AVS 52nd International Symposium
    Vacuum Technology Tuesday Sessions
       Session VT-TuP

Paper VT-TuP7
Effect of a Depth of a V-shaped Groove of Substrate Keeping Adsorption Layer on Sliding in a Vacuum

Tuesday, November 1, 2005, 4:00 pm, Room Exhibit Hall C&D

Session: Vacuum Technology Poster Session
Presenter: A. Kasahara, National Institute for Materials Science, Japan
Authors: A. Kasahara, National Institute for Materials Science, Japan
M. Goto, National Institute for Materials Science, Japan
M. Tosa, National Institute for Materials Science, Japan
Correspondent: Click to Email
We found that materials with a surface roughness around 100nm can offer as smooth sliding in a vacuum as at atmospheric pressure, and have also studied relation between direction of sliding probe and generated friction force. Results showed a decrease in friction force under optimum combination conditions that surface roughness of substrate was smaller than that of probe with surface roughness about 100nm and also showed that V-shaped groves line patterns of substrate and sliding probe cross each other at right angles. It is considered that smooth sliding might arise from absorption gas layer of the V-shape groove kept strongly. We therefore prepared V-shaped grooves with different heights for type 304 austenitic stainless steel sheets and studied a form of adsorption gas layer on the V-shaped groove of substrates to understand the effect of the grove on adsorption layer acting as a vacuum lubricant. Structure of the V-shaped groove such as height, open-angle and shape were analyzed by an atomic force microscopy (AFM) at an atmosphere. Cross-section of form adsorption layer on the V-shaped groove was then calculated by difference in pull-off distance from force curve diagrams obtained with AFM. Cross-section form of adsorption layer and the structure of the V-shaped groove were drastically changed by the structure depth. The structure of the V-shaped groove at a depth less than 120nm seemed to be satisfied with condition that absorption layer was trapped strongly. It is therefore concluded that the V-shaped groove at a depth about 100nm is ideal modified surface for satisfy adsorbed gases that can act as good vacuum lubricant because of exhibiting as low friction in a vacuum as friction at an atmospheric pressure.