Recent trends in surface engineering using cathodic arc technique

The paper describes the developmental work of single layer and multilayer TiN, m-TiCN, (Ti,Al)N and m-(Ti,Al)N coatings for industrial applications (where the prefix ‘m’ stands for multilayer). The cathodic arc technique was used to deposit these coatings on high speed steel substrates (M2 grade) and cutting tools. For multi-layer m-TiCN deposition, (N2+CH4) gas mixture was used. For (Ti,Al)N and m-(Ti,Al)N coatings, sintered-TiAl targets with 70 at.% aluminum were used. Thickness, hardness, abrasive wear and adhesion strength of the coatings were measured for a large number of samples (∼50) from different cycles and average values are presented in this paper. X-Ray diffraction (XRD) measurements reveal that all the coatings have (111) orientation. (Ti,Al)N coating has a better oxidation resistance than the other coatings under investigation. The corrosion resistance of the coatings under investigations is found to be comparable, (Ti,Al)N being marginally superior amongst the coatings studied. Wear constant measured using Calo-wear equipment for TiN, m-(Ti,Al)N, m-TiCN, and (Ti,Al)N are 2.7, 1.9, 1.7 and 0.7×10−13 m2 N−1, respectively, indicating lowest wear resistance for TiN and highest for (Ti,Al)N amongst the coatings under investigation. A good correlation has been observed between the wear constant and the tool wear during machining.