Polishing diamond coatingsby combination of electron cyclotron resonance plasma etching and mechanical polishing

The diamond coatings, synthesized by chemical vapor deposition, were polished by a combination of electron cyclotron resonance (ECR) plasma etching and mechanical polishing. The diamond coatings, before and after polishing cycles, were characterized with scanning electron microscopy and Raman spectroscopy. The impact of the cycle of plasma etching and mechanical polishing on the microstructures were investigated. The results show that the newly-developed technique significantly reduced its surface roughness possibly because much of the non-diamond phased carbon was etched away. For example, mechanical polishing for 10 min decreased the roughness of the plasma etched diamond coatings from 7.284 to 1.054 μm, whereas mechanical polishing for 30 min reduced the roughness of the control sample from 7.284 to 1.133 μm. Moreover, in the initial polishing stage, the polishing rate of the etched surfaces was 3 times higher than that of the un-etched one; and 3 polishing cycles decreased the surface roughness down to 0.045 μm. ©, 2015, Science Press. All right reserved.