The Improved Friction Properties of Bonded MoS2 Films by MAO Treating of Al Substrates

Abstract

The bonded MoS2 films is widely used as solid lubricants in aerospace mechanisms due to their excellent tribological properties. Traditionally, the MoS2 was directly bonded on the Al substrate that was only treated by the technique named of sandblast. For improving the tribological properties of MoS2 films, micro arc oxidation (MAO) instead of sandblast was introduced as a new technique for treatment of Al substrate. In this article, the tribological properties of MoS2 films bonded on different surface of Al substrate as mentioned above was discussed, respectively. It is concluded from the test results that the MoS2 films bonded on substrate treated by MAO have better tribological properties than the ones treated by sandblast, and the endurance life against abrasion of the former is as high as twenty times than the latter by the stand test method of ball on disk using the UMT Multi-Specimen Test System. This test results can be illustrated by the following reasons. One point is the porous microstructures of MAO ceramic coatings on the Al substrate. The coatings have numerous pits to be good at increasing the binding force with the MoS2 films, and the pits can also provide a MoS2 lubricants reservoir during processes of friction. Both of them improved the MoS2 film’s ability of wear-protective. Otherwise, naturally the MAO coatings’ hardness is higher than the Al, and this ensures well wearing resistance, especially in practical application to big load-supporting moving parts, such as bearing, gear, etc…