The luminescence emitted from the type Ib and IIa diamonds under the SiO2 polishing process

Abstract

The luminescence of triboplasma during diamond polishing was investigated. The main luminescence in the ultraviolet range came from N2 molecules in the air. The colors of the visible range of triboplasma were the same as those observed in the photoluminescence images, excited by the ultraviolet light. The color of the triboplasma luminescence was green for type Ib diamond, which was mainly from the H3 center. The blue luminescence for type IIa diamond was mainly from Band A. The correlation between the diamond temperature and periphery speed indicate that that the mechanical abrasion component also increased linearly. However the polishing rate showed a threshold at the periphery speed of 26 km/h which corresponds well with the threshold of the triboplasma generation. These results imply that the electrical and optical energy of the triboplasma excited the defect level at the diamond surface and enhanced the chemical polishing rate of the diamond.