Synthesis and properties of nanocomposite MoSiN hard films

MoSiN hard films with different Si content (Mo / Si = 0.6–4.2) were deposited at 500 °C in a gas mixture of Ar and N2 (Ar : N2 = 2 : 1) at a total pressure of 0.5 Pa by DC reactive magnetron sputtering, using a composite target consisting of Mo and Si in different area ratios. It was found that the microstructure of the MoSiN films at low Si content (Mo / Si = 4.2) is nanocomposite in which the nanocrystallites n-Mo2N imbedded in the amorphous matrix α-Si3N4. At high silicon content, however, the structure of the as-deposited MoSiN films are amorphous as analysed by XRD. Both hardness and elastic modulus of the as-deposited MoSiN films increase with decreasing Si contents and reach 30 and 366 GPa at Mo / Si = 4.2, respectively. The elastic recovery of the as-deposited MoSiN films is below 40% and the friction coefficient is between 0.22 and 0.28 independent of the Si content.