The effect of cn coatings doped with niobium, titanium and zirconium metal on mechanical, tribological and corrosion resistance properties of thin films

CN-Nb, CN-Ti and CN-Zr that are respectively doped with Nb, Ti and Zr metal in a CN coating are deposited on SKH51 substrate using DC unbalanced magnetron sputtering (DC-UBM). The coatings’ chemical characterization, morphology, mechanical, tribological and corrosion properties are determined. The XRD analysis shows when a low content of metal is added, the coatings exhibit DLC structures. Result from the incorporation of metals, coatings performed denser texture. Simultaneously, the surface became smoother and denser while surface roughness varied from 0.036 to about 0.020 µm. Various properties are improved over CN coating, CN-Ti has a 64% greater hardness at 21.9 Gpa and adhesion 26% better, with a critical load of 87 N. The elastic recovery ranges from 68% (CN) to 100% (CN-Nb and CN-Zr), the wear rate varies from 0.51 10^-6 mm³/Nm (CN) to 0.1 10^-6 mm³/Nm (CN-Zr) and the wear depth is reduced by about 73%. An increase in the elastic recovery gives a decreased wear rate. In addition, the corrosion resistance is increased because there is a decrease in the corrosion current density and the CN-Zr coating performed about 35 times better than a CN coating.