TiCN coatings deposited by large area filtered arc deposition technique

Abstract

Nanocrystalline TiCN coatings were deposited from Ti targets under the atmosphere of mixed N2 and CH4 gases using a novel large area filtered arc deposition technique at a temperature of 350 °C. The microstructure, crystalline structure, bonding structure, coating composition, hardness, modulus, plasticity, and adhesion of the deposited TiCN coatings were systematically characterized using optical microscopy, x-ray diffraction (XRD), x-ray photoelectron spectroscopy, nanoindentation, Rockwell adhesion test, and scratch adhesion test, respectively. By adding 5% CH4 gas into the chamber, only 2.31 at. % of C was incorporated into the TiN coating to form Ti–C bonds. However, XRD results show a drastic change in the preferred orientation of the TiN grains from strong (111) to strong (220) orientation, as well as a decrease in grain size. Nanoindentation tests indicate a significant increase in hardness and elastic modulus. The plasticity and toughness of the TiCN coatings are comparable to that of the TiN coatings. Adhesion tests show that the TiCN coatings possess excellent adhesion on both 316 and 440a stainless steel substrates.