Sliding wear behavior of polycrystalline TiN/CrN multilayers against an alumina ball

Sliding wear experiments were conducted using a ball-on-disc rotating frict ion apparatus to evaluate the wear behavior and properties for TiN, CrN and TiN/CrN multilayers with different modulation periods deposited on WC/Co c emented substrates with reactive magnetron cathodic sputtering. TiN showed the higher coefficient of friction of 0.9 and the higher wear rate due to t he larger debris as abrasive remained on wear scar. It was found that the c oefficient of friction of TiN/CrN multilayers against the alumina ball rang ed from 0.3 to 0.5. TiN/CrN multilayer at Lambda of 21 nm, possessing the m aximum hardness enhancement, showed the smallest friction coefficient value of 0.3. The lower coefficient of friction of TiN/CrN multilayers correspon ds to the enhancement of hardness, the promotion of the formation of the de nse Cr2O3, and CrO3 oxide layer, and the exclusion mechanism of debris from the wear scar. The wear volume of TiN/CrN multilayers was decreased with o ne digit in comparison with that of TiN single layer coatings. TiN/CrN mult ilayer technique, by enhancing the hardness, promoted the formation of an o xide layer on the wear scar. The dense Cr2O3 and CrO3 oxide layers help to build additional protective films on the worn surface, induce a lower coeff icient of friction and will contribute to the decrease of wear loss for TiN /CrN multilayers. (C) 2000 Elsevier Science S.A. All rights reserved.