Wear Life of MoS{sub}2 Films Sputtered onto SUS 440 C Rollers: The Relation Between Film Density and Effect of Storage Period in Air on Wear Life

摘要

MoS{sub}2 films with various densities have been prepared by radio-frequency (RF) sputter deposition onto SUS440C steel rollers. Films were stored in air atmospheres of 30% relative humidity. The relationships between the wear life in air atmosphere of 9% relative humidity and storage period have been investigated. The variety in the wear life was divided into two patterns for density. The wear life of films with the density under 3.7 g/cm{sup}3 shortened with the storage period. As the density was smaller, the storage period until the wear life began to drop became shorter. The granular oxides of 2-3μm in size were scattered on the surface of stored film. These oxides might be formed by the crevice corrosion in the void division of films. On the other hand, the wear life of the films with 4.3 g/cm{sup}3 density lowered, after it increased once by the storage in air. The largest factor which influenced storage days until the wear life began to increase was the size of the (00·2) interplanar spacing of a film. As the size was smaller, the storage period until it began to prolong wear life was long. As a result of secondary ion mass spectroscopy (SIMS) analysis, the oxygen was mainly observed in the film side near the MoS{sub}2/roller interface. The films might be more oxidized by the contact corrosion.