A yttrium-stabilized zirconia powder and its preparation method

Abstract

This application relates to the field of zirconia powder materials technology, specifically providing a yttrium-stabilized zirconia powder and its preparation method. The yttrium-stabilized zirconia powder, by 100% molar composition, has a composition of 0.8-2.5% Y₂O₃·97.5-99.2% ZrO₂. The preparation method involves dissolving a water-soluble yttrium salt, a water-soluble zirconium salt, and a dispersant in water to prepare a solution A with a salt concentration of 1.0-2.5 mol / L. Solution A and a 10-20% (w / w) ammonium bicarbonate aqueous solution are simultaneously added dropwise to a reactor, controlling the dropwise addition rate of the ammonium bicarbonate aqueous solution to maintain the pH of the reaction system at 8.5-9.5. After the addition is complete, dehydration is performed, and the collected precipitate is dispersed in a second surfactant aqueous solution at 3-10 times its volume. The mixture is stirred for 30-60 minutes, dehydrated, and then washed and dehydrated 2-8 times with water to obtain a washed product. The washed product is then heated to 800-900℃ and calcined for 1.5-3.5 hours, cooled, and crushed to obtain the final product. The yttrium-stabilized zirconia powder of this application has the characteristics of uniform composition and low monoclinic phase content, and can be used as a toughening agent for toughening ZTA ceramics.

Description

Technical Field

[0001] This application relates to the field of zirconia powder materials technology, specifically to a yttrium-stabilized zirconia powder and its preparation method. Background Technology

[0002] Alumina ceramic substrates possess excellent insulation properties, thermal conductivity, and mechanical strength, making them widely used in the electronics industry. Currently, most alumina ceramic substrates on the market are based on 96% alumina, primarily used in thick-film integrated circuits and LED packaging. However, the relatively poor fracture toughness of alumina ceramics somewhat limits their application. By dispersing ZrO2 particles within an alumina ceramic matrix and utilizing the ZrO2 toughening stress-induced phase transformation mechanism, ZrO2-toughened multiphase ceramics (ZTA) with superior fracture toughness compared to single-phase alumina ceramics can be prepared. The production cost of ZTA ceramics is generally much lower than that of ZrO2 ceramics, giving them a strong cost-performance advantage in practical applications.

[0003] During sintering, zirconia (ZrO2) ceramics undergo significant volume changes (around 5%) due to phase transformation, impacting their performance and applications, including in ZrO2 sintering. A common improvement method is to add yttrium oxide powder to the zirconia powder, generally known as yttrium-stabilized zirconia. Monoclinic zirconia can enhance the fracture toughness and strength of zirconia ceramics, but it also reduces the yield of the ceramic product. The most commonly used yttrium-stabilized zirconia is 3 mol% yttrium oxide, i.e., a molar ratio of yttrium oxide to zirconia of 3:97. Summary of the Invention

[0004] The preparation method of yttrium-stabilized zirconia, the molar ratio of yttrium oxide to zirconia, and the proportion of different crystal forms in zirconia all affect the performance of yttrium-stabilized zirconia. To prepare ZTA ceramics with better performance, the inventors have conducted in-depth research on the preparation method of yttrium-stabilized zirconia. Based on this, this application proposes a yttrium-stabilized zirconia powder and its preparation method.

[0005] The technical solution adopted in this application is as follows:

[0006] A yttrium-stabilized zirconia powder, with a composition of 0.8-2.5% Y₂O₃·97.5-99.2% ZrO₂ per 100 mol.

[0007] Preferably, the composition is 1-2.5% Y2O3·97.5-99% ZrO2.

[0008] A method for preparing yttrium-stabilized zirconia powder according to any of the above embodiments, comprising the following steps:

[0009] S1. Dissolve water-soluble yttrium salt, water-soluble zirconium salt and dispersant in water to prepare solution A with a salt concentration of 1.0-2.5 mol / L;

[0010] S2. Simultaneously add solution A from step S1 and a 10-20% (w / w) ammonium bicarbonate aqueous solution to the reactor, controlling the dropping rate of the ammonium bicarbonate aqueous solution to maintain the pH of the reaction system at 8.5-9.5. After the addition is complete, dehydrate the solution, disperse the collected precipitate in a second surfactant aqueous solution at 3-10 times its volume, stir for 30-60 minutes, dehydrate, and continue washing and dehydrating with water 2-8 times to obtain a water-washed product. Calcine the water-washed product at 800-900℃ for 1.5-3.5 hours, cool, and crush to obtain the yttrium-stabilized zirconium oxide powder.

[0011] Preferably, the water-soluble yttrium salt in step S1 is selected from one or a combination of yttrium chloride, yttrium nitrate and yttrium sulfate.

[0012] Preferably, the water-soluble zirconium salt in step S1 is selected from one or more combinations of zirconium oxychloride, zirconium oxysulfate, zirconium nitrate, zirconium acetate, zirconium sulfate, and zirconium chloride.

[0013] Preferably, the dispersant in step S1 is selected from one or more combinations of polymeric dispersants and a first surfactant.

[0014] Preferably, the ratio of the weight of the dispersant in step S1 to the combined weight of the water-soluble yttrium salt and the water-soluble zirconium salt is 0.01-0.1:1.

[0015] Preferably, the dropping rate of solution A in step S2 is 1 ml-50000 ml / min.

[0016] Preferably, the concentration of the second surfactant aqueous solution in step S2 is 0.3-2 wt%.

[0017] Preferably, the heating rate in step S2 is 1-5℃ / min.

[0018] In summary, this application has the following beneficial effects:

[0019] 1. In the prior art, the molar content of yttrium in yttrium-stabilized zirconia powder is generally 3% or higher. The molar content of yttrium in the yttrium-stabilized zirconia powder of this application is 2.5% or lower, which is significantly lower than that in the prior art. It has been found that this can significantly improve the toughness of ZTA ceramic substrates and reduce the problem of easy breakage caused by the brittleness of ZTA ceramic substrates.

[0020] 2. This application employs a simple precipitation method to prepare yttrium-stabilized zirconia powder. By controlling the dropping rate of solution B, the pH of the precipitation reaction is controlled to obtain the precipitate, which is then further washed with an aqueous surfactant solution to remove impurities. The preparation method of this application is simple and efficient, and can yield yttrium-stabilized zirconia powder with uniform composition and low yttrium oxide content. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below.

[0022] Throughout this specification, unless otherwise specified, the terminology used herein should be understood as having the meaning commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In the event of any conflict, this specification shall prevail.

[0023] On the one hand, this application proposes a yttrium-stabilized zirconia powder with a low yttrium oxide content, consisting of 0.8-2.5% Y₂O₃ and 97.5-99.2% ZrO₂ per 100 mol. 2。 That is, the yttrium-stabilized zirconia powder of this application is yttrium oxide-stabilized zirconia powder, wherein the molar content of yttrium oxide is 0.5-2.5%. Further, the composition of the yttrium-stabilized zirconia powder is 1-2.5% Y₂O₃·97.5-99% ZrO₂. That is, the molar content of yttrium oxide in the yttrium-stabilized zirconia powder is 1-2.5%, for example, the molar content of yttrium oxide can be 1%, 1.2%, 1.3%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%, 2.1%, 2.2%, 2.4%, 2.5%, etc.

[0024] On the other hand, this application proposes a method for preparing yttrium-stabilized zirconia powder according to any of the above embodiments, the steps of which include:

[0025] S1. Dissolve the water-soluble yttrium salt, water-soluble zirconium salt, and dispersant in water to prepare a solution A with a salt concentration of 1.0-2.5 mol / L. In this application, the salt concentration refers to the sum of the concentrations of the yttrium salt and the zirconium salt. The proportion of the yttrium salt in the sum of the molar numbers of the yttrium salt and the zirconium salt is 0.8-2.5%, that is, based on 100% molar numbers, the molar ratio of the yttrium salt to the zirconium salt can be 0.8:99.2, 1:99, 1.2:98.8, 1.5:98.5, 1.8:98.2, 2:98, 2.2:97.8, 2.5:97.5, etc. Alternatively, the proportion of the yttrium salt in the sum of the molar numbers of the yttrium salt and the zirconium salt is 1-2.5%.

[0026] S2. Simultaneously add solution A from step S1 and a 10-20% (w / w) ammonium bicarbonate aqueous solution to the reactor, controlling the dropping rate of the ammonium bicarbonate aqueous solution to maintain the pH of the reaction system at 8.5-9.5. After the addition is complete, dehydrate the product and disperse the collected precipitate in a second surfactant aqueous solution with a volume of 3-10 times the precipitate. Stir for 30-60 minutes, dehydrate, and continue washing and dehydrating with water 2-8 times to obtain a water-washed product. Then, heat the water-washed product to 800-900℃ and calcine for 1.5-3.5 hours, cool, crush, and obtain yttrium-stabilized zirconium oxide powder.

[0027] This application employs a method of controlling the dropping rate of the precipitant—ammonium bicarbonate aqueous solution—relative to solution A, thereby controlling the pH value of the precipitation reaction system between 8.5 and 9.5. This allows the water-soluble yttrium salt and water-soluble zirconium salt to precipitate simultaneously and uniformly, resulting in yttrium-stabilized zirconium oxide powder with a more homogeneous composition before and after the reaction. Furthermore, using ammonium bicarbonate aqueous solution as the precipitant results in a milder precipitation reaction and a more constant precipitation rate, leading to a more uniform composition of yttrium-stabilized zirconium oxide powder. In contrast, using sodium hydroxide or sodium bicarbonate as the precipitant is problematic because sodium hydroxide is too alkaline, and Na... + The presence of ions introduces impurities, affecting the purity of the product. After washing with a second surfactant aqueous solution, the precipitate contains fewer impurities and has higher purity.

[0028] In this application, the water-soluble yttrium salt in step S1 is not particularly limited and can be selected from one or a combination of yttrium chloride, yttrium nitrate and yttrium sulfate.

[0029] In this application, the water-soluble zircon salt in step S1 is not particularly limited and can be selected from one or a combination of zirconium oxychloride, zirconium oxysulfate, zirconium nitrate, zirconium acetate, zirconium sulfate and zirconium chloride.

[0030] When preparing yttrium-stabilized zirconia powder using precipitation or solvothermal methods, a dispersant is needed to disperse and protect the formed precipitate particles, preventing agglomeration, grain growth, or impurities due to agglomeration. In this application, the dispersant in step S1 can be selected from one or more combinations of a polymeric dispersant and a first surfactant. In this application, the polymeric dispersant refers to a dispersant with an average molecular weight of not less than 1000, such as polyacrylic acid and its salts, polyethylene glycol, polyvinylpyrrolidone, polyvinyl alcohol, etc.; the first surfactant has a molecular weight of not more than 500 and can be a nonionic surfactant and / or anionic surfactant. For example, nonionic surfactants can be fatty alcohol polyoxyethylene ethers, alkylphenol polyoxyethylene ethers, Span series, Tween series, etc., and anionic surfactants can be sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, sodium stearate, etc.

[0031] Furthermore, in this application, the dispersant can be a combination of a polymeric dispersant and a first surfactant. The inventors have found that using such a combination can further obtain yttrium-stabilized zirconia powder with a more uniform composition. The polymeric dispersant and the first surfactant can be a combination in a weight ratio of 1:0.3-4. For example, the weight ratio of the polymeric dispersant to the first surfactant can be 1:0.3, 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, 1:1.2, 1:1.4, 1:1.5, 1:1.7, 1:1.8, 1:2, 1:2.1, 1:2.3, 1:2.5, 1:2.7, 1:2.8, 1:3, 1:3.1, 1:3.3, 1:3.5, 1:3.7, 1:3.8, 1:4, etc.

[0032] In this application, the weight ratio of the dispersant to the sum of the weights of the water-soluble yttrium salt and the water-soluble zirconium salt in step S1 is 0.01-0.1:1, that is, the weight of the dispersant is 0.01-0.1 times the sum of the weights of the yttrium salt and the zirconium salt, or further, the weight of the dispersant is 0.015-0.07 times the sum of the weights of the yttrium salt and the zirconium salt, for example, it can be 0.015 times, 0.018 times, or 0.02 times. 0.022 times, 0.025 times, 0.028 times, 0.03 times, 0.033 times, 0.035 times, 0.037 times, 0.04 times, 0.042 times, 0.045 times, 0.048 times, 0.05 times, 0.052 times, 0.055 times, 0.057 times, 0.06 times, 0.063 times, 0.065 times, 0.067 times, 0.07 times, etc.

[0033] In this application, the dropping rate of solution A in step S2 can be determined based on the volume of solution A, and the dropping rate can be 1 ml to 50,000 ml / min. For example, if the volume of solution A is 1 L, the dropping rate of solution A can be 1 ml to 50 ml / min, without any particular limitation; if the volume of solution A is 10 L, the dropping rate of solution A can be 50 ml to 500 ml / min, without any particular limitation.

[0034] In this application, the purpose of washing the precipitate with an aqueous solution of a second surfactant in step S2 is twofold: (1) to remove some impurities from the precipitate, and (2) to facilitate the dispersion of the precipitate and prevent agglomeration. For example, the second surfactant can be a nonionic surfactant, such as fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, Span series, Tween series, etc. Specifically, it can be AEO series, Pingpingjia O series, OP series, etc. The concentration of the second surfactant can be 0.3-2 wt%, or further, the concentration of the second surfactant can be 0.5-1.5 wt%. For example, the concentration can be 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1 wt%, 1.1 wt%, 1.2 wt%, 1.3 wt%, 1.4 wt%, 1.5 wt%, etc.

[0035] In this application, the precipitate is dispersed in the aqueous solution of the second surfactant in step S2 by means of ultrasonic dispersion or high-speed stirring dispersion, and dehydration can be carried out by centrifugation followed by water removal. When washing with water, the precipitate can be ultrasonically dispersed in deionized water or ultrapure water, and then stirred and washed.

[0036] In this application, there is no particular limitation on the heating rate in step S2. However, considering efficiency and ensuring the quality of the powder product, a heating rate of 1-5℃ / min is more appropriate. For example, the heating rate can be 1℃ / min, 2℃ / min, 3℃ / min, 4℃ / min, 5℃ / min, etc., without any particular limitation.

[0037] The technical solution of this application will be described in detail below with reference to embodiments and comparative examples.

[0038] Example 1

[0039] Add yttrium chloride and zirconium oxychloride to water at a molar ratio of 1.5:98.5, stir to dissolve, and the salt concentration is 1.5 mol / L. Then add 3% polyethylene glycol-2000 (2000 represents the average molecular weight) by weight of yttrium chloride and zirconium oxychloride, stir to dissolve, and obtain solution A.

[0040] 1 L of the above solution A and a 15% (w / w) ammonium bicarbonate aqueous solution were simultaneously added dropwise to the reactor at a rate of 20 ml / L, with stirring occurring simultaneously. The stirring speed of the reaction system was 300 rpm. The dropwise rate of the ammonium bicarbonate aqueous solution was controlled to maintain the pH of the reaction system at 8.5-9. After the addition was complete, the mixture was centrifuged at 12000 rpm to remove water. The precipitate was collected and ultrasonically dispersed in a 1.5 wt% (w / w) OP-10 aqueous solution, which was stirred for 40 min. After centrifugation, the mixture was washed and dehydrated three times with deionized water. The washing solution was tested with a 0.5 wt% (w / w) silver nitrate aqueous solution and found to be free of chloride ions, thus obtaining the washed product.

[0041] The washed product was placed in an alumina sagger, which was then placed in a kiln. The temperature was increased to 850°C at a rate of 2°C / min and calcined for 2 hours. After cooling and crushing, yttrium-stabilized zirconia powder was obtained.

[0042] Example 2

[0043] The difference between Example 2 and Example 1 is that in Example 1, the molar ratio of yttrium chloride and zirconium oxychloride was adjusted from 1.5:98.5 to 1:99. The remaining steps remained unchanged.

[0044] Example 3

[0045] The difference between Example 3 and Example 1 is that in Example 1, the molar ratio of yttrium chloride and zirconium oxychloride was adjusted from 1.5:98.5 to 2.5:97.5. The remaining steps remained unchanged.

[0046] Example 4

[0047] The difference between Example 4 and Example 1 is that in Example 1, polyethylene glycol-2000 was replaced with an equal weight of Pingpingjia O-20. The remaining steps remained unchanged.

[0048] Example 5

[0049] The difference between Example 5 and Example 1 is that in Example 1, polyethylene glycol-2000 was adjusted to be an equal weight combination of polyethylene glycol-2000 and Pingping plus O-20 in a weight ratio of 3:1. The remaining steps remained unchanged.

[0050] Example 6

[0051] The difference between Example 6 and Example 1 is that in Example 1, polyethylene glycol-2000 was adjusted to be an equal weight combination of polyethylene glycol-2000 and Pingping plus O-20 in a weight ratio of 1:2. The remaining steps remained unchanged.

[0052] Comparative Example 1

[0053] The difference between Comparative Example 1 and Example 1 is that in Example 1, the washing with OP-10 aqueous solution was replaced with washing with deionized water. The remaining steps remained unchanged.

[0054] Comparative Example 2

[0055] The difference between Comparative Example 2 and Example 1 is that in Example 1, the 15% ammonium bicarbonate aqueous solution was replaced with a 3% NaOH aqueous solution. The remaining steps remained unchanged.

[0056] Comparative Example 3

[0057] The difference between Comparative Example 3 and Example 1 is that in Example 1, the 15% ammonium bicarbonate aqueous solution was replaced with a 15% sodium bicarbonate aqueous solution. The remaining steps remained unchanged.

[0058] Comparative Example 4

[0059] The difference between Comparative Example 4 and Example 1 is that in Example 1, the dropping rate of the ammonium bicarbonate aqueous solution was controlled to adjust the pH of the reaction system from 8.5-9 to 10-10.5. The remaining steps remained unchanged.

[0060] Comparative Example 5

[0061] The difference between Comparative Example 5 and Example 1 is that in Example 1, the dropping rate of the ammonium bicarbonate aqueous solution was controlled to adjust the pH of the reaction system from 8.5-9 to 7-7.5. The remaining steps remained unchanged.

[0062] Example 7

[0063] The molar ratio of yttrium nitrate to zirconium oxychloride is 2:98, the salt concentration is 1.2 mol / L, and the weight of PVA 1792 is 2.5% of the sum of the weights of yttrium nitrate and zirconium oxychloride.

[0064] PVA 1792 was added to water at 92°C and stirred until dissolved. After cooling to room temperature, yttrium nitrate and zirconium oxychloride were added and stirred until dissolved to obtain solution A.

[0065] 1 L of the above solution A and a 12% (w / w) ammonium bicarbonate aqueous solution were simultaneously added dropwise to the reactor at a rate of 40 ml / L, with stirring occurring simultaneously. The stirring speed of the reaction system was 350 rpm, and the dropwise rate of the ammonium bicarbonate aqueous solution was controlled to maintain the pH of the reaction system at 9-9.5. After the addition was complete, the mixture was centrifuged at 15000 rpm to remove water. The precipitate was collected and ultrasonically dispersed in an 8-fold volume of a 2 wt% AEO-9 aqueous solution. The mixture was stirred for 50 min, centrifuged to remove water, and then washed and dehydrated four times with deionized water. The washing solution was tested with a 0.5 wt% silver nitrate aqueous solution and found to be free of chloride ions, thus obtaining the washed product.

[0066] The washed product was placed in an alumina sagger, which was then placed in a kiln. The temperature was increased to 880°C at a rate of 4°C / min and calcined for 2 hours. After cooling and crushing, yttrium-stabilized zirconia powder was obtained.

[0067] Example 8

[0068] The difference between Example 8 and Example 7 is that in Example 7, the salt concentration was adjusted from 1.2 mol / L to 1.8 mol / L. The remaining steps remained unchanged.

[0069] Example 9

[0070] The difference between Example 9 and Example 7 is as follows: In Example 7, PVA 1792 is replaced with a combination of PVA 1792 and AEO-9 in a weight ratio of 1.5:1. AEO-9 is added after PVA 1792 has dissolved and cooled to room temperature. The remaining steps remain unchanged.

[0071] Example 10

[0072] The difference between Example 10 and Example 7 is that in Example 7, zirconium oxychloride was replaced with an equimolar amount of zirconium chloride. The remaining steps remained unchanged.

[0073] Performance Tests and Results

[0074] Ten powder samples from different locations were randomly selected from the yttrium-stabilized zirconia powders used in the examples and comparative examples. The zirconia content in the powders was tested according to the journal article "Determination of Zirconia Content in Yttrium-Stabilized Zirconia" (Rare Earth, 2015, 36(03), 105-108). The average and standard deviation of the ten data results were taken.

[0075] The content of monoclinic crystal form in yttrium-stabilized zirconia powder of the examples and comparative examples was tested using XRD.

[0076] The results are shown in Table 1 below.

[0077] Table 1

[0078]

[0079] As shown in Table 1, the yttrium-stabilized zirconia powder obtained by the preparation method of this application has a more uniform composition and a lower monoclinic phase content. Compared with Example 1 and Comparative Examples 2-5, the use of sodium hydroxide or sodium bicarbonate as a precipitant affects the uniformity of the composition of the yttrium-stabilized zirconia powder, and also results in a higher monoclinic phase content.

[0080] The yttrium-stabilized zirconia powders of Examples 1-3 and Comparative Examples 1-5 were mixed with α-alumina powder at a weight ratio of 2:8, and then 0.3% titanium dioxide was added as a sintering aid by weight of the yttrium-stabilized zirconia powder and α-alumina powder.

[0081] Yttrium-stabilized zirconia powder, α-alumina powder, and titanium dioxide were dispersed in water to prepare a 60 wt% dispersion. The dispersion was then ball-milled in a 65% full jar. The powder was ground until the D50 was no more than 5 μm, then sand-milled until the D97 was no more than 1 μm. The mixture was spray-dried, pressed into shape using a 35 MPa press, and then cold isostatically pressed at 250 MPa for 5 min to produce 20 cm × 10 cm × 1 mm sheet blanks. These blanks were then placed in a kiln and heated to 1500 °C at a rate of 5 °C / min, and sintered at 1500-1520 °C for 3 hours to obtain ZTA ceramics. 100 blanks of each powder were pressed into each blank, and the number of broken blanks after sintering was calculated.

[0082] The performance comparison of ZTA ceramics is shown in Table 2 below. Among them, Comparative Example 6 is without yttrium-stabilized zirconia powder, and Comparative Example 7 uses commercially available VK-R50Y3 yttrium-stabilized zirconia powder (yttrium oxide content is 3 mol%).

[0083] Table 2

[0084] Hardness / HV30 <![CDATA[Fracture toughness / MPa·m 1 / 2 > Number of damaged items Example 1 1440 7.3 0 Example 2 1400 7.7 0 Example 3 1470 7.5 0 Comparative Example 1 1240 4.4 15 Comparative Example 2 1180 4.9 11 Comparative Example 3 1250 5.5 8 Comparative Example 4 1320 6.1 3 Comparative Example 5 1210 5.1 10 Comparative Example 6 1030 3.7 21 Comparative Example 7 1480 7.5 0

[0085] As shown in Table 2, the yttrium-stabilized zirconia powder of this application can significantly improve the fracture toughness and reduce the sintering breakage rate when used to prepare ZTA ceramics, and its performance is close to that of commercially available 3 mol% yttrium-stabilized zirconia powder.

[0086] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A method for preparing yttrium-stabilized zirconia powder, characterized in that, The yttrium-stabilized zirconium oxide powder, with a 100% molar composition of 0.8-2.5% Y₂O₃·97.5-99.2% ZrO₂, is prepared by the following steps: S1. Dissolve water-soluble yttrium salt, water-soluble zirconium salt and dispersant in water to prepare solution A with a salt concentration of 1.0-2.5 mol / L; The dispersant in step S1 is selected from one or more of a polymeric dispersant and a first surfactant; wherein the polymeric dispersant is selected from polyethylene glycol-2000 and the first surfactant is selected from Pingpingjia O-20; In step S1, the weight ratio of the dispersant to the sum of the weights of the water-soluble yttrium salt and the water-soluble zirconium salt is 0.01-0.1:

1. S2. Simultaneously add solution A from step S1 and a 10-20% (w / w) ammonium bicarbonate aqueous solution to the reactor, controlling the dropping rate of the ammonium bicarbonate aqueous solution to maintain the pH of the reaction system at 8.5-9.

5. After the addition is complete, dehydrate the solution, disperse the collected precipitate in a second surfactant aqueous solution at 3-10 times its volume, stir for 30-60 minutes, dehydrate, and continue washing and dehydrating with water 2-8 times to obtain a water-washed product. Calcine the water-washed product at 800-900℃ for 1.5-3.5 hours, cool, and crush to obtain the yttrium-stabilized zirconium oxide powder. In step S2, the concentration of the second surfactant aqueous solution is 0.3-2 wt%; the second surfactant is selected from OP-10.

2. The method for preparing yttrium-stabilized zirconia powder according to claim 1, characterized in that, The water-soluble yttrium salt mentioned in step S1 is selected from one or a combination of yttrium chloride, yttrium nitrate and yttrium sulfate.

3. The method for preparing yttrium-stabilized zirconia powder according to claim 2, characterized in that, The water-soluble zirconium salt mentioned in step S1 is selected from one or more combinations of zirconium oxychloride, zirconium oxysulfate, zirconium nitrate, zirconium acetate, zirconium sulfate and zirconium chloride.

4. The method for preparing yttrium-stabilized zirconia powder according to claim 3, characterized in that, The dropping rate of solution A in step S2 is 1 ml - 50000 ml / min.

5. The method for preparing yttrium-stabilized zirconia powder according to claim 3, characterized in that, The heating rate in step S2 is 1-5℃ / min.

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