A study of the tribological behavior of duplex treatment

The objective of this study is to determine the influence of duplex treatment (low pressure thermochemical treatment and PVD coating) on tribological properties. The carbide and carbonitride coatings are deposited by dual RF magnetron sputtering on the reference steel 18CrMo4 and the carburized and carbonitrided one (respectively). The low-pressure carburized and carbonitrided samples present 0.72 and 0.69 w. % carbon content at their surface respectively and a hardness of about 700 Hv0.1. The carburizing and carbonitriding layer are respectively 540 and 390 µm thick, while TiWC and TiWCN were 2.8 and 3.4 µm thick respectively. Tribological tests were performed by a Pin-on-Disk rotative tribometer with alumina and steel (100Cr6) balls. A comparison of the friction coefficient and the wear rate for each sample has been made. The adhesion of the coatings has been performed by analyzing the wear track using optical profilometry, optical microscopy and scanning electron microscopy equipped with an energy-dispersive X-ray spectrometer. The best tribological performances were observed by combining carbides coatings and carburized 18CrMo4 or reference steel. In contrast, the TiWCN thin film completely delaminated