Factors affecting wear-resistant ceramic coatings in use
Wear-resistant ceramic coating is a non-metallic cementitious material. It is a powdered ceramic material made of acid- and alkali-resistant synthetic raw materials through strict process ratio and advanced inorganic polymerization technology. At the construction site, special liquid inorganic glue is added to this material, and it is applied to the lining or surface of the equipment manually or mechanically. After a series of chemical reactions, the bonding strength and hardness of the ceramics are reached after 3 days at room temperature, so the name is resistant. Grind ceramic paint.
Wear-resistant ceramic coatings are widely used in metallurgy, petroleum industry, natural gas exploration, aerospace and other industrial fields, and can withstand temperatures up to 1500°C or higher. It not only resists high temperature, but also has the properties of heat shock and wear resistance. Through the coating, the surface of the metal surface and the surface of various refractory materials can be modified to improve the performance of the base material, while saving energy and improving the metal The service life of the base material is more than 1-2 times. But what are the factors that affect the use of wear-resistant materials, have you ever understood it?
1. The influence of raw material powder
The main raw material of wear-resistant ceramics is high-purity AI2O3 powder. Its performance and content have a great influence on alumina ceramics. It is inevitable to introduce impurities during the preparation process of ceramic powder. The organic impurities are burned off during the firing process, and irregular pores are formed during the early densification process. Inorganic impurities may react with ceramic powder at high temperature. Or remain in the matrix to form microcracks. These microstructure defects caused by impurities have a significant impact on the densification of alumina ceramics. Therefore, the use of high-purity AI2O3 powder is an important prerequisite for the preparation of alumina ceramics with excellent performance.
2. The influence of raw material powder particle size
The particle size of the raw material powder has a great influence on the performance of the product. Only when the raw material is fine enough, can the fired product form a microstructure, which makes it have good wear resistance. The finer the AI2O3 powder particles, the greater the activity, which can promote sintering, and the higher the strength of the made porcelain. The small particles can also disperse the stress concentration at the grain boundary caused by the different linear expansion coefficients of corundum and glass, reducing cracking The fine grains can also hinder the development of microcracks, and are not easy to break through the formation of crystals, which is beneficial to improve fracture toughness and wear resistance.
3. Influence of molding method
Practical production and a large number of studies have shown that: alumina ceramics with low porosity and high density have excellent structural properties. Informing the density means that the crystal grains in the ceramic body are closely arranged, and it is not easy to form destructive breakthrough points when subjected to external loads or corrosive substances. To obtain a ceramic body with a calcium density, the molding method is the key. The forming of alumina ceramics generally adopts methods such as dry pressing, isostatic pressing, and hot die casting. Different methods have different characteristics and have different effects on the sinterability and microstructure of ceramics. Generally, grouting and hot die-casting processes are mainly used for products with complex shapes, and dry pressing can be used for products with simple shapes. Generally speaking, the compactness of the products formed by dry pressing is better than the products formed by hot pressing.
4. The influence of sintering
The sintering of ceramics is simply the densification process of ceramic green bodies at high temperatures. With the increase of temperature and the extension of time, the adhesion between the powder particles occurs, the strength of the sintered body increases, and the aggregate of the powder particles becomes a strong polycrystalline sintered body with a certain microstructure, and the desired The physical or mechanical properties of products or materials. The densification rate and structure of the sample often reflect what kind of heat treatment it has experienced.