There are several methods for making silicon nitride: reacting powdered silicon with nitrogen at 1300-1400°C; reacting pure silicon with ammonia at 1500°C; burning silicon dioxide and carbon in nitrogen containing a small amount of hydrogen. mixture; completely thermally decompose Si(NH2)4, the ammonolysis product of SiCl4. Silicon nitride can be used as catalyst carrier, high temperature resistant material, coating and abrasive, etc.
Silicon nitride ceramics have the characteristics of high strength and high temperature resistance. Among ceramic materials, they have excellent comprehensive mechanical properties, thermal shock resistance, oxidation resistance, wear resistance and corrosion resistance. They are the first ceramics used in thermal engine parts. candidate materials. In the machinery industry, silicon nitride ceramics are used as bearing balls, rollers, ball races, tool molds, new ceramic cutting tools, pump plungers, spindle sealing materials, etc.
In the metallurgical industry, silicon nitride ceramics are resistant to high temperatures, have small friction coefficients and are self-lubricating. It is stable to most metals and alloy solutions. Therefore, it can be used to make tools and dies for metal material processing, such as dialing mandrels, extrusion, wire-drawing dies, rollers, transfer rollers, heating element fixtures, thermocouple sets, and metal heat treatment supports. , crucible, aluminum liquid guide camp, aluminum bag lining, etc.
In the chemical industry, silicon nitride ceramics are used as wear-resistant and corrosion-resistant components. Such as ball valves, pump bodies, combustion vaporizers, filters, etc.
