Formation and characterisation of cobalt depleted outermost layer of WC–Co composite materials

Abstract

The cobalt depleted layer of WC–Co composite materials was investigated after selective cobalt etching in diluted Caro’s acid. The time dependence of Co etching and the thickness of the etched layer was determined by using Glow Discharge Optical Emission Spectrometer (GD-OES) depth profiling as well as by calculation method based on determination of the dissolved Co by Atomic Absorption Spectrophotometric (AAS) measurement. The integrity of the modified outermost layer of the WC–Co composite materials were qualified using Rockwell C indentation test. This test methods were found usable for optimisation of the pre-treatment applied before the diamond thin film deposition.