A preparation method for producing yttrium oxide spraying powder by hydrothermal method

Abstract

This application relates to the technical field of ceramic materials, and particularly to a preparation method for producing yttrium oxide spraying powder by hydrothermal method, which comprises the following steps: preparing slurry by adding water to yttrium hydroxide - hydrothermal treatment - calcination - grinding - modification - granulation - degumming - screening - impurity removal; the preparation method for producing yttrium oxide spraying powder by hydrothermal method in this application enables yttrium hydroxide to form an effective crystallization mechanism through specific hydrothermal treatment and specific surface modification, so that the yttrium oxide slurry has good suspension property, the compacted density of the powder after granulation is large, the strength is high, it is not easy to break, and the use effect is good; the spraying powder with good crystal lattice has a white coating appearance under the thermal spraying process, high bonding strength with the substrate, and low cost.

Description

Technical Field

[0001] The present application relates to the technical field of semiconductor-specific ceramic materials, and in particular to a preparation method for yttrium oxide spray powder produced by a hydrothermal method. Background Art

[0002] In the new era, yttrium oxide and its composites are not only used in functional ceramic inductors, automotive sensors, fiber optic ferrules, fingerprint readers, bioceramics, and hydrogen-powered solid fuel cells, but are also widely used in structural ceramics such as mobile phone backplanes, artificial gemstones, ceramic bearings, ceramic pipes and valves, and smart wearables. They can also be used as the substrate for tower filter valves in photolithography machine etching chambers. Yttrium oxide-zirconia composites are the best-performing thermal barrier coatings for aircraft engine blades, and yttrium copper barium oxide, with its superconducting zero flux at the critical temperature, is widely used in the manufacturing of maglev train substrates.

[0003] Because yttrium atoms exhibit excellent thermal radiation passivation in high-fluorine environments, preventing fluorine from corroding non-yttrium substrates, it is the ideal choice for protective coatings on all substrates, including semiconductor etching chambers and solar cell substrates and graphene surfaces. Conventionally produced yttrium oxide spray powders for thermal spray coatings have poor substrate adhesion and an abnormally reddish color, making them inadequate for corrosion protection on substrate surfaces in photolithography chambers.

[0004] For example, in the "Hydrothermal Preparation Method of Yttrium Oxide Nanopowder" disclosed in application number 202010266304.8, claim 6 states that the hydrothermal temperature is 200-280°C and the reaction time is 1-48 hours. As can be seen from the examples of the application, the yttrium oxide in the application is obtained from yttrium hydroxide by a hydrothermal reaction at 280°C for 1 hour, or from yttrium carbonate by a hydrothermal reaction at 240°C for 24 hours, and the process ends here.

[0005] The purpose of hydrothermal treatment is to modify the crystal lattice, regularizing its atomic lattice arrangement. In sensitive temperature regions, its nucleus modification and growth time exhibit interval selectivity or correspondence between previous and subsequent processes. The patent application published with application number 202010266304.8 ultimately yields a mixture of yttrium oxide, which remains agglomerate. Materials emerging from water or steam contain adsorbed water and lack fluidity. Furthermore, the application lacks surface modification or granulation steps. Based on physical and chemical indicators, this does not meet the primary requirement for yttrium oxide powder used in plasma spraying processes: uniform movement by gas.

[0006] Another example is the patent with the authorization announcement number CN 103058277 B and the name of "A Supercritical Hydrothermal Synthesis Method for Nano-Zirconia Powder". In the embodiments of this patent, it is stated that zirconium oxalate is formed by precipitating zirconium salt with oxalic acid, dried at 400 °C for 40 minutes, ground for 7 hours, and hydrothermally treated at 420 °C for 30 s. The original intention of the process of this application is to discard the problems of low crystallinity of directly calcined zirconia and long low-temperature hydrothermal time that cannot avoid grain growth. The above arguments are clearly stated in the background art

[0003] of this specification. The technical connotation of the inventor acknowledges that the purpose of hydrothermal treatment is to purify the crystal lattice of zirconia - that is, to consider the degree of crystallization; secondly, it proves that the hydrothermal method has good material dispersibility; thirdly, the powder obtained by the hydrothermal method has high activity, which is a common advantage of the hydrothermal process. Senior technicians who develop hydrothermal processes all know that in the hydrothermal process, the agglomeration of salt bridges, liquid bridges, and oxygen bridges in the process should be deliberately avoided, and the synergistic effect of these three points is very obvious. Otherwise, no matter how high the degree of crystallization is, the degree of agglomeration is also high, and it is still not a high-quality powder material.

[0007] The hydrothermal process is sensitive and time-effective. It is related to the selected hydrothermal temperature and holding time, and is related to the preparation of the precursor. Not all hydrothermal temperatures can effectively improve the quality of oxide powders, and there is no literature available on hydrothermal temperature and holding time, nor a definite theoretical basis for reference.

[0008] Regarding the patent with the authorization announcement number CN 103058277 B, the applicant believes that: 1. Grain growth is not only related to the hydrothermal holding time but also to the hydrothermal temperature. The latter was not described by the inventor because it is contrary to the process principle of this invention. 2. For zirconium oxalate at 400°C for 40 minutes, it is difficult to be certain from a kinetic perspective that zirconium oxalate is completely decomposed. That is, the material composition of this section should be a mixture of zirconium oxalate and zirconia. Hydrothermal treatment of the already formed zirconia at 420°C, whether its energy can change the lattice arrangement of zirconium and oxygen atoms in the formed zirconia lattice, unseal the internal pores in the crystal, and expel the internal impurities in the crystal, and with only 30 seconds, it still lacks thermodynamic principles. 3. The grinding time is as long as 7 hours, and the frictional loss between the grinding media causes relatively large pollution to the original product. Even if zirconia grinding media are used, their physical and chemical indexes are completely different. 4. High-temperature hydrothermal treatment itself will cause grain growth, and zirconium oxalate will also decompose at this temperature, and the released carbon dioxide increases the pressure in the reaction vessel, leading to an increase in unsafe factors. 5. The invention content

[0020] states that the product can be used for coatings, and all coatings are composite zirconia, while this invention is monoclinic zirconia. (Confirmed from the process formula and the end of the embodiment

[0038] ) Stress changes caused by martensite transformation will lead to coating peeling. Although this invention is novel, the process description is contrary to the crystal growth principle, especially for semiconductor materials used in ceramics or coatings. The applications of Shandong Guoci and Suzhou Aimeike are the same in that they do not fully trace the process of an oxide powder. They belong to partial processes and cannot be used in the actual fields they described, and they do not have usability. From the extremely high specific surface area in the Shandong Guoci invention and the crystal phase drawing in the abstract, it can be seen that this zirconia has a relatively high water content. The main crystal phase diffraction peak energy of XRD is low, and the diffraction marginal lines of each crystal plane are rough, indicating that the lattice parameter of this zirconia is relatively low and its development is incomplete, which goes against the original intention of the hydrothermal process.

[0009] The application number CN114014651A discloses a method for producing nano-composite zirconia powder by hydrothermal method. The specific technology of this application is the hydrothermal method, and the product is composite zirconia powder. For wet production of oxide products using soluble salts as raw materials, ammonification metathesis is generally preferred, and then the precipitate is washed to remove anions, followed by hydrothermal treatment of the intermediate, and then processes such as calcination, grinding, surface modification, and atomization granulation. Among them, the core technologies are the production of the hydrothermal precursor, the determination of the hydrothermal temperature and holding time, the calcination temperature, the grinding particle size, and the type and addition amount of the organic polymer selected for surface modification. Others such as the filter cloth for filtration, the stirring speed, the amount of washing water, the number of washing times, the head or flow rate of the transfer pump, etc. can be known without infinite and long-term experiments and are not sufficient as hidden technologies obtained through creative labor, but only to meet the improvement of the patent application content.

[0010] An oxide powder, especially a high-end powder with a hydrothermal process section. It is not the case that the higher or lower the hydrothermal temperature is, or the longer or shorter the holding time is, the better. The same applies to the calcination temperature and grinding particle size. They are interval values obtained through countless experiments, not directional values. Therefore, for the same hydrothermal process, different products have different hydrothermal parameters, different calcination temperatures, grinding particle sizes, and surface modification methods. There is no easily successful and interconnected relationship among them. The improvement of quality must go through countless experiments to obtain the combination of optimized parameters for each process respectively. That is, those who can produce high-quality alumina or zirconia powders by the hydrothermal method may not necessarily be able to produce high-quality yttrium oxide or yttrium aluminate powders by the hydrothermal method, and vice versa, because their raw materials are different, process parameters are different, application fields are different, and physical and chemical indexes are different. Therefore, the core process parameters must be very different.

[0011] The zirconia produced by the hydrothermal method with the application number CN114014651A for dental use is a composite. First of all, the appearance of the teeth is evaluated. It should have a texture like jade. At the same time, it emphasizes good strength, hardness, crystal phase attenuation, and biocompatibility. The yttrium oxide spraying powder produced by the hydrothermal method is mainly used for semiconductor fluorine corrosion resistance, considering the bonding strength with the substrate, and requires the coating to be naturally white without lattice mutation.

[0012] In practical applications, different products have different application fields, different process parameters with hydrothermal as the core, different calcination temperatures, grinding particle sizes, and surface modifications. The mechanical indexes and functional parameters evaluated by customers at the downstream are also different. There is no comparability among them.

[0013] Therefore, studying how to improve the bonding strength and natural chromaticity between the yttrium oxide spraying powder and the substrate, and improving the anti-corrosion ability and service life of the substrate surface is of great significance in the current semiconductor ceramics and solar energy fields. Summary of the Invention

[0014] In order to improve the bonding strength and natural chromaticity between the yttrium oxide spraying powder and the substrate, and improve the anti-corrosion ability of the semiconductor product surface, the present application provides a preparation method for producing yttrium oxide spraying powder by the hydrothermal method.

[0015] The present application provides a preparation method for producing yttrium oxide spraying powder by the hydrothermal method, including the following steps:

[0016] S1, Add water to wet-produced yttrium hydroxide containing 23 - 27 wt% yttrium oxide at a ratio of 1:1.5, stir to make a slurry, adjust the pH value of the slurry to 9.0 - 9.5 with ammonia water, perform hydrothermal treatment, and filter press to obtain a hydrothermally treated filter cake.

[0017] S2, After low-temperature drying of the hydrothermally treated filter cake at 300 - 400 °C for 3 - 4 hours, then calcine it in a high-temperature rotary kiln at 1020 - 1030 °C for 2 - 3 h, and cool it to room temperature to obtain a calcined material.

[0018] S3, Add water to the calcined material at a mass ratio of 1:(0.8 - 1.2), use zirconia balls with a diameter of 0.3 - 0.4 mm in a ball mill to grind it to 0.3 - 0.4 μm, add a dispersant and an antifoaming agent, and after the grinding is completed, add a coagulation inhibitor and a binder, and mix them evenly to obtain a surface-modified slurry;

[0019] S4, Pump the surface-modified slurry into the pre-tower storage bucket, set the inlet temperature at 240°C - 260°C, adjust the flow rate of the diaphragm pump to control the outlet temperature of the granulation tower at 95 - 100°C, and sieve the collected granulated powder to collect the undersize material;

[0020] S5, Keep the collected undersize material at 600 - 800°C for 2 - 4 h to remove the glue, cool it to room temperature to obtain yttrium oxide spraying powder, and remove impurities from the spraying powder with a magnetic field strength greater than 18000 Gs until the content of magnetic foreign matters in the powder is less than 10 ppm to obtain the finished yttrium oxide spraying powder.

[0021] By adopting the above technical solution, in this application, by controlling the hydrothermal temperature and the calcination temperature, the implementation of the front and back processes is matched, so that the finished yttrium oxide spraying powder with uniform particle size and excellent lattice quality can be obtained.

[0022] For powder grinding, the determination of particle size is considered first. It is not that the larger the better, nor the smaller the better. It is based on the evaluation value of the effect after the final product is used. There is no clear theory or literature for reference, including the selected grinding medium material and size; the particle sizes of powder grinding in different processes are different. For the same product name, different application fields result in different grinding particle sizes; for the same product, the same application field, and the same particle size, different surface modifications lead to different grinding efficiencies, different slurry suspension stability times, different powder sphericity and strength, and different compaction shrinkage ratios. For example, for plasma coating, its uniformity, adhesion to the substrate, and deposition efficiency are also different.

[0023] In this process, by controlling the powder dispersion factors, in the grinding process, adding 2 - 3% of the daily production amount of dispersant D-134 can easily disperse the calcined material that forms false agglomeration into monodisperse fine particles. Adding 0.02% of the antifoaming agent plays a synergistic effect with the dispersant to increase the grinding efficiency; due to the hydrothermal process, the specific gravity of yttrium oxide is larger than that of the traditional oxalic acid process, and the aqueous slurry is prone to sink. Selectively adding 2% of secondary alcohol AEO-9 can extend the slurry suspension time from half an hour to more than 12 hours; selectively adding 6 - 7% of the binder with the model number AP-30 produced by Nippon Kasei Co., Ltd., the compaction density of the granulated powder reaches 2.35 g / cm 3 , ,

[0024] .

[0024] In summary, the yttrium oxide spraying powder produced by the hydrothermal method in this application not only has a high bonding strength with the substrate, and the appearance of the thermal spraying coating is naturally white, but also greatly reduces the production cost.

[0025] Preferably, in the step S1, the wet-process yttrium hydroxide is an intermediate prepared from high-purity yttrium chloride or yttrium nitrate through an ammonia reaction, and it is required that: the yttrium oxide content is 23-27 wt%, the water content is greater than 74.9%, the chloride ion or nitrate radical is lower than 80 ppm, the total amount of non-yttrium rare earths is lower than 10 ppm, and the ratios of the contents of impurity elements such as iron, silicon, titanium, and aluminum calculated as oxides to yttrium hydroxide converted into yttrium oxide are all less than 5 ppm.

[0026] Preferably, in the step S1, the hydrothermal treatment method is to raise the yttrium hydroxide slurry to 128-132 °C at a rate of 2-3 °C / min for dynamic hydrothermal treatment, the stirring speed is 80 rpm, after holding for 8-12 h, it is cooled to room temperature at a rate of 2-4 °C / min and then subjected to pressure filtration and dehydration treatment.

[0027] By adopting the above technical solution, it is avoided that the nucleation rate of yttrium oxalate in the traditional process is much greater than the crystal growth rate, so that yttrium oxide forms semi-automorphic or allotriomorphic crystals. During the thermal spraying process, the defective yttrium oxide has higher energy and is extremely easy to gain or lose electrons with the outside world, causing the lattice of yttrium oxide to distort, generating color spots, making the coating appear light red, and reducing the lattice strength of the coating particles. At the same time, since the molar mass of oxalic acid is 2.6 times higher than that of liquid ammonia with an equivalent valence number, and its unit market price is more than twice that of ammonia, therefore, the auxiliary material cost of the traditional oxalic acid precipitation method is more than 5 times higher than that of the ammonia chemical process in the hydrothermal method.

[0028] The yttrium hydroxide in the natural state under the wet process is easy to undergo hydrothermal reaction, enabling yttrium hydroxide to have the flexible conditions for effective crystallization. In the hydrothermal method process, the preparation of the precursor, the setting of the hydrothermal temperature and the holding time, none of these have predetermined parameters as a guiding direction. Most of the R & D failures in many zirconium industry factories are due to being confused by the combined factors of the precursor, hydrothermal temperature, holding time, and the subsequent process sections. Because the profit of zirconia dental powder is relatively high, it has induced zirconium industry R & D personnel to keep coming and going without stopping, including zirconium powder listed companies, and so far no one has succeeded in making dental zirconia powder.

[0029] Ceramic powder is not a chemical, and it is not that the higher the purity, the better. The direction of the process is extremely clear. However, for the hydrothermal treatment parameters, there is no literature or theoretical data for guidance, and it all depends on the experience of R & D personnel and learning from countless failed experiments to grope. No one can infer through chemical engineering principle calculations how much the hydrothermal temperature of hydrothermal zirconia is, how long the holding time is, and how to design and plan the subsequent series of calcination, grinding, and surface modification to make zirconia dental powder that meets the performance of dentures. No R & D institution or practitioner can surely predict the parameter setting of the entire process, and the same is true for yttrium oxide powder by the hydrothermal method.

[0030] Preferably, in S3, when the mass ratio of the calcined material, dispersant, defoamer, coagulation inhibitor, and binder is based on 100 for the calcined material, the sequence is 100:(2 - 3); 100:0.02; 100:2; 100:(6 - 7); the dispersant is the dispersant with the model D - 134 produced by Nakakyo Yushi Co., Ltd. of Japan; the binder is the binder with the model AP - 30 produced by Takachiho Chemical Co., Ltd. of Japan; the defoamer is the defoamer with the model M produced by Takachiho Chemical Co., Ltd. of Japan.

[0031] By adopting the above technical solution, this process selects specific dispersants, defoamers, coagulation inhibitors, and binders, and conducts specific slurry treatment for the hydrothermal process, making it easy for yttrium oxide particles to disperse. The sphericity and uniformity of the yttrium oxide granulated powder are both good, and the ideal compaction density reflects that the strength of the granulated powder is moderate and perfect; while for the granulated powder formed by the traditional process, the proportion of irregular miscellaneous particles such as hollow false balls is relatively large, and the sphericity is poor.

[0032] Preferably, in S5, the spray drying includes the following process: the drying of the ground slurry is carried out in a granulation tower. Set the inlet temperature of the granulation tower to 240 - 260 °C, control the outlet temperature at 90 - 105 °C with the feed flow rate, the rotation frequency of the atomization disk is 40 HZ, carry out spray granulation, and the granulated powder is sieved through a 80 - 120 - mesh sieve, and the undersize is collected.

[0033] This section combines the previous processes, and the obtained granulated powder has controllable particle size, moderate strength, and good sphericity.

[0034] In summary, this application includes at least one of the following beneficial technical effects:

[0035] 1. By adopting a specific yttrium hydroxide raw material, conducting experiments to select the hydrothermal temperature and holding time, the yttrium oxide produced in this application has a small - size effect. It is extremely easy to instantaneously melt and adhere to the surface of the substrate, forming a uniform and strong bonding force. Compared with the yttrium oxide produced by the existing oxalic acid precipitation method, the coating is not red - flushed, naturally white without abnormal color, and the production cost is reduced year - on - year.

[0036] 2. This application selects specific surfactants, making it easy to grind and disperse the calcined material yttrium oxide. The obtained granulated powder has high sphericity, good fluidity, and controllable particle size, and plays a synergistic effect on the strength of the thermal spraying coating. They complement each other. Without well - modified granulated powder, there will be no high - strength coating.

[0037] 3. The preparation method adopted in this application does not involve high temperature and high pressure, does not use expensive production equipment, the raw materials are general and easy to purchase, oxalic acid with a large amount and high price is not added during the production process, the cost of auxiliary materials is greatly reduced, and the performance fully meets the usage requirements of the semiconductor and solar energy industries. Description of the Drawings

[0038] Figure 1 It is the SEM image of the yttrium oxide coating in Example 3.

[0039] Figure 2 It is the morphology image of the yttrium oxide granulated powder under the microscope in Example 3.

[0040] Figure 3 It is the appearance image of the coating after thermal spraying of the yttrium oxide spraying powder in Example 3.

[0041] Figure 4 It is the appearance image of the coating after thermal spraying of the yttrium oxide spraying powder in Comparative Example 2.

[0042] Figure 5 It is the particle size distribution of the spraying powder tested by laser particle size analyzer in Example 3.

[0043] Figure 6 It is the XRD pattern of the yttrium oxide spraying powder in Example 3.

[0044] Figure 7 It is the morphology image of the yttrium oxide granulated powder under the microscope in Comparative Example 4.

[0045] The present application will be further described in detail below with reference to the drawings and examples.

[0046] All water used in the preparation method is deionized water; unless otherwise specified, all material ratios are in mass ratio; 25% refers to the mass ratio of yttrium hydroxide converted to yttrium oxide; all particle sizes are average particle sizes, specifically referring to the particle size of S3 slurry and the particle size of S5 spraying powder; for S5 degumming, the "glue" refers to all organic substances added during grinding and pulping, which is commonly called "glue" in the industry; the residue after sieving of the granulated powder is returned to the sand mill for re-grinding after degumming to improve the recovery rate, which is hereby supplemented and explained. Examples

[0047] Example 1

[0048] In this example, a preparation method for producing yttrium oxide spraying powder by hydrothermal method is disclosed, and the specific process is as follows:

[0049] Weigh 500 Kg of yttrium hydroxide containing 23% yttrium oxide in the wet process and put it into a hydrothermal autoclave containing 500 Kg of pure water. Stir at a speed of 600 rpm for 1 h, adjust the pH value of the slurry to 9.0 with ammonia water, adjust the stirring speed to 80 rpm, heat up at a rate of 2 °C / min to 128 °C for hydrothermal treatment, keep it for 12 h, cool down to room temperature at a rate of 2 °C / min, filter press to obtain a hydrothermal filter cake. Bake the filter cake at 300 °C for 4 hours to dry it, and then calcine it in a rotary kiln at 1020 °C for 3 h to obtain 115 kg of calcined material. Add 92 kg of water, 2.3 kg of D-134 dispersant produced by Nakakyo Yushi Co., Ltd. in Japan, and 23 g of M-type defoamer produced by Takachimia Co., Ltd. in Japan. Use zirconia balls with a diameter of 0.3 mm in a ball mill and grind it to 0.3 μm at a speed of 400 rpm. Pump it into the storage tank in front of the tower with a diaphragm pump at a flow rate of 20 L / min. Add 2.3 kg of secondary alcohol AEO-9 coagulation inhibitor and 6.9 kg of AP-30 binder produced by Takachimia Co., Ltd. in Japan. Stir at a speed of 80 rpm for 1 h, granulate, set the inlet temperature at 240 °C, adjust the flow rate of the diaphragm pump to control the outlet temperature of the granulation tower at 95 °C, and the rotation frequency of the atomization disk is 40 HZ. Pass the collected granulated powder through an 80-mesh sieve, collect the material under the sieve. Subject the granulated powder under the sieve to degumming at 600 °C for 4 h, and cool it to room temperature to obtain yttrium oxide spraying powder. Remove impurities from the spraying powder until the content of magnetic foreign matters in the powder is less than 10 ppm with a magnetic field strength greater than 18000 Gs to obtain the finished yttrium oxide spraying powder.

[0050] Example 2

[0051] This example discloses a preparation method for producing yttrium oxide spraying powder by the hydrothermal method. The specific process is as follows:

[0052] Weigh 600 Kg of yttrium hydroxide containing 27% yttrium oxide by wet method and put it into a hydrothermal autoclave containing 900 Kg of pure water. Stir at a speed of 600 rpm for 1 h, adjust the pH value of the slurry to 9.5 with ammonia water, adjust the stirring speed to 80 rpm, heat, and increase the temperature at a rate of 3 °C / min to 132 °C for hydrothermal treatment for 8 h. Then cool to room temperature at a rate of 4 °C / min, and filter press to obtain a hydrothermal filter cake. Bake the filter cake at 400 °C for 3 hours to dry it, and then calcine it at 1030 °C for 2 h in a rotary kiln to obtain 162 kg of calcined material. Add 194.4 kg of water, 4.86 kg of D-134 dispersant produced by Nakakyo Yushi Co., Ltd. of Japan, and 32.4 g of M-type defoamer produced by Takachimia Co., Ltd. of Japan. Use zirconia balls with a diameter of 0.4 mm in a ball mill and grind to 0.4 μm at a speed of 400 rpm. Pump it into the pre-tower storage tank with a diaphragm pump at a flow rate of 20 L / min, add 3.0 kg of secondary alcohol AEO-9 coagulation inhibitor and 11.34 kg of AP-30 binder produced by Takachimia Co., Ltd. of Japan, stir at a speed of 80 rpm for 1 h, granulate, set the inlet temperature at 260 °C, adjust the flow rate of the diaphragm pump to control the outlet temperature of the granulation tower at 100 °C, and the rotation frequency of the atomization disk is 40 HZ. Pass the collected granulated powder through a 120-mesh sieve, collect the undersize material. Subject the undersize granulated powder to degumming at 800 °C for 2 h and cool to room temperature to obtain yttrium oxide spraying powder. Remove impurities from the spraying powder with a magnetic field strength greater than 18000 Gs until the content of magnetic foreign matters in the powder is less than 10 ppm to obtain the finished yttrium oxide spraying powder.

[0053] Example 3

[0054] In this example, a preparation method for producing yttrium oxide spraying powder by hydrothermal method is disclosed, and the specific process is as follows:

[0055] Weigh 500 Kg of yttrium hydroxide containing 25% yttrium oxide by wet method, put it into a hydrothermal autoclave containing 600 Kg of pure water, stir at a speed of 600 rpm for 1 h, adjust the pH value of the slurry to 9.3 with ammonia water, adjust the stirring speed to 80 rpm, heat, raise the temperature at a rate of 2.5 °C / min to 130 °C for hydrothermal treatment, keep it for 10 h, cool to room temperature at a rate of 3 °C / min, filter press to obtain a hydrothermal filter cake, dry the filter cake at 350 °C for 3 hours, then calcine it in a rotary kiln at 1025 °C for 2.5 h to obtain 125 kg of calcined material, add 125 kg of water, add 312 g of D-134 dispersant produced by Nakakyo Yushi Co., Ltd. of Japan and 25 g of M-type defoaming agent produced by Takachimical Co., Ltd. of Japan, use zirconia balls with a diameter of 0.35 mm in a ball mill, grind to 0.35 μm at a speed of 400 rpm, pump it into the pre-tower storage tank with a diaphragm pump at a flow rate of 20 L / min, add 2.5 kg of sec-alcohol AEO-9 coagulation inhibitor and 812 g of AP-30 binder produced by Takachimical Co., Ltd. of Japan, stir at a speed of 80 rpm for 1 h, granulate, set the inlet temperature at 250 °C, adjust the flow rate of the diaphragm pump to control the outlet temperature of the granulation tower at 98 °C, the rotation frequency of the atomization disk is 40 HZ, pass the collected granulated powder through a 100-mesh sieve, collect the undersize material, subject the undersize granulated powder to degumming at 700 °C for 3 h, cool to room temperature to obtain yttrium oxide spraying powder, and remove impurities from the spraying powder with a magnetic field strength greater than 18000 Gs until the content of magnetic foreign matters in the powder is less than 10 ppm to obtain the finished yttrium oxide spraying powder.

[0056] In the above preparation method, after the S1 filter press water is recycled 10 times, it is transported to a qualified third party for wastewater treatment. This process is not within the scope of the main process invention of this application and will not be described as a complete process.

[0057] Comparative Example

[0058] Comparative Example 1 is yttrium oxide spraying powder produced by Shin-Etsu Co., Ltd. of Japan;

[0059] Comparative Example 2 is yttrium oxide spraying powder of a certain company in Changzhou, China.

[0060] Comparative Example 3

[0061] The preparation method of the yttrium oxide spraying powder produced by the hydrothermal method in Comparative Example 3 is different from that in Example 1 only in that the coagulation inhibitor is replaced by silicon dioxide.

[0062] Comparative Example 4

[0063] The difference between this comparative example and Example 3 is only that the hydrothermal temperature is 140 °C.

[0064] Comparative Example 5

[0065] A preparation method of the yttrium oxide spraying powder produced by the hydrothermal method is disclosed in this comparative example. The specific process is as follows:

[0066] Weigh 500 Kg of yttrium hydroxide containing 25% yttrium oxide by wet method and put it into a hydrothermal autoclave containing 750 Kg of pure water. Stir at a speed of 600 rpm for 1 h, adjust the pH value of the slurry to 9.3 with ammonia water, adjust the stirring speed to 80 rpm, heat up, and increase the temperature at a rate of 2.5 °C / min to 133 °C for hydrothermal treatment, and keep it for 10 h. Then cool down to room temperature at a rate of 3 °C / min, filter press to obtain a hydrothermal filter cake. Bake the filter cake at 350 °C for 3 h, and then calcine it in a rotary kiln at 1025 °C for 2.5 h to obtain 125 kg of calcined material. Add 125 kg of water, 3125 g of D-134 dispersant produced by Nakakyo Yushi Co., Ltd. in Japan, and 25 g of M-type defoamer produced by Nippon Kasei Co., Ltd. in Japan. Grind it in a ball mill with zirconia balls with a diameter of 0.35 mm at a speed of 400 rpm to 0.35 μm, and pump it into the pre-tower storage tank with a diaphragm pump at a flow rate of 20 L / min. Add 2.5 kg of modified polyacrylic acid type D-305 distributed by Nakakyo Yushi Co., Ltd. in Japan and 812 g of polyethylene glycol with a molecular weight of 400, stir at a speed of 80 rpm for 1 h, granulate, set the inlet temperature at 250 °C, adjust the flow rate of the diaphragm pump to control the outlet temperature of the granulation tower at 98 °C, and the rotation frequency of the atomizing disk at 40 HZ. Pass the collected granulated powder through a 120-mesh sieve, collect the undersize material, degum the undersize granulated powder at 700 °C for 3 h, and cool it to room temperature to obtain yttrium oxide spraying powder. Remove impurities from the spraying powder with a magnetic field strength greater than 18000 Gs until the content of magnetic foreign matters in the powder is less than 10 ppm to obtain the finished yttrium oxide spraying powder.

[0067] Performance testing

[0068] The yttrium oxide spraying powder obtained from Examples 1-3 and Comparative Examples 1-5 was used to form a coating by plasma spraying, and the peel strength, deposition efficiency, and appearance of the coating were tested and recorded. The results are shown in Table 1.

[0069] Among them, the peel strength test refers to GB / T415,11-2022; the deposition efficiency test refers to GB / T21782.10-2008; the whiteness of the appearance is measured by a photometer. When the average wavelength of the spectrophotometer is 430-490 μm, the reflectance of titanium dioxide is used as 100 to represent the whiteness of each coating.

[0070] Table 1 Performance test data table of Examples 1-3 and Comparative Examples 1-5

[0071]

[0072] Table 2 Product characterization of yttrium oxide spraying powder in Example 3

[0073]

[0074] Referring to Table 1 and Table 2, in combination with Examples 1-3 and Comparative Examples 1-2, it can be seen that the yttrium oxide spraying powder prepared by the hydrothermal method in this application has a small size effect. It is extremely easy to instantaneously melt and adhere to the surface of the substrate, forming a uniform and strong bonding force. Therefore, its peel strength, deposition efficiency, and appearance whiteness are all superior to the coating performance of the yttrium oxide spraying powder produced by a certain company in Changzhou on the substrate. At the same time, it can be seen from Table 2 that the prepared yttrium oxide spraying powder has high purity, small particle size, large flow rate, and is of cubic crystal system.

[0075] Referring to Figure 1 , the SEM image of the coating after plasma spraying of yttrium oxide in the preparation of Example 3, it is measured that the average size of the coating is concentrated at about 510 nm.

[0076] Referring to Figure 2 , it can be seen that the yttrium oxide spraying powder prepared in Example 3 of this application is relatively uniform and has good sphericity.

[0077] Referring to Figure 3 , it can be seen that the appearance of the coating after plasma spraying of the yttrium oxide spraying powder prepared in Example 3 of this application has a relatively high whiteness, while Figure 4 the appearance of the coating after plasma spraying of the yttrium oxide spraying powder produced by the Changzhou company is reddish.

[0078] Referring to Figure 5 , it can be seen that the median particle size of the yttrium oxide spraying powder is 50 μm.

[0079] Referring to Figure 6 , it can be seen that the yttrium oxide spraying powder prepared in Example 3 of this application is 100% cubic phase.

[0080] Referring to Figure 7 , it can be seen that by replacing the coagulation inhibitor and binder used in this application, the sphericity and particle size of the prepared yttrium oxide spraying powder are uneven.

[0081] Combining Example 1 and Comparative Example 3, the yttrium oxide spraying powder prepared by using silicon dioxide as the coagulation inhibitor is inferior to Example 1 in terms of coating performance, indicating that this application can ensure the acquisition of yttrium oxide spraying powder with high purity, small particle size, and excellent performance by selecting a specific coagulation inhibitor.

[0082] In summary, the yttrium oxide spraying powder prepared by the hydrothermal method in this application has high lattice purity and self-shaping degree. The generated yttrium oxide spraying powder has a small size effect and is extremely easy to instantaneously melt and adhere to the surface of the substrate, forming a uniform and strong bonding force, which improves the peel strength of the coating. Compared with the yttrium oxide produced by the traditional oxalic acid precipitation method, the appearance of the yttrium oxide coating under the spraying process is white and natural, and has a high bonding strength with the substrate; for the same yttrium salt, the cost of yttrium hydroxide under ammonia water is extremely low compared with oxalic acid; good surface modification not only improves the grinding efficiency, but also can obtain granulated powder with high sphericity, good fluidity and high strength after atomization drying. Therefore, it is the main factor for obtaining a uniform and high-density coating under the spraying conditions, and plays a synergistic role in the strength of the coating.

[0083] This specific embodiment is only an explanation of this application, and it does not limit this application. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions according to needs, but as long as they are within the scope of the claims of this application, they are protected by the patent law.

Claims

1. A preparation method for producing yttrium oxide spraying powder by hydrothermal method, characterized in that: It includes the following steps: S1. Add water to yttrium hydroxide produced by the wet process containing 23-27 wt% of yttrium oxide at a ratio of 1:1.5, stir to make a slurry, adjust the pH value of the slurry to 9.0-9.5 with ammonia water, conduct hydrothermal treatment, and perform pressure filtration to obtain a hydrothermally treated filter cake; S2. After the hydrothermally treated filter cake is dried at a low temperature of 300-400 °C for 3-4 hours, it is then calcined in a high-temperature rotary kiln at 1020-1030 °C for 2-3 hours and cooled to room temperature to obtain a calcined material; S3. Add water to the calcined material at a mass ratio of 1:(0.8-1.2), use zirconia balls with a diameter of 0.3-0.4 mm in a ball mill to grind it to 0.3-0.4 μm, add a dispersant, an antifoaming agent, and after the grinding is completed, add a coagulation inhibitor and a binder, and mix evenly to obtain a surface-modified slurry; S4. Pump the surface-modified slurry into the pre-tower storage tank, set the inlet temperature at 240 °C - 260 °C, adjust the flow rate of the diaphragm pump to control the outlet temperature of the granulation tower at 95-100 °C, sieve the collected granulated powder, and collect the undersize; S5. The collected undersize is degummed at 600-800 °C for 2-4 hours and cooled to room temperature to obtain yttrium oxide spraying powder. The spraying powder is removed of impurities until the content of magnetic foreign matters in the powder is less than 10 ppm under a magnetic field strength greater than 18000 Gs to obtain the finished yttrium oxide spraying powder; In S1, the method of the hydrothermal treatment is to raise the yttrium hydroxide slurry to 128-132 °C at a rate of 2-3 °C / min for dynamic hydrothermal treatment, with a stirring speed of 80 rpm. After holding for 8-12 hours, it is cooled to room temperature at a rate of 2-4 °C / min and then subjected to pressure filtration and dehydration treatment; In S3, the mass ratio of the calcined material, the dispersant, the antifoaming agent, the coagulation inhibitor, and the binder is 100:(2-3):0.02:2:(6-7).

2. The preparation method of yttrium oxide spraying powder produced by hydrothermal method according to claim 1, characterized in that: In S1, the wet-process yttrium hydroxide is an intermediate prepared from high-purity yttrium chloride or yttrium nitrate as raw materials through an ammonia reaction, and it is required to have: a yttrium oxide content of 23-27 wt%, a water content greater than 74.9%, a chloride ion or nitrate radical lower than 80 ppm, a total non-yttrium rare earth content lower than 10 ppm, and the ratios of the contents of impurity elements such as iron, silicon, titanium, and aluminum calculated as oxides to yttrium oxide converted from yttrium hydroxide are all less than 5 ppm; 3. The preparation method of yttrium oxide spraying powder produced by hydrothermal method according to claim 1, characterized in that: The dispersant is the dispersant with the model D-134 produced by Nakakyo Yushi Co., Ltd. of Japan; the antifoaming agent is the antifoaming agent with the model M produced by Takachiho Chemical Co., Ltd. of Japan; the coagulation inhibitor is secondary alcohol AEO-9; the binder is the binder with the model AP-30 produced by Takachiho Chemical Co., Ltd. of Japan.

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