Polycrystalline alumina fiber short cut bulk is manufactured by the globally advanced "sol-gel" process, and after doping and high-temperature calcination treatment, it is transformed into high-performance polycrystalline ceramic fiber. It has excellent high-temperature resistance and excellent wear resistance, and can be used for high-temperature insulation and friction material preparation. Different forms of ceramic products can be prepared through methods such as hot pressing, wet forming, spinning, spraying, and injection molding. In terms of friction materials, they can be compounded with resin, rubber, metal and other materials to produce high-temperature friction materials, which are used for braking, clutch, conveyor, rolling mill and other equipment in high-temperature environments