阅读说明：本技术 一种碳化硅制品表面用耐火涂料 (Refractory coating for surface of silicon carbide product ) 是由 刘鹏程 张伟 王刚 张涛 石书冰 于 2020-06-17 设计创作，主要内容包括：本发明专利涉及一种碳化硅推板表面用耐火涂料,可用于碳化硅抗氧化以及防止相关制品粘连的问题。所述涂层按组成及重量份为：氧化铝微粉10~30份,氧化锆细粉50~80份,板状刚玉颗粒10~30份；此外所用结合剂30~60份,所用质量为0.1~0.4份的添加剂和0.05-0.2份增稠流平剂。按所述组成混合均匀得到耐火浆料,在SiC制品上均匀涂敷,自然晾干,经高温处理,得到结合强度高、性能稳定的SiC制品表面用耐火涂层。与现有技术的涂料相比,本发明制得的涂层具有结合强度高、耐高温(最高使用温度可达1600℃)以及抗热震性能好、操作简单、使用寿命长、绿色环保的特点。(The invention relates to a refractory coating for the surface of a silicon carbide push plate, which can be used for resisting oxidation of silicon carbide and preventing the adhesion of related products. The coating comprises the following components in parts by weight: 10-30 parts of alumina micro powder, 50-80 parts of zirconia fine powder and 10-30 parts of tabular corundum particles; in addition, 30-60 parts of a binding agent, 0.1-0.4 part of an additive and 0.05-0.2 part of a thickening and leveling agent are used. And (3) uniformly mixing the components to obtain refractory slurry, uniformly coating the refractory slurry on the SiC product, naturally airing, and performing high-temperature treatment to obtain the refractory coating for the surface of the SiC product, which has high bonding strength and stable performance. Compared with the coating in the prior art, the coating prepared by the invention has the characteristics of high bonding strength, high temperature resistance (the maximum service temperature can reach 1600 ℃), good thermal shock resistance, simple operation, long service life and environmental protection.)

1. A refractory coating for the surface of a silicon carbide product is characterized in that: the fire-resistant coating comprises the following raw material components in parts by weight: 10-30 parts of alumina micro powder, 50-80 parts of zirconia fine powder and 10-30 parts of tabular corundum particles; 30-60 parts of a bonding agent, 0.1-0.4 part of an additive and 0.05-0.2 part of a thickening and leveling agent are additionally added into the refractory coating; the particle size of the alumina micro powder is 3-5 mu m, the average particle size of the zirconia powder is less than or equal to 0.088mm, and the average particle size of the tabular corundum particles is 0-0.2 mm.

2. The refractory coating for the surface of a silicon carbide article according to claim 1, wherein: the binding agent is one of water glass or alumina sol.

3. The refractory coating for the surface of a silicon carbide article according to claim 1, wherein: the thickening and leveling agent is carboxymethyl cellulose.

4. The refractory coating for the surface of a silicon carbide article according to claim 1, wherein: the additive is sodium tripolyphosphate.

Technical Field

The invention belongs to the technical field of refractory materials, and particularly relates to a refractory coating for the surface of a silicon carbide product.

Background

The silicon carbide material has excellent high-temperature properties such as high-temperature strength, creep resistance, thermal conductivity and thermal shock resistance, so that the silicon carbide material becomes an ideal choice for materials such as high-temperature structural materials, electric heating elements and the like, and can be widely used as high-temperature ceramic decking, ceramic supporting elements, heat exchangers, gas turbines, advanced internal combustion engine materials, electric heating elements, thermocouple protection tubes and the like. In a dry high-temperature oxidation environment, when the temperature exceeds 900 ℃, a layer of compact and slowly-grown silicon dioxide is generated on the surface of the silicon carbide, so that the silicon carbide has certain oxidation resistance. However, the silicon dioxide protective film changes at a higher temperature, cracks are easily generated by repeated heating and cooling due to the difference of the thermal expansion coefficient of the silicon dioxide protective film and the thermal expansion coefficient of silicon carbide, and in addition, when the silicon carbide is used as a ceramic ceiling or a supporting upright column in the ceramic ball industry, the generation of the silicon dioxide can adhere to the ceramic ball to influence the quality of the ceramic ball, and the service life of a silicon carbide product can be shortened. The coating method achieves the purposes of adhesion prevention and oxidation prevention by separating the product from the silicon carbide product. However, the research on the silicon carbide product anti-adhesion coating for the porcelain ball industry is not reported, so that the successful development of the silicon carbide product surface coating can solve a great problem in the porcelain ball industry at present and has higher practical value.

The silicon carbide anti-oxidation coating is reported, but the product is complex to manufacture, the problems that the coating is easy to crack and fall off at high temperature and the like are not well solved, and a series of short plates exist; particularly, the problems that the product quality is seriously influenced due to the fact that silicon carbide push plate products are easy to oxidize and adhere to porcelain balls in the porcelain ball industry and the waste is serious and the service life of a kiln car is influenced compared with the existing scheme of spreading a layer of corundum sand are solved in a targeted mode.

Disclosure of Invention

The invention aims to provide a refractory coating for the surface of a silicon carbide product, which has the characteristics of simple manufacture, environmental protection, high bonding strength with the silicon carbide product, high temperature resistance and good thermal shock stability.

The invention adopts the following technical scheme to achieve the purpose:

the refractory coating for the surface of the silicon carbide product comprises the following raw material components in parts by weight: 10-30 parts of alumina micro powder, 50-80 parts of zirconia fine powder and 10-30 parts of tabular corundum particles; 30-60 parts of a bonding agent, 0.1-0.4 part of an additive and 0.05-0.2 part of a thickening and leveling agent are additionally added into the refractory coating; the particle size of the alumina micro powder is 3-5 mu m, the average particle size of the zirconia powder is less than or equal to 0.088mm, and the average particle size of the tabular corundum particles is 0-0.2 mm.

The binding agent is one of water glass or alumina sol.

The thickening and leveling agent is carboxymethyl cellulose.

The additive is sodium tripolyphosphate.

The composition of the refractory coating can be prepared into refractory slurry by uniformly mixing the materials in parts by weight, then uniformly coating the surface of a SiC product, naturally airing, drying at 100 ℃ in an oven, and carrying out heat preservation for 3 hours at 1400-1600 ℃ to sinter, so that the bonding force between the coating and a matrix is enhanced, and the composition of the coating is changed along with the phase composition. The results show that the refractory coating for the surface of the silicon carbide product has the beneficial effects that:

1) and (4) high temperature resistance. The refractory coating disclosed by the invention can bear high-temperature calcination at about 1600 ℃ and can not deform or melt. The raw materials of zirconia and alumina used in the coating are high-temperature resistant and high-purity systems. The basic support of the coating used at high temperature is ensured.

2) The operation is easy. The method is simple to operate, only two kinds of powdery particles of alumina and zirconia with different particle sizes, proper bonding agent and additive are uniformly mixed by a mortar mixer, the mixture is directly coated on the surface of a silicon carbide product by a brush, and then the silicon carbide product is dried and calcined.

3) And oxidation is prevented. The coating disclosed by the invention is uniformly coated on the surface of a product, and can effectively prevent the silicon carbide substrate from directly contacting with oxygen, so that the oxidation of the silicon carbide product is prevented to a certain extent, and the long-term use of the silicon carbide product is ensured.

Detailed Description

The invention is further described below in conjunction with the specific embodiments.

The aluminum oxide micro powder has the particle size of 3-5 mu m, the average particle size of zirconium oxide powder is less than or equal to 0.088mm, and the average particle size of tabular corundum particles is 0-0.2 mm.