Excellent Performance of Silicon Nitride Ceramics
The excellent performance of silicon nitride ceramics has a special use value for the work environments of high-temperature, high-speed, and highly corrosive media often encountered in the modern technology, and relatively prominent properties are:
(1) . The mechanical strength is high, hardness close to corundum, with self-lubricating property, and wear resistance. At room temperature, the flexural strength can reach up to 980MPa or more, and can be compared with alloy steel. The intensity can be maintained until 1200 ℃ and does not decline.
(2) . The thermal stability is good, and the thermal expansion coefficient is small, with good thermal conductivity, so the thermal shock resistance is good, and cracks will not occur under the thermal shock from room temperature to 1000 ℃.
(3) . The chemical properties are stable, with resistance to corrosion of almost all inorganic acids (except for HF), caustic soda with a concentration below 30%, as we as resistance to erosion of many organic substances. It cannot wet a variety of non-ferrous melts (especially the aluminum liquid), and can withstand intense radiation and irradiation.
. The density is low, specific gravity is small, only 2/5 that of steel, and the electrical insulation is good.