Influence of raw material powder: The most important raw material of alumina wear-resistant ceramics is high-purity alumina powder. Its performance and content have a great influence on alumina wear-resistant ceramics. It is inevitable to introduce impurities during the preparation process of ceramic powder. The organic impurities will be burned off during the sintering process, and irregular pores will be formed during the densification process. Inorganic impurities may interact with the ceramic powder at high temperatures. React or remain in the matrix to form microcracks. These microstructure defects caused by impurities have a significant impact on the densification of alumina wear-resistant ceramics. The particle size of the raw material powder also has a great influence on the performance of the product. Only the raw material is fine enough, the final fired product may form a microcrystalline structure, which makes it have good wear resistance. Therefore, high-purity, fine-grained alumina is used. Powder is an important prerequisite for the preparation of alumina wear-resistant ceramics with excellent performance.
Influence of molding method: Production practice and a large number of studies show that alumina ceramics with low porosity and high density have excellent structural properties. High density means that the crystal grains in the ceramic body are tightly arranged, and it is not easy to form destructive breakthrough points when subjected to external loads or corrosive substances. To obtain a high-density ceramic body, the molding method is the key. The forming of alumina wear-resistant 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 sintering performance and microstructure of alumina ceramics. Generally, grouting or hot die-casting processes are mainly used for products with complex shapes, and dry products can be used for products with simple shapes. Compression molding.
The influence of sintering: sintering is a key stage of ceramic preparation, and the sintering atmosphere has a great influence on the preparation of ceramic materials. Too high a sintering temperature or too long a holding time will promote crystal growth, so that the fine raw materials will develop into coarse grains at high temperatures, and the amount of liquid phase will increase. This will not only decrease the strength but also weaken the wear resistance. Of course, if the temperature is too low, the sintered body will not be dense, and the wear resistance of the product will not be good. The use of advanced electric kiln sintering can precisely control the heating, heat preservation, and cooling process of sintering, which plays an important role in improving the performance of wear-resistant ceramics. However, the sintering cost of electric kilns and the consumption of refractory materials are higher than that of gas kilns and coal kilns.
Sintering aid: A suitable sintering aid reduces the sintering temperature, improves the microstructure of the ceramic, improves the mechanical properties, and then improves the wear resistance of alumina wear-resistant ceramics.
