Effects of Microstructure of Compacted Graphite Iron in Tribological Strategy

Abstract

In this paper, the effect of compacted graphite iron (CGI) microstructure has been investigated in tribological strategy. From industrial context, two coatings have been chosen: a single layer coating (physical vapor deposition (PVD)) and a multilayer coating (chemical vapor deposition (CVD)). Pin-on-disk tests have been done to analyze wear mechanisms and to directly obtain the coefficient of friction. Rotation speed of the disk has been adjusted to get the same linear velocity on different disk radii to get up to 150 m min−1 similar to machining condition. Three-dimensional (3D) profilometer, scanning electron microscopy, and nano-indentation were used to observe the track profiles, the pin, and the disk wears and to measure the hardness of microstructure components, respectively. Results showed that PVD coating was more abrasive and had more volume of sticking materials. Chemical vapor deposition coating, which could be the most appropriate for machining CGI, has a real antisticking property and has less friction coefficient than PVD coating. But the presence of small TiCN precipitates in CGI material has a proven negative effect in CVD coating lifetime.