A ceramic coating, method of manufacture and use thereof

Abstract

The application provides a ceramic coating, which comprises, in parts by weight, 50-70 parts of aluminum oxide, 20-30 parts of silicon dioxide, 5-10 parts of polysilazane resin, 0.5-5 parts of sintering aid, 0.5-5 parts of plasticizer, 0.5-5 parts of lubricant and 10-20 parts of water; a preparation method thereof comprises the following steps: mixing aluminum oxide and silicon dioxide, wet grinding, drying to obtain a mixture; uniformly mixing polysilazane resin and the mixture, vacuum drying, vacuum defoaming, then adding the mixture, uniformly mixing, then adding the remaining raw materials, heating and mixing to obtain the ceramic coating; the ceramic coating has strong interface bonding capacity with a base material and is not easy to fall off, so that the base material has excellent use performance; and the application further provides a base material coated with the ceramic coating; the base material has good thermal stability and durability and good corrosion resistance.

Description

Technical Field

[0001] This invention relates to the field of ceramic coating technology, and more specifically, to a ceramic coating, a preparation method thereof, and its application. Background Technology

[0002] Ceramic coatings are commonly used as protective coatings and are applied to the surface of substrates (such as suspended baskets). Currently, suspended baskets are mainly platinum or ceramic. Platinum baskets are prone to wire adhesion and snagging during high-temperature testing, causing deformation or damage and affecting the accuracy of test results. Furthermore, they require regular replacement or maintenance, increasing costs and reducing efficiency. Ceramic baskets, on the other hand, are brittle and easily broken during use, also increasing costs. Therefore, developing a platinum suspended basket with a ceramic coating is particularly important. Summary of the Invention

[0003] The first objective of this invention is to provide a ceramic coating that has strong interfacial bonding with the substrate material, is not easily detached, and enables the substrate material to exhibit excellent performance.

[0004] The second objective of this invention is to provide a platinum hanging basket with a ceramic coating that exhibits good thermal stability and durability, as well as good corrosion resistance.

[0005] The embodiments of the present invention are achieved through the following technical solutions:

[0006] A ceramic coating comprises, by weight: 50-70 parts aluminum oxide, 20-30 parts silicon dioxide, 5-10 parts polysilazane resin, 0.5-5 parts sintering aid, 0.5-5 parts plasticizer, 0.5-5 parts lubricant, and 10-20 parts water.

[0007] The inventors discovered that after ceramic slurry is coated onto the suspended platform substrate, the weak interfacial adhesion makes the coating prone to peeling off during operation, especially under rapid heating and cooling conditions, thus affecting its performance. Therefore, this invention utilizes polysilazane resin as a binder to enhance toughness. Surface coating of the sintered substrate material improves interfacial adhesion, preventing peeling and significantly improving the performance of the substrate material. Specifically:

[0008] Polysilazane resin has greater deformation capacity than brittle ceramics. When the matrix is ​​subjected to external force, fracture generally occurs first in internal defects of the matrix and then gradually extends to the matrix surface. The presence of the coating can effectively prevent this phenomenon. Moreover, the binder-containing coating used in this invention only physically coats the matrix surface and will not chemically react with the matrix, ensuring the inherent properties and stability of the matrix material. Furthermore, polysilazane resin has good flowability and high temperature resistance. In the event of external impact, it can fill surface pores, and the coating is thin and uniform, facilitating application. Under high temperature conditions, it can be transformed into SiCN, SiCNO, or silica ceramic coatings, improving the strength of the matrix and bonding with the matrix interface, thereby increasing the interfacial shear strength and improving the stress transfer effect from the matrix to the polysilazane resin, thus improving the overall strength and energy absorption of the matrix.

[0009] Furthermore, the sintering aid includes one or more of the following: iron oxide, calcium carbonate, magnesium oxide, potassium oxide, and sodium oxide. This invention utilizes the above-mentioned sintering aid to adjust the adhesion, hardness, and heat resistance of ceramics, and to enhance the chemical corrosion resistance of the coating.

[0010] Furthermore, the plasticizer includes one or more of ethylene glycol, polyacrylate, glycerol, benzoic acid, and malonate.

[0011] Furthermore, the lubricant includes starch and glycerin.

[0012] A method for preparing a ceramic coating includes the following steps:

[0013] S1. Aluminum oxide and silicon dioxide are mixed, wet-milled, and dried to obtain a mixture;

[0014] S2. After the polysilazane resin and the mixture are mixed evenly, the mixture is vacuum degassed in a vacuum drying oven at a temperature of 80-100℃ and a negative pressure of 90kPa. Then the remaining raw materials are added and heated and mixed to obtain the ceramic coating.

[0015] Furthermore, in S1, the ball-to-material mass ratio during wet milling is 4:1, and the slurry after wet milling is vacuum dried at 50-80℃.

[0016] Furthermore, in S1, the heating and mixing process involves mixing and stirring in a constant temperature water bath at 30–40°C for 1–2 hours.

[0017] The application of the above-mentioned ceramic coating includes coating it onto the surface of a substrate, and after curing, obtaining a substrate material coated with a ceramic coating.

[0018] Specifically, in this invention, the ceramic coating is uniformly applied to the surface of the hanging basket, and then the platinum hanging basket with the ceramic coating is subjected to staged temperature control to obtain a platinum hanging basket with a ceramic coating. Specifically, during the staged temperature control: first, it is fired at 150-250℃ for 0.5-1.5h, then at 350-450℃ for 0.5-1.5h, then at 550-650℃ for 0.5-1.5h, and finally at 1000-1500℃ for 0.5-1.5h. After sintering, it is cooled to room temperature in the furnace; or it can be held at a vacuum or inert atmosphere for 2h and then cooled to room temperature. This invention employs staged temperature control, with the first sintering step performed at a lower temperature, which enhances the viscous sintering of aluminum oxide and silicon dioxide. Through gradient temperature increase, layer-by-layer viscous sintering is achieved, thereby improving the strength of the coating and preventing crack propagation under external force. At the same time, under the protection of the coating, the thermal stability and durability of the substrate (e.g., a hanging basket) are further improved.

[0019] The technical solutions of the embodiments of the present invention have at least the following advantages and beneficial effects:

[0020] 1. The ceramic coating of the present invention can achieve the purpose of coating and enhancing the toughness of the substrate. Applying a surface coating to the sintered substrate material can improve the interfacial bonding ability, making it less prone to peeling off, thereby significantly improving the performance of the substrate material.

[0021] 2. The present invention employs staged temperature control during the preparation process. The first step of sintering is carried out at a lower temperature, which strengthens the viscous sintering of aluminum oxide and silicon dioxide. Through gradient temperature increase, layer-by-layer viscous sintering is achieved, thereby improving the strength of the coating and preventing the propagation of cracks under external force. At the same time, under the protection of the coating, the thermal stability and durability of the substrate (such as a hanging basket) are further improved. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0023] Example 1

[0024] A ceramic coating comprises, by weight: 60 parts aluminum oxide, 25 parts silicon dioxide, 10 parts polysilazane resin binder, 1 part iron oxide, 1 part calcium carbonate, 2 parts ethylene glycol, 3 parts glycerin, and 15 parts water.

[0025] The method for preparing the above-mentioned ceramic coating includes the following steps:

[0026] S1. Aluminum oxide and silicon dioxide are mixed, wet-milled, and dried to obtain a mixture; the ball-to-material mass ratio during wet milling is 4:1, and the slurry after wet milling is vacuum-dried at 50-80℃;

[0027] S2. After the polysilazane resin and the mixture are mixed evenly, the mixture is vacuum degassed in a vacuum drying oven at 90°C under a negative pressure of 90 kPa. Then the remaining raw materials are added and the mixture is stirred in a constant temperature water bath at 35°C for 2 hours to obtain the ceramic coating.

[0028] The ceramic coating is uniformly applied to the surface of the platinum hanging basket, and then the temperature is controlled in stages. Specifically, it is first fired at 200℃ for 1 hour, then at 400℃ for 1 hour, then at 600℃ for 1 hour, and finally at 1200℃ for 1 hour. After sintering, it is cooled to room temperature with the furnace to obtain the platinum hanging basket with ceramic coating.

[0029] Example 2

[0030] The difference between this embodiment and Embodiment 1 is that:

[0031] A ceramic coating comprises, by weight, 55 parts aluminum oxide, 23 parts silicon dioxide, 5 parts polysilazane resin, 2 parts magnesium oxide, 4 parts polyacrylate, 1 part glycerol, and 20 parts water.

[0032] Example 3

[0033] The difference between this embodiment and Embodiment 1 is that:

[0034] A ceramic coating comprises, by weight, 65 parts aluminum oxide, 27 parts silicon dioxide, 8 parts polysilazane resin, 4 parts sintering aid, 1 part plasticizer, 3 parts lubricant, and 18 parts water.

[0035] Example 4

[0036] The difference between this embodiment and Embodiment 1 is that:

[0037] A ceramic coating comprises, by weight, 66 parts aluminum oxide, 22 parts silicon dioxide, 6 parts polysilazane resin, 3 parts sintering aid, 4 parts plasticizer, 2 parts lubricant, and 13 parts water.

[0038] Example 5

[0039] The difference between this embodiment and Embodiment 1 is that:

[0040] A ceramic coating comprises, by weight: 55 parts aluminum oxide, 28 parts silicon dioxide, 9 parts polysilazane resin, 2 parts sintering aid, 2 parts plasticizer, 1 part lubricant, and 16 parts water.

[0041] Comparative Example 1

[0042] The difference between this comparative example and Example 1 is that the binder is polyvinyl alcohol.

[0043] Experimental Example 1

[0044] The platinum hanging baskets prepared in each embodiment and comparative example were subjected to performance tests, and the results are shown in Table 1. The test methods for acid corrosion and alkaline corrosion are as follows: The platinum hanging baskets with ceramic coatings prepared in each embodiment and comparative example were cut into the same size and placed in 5 wt% sulfuric acid solution and 20 wt% sodium hydroxide solution, respectively, for 12 hours. The changes on the surface of the platinum hanging baskets were observed. The wear rate of the ceramic material was measured according to JC / T848.1-1999 "Wear-resistant alumina ceramic balls". The data were recorded in three parallel tests.

[0045] Table 1 - Test Results

[0046] Example 1 no No spots or corrosion pits No spots or corrosion pits Example 2 no No spots or corrosion pits No spots or corrosion pits Example 3 no No spots or corrosion pits No spots or corrosion pits Example 4 no No spots or corrosion pits No spots or corrosion pits Example 5 no No spots or corrosion pits No spots or corrosion pits Comparative Example 1 Shedding A few spots, corrosion pits A few spots, corrosion pits

[0047] As shown in Table 1, the platinum hanging basket with ceramic coating of the present invention has strong interfacial bonding between the ceramic coating and the platinum hanging basket, and is not easy to fall off. This makes the platinum hanging basket exhibit good thermal stability and durability, as well as good corrosion resistance, thus improving the overall stability and safety of the platinum hanging basket.

[0048] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A ceramic coating, characterized in that, By weight, it includes: 50-70 parts aluminum oxide, 20-30 parts silicon dioxide, 5-10 parts polysilazane resin, 0.5-5 parts sintering aid, 0.5-5 parts plasticizer, 0.5-5 parts lubricant, and 10-20 parts water. Its preparation method includes the following steps: S1. Aluminum oxide and silicon dioxide are mixed, wet-milled, and dried to obtain a mixture; S2. After the polysilazane resin and the mixture are mixed evenly, the mixture is vacuum degassed in a vacuum drying oven at a temperature of 80-100℃ and a negative pressure of 90kPa. Then the remaining raw materials are added and the mixture is stirred in a constant temperature water bath at 30-40℃ for 1-2 hours to obtain the ceramic coating. The ceramic coating is uniformly applied to the surface of the platinum hanging basket. The platinum hanging basket with the ceramic coating is first fired at 150-250℃ for 0.5-1.5h, then at 350-450℃ for 0.5-1.5h, then at 550-650℃ for 0.5-1.5h, and finally at 1000-1500℃ for 0.5-1.5h. After sintering, it is cooled to room temperature in the furnace; or it is held at a vacuum or inert atmosphere for 2h and then cooled to room temperature to obtain the platinum hanging basket with the ceramic coating.

2. The ceramic coating according to claim 1, characterized in that, The sintering aids include one or more of the following: iron oxide, calcium carbonate, magnesium oxide, potassium oxide, and sodium oxide.

3. The ceramic coating according to claim 1, characterized in that, The plasticizer includes one or more of the following: ethylene glycol, polyacrylate, glycerol, benzoic acid, and malonate.

4. The ceramic coating according to claim 1, characterized in that, The lubricant includes starch and glycerin.

5. The ceramic coating according to claim 1, characterized in that, In S1, the ball-to-material mass ratio during wet milling is 4:1, and the slurry after wet milling is vacuum dried at 50-80℃.

6. An application of a ceramic coating, characterized in that, The ceramic coating according to any one of claims 1-5 is applied to the surface of the platinum hanging basket.