SIMS Analysis of the wear of boron nitride tools for the machining of compacted graphite iron and grey cast iron

Cubic boron nitride (cBN) is a common material for tools for the machining of cast irons at high cutting speed. During the machining of compacted graphite iron (CGI) in continuous cutting the wear of the cBN tools was found to be significantly higher compared to the machining of grey cast iron. This is possibly a result of a heating of the tool surface during the cutting of CGI. One possible reason for the wear is diffusion of some elements from the cutting tool into the CGI or from the CGI into the cutting tool. SIMS measurements were carried out which prove the existence of such diffusion processes. A static model experiment has been performed by heating cBN tools to 700 °C while in contact with CGI or cast iron (CI). SIMS depth profiles of the cBN tools and of CGI/CI show that there is a diffusion of several elements in both directions (B, W and Ti from the cBN tools into the CGI or CI, Fe and Si from the CGI or CI samples into the cBN) up to a depth of 20 μm.