Application of alumina ceramics in machinery industry
Alumina ceramic tools are widely used in hard material cutting, high-speed steel cutting, ultra-high-speed cutting and other difficult machining due to their high hardness, strong high-temperature mechanical properties, good wear resistance, good chemical stability, and not easy to bond with metals. cutting of material. The optimum cutting speed of alumina ceramic tools is higher than that of ordinary carbide tools, which can greatly improve the cutting efficiency of different materials.
①Pure alumina ceramic tool
Pure alumina ceramic tools refer to high-purity alumina ceramics containing only a small amount of other oxides, of which the purity of alumina is more than 99%. In pure alumina ceramics, zirconia can be added as a sintering aid to improve its fracture toughness. In the preparation of ceramic cutting tools, the effective control of the original purity and grain size is realized, and other components are added to form two-phase or solid solution in the form of alumina-based composite ceramics and whisker-reinforced ceramics in the matrix. These technologies make up for the deficiencies of pure alumina ceramics, thereby improving its cutting performance and durability. Because of the high temperature performance and wear resistance of pure alumina ceramic tools, but low flexural strength and poor impact resistance, it is increasingly replaced by various composite alumina ceramic tools.
②Composite alumina ceramic tool
In composite ceramics, there are several composite directions: alumina-carbide ceramic tools, alumina-carbide-cermet tools, alumina-nitride or boride ceramic tools, etc. For example, for alumina-carbide ceramic tools, adding certain carbides (TiC, WC, TaC, NbC, Mo, C, Cr, C2, etc.) to alumina can improve its strength, wear resistance, impact resistance As well as high temperature performance, among the additives, TiC is the most used. Compared with pure alumina ceramics, the flexural strength of alumina-carbide composite ceramics is better than that of pure alumina ceramics at room temperature and high temperature. . This composite tool is suitable for high-speed roughing and finishing of hard-to-machine materials such as wear-resistant cast iron, hardened steel and high-strength steel.
③Toughened alumina ceramic tool
Toughened alumina ceramic tool refers to adding toughening or reinforcing materials to the alumina matrix. At present, the commonly used toughening methods are: Zr02 transformation toughening, whisker toughening, second phase particle dispersion toughening and so on.
