Preparation method of yttria-stabilized zirconia powder

Abstract

The application belongs to the technical field of powder preparation, and particularly discloses a preparation method of yttria-stabilized zirconia powder. The preparation method comprises the following steps: covering a block-shaped yttria-stabilized zirconia with a composite salt, placing the block-shaped yttria-stabilized zirconia in a tubular furnace with mixed gas, heating, and melting the composite salt into a composite molten salt; then removing the composite molten salt, cleaning and centrifuging to obtain the yttria-stabilized zirconia powder; wherein the composite salt comprises lithium chloride and potassium chloride; and the mixed gas comprises water vapor, oxygen and inert gas. The yttria-stabilized zirconia grain boundary is corroded and penetrated at low temperature by the composite molten salt, and the catalytic promotion of water vapor and oxygen accelerates the corrosion and decomposition of the block-shaped yttria-stabilized zirconia, so that the yttria-stabilized zirconia powder is obtained; the powder is composed of single grains, is regular in shape, clear in grain outline, and low in defects, and has excellent powder performance due to small average particle size and uniform particle size distribution.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of powder preparation, and particularly relates to a preparation method of yttria-stabilized zirconia powder. BACKGROUND

[0002] Yttria-stabilized zirconia has excellent high-temperature stability and low thermal conductivity, can withstand high-temperature corrosion and oxidation, is an important material for thermal barrier coatings of turbine blades of an aero-engine, and can greatly improve the working temperature and efficiency of the engine. Meanwhile, yttria-stabilized zirconia also has good biocompatibility and biological inertia, and is used as a material for dental implants in the dental field.

[0003] The preparation of yttria-stabilized zirconia generally adopts a sintering method, and specifically needs to go through complex process procedures such as ball milling, drying, screening, sintering, repeated ball milling, drying, screening, and high-temperature calcination treatment, so as to obtain yttria-stabilized zirconia powder. Meanwhile, the preparation of yttria-stabilized zirconia powder determines the high density and high strength of the bulk material (yttria-stabilized zirconia ceramic) prepared therefrom, and it is difficult to obtain the powder again through a physical crushing method. With the continuous expansion of the application range of yttria-stabilized zirconia powder, more and more bulk yttria-stabilized zirconia waste materials are accumulated in the process of preparing yttria-stabilized zirconia ceramic, and if not recycled again, it will not only bring great challenges to the environment, but also waste resources.

[0004] At present, the recovery of bulk yttria-stabilized zirconia ceramic generally adopts physical methods such as crushing and grinding to obtain yttria-stabilized zirconia powder material, and then the material is utilized. However, due to the characteristics of high hardness, high density and high wear resistance of the dense bulk yttria-stabilized zirconia ceramic prepared through high-temperature sintering, the yttria-stabilized zirconia powder prepared by adopting the traditional crushing and grinding method has uneven particle size and many shape defects, and impurities are easily mixed from the grinding medium; meanwhile, the grinding equipment has a large abrasion, and the noise pollution is serious. Therefore, it is crucial to develop an energy-saving and efficient recovery and preparation technology for bulk yttria-stabilized zirconia ceramic waste.

[0005] Therefore, it is urgent to develop a preparation method for preparing yttria-stabilized zirconia powder from bulk yttria-stabilized zirconia ceramic waste, which can ensure the yield of yttria-stabilized zirconia powder, reduce the fineness and shape defects of the powder, and improve the uniformity of the particle size distribution of the powder. SUMMARY

[0006] The present application aims to at least solve one of the technical problems existing in the prior art. To this end, the present application provides a preparation method of yttria-stabilized zirconia powder, which adopts specific molten salt and water vapor to perform low-temperature corrosion treatment on bulk yttria-stabilized zirconia, so that the prepared yttria-stabilized zirconia powder has small average particle size, uniform particle size distribution, clear particle profile, regular shape, few defects, and high yield.

[0007] To solve the above technical problems, the first aspect of the present application provides a preparation method of yttria-stabilized zirconia powder, comprising the following steps:

[0008] The composite salt is used to cover the bulk yttria-stabilized zirconia, and the bulk yttria-stabilized zirconia is placed in a tubular furnace through which a mixed gas passes, and then heated to make the composite salt melt into a composite molten salt; and then the composite molten salt is removed, and the yttria-stabilized zirconia powder is obtained after cleaning and centrifugation;

[0009] The composite salt comprises lithium chloride and potassium chloride;

[0010] The mixed gas comprises water vapor and oxygen.

[0011] Specifically, the present application uses bulk yttria-stabilized zirconia ceramic waste as the initial raw material, and uses specific composite molten salt containing LiCl-KCl to perform low-temperature corrosion treatment on the bulk yttria-stabilized zirconia in the presence of water vapor and oxygen, so that the yttria-stabilized zirconia powder with small average particle size, uniform particle size distribution, and clear particle profile can be obtained. The main principle is that the composite salt forms a molten state after heat treatment, and the molten salt corrodes and penetrates along the grain boundary of the bulk yttria-stabilized zirconia, and the catalytic promotion of water vapor and oxygen accelerates the corrosion and decomposition of the bulk yttria-stabilized zirconia, so that the yttria-stabilized zirconia powder with excellent performance is obtained.

[0012] Preferably, the mass ratio of lithium chloride to potassium chloride is 1:(0.5-2); further preferably, the mass ratio of lithium chloride to potassium chloride is 1:(1-2).

[0013] Preferably, the mass ratio of the composite salt to the bulk yttria-stabilized zirconia is (1-3):1; further preferably, the mass ratio of the composite salt to the bulk yttria-stabilized zirconia is (2-3):1.

[0014] Preferably, the mixed gas further comprises an inert gas, and the mixed gas comprises, by volume percentage, water vapor 5-30%, oxygen 5-30%, and inert gas 40-90%; further preferably, the mixed gas comprises, by volume percentage, water vapor 10-20%, oxygen 5-15%, and inert gas 70-80%. The inert gas acts as a carrier gas to transport the water vapor to the surface of the bulk yttria-stabilized zirconia, further promoting the corrosion effect of the composite molten salt.

[0015] Preferably, the inert gas comprises argon and / or nitrogen.

[0016] Preferably, the heating temperature is 450-900℃; further preferably, the heating temperature is 450-600℃.

[0017] Preferably, the heating time is 80-120 hours; further preferably, the heating time is 90-110 hours.

[0018] Preferably, the composite molten salt is removed by boiling water. That is, the product after molten salt corrosion is placed in boiling water for cooking to remove the residual composite molten salt.

[0019] Preferably, the cleaning is performed by boiling water cleaning 1-5 times; further preferably, the cleaning is performed by boiling water cleaning 2-3 times.

[0020] Preferably, the centrifugation is performed at a speed of 3000-5000 rpm for 5-10 minutes; further preferably, the centrifugation is performed at a speed of 4000-5000 rpm for 5-8 minutes.

[0021] The second aspect of the present application provides a yttria-stabilized zirconia powder, which is prepared by the above-mentioned method for preparing a yttria-stabilized zirconia powder, the average particle size of the yttria-stabilized zirconia powder is 4-8 μm, and the particle size range of the yttria-stabilized zirconia powder is D50 between 3-7 μm and D90 between 6-10 μm.

[0022] Specifically, the yttria-stabilized zirconia ceramic powder prepared by the molten salt corrosion method of the present application is composed of single grains, which not only has regular shape, clear grain outline, and few defects, but also has small average particle size, uniform particle size distribution, and excellent powder performance.

[0023] The third aspect of the present application provides the application of the above-mentioned yttria-stabilized zirconia powder in the field of aerospace or medical treatment.

[0024] The above technical solutions of the present application have at least the following technical effects or advantages compared with the prior art:

[0025] (1) The present application takes block yttria stabilized zirconia ceramic waste as initial raw material, uses molten salt corrosion method, adopts specific LiCl-KCl composite molten salt to corrode and penetrate the grain boundary of yttria stabilized zirconia at low temperature, and accelerates the corrosion and decomposition of block yttria stabilized zirconia by the catalytic promotion of water vapor and oxygen, so that the yttria stabilized zirconia powder with excellent performance is obtained.

[0026] (2) The yttria stabilized zirconia powder prepared by the present application is composed of single crystal grains, which not only has regular shape, clear grain outline and few defects, but also has small average particle size and uniform particle size distribution; the average particle size is 4-8 μm, the particle size range is D50 between 3-7 μm and D90 between 6-10 μm, and the powder has excellent performance, which opens up a new path for the recycling of block yttria stabilized zirconia ceramic waste and the preparation of yttria stabilized zirconia powder. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 The XRD pattern of the initial raw material of Example 1 and the prepared yttria stabilized zirconia powder;

[0028] Figure 2 The actual picture and SEM picture of the yttria stabilized zirconia powder prepared in Example 1;

[0029] Figure 3 The particle size distribution chart of the yttria stabilized zirconia powder prepared in Example 1;

[0030] Figure 4 The actual picture and SEM picture of the yttria stabilized zirconia powder prepared in Comparative Example 1;

[0031] Figure 5 The actual picture and SEM picture of the yttria stabilized zirconia powder prepared in Comparative Example 2;

[0032] Figure 6 The actual picture and SEM picture of the yttria stabilized zirconia powder prepared in Comparative Example 4. DETAILED DESCRIPTION

[0033] The present application will be described in detail below with reference to examples, so as to facilitate the understanding of the present application by those skilled in the art. It is necessary to point out here that the examples are only used to further illustrate the present application, and cannot be understood as limiting the protection scope of the present application. Non-essential improvements and adjustments of the present application made by those skilled in the art according to the above application content should still belong to the protection scope of the present application. At the same time, the raw materials mentioned below which are not described in detail are all commercially available products; the process steps or preparation methods which are not mentioned in detail are all known process steps or preparation methods to those skilled in the art.

[0034] Example 1

[0035] A preparation method of yttria-stabilized zirconia powder, comprising the following steps:

[0036] (1) Put 5g of square block-shaped yttria-stabilized zirconia ceramic waste material with a side length of 1cm into a crucible, and then cover 10g of composite salt (mixed by LiCl and KCl with a mass ratio of 1:1) on the surface of the block-shaped yttria-stabilized zirconia;

[0037] (2) Put the crucible with the composite salt and the block-shaped yttria-stabilized zirconia in step (1) into a tube furnace, heat to 500℃, so that the composite salt is melted into a composite molten salt; and keep the temperature for 100 hours, so that the composite molten salt fully corrodes and penetrates the block-shaped yttria-stabilized zirconia, and stop heating; while heating, water vapor, oxygen and argon are introduced; wherein the volume fractions of the water vapor, oxygen and argon are 15%, 10% and 75% respectively;

[0038] (3) Take out the crucible after the heating treatment in step (2), add boiling water for cooking to remove the composite molten salt; then wash the solution with boiling water for 3 times, and use a centrifuge to centrifuge at a speed of 5000rpm for 5 minutes, to obtain the yttria-stabilized zirconia ceramic powder of the present embodiment.

[0039] The XRD pattern of the initial raw material (block-shaped yttria-stabilized zirconia ceramic waste material) used in the present embodiment and the yttria-stabilized zirconia powder prepared is shown in Figure 1 Figure 1 , wherein the abscissa 2θ represents the diffraction angle, and the ordinate Intensity represents the diffraction peak intensity. It can be seen from Figure 1 that the main crystal phase of the yttria-stabilized zirconia powder after molten salt corrosion is the same as that of the initial raw material (original yttria-stabilized zirconia), which is yttria-stabilized zirconia, and also contains a certain amount of zirconia. This indicates that the yttria-stabilized zirconia ceramic powder prepared by the present application does not introduce other impurity components.

[0040] Figure 2 The actual object diagram and the SEM diagram of the yttria-stabilized zirconia powder prepared in Example 1 are shown in Figure 2 , wherein the (a) diagram and the (b) diagram in Figure 2 are SEM diagrams under different magnifications. It can be seen from that the yttria-stabilized zirconia powder prepared by the present application is composed of single grains, the shape of the particles is regular, the outline is clear, the defects are few, and the particle size distribution is relatively uniform.

[0041] Figure 3 The particle size distribution diagram of the yttria-stabilized zirconia powder prepared in Example 1 is shown in Figure 3In the figure, the horizontal axis Grain Dimension represents the grain size, the left vertical axis Enumerate represents the enumeration number, and the right vertical axis Cumulative Frequency represents the cumulative frequency. As shown in the figure, the grain size of the yttria-stabilized zirconia powder prepared in Example 1 is 6.01 ± 2.13 μm, the particle size range is D50 of 5.15 μm and D90 of 8.39 μm. Figure 3 It can be seen that the average grain size of the yttria-stabilized zirconia powder prepared in Example 1 is 6.01 ± 2.13 μm, the particle size range is D50 of 5.15 μm and D90 of 8.39 μm.

[0042] The yield of the yttria-stabilized zirconia powder prepared in this example is 94%. The yield of the powder is the weight percentage of the prepared yttria-stabilized zirconia powder to the initial bulk yttria-stabilized zirconia ceramic waste.

[0043] Example 2

[0044] A method for preparing a yttria-stabilized zirconia powder, comprising the following steps:

[0045] (1) 5 g of square bulk yttria-stabilized zirconia ceramic waste with a side length of 1 cm is loaded into a crucible, and then 10 g of a composite salt (mixed by LiCl and KCl with a mass ratio of 1:1) is covered on the surface of the bulk yttria-stabilized zirconia;

[0046] (2) The crucible loaded with the composite salt and the bulk yttria-stabilized zirconia in step (1) is placed in a tube furnace, heated to 500°C, and the composite salt is melted into a composite molten salt; and the composite molten salt is allowed to sufficiently corrode and penetrate the bulk yttria-stabilized zirconia at this temperature for 100 hours, and the heating is stopped; water vapor, oxygen and argon are introduced at the same time during heating; wherein the volume fractions of water vapor, oxygen and argon are 30%, 10% and 60%, respectively;

[0047] (3) The crucible after the heating treatment in step (2) is taken out, boiled in boiling water to remove the composite molten salt; then the solution is washed with boiling water for 3 times, and then centrifuged at a speed of 5000 rpm for 5 minutes by a centrifuge to obtain the yttria-stabilized zirconia ceramic powder of this example.

[0048] The XRD pattern, SEM pattern and particle size distribution pattern of the yttria-stabilized zirconia powder prepared in Example 2 are similar to those of the yttria-stabilized zirconia powder prepared in Example 1.

[0049] Example 3

[0050] A method for preparing a yttria-stabilized zirconia powder, comprising the following steps:

[0051] (1) Put 5 g of square block-shaped yttrium oxide stabilized zirconia ceramic waste with a side length of 1 cm into a crucible, and then cover the surface of the block-shaped yttrium oxide stabilized zirconia with 15 g of composite salt (mixed by mass ratio of 2:1 of LiCl and KCl);

[0052] (2) Put the crucible with the composite salt and the block-shaped yttrium oxide stabilized zirconia of step (1) into a tube furnace, heat to 600℃, and melt the composite salt into a composite molten salt; and keep the temperature for 100 hours to allow the composite molten salt to fully erode and penetrate the block-shaped yttrium oxide stabilized zirconia, stop heating; while heating, water vapor, oxygen and argon are introduced; the volume fractions of water vapor, oxygen and argon are 15%, 10% and 75% respectively;

[0053] (3) Take out the crucible after heating treatment of step (2), add boiling water for cooking to remove the composite molten salt; then wash the solution with boiling water for 3 times, and use a centrifuge at a speed of 5000 rpm for 5 minutes to obtain the yttrium oxide stabilized zirconia ceramic powder of the example.

[0054] The XRD pattern, SEM pattern and particle size distribution pattern of the yttrium oxide stabilized zirconia powder prepared in Example 3 are similar to those of the yttrium oxide stabilized zirconia powder prepared in Example 1.

[0055] Comparative Example 1

[0056] A preparation method of yttrium oxide stabilized zirconia, comprising the following steps:

[0057] (1) Put 5 g of square block-shaped yttrium oxide stabilized zirconia ceramic waste with a side length of 1 cm into a crucible, and then cover the surface of the block-shaped yttrium oxide stabilized zirconia with 10 g of composite salt (mixed by mass ratio of 1:1 of LiCl and CsCl);

[0058] (2) Put the crucible with the composite salt and the block-shaped yttrium oxide stabilized zirconia of step (1) into a tube furnace, heat to 650℃, and melt the composite salt into a composite molten salt; and keep the temperature for 100 hours to allow the composite molten salt to fully erode and penetrate the block-shaped yttrium oxide stabilized zirconia, stop heating; while heating, water vapor, oxygen and argon are introduced; the volume fractions of water vapor, oxygen and argon are 15%, 30% and 55% respectively;

[0059] (3) Take out the crucible after heating treatment of step (2), add boiling water for cooking to remove the composite molten salt; then wash the solution with boiling water for 3 times, and use a centrifuge at a speed of 5000 rpm for 5 minutes, the product obtained is still block-shaped, and the powder cannot be obtained.

[0060] The actual product pattern and SEM pattern of the yttrium oxide stabilized zirconia powder prepared in Comparative Example 1 are as follows:Figure 4 As shown in Figure 4 It can be seen that using LiCl and CsCl as composite molten salt cannot corrode the bulk yttria-stabilized zirconia ceramic into uniform powder.

[0061] Comparative Example 2

[0062] A preparation method of yttria-stabilized zirconia, comprising the following steps:

[0063] (1) 5g of square bulk yttria-stabilized zirconia ceramic waste with a side length of 1cm is loaded into a crucible, and then 10g of composite salt (mixed by mass ratio of 1:1 of NaCl and KCl) is covered on the surface of the bulk yttria-stabilized zirconia;

[0064] (2) The crucible loaded with the composite salt and the bulk yttria-stabilized zirconia in step (1) is placed in a tube furnace, heated to 800℃, and the composite salt is melted into a composite molten salt; and the composite molten salt is allowed to fully corrode and penetrate the bulk yttria-stabilized zirconia at this temperature for 100 hours, and the heating is stopped; water vapor, oxygen and argon are introduced at the same time while heating; wherein: the volume fractions of water vapor, oxygen and argon are 5%, 10% and 85% respectively;

[0065] (3) The crucible after heating treatment in step (2) is taken out, boiled water is added for cooking to remove the composite molten salt; then the solution is washed with boiling water for 3 times, and then centrifuged with a centrifuge at a speed of 5000rpm for 5 minutes, and the product obtained is still in bulk, and powder cannot be obtained.

[0066] The actual product graph and SEM graph of the yttria-stabilized zirconia powder prepared in Comparative Example 2 are as shown in Figure 5 As shown in Figure 5 It can be seen that using NaCl and KCl as composite molten salt cannot corrode the bulk yttria-stabilized zirconia ceramic into uniform powder.

[0067] Comparative Example 3

[0068] A preparation method of yttria-stabilized zirconia, comprising the following steps:

[0069] (1) 5g of square bulk yttria-stabilized zirconia ceramic waste with a side length of 1cm is loaded into a crucible, and then 10g of composite salt (mixed by mass ratio of 1:1 of LiCl and KCl) is covered on the surface of the bulk yttria-stabilized zirconia;

[0070] (2) Put the crucible with the composite salt and the blocky yttria stabilized zirconia of step (1) into a tube furnace, heat to 500℃, and melt the composite salt into a composite molten salt; and keep the temperature for 100 hours to make the composite molten salt erode and penetrate the blocky yttria stabilized zirconia sufficiently, stop heating; while heating, oxygen and argon are introduced; the volume fractions of the oxygen and argon are 25% and 75% respectively;

[0071] (3) Take out the crucible after the heating treatment of step (2), add boiling water to cook and remove the composite molten salt; then wash the solution with boiling water for 3 times, and use a centrifuge to centrifuge at a speed of 5000 rpm for 5 minutes, most of the prepared product is blocky, and powder cannot be obtained.

[0072] Comparative Example 4

[0073] A method for preparing yttria stabilized zirconia powder, comprising the following steps:

[0074] First, knock the 5g square blocky yttria stabilized zirconia ceramic waste with the size of length x width = 1cm x 1cm into granular, then add a certain amount of alcohol to a planetary ball mill for wet grinding for 24 hours, then dry the ground slurry at 80℃ for 10 hours, and then separate the grinding balls from the powder with a screen, to obtain the yttria stabilized zirconia ceramic powder of the present comparative example.

[0075] The actual product graph and SEM graph of the yttria stabilized zirconia powder prepared in Comparative Example 4 are shown in Figure 6 As can be seen from Figure 6 , the yttria stabilized zirconia ceramic powder prepared by the traditional grinding method has a large amount of blocky debris and small debris, the particle size is not uniform, the debris is an aggregate of multiple yttria stabilized zirconia grains, the particle size is 1-2mm, and single grain cannot be obtained.

[0076] For those skilled in the art to which the present application belongs, without departing from the concept of the present application, a number of simple deductions or substitutions can be made without having to have creative labor. Therefore, the simple improvements made by those skilled in the art to the present application according to the disclosure of the present application should be within the protection scope of the present application. The above examples are preferred embodiments of the present application, and any similar processes and equivalent changes made should be within the protection scope of the present application.

Claims

1. A method for producing a yttria-stabilized zirconia powder, characterized by comprising the steps of: The method comprises the following steps: ​ covering the blocky yttrium oxide stabilized zirconium oxide with a composite salt, and placing the blocky yttrium oxide stabilized zirconium oxide in a tube furnace with mixed gas to heat and melt the composite salt into a composite molten salt; then removing the composite molten salt, and washing and centrifuging to obtain the yttrium oxide stabilized zirconium oxide powder; the composite salt comprises lithium chloride and potassium chloride; the mixed gas comprises water vapor and oxygen.

2. The method of claim 1, wherein the yttria-stabilized zirconia powder is prepared by the steps of: the mass ratio of the lithium chloride and the potassium chloride is 1: (0.5-2). ​ 3. The method for preparing yttrium oxide-stabilized zirconia powder according to claim 1, characterized in that, the mass ratio of the composite salt to the blocky yttrium oxide stabilized zirconium oxide is (1-3):

1.

4. The method for preparing yttrium oxide-stabilized zirconia powder according to claim 1, characterized in that, the mixed gas further comprises an inert gas, and the mixed gas comprises, in terms of volume percentage, 5-30% of water vapor, 5-30% of oxygen, and 40-90% of the inert gas.

5. The method for preparing yttrium oxide-stabilized zirconia powder according to claim 4, characterized in that, the inert gas comprises argon and / or nitrogen.

6. The method for preparing yttrium oxide-stabilized zirconia powder according to claim 1, characterized in that, the heating temperature is 450-900℃; and / or, the heating time is 80-120 hours.

7. The method for preparing yttrium oxide-stabilized zirconia powder according to claim 1, characterized in that, the composite molten salt is removed by boiling water.

8. The method for preparing yttrium oxide-stabilized zirconia powder according to claim 1, characterized in that, the washing is performed by boiling water for 1-5 times; and / or, the centrifugation is performed at a speed of 3000-5000 rpm for 5-10 minutes.

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