Characterization and properties of TiN-containing amorphous Ti-Si-N nanocomposite coatings prepared by arc assisted middle frequency magnetron sputtering

Abstract TiN-containing amorphous Ti–Si–N (nc-TiN/a-Si 3 N 4 ) nanocomposite coatings were deposited by using a modified closed field unbalanced middle frequency magnetron sputtering system which is arc assisted and consists of two circles of targets, at a substrate temperature of 400 °C. The coatings exhibit good mechanical properties that are greatly influenced by the total gas pressure and N 2 /Ar ratios. For coatings prepared at a N 2 /Ar ratio of 3:1, the hardness increases from 24 GPa at a total gas pressure of 0.2 Pa–58 GPa at 0.4 Pa, and then, the hardness decreases gradually when the total gas pressure was further increased. On the other hand, the friction coefficient decreases monotonously with increasing total gas pressure. XRD, XPS and high resolution TEM experiments showed that the coatings contain TiN nanocrystals embedded in the amorphous Si 3 N 4 matrix. The coating deposited under optimum conditions exhibits excellent tribological performance with a low friction coefficient of 0.42 and a high hardness of 58 GPa. These properties make it possible for industrial applications.