A low shear resistance layer was formed on a diamond surface to reduce wear under high temperature conditions. After finishing by polishing CVD, a diamond layer was treated by ion implantation. Tribological characteristics were evaluated under high temperature conditions and the following results were obtained. (1) At temperatures of 25℃ and 200℃, diamond films showed a low friction of below μ = 0.2, but at 400℃, the coefficient of friction increased to about μ = 0.4. In contrast, ion-implanted diamond films showed an effective reduction of friction at 200℃, the coefficient of friction remaining low even at 400℃. This indicated a notable effect of the ion-implantation treatment. The phenomenon was explained by the formation of an amorphous carbon layer by the ion-implantation process and its functioning as a low shear resistance layer. (2) At a temperature of 600℃, both diamond and ion-implanted diamond films showed a sharp increase in the coefficient of friction, but in both cases, damage was comparatively low. An increase of friction of ion-implanted diamond films at 600℃ was caused by a temperature rise on an amorphous layer formed by ion implantation and by the removal of the layer by friction. (3) A low friction that was shown by a diamond film and an ion-implanted diamond film at room temperature and 200℃ was affected by the formation of the adsorbed surface layer and a layer formed by friction.
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