Material of welding ceramic:
Alumina ceramics, zirconia ceramics, silicon nitride ceramics, silicon carbide ceramics, aluminum nitride ceramics, boron nitride ceramics and other industrial ceramics.
Use high-purity silicon nitride powder as raw material, and high-density and high-strength silicon nitride welding ceramics are obtained by sintering at a high temperature of more than 1600 °C.
Features of silicon nitride welding ceramic:
1.Heat-resistant, under atmospheric pressure, silicon nitride has no melting point, directly decomposes at about 1870 °C, can withstand oxidation to 1400 °C, and the actual use reaches 1200 °C (the mechanical strength will decrease if it exceeds 1200 °C).
2.The coefficient of thermal expansion is small (2.8-3.2) × 10-6/°C, the thermal conductivity is high, the thermal shock resistance is resistant, and the thermal shock will not crack from room temperature to 1000°C.
3.The friction coefficient is small (0.1), and there is self-lubrication, (the friction coefficient of the metal surface of the oil is 0.1-0.2).
4.Stable chemical properties, corrosion resistance, no reaction with other inorganic acids except hydrofluoric acid, no reaction with oxygen in 800 °C dry atmosphere, more than 800 °C, begin to generate silicon oxide film on the surface, with the increase of temperature, the silicon oxide film gradually becomes stable, and about 1000 °C can form a dense silicon oxide film with oxygen. It can be maintained up to 1400°C and is basically stable.
5.Silicon nitride has high hardness and wear resistance, second only to diamond, cubic boron nitride, boron carbide, silicon carbide, and mechanical impact resistance.
