Diamond like carbon films deposited by HiPIMS using oscillatory voltage pulses

Diamond like carbon films were deposited by sputtering a graphite target using deep oscillation magnetron sputtering (DOMS). DOMS is an alternative high power impulse magnetron sputtering technique that uses large voltage oscillation packets to achieve high power pulses for sputtering. The deposition variables include negative substrate bias voltage, working pressure and peak target current density (I). In this study, the deposition rate was varied from 23 nm.min(-1) to 70 nm.min(-1) by changing the above variables. The peak substrate current density during high power pulses was measured up to 50 mA.cm(-2). The microstructure of the films was characterized using scanning electron microscopy and Raman spectroscopy. Higher J, lower working pressure, and properly controlled bias voltage promoted sp(3) bond formation and increased the density of the films. Super dense DLC films were obtained by increasing J above 0.75 A.cm(-2) at 0.13 Pa with a substrate bias voltage of -60 V. The surface of the films became smoother as the J was increased. The adhesion and mechanical and tribological properties of the films were measured using HRC tests, nanoindentation and ball on disk wear tests. The films exhibited excellent adhesion on stainless steel. The films exhibited the maximum hardness value of 35 GPa, the lowest dry sliding COF of 0.09 and the lowest wear rate of 1.5 x 10(-8) mm(3) N-1 m(-1). Published by Elsevier B.V.