High wear-resistance characteristic of boron-doped nano-polycrystalline diamond on optical glass

Boron-doped nano-polycrystalline diamond (B-NPD) uniformly containing boron atoms in the diamond lattice has been successfully produced by direct conversion sintering under ultra-high pressure and high temperature using boron-doped graphite as a starting material, and its wear properties on optical glass materials have been investigated. The chemical wear of B-NPD sliding on glass was highly suppressed under sliding conditions where undoped NPD is worn considerably by chemical reaction with glass because the frictional resistance of NPD decreased and its sliding performance was improved by adding boron. In addition, because B-NPD has electrical conductivity, tribo-microplasma damages attributed to frictional electrification were not observed. Thus, the wear resistance of B-NPD on glass materials was improved greatly in comparison with that of undoped NPD. These results indicate that B-NPD has outstanding potential as a cutting tool material for high-performance and high-precision cutting on various types of glass, nonconductive ceramics and rigid plastics which are difficult to cut by conventional diamonds because of tribo-chemical wear or tribo-electrical wear.