PERFORMANCE AND MICROSTRUCTURE OF SUPERHARD Si_3N_4 FILM BY HIGH POWER CO_2 LASER CVD

A superhard α-Si_3N_4 film,deposited on metal substrate,was produced by laser chemicalvapor deposition adopting a kW-level high power CO_2 laser.Most films are composedof fine Si_3N_4 partieles.They join the metal substrate in strong bond.The films havesuper hardness,excellent resistance to wear and corrosion,etc.Their thickness may becontrolled within 5-30 μm.