Structure, mechanical and tribological properties of Ti-doped and Cr-doped a-C:H:SiOx coatings

Abstract

The work is devoted to the deposition of Ti- and Cr-doped a-C:H:SiOx coatings on WC-8Co substrates using plasma-assisted chemical vapor deposition and magnetron sputtering methods. The structure, surface morphology, mechanical and tribological properties of coatings are investigated depending on the Ti or Cr content. It is shown that only a small concentration of Ti or Cr in coatings improves their mechanical and tribological properties compared to undoped coatings. The addition of 0.8 at.% Ti to the a-C:H:SiOx coating reduces its wear rate by 3 times, and the addition of 3 at.% Cr to the a-C:H:SiOx coating reduces its friction coefficient by 30% and the wear rate by 10 times. According to VDI 3198 standard, the Ti- and Cr-doped a-C:H:SiOx coatings with a low concentration of metals have the adhesive strength quality HF1. At higher metal concentrations, the properties of the coatings deteriorate due to graphitization of the carbon structure.