phases; wherein the tetragonal phase accounts for 50% to 98% and the monoclinic phase accounts for 2% to 50%; Preferably, the zirconium oxide granulated powder has a particle size D50 of 10 μm-200 μm and a specific surface area of ​​5 m 2 / g-20m 2 / g, bulk density 1.0g / cm 3 -1.6g / cm 3 .

6. A method for preparing the zirconium oxide powder according to any one of claims 1 to 5, characterized in that: include: mixing zirconium nitrate and water to obtain an aqueous solution; adding yttrium nitrate to the aqueous solution to perform a synthesis reaction to obtain a reaction slurry; filter-pressing, drying and calcining the reaction slurry to obtain a mixed oxide; Grinding and dispersing the mixed oxide to obtain a dispersed slurry; controlling the particle size of the particles in the dispersed slurry to meet the requirements of the primary particles of zirconium oxide; The dispersion slurry is mixed with the dispersant and the organic compound, and dried into powder.

7. The preparation method according to claim 6, characterized in that: During the preparation of the reaction slurry, the reaction is carried out under closed conditions, the reaction temperature is controlled to be 90° C.-250° C., and the synthesis time is 3 h-100 h; Preferably, the mass ratio of zirconium nitrate to water is (10-50):100, more preferably (15-40):

100.

8. The preparation method according to claim 6, characterized in that: The calcination temperature of the mixed powder is 900° C.-1300° C., and the calcination time is 2 h-50 h.

9. The preparation method according to claim 6, characterized in that: The mixed oxide and water are mixed and ground and dispersed, and the mass ratio of the mixed oxide to water is controlled to be 1:(0.2-2.0).

10. Use of the zirconium oxide powder according to any one of claims 1 to 5 or the zirconium oxide powder prepared by the preparation method according to any one of claims 6 to 9 in preparing layered zirconium oxide dentures.

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