A trace metal leaching test was applied to investigate coverage of a diamond-like carbon layer. Three trace metals - cobalt, nickel and iron - were measured. The change of seed and diamond-like carbon thicknesses influenced the trace metal concentration detected due to the passivation of the substrate via pinholes. Artificial pinholes were applied for a diamond-like carbon pinhole study, and it was found that the diameter, shape and total surface area of the holes affected the trace metals detected. The surface morphology and thickness were examined using scanning electron microscope and transmission electron microscope. The passivation was analyzed using electron energy loss spectroscopy.
