Enhanced sealing performance with CVD nanocrystalline diamond films in self-mated mechanical seals

摘要

Nanocrystalline diamond (NCD) films were evaluated as protective tribo-coatings on silicon nitride mechanical seal rings. The NCD films were deposited by microwave plasma assisted chemical vapour deposition (MPCVD) method from a CH_4/H_2/N_2 gas mixture. The sealing performance and friction behaviour of self-mated NCD films were assessed using the ring-on-ring tribological test in planar configuration varying the rotating speed and the applied load. Water sealing conditions were obtained in the P centre dot V (P, the effective pressure and V, the linear speed) range of 0.5-4.8 MPa ms~(-1). The high hardness and smoothness of the NCD films resulted in a very low and stable friction coefficient value of 0.01, without any measurable wear.