Effects of Plasma-Polymerized Coatings on the Frictional Behavior of Beryllium Surfaces

Eight different polymers were coated on beryllium surfaces by glow discharge polymerization in an inductively coupled tubular reactor. Using a pin-on-disk apparatus, friction tests were then conducted on the polymer-coated beryllium disks with Pyroceram pins. Of all the coated surfaces, polyethylene-coated beryllium exhibited the lowest friction with no measurable wear. The friction coefficient of the polyethylene-coated beryllium surface was found to depend strongly on the film thickness. The variation of friction coefficient with film thickness was analyzed, and a reasonable agreement between theoretical prediction and experimental data was obtained.