LAUSR

Abstract The deposition rate of ta-C films was increased by imposed pulse cathodic arc deposition (IP-CAD). The arc discharge behavior, deposition rate and micro-hardness of the ta-C films were investigated at average arc currents (Iaverage) ranging from 60 A to 100 A. The average substrate current density of IP-CAD was higher than that of DC-CAD at the same Iaverage. The optical emission spectra demonstrated that a dramatic increase in the evaporation rate of both carbon atoms and ions were achieved by imposing high pulsed current with Iaverage of 80 A. As the IAverage increased from 60 A to 100 A, the deposition rate increased by about 110% for the IP-CAD and by 33% for DC-CAD. This might be attributed to the cooperative actions of high evaporation rate of the carbon, large arc pressure near the arc spots and the focusing effect induce by high current. As compared to DC-CAD, the IP-CAD mode led to smaller concentration of sp3 (44%) than DC-CAD (59%) at the IAverage of 80 A. However, the IP-CAD ta-C films exhibited higher micro-hardness (~44.7 GPa) than that of DC-CAD (24 GPa). A preferable toughness was simultaneously obtained for IP-CAD.