Effects of superimposed pulse bias on TiN coating in cathodic arc deposition

Orthogonal designs are used to investigate the main factors when doing experiments in which pulse bias is superimposed on d.c. bias during cathodic arc deposition of TiN. Pulse peak, duty cycle, frequency, direct voltage, arc current and pressure all are investigated when coating TiN on HSS substrates. Roughness, surface micrograph, microhardness and thickness are tested. By analysis of variance, it is shown that pressure and frequency are the main factors. Ra and droplet density of the film with (d.c.+pulse) bias decrease. A simple explanation for the result is suggested.