Analysis of polished polycrystalline diamond using dual beam focused ion beam microscopy

Abstract

This paper presents a study on polycrystalline diamond (PCD) polished by dynamic friction polishing (DFP) with the aid of advanced dual beam FIB (focused ion beam) microscopy. After disclosing a variety of wear tracks by DFP using electron imaging in combination with the ion channelling effect, a dual beam FIB was successfully employed at wear track sites to specifically create both the large cross-sectional specimen for microanalysis and thin foil for nanoanalysis. The study concluded that the polished PCD subsurface was free from microscale cracking. However, the attached debris layer on the top surface contained metal oxides and non-diamond carbon phase with inhomogeneous distributions of C, Fe, Cr, Ni, Si and O across the layer. An attached layer directly above a diamond grain was composed of essentially amorphous carbon, suggesting that a direct phase transformation from diamond crystalline to amorphous occurred during DFP.

Keywords:

• diamond
• microstructure
• nanostructures
• focused ion beam
• SEM
• HRTEM
• EELS
• EDS

Acknowledgements

The authors thank the staff of AMMRF, Charlie Kong of the University of New South Wales (UNSW) for his help in specimen preparation and Shaun Bulcock of the University of Sydney (USyd) for training in EELS analysis. Peter Felfer at USyd and Leonard Green of the University of Adelaide are also acknowledged for their help. This work was funded by Australian Research Council.