Influence of copper coatings formation methods on tribological properties of friction couples

Abstract

In this study, the tribological behavior of copper coatings was investigated on 100Cr6 AISI 52100 steel substrates. Electrospark (ESA) and electric conductor explosion (ECE) techniques was employed on substrate with the deposition of copper and bronze powder. Friction tests were made by tribomachine TRM 500 using a friction couple “ball-three plates”. The microstructure of coatings was investigated by means of an optical microscopy and microhardness measurement. In addition, scanning electron microscopy (SEM) and X-ray diffraction meter (XRD) of the used powder and coatings was utilized. The results showed, that Cu coatings induces a large improvement of friction coefficient and, more generally, of all the wear characteristics. The Xrays diffraction studies have not shown the appearance of a new secondary phase, they only relieved internal stresses and lattice defects in the superficial layer. Metallographic analysis showed metallurgically bonded ESA and ECE coatings with no interconnected porosity and microcracking through the coating to the substrate. Microhardness measurements indicate uniformity in microhardness across the coating as well as within the 100Cr6 AISI 52100 substrate substantiating the premise that the ECA and ECE processes does not alter the microstructure of the base material