Paper VT-ThP9
Influence of the Adsorption Gas on Friction Coefficient and Wear Track.

Thursday, October 18, 2007, 5:30 pm, Room 4C

Surface modification of sliding motion materials is inevitable to reduce friction as well as outgassing in a vacuum. We have therefore studied the development of advanced vacuum motion materials by control of surface roughness on a submicron scale. We have successfully found that any material sheet with about 100nm-250nm surface roughness showed same friction coefficient in a vacuum as at an atmospheric pressure for Type 304 austenitic stainless steel materials and anodic oxidation processed aluminum materials. Materials with except 100nm-250nm surface roughness shows a different friction coefficient for the friction measurement in a vacuum and at an atmospheric pressure. Type 304 austenitic stainless steel sheets had a larger friction coefficient in a vacuum than at an atmospheric pressure. The anodic oxidation processed aluminum sheets had a smaller friction coefficient in a vacuum than at an atmospheric pressure. We therefore studied the relation between friction coefficient and cross-section shape of wear track depth by an atomic force microscope (AFM) Type 304 austenitic stainless steel sheets had a deeper wear track in a vacuum than at an atmospheric pressure probably because the increase in friction coefficient to the desorption of the adsorption gas as a lubricant. The anodic oxidation processed aluminum sheets had shallow wear track in a vacuum than at an atmospheric pressure probably because the adsorption force generated by the applied load was reduced by the desorption of the adsorption gas. As a result, it was thought that the absorption layer on the materials surface influenced by the surface roughness had an important role on friction.