Preparation of CVD Diamond Material and Its Application in High Parameter Mechanical Seal

Mechanical seal is the key device to prevent the leakage of medium in a rotating equipment. It is widely used in petrochemical, aerospace and other industries. Its sealing performance is mainly determined by the friction pair of mechanical seal. Under the harsh conditions of high pressure, high speed, and high temperature, traditional ceramics materials are difficult to meet the needs of extreme environments. It is urgent to develop new materials with low friction and high wear resistance to meet the requirements of high reliability and long life of mechanical seal equipment.<br/>CVD diamond material has excellent performance of hardness, friction, wear resistance and corrosion resistance. Therefore, it is an ideal material for mechanical seal friction pairs in extreme environment. In this paper, micron crystalline diamond (MCD) films and nano-crystalline diamond (NCD) films were prepared on SiC friction pairs by hot filament chemical vapor deposition (HFCVD). The roughness of the friction pair surface can be modified by grinding and polishing. Different selections of friction pairs are used to evaluate the performance of mechanical seals. Diamond can greatly improve the friction coefficient and wear rate of silicon carbide friction pairs, its dry friction coefficient can be as low as 0.1, the wear rate can be as low as 4.00×10^-7mm³.N^-1.m^-1, and PV value can be greater than 63.5MPa. m/s. In oil drilling, the friction pairs made of diamond material can work normally for more than 1000 hours.