shaft sleeve material: silicon nitride Silicon nitride shaft sleeve, wear-resistant, impact resistant, hardness higher than steel Silicon nitride (Si3N4), is an important structural ceramic material. It is a kind of superhard material, which has lubricity and wear resistance, and is atomic crystal; Oxidation resistance at high temperature. Moreover, it can resist cold and hot shock, and it will not break when heated to 1000 or more in the air, and then cooled and heated sharply. It is precisely because silicon nitride ceramics have such excellent characteristics that people often use it to manufacture mechanical components such as bearings, gas turbine blades, mechanical seal rings, permanent molds, pump bushings, etc.