摘要 |
A coating is formed on a substrate by sputter ion plating wherein a DC glow discharge is generated under soft vacuum conditions in the presence of the substrate and of a cathode constituted by the coating material thereby to release material at the cathode by ion bombardment, which released material diffuses to the substrate to form the coating thereon, and wherein a potential is applied to the substrate during coating. In order to control the coating, for example when it is an alloy containing Al and when the substrate has sharp edges, the potential is applied in the form of an AC bias of e.g. 20 to 200 volts wherein ion polishing occurs in the negative part of the cycle and retention of coating material in the positive part thereof.
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