Low friction coatings prepared by high performance type spray gun

To produce low friction coatings to be used as overlays for automobile journal bearings and to perform depositions with high rate, we prepared composite coatings of Ag and graphite by using the new-type spray gun based on the forced constricted type plasma jet generator (i.e. the high performance type spray gun). Characterization of the films showed the graphite phase dispersed into the Ag matrix, analyzed by optical microscopy, electron probe microanalysis and X-ray diffraction. The coefficient of friction of the Ag/graphite overlay measured using ball-on-disc tribometer was reduced by a factor of five compared with that of bronze substrate and by factor of two compared with that of the Ag/graphite overlay prepared by ECR sputtering.