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Preparation of Samples with Both Hard and Soft Phases for Electron Backscatter Diffraction: Examples from Gold Mineralization

Published online by Cambridge University Press:  31 May 2013

Angela Halfpenny ,
Robert M. Hough  and
Michael Verrall
Angela Halfpenny*
Affiliation:
CSIRO Earth Science and Resource Engineering, Minerals Down Under Flagship, ARRC, 26 Dick Perry Avenue, Kensington, WA 6151, Australia
Robert M. Hough
Affiliation:
CSIRO Earth Science and Resource Engineering, Minerals Down Under Flagship, ARRC, 26 Dick Perry Avenue, Kensington, WA 6151, Australia
Michael Verrall
Affiliation:
CSIRO Earth Science and Resource Engineering, Minerals Down Under Flagship, ARRC, 26 Dick Perry Avenue, Kensington, WA 6151, Australia
*
*Corresponding author. E-mail: angela.halfpenny@csiro.au
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Abstract

Preparation of high-quality polished sample surfaces is an essential step in the collection of microanalytical data on the microstructures of minerals and alloys. Poorly prepared samples can yield insufficient or inconsistent results and, in the case of gold, potentially no data due to the “beilby” layer. Currently, preparation of ore samples is difficult as they commonly contain both hard and soft mineral phases. The aim of our research is to produce suitably polished sample surfaces, on all phases, for electron backscatter diffraction analysis. A combination of chemical–mechanical polishing (CMP) and broad ion-beam polishing (BIBP) was used to tackle the problem. Our results show that it is critical to perform CMP first, as it produces a suitable polish on the hard mineral phases but tends to introduce more damage to the soft mineral surfaces. BIBP is essential to produce a high-quality polish to the soft phases (gold). This is a highly efficient method of sample preparation and is important as it allows the complete quantification of ore textures and all constituent mineral phases, including soft alloys.

Keywords

broad ion-beam polishingchemical–mechanical polishingcarbonatequartzgoldelectron backscatter diffraction (EBSD)sample preparation
Type
Materials Applications
Information
Microscopy and Microanalysis , Volume 19 , Issue 4 , August 2013 , pp. 1007 - 1018
Copyright
Copyright © Microscopy Society of America 2013 

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