Flat washer specimens of various r.f. sputtered MoS2 coatings were subjected to sliding loads on a standard thrust washer tester to determine the relationship between coating parameters and wear life. Argon pressure, target-to-substrate distance, r.f. wattage to target, and duration of sputter etch cleaning, in addition to coating thickness, were the parameters varied. All testing was performed in a nitrogen atmosphere. The r.f. sputtered coatings were applied using a planar target of diameter 25.4 cm in the r.f. diode mode without substrate biasing. Testing was conducted in two phases. The first phase was a single variable test; the second was a factorial design. Some initial difficulty was experienced in obtaining adequate wear test samples owing to insufficient flatness of the surface finish of the sample material; this difficulty was overcome by polishing the material to a mirror finish. In phase two testing, analysis of variance by Yates' method was used to obtain maximum information for the number of samples used. The results of the phase one testing indicate that wear life increases as the target-to-substrate distance is decreased and as chamber pressure is increased; that wear life decreases as the r.f. wattage to the target is increased; that the duration of sputter etch cleaning has little or no effect on wear life; and that wear life is strongly dependent, as expected, on coating thickness, the thicker films providing longer life. Phase two testing indicated that the distance-pressure interaction is the most significant factor affecting wear life. Chamber pressure was found to be the only single variable having significant effect. © 1979.
