Tribological Performance of Alternating Multilayer Diamond Films on Si3N4 Ceramic Substrates

To avoid failures such as friction and wear of silicon nitride(Si₃N₄), Single-layer diamond films and Multi-layer diamond films were deposited on silicon nitride substrate by HOT FILAMENT CHEMICAL VAPOR DEPOSition. The nucleation, film quality, diamond surface and cross-sectional morphology, and surface roughness of the diamond films were characterized using X-ray Diffraction(XRD), Scanning Electron Microscopy(SEM), Atomic Force Microscopy(AFM), and Raman Spectroscopy(Raman). The friction and wear properties of different structural thin films were studied by the "ball disc" reciprocating friction and wear testing machine. The results show that multi-layer diamond films exhibit better tribological properties than single-layer diamond films. When the number of alternations is 4(the number of multilayer layers is 8), the friction coefficient and wear rate are the lowest, with values of 0.016 and 1.042×10^-7 mm³·N^-1·m^-1; but as the number of layers in the multi-layer structure increases, the interlayer thickness decreases, and the films rupture and peel off during the friction process; the bonding strength between the film and the substrate decreases, the quality of the film decreases, the friction coefficient increases to 0.042, and the wear rate increases to 4.661×10^-7 mm³·N^-1·m^-1, the friction and wear properties of films decreases.