Silicon nitride ceramic cylindrical tube
Aluminum oxide ceramics, silicon nitride ceramics, zirconia ceramics
Silicon nitride is an important structural ceramic material. It is a superhard material, which has lubricity, and wear resistance, and is an atomic crystal ; it is resistant to oxidation at high temperatures. It can resist cold and heat shocks, and when the air reaches above 1000 ℃, it will cool down quickly and then heat up quickly without breaking.
Silicon nitride ceramic materials have high thermal stability, strong oxidation resistance and high dimensional accuracy.
1.59% lighter than steel balls, which means less centrifugal force, less wear grooves under high speed and acceleration.
2. The elastic modulus is 44% larger, which means smaller load deformation.
3. Rockwell hardness 92
4. A small coefficient of friction
5. Only 1/4 of the thermal expansion coefficient ﬁ of steel can withstand high temperature.
6. Excellent surface finish can be achieved, Ra can be 4~6.
7. Can withstand high temperature, high hardness and strength up to 1050 °C.
8. Never rust, no lubricant required.
9. It is more corrosion resistant than steel.
Silicon nitride ceramic parts are precision ceramic products sintered at high temperature in a non-oxidizing environment. They have the characteristics of acid and alkali resistance and corrosion resistance. It is used in the environment with high pollution of non-lubricating medium. At 800°C, the strength and hardness of silicon nitride ceramic balls are almost unchanged, the density is 3.20g/cm3, the weight is almost 1/3 of the weight of bearing steel, and the centrifugal force is small during rotation. High-speed operation can be realized. Therefore, silicon nitride ceramic balls can largely become the ball of choice for ceramic bearings and hybrid ceramic bearings, and also play an important role in the field of ultra-fine grinding.
In addition, its high-temperature stress relaxation rate is very low. The high-temperature physical properties of silicon nitride, which are all determined by the strong covalent bond nature of si3N4, largely lie in the grain boundary interlayer glass phase to improve the calcination of silicon nitride. Features Add a calcined modifier to the raw material, and the calcined modifier will produce a laminated glass phase at high temperature, and the laminated glass phase will exist at the grain boundary after cooling, and this property of silicon nitride can only be maintained and fully exerted after the product industry project solution A high-temperature characteristic, otherwise the grain boundary glass phase softens at high temperature and causes grain boundary loading, which has a great impact on high-temperature strength, stress relaxation and slow crack propagation in static fatigue.