Influence of boron ion implantation on the wear resistance of TiAlN coatings

TiAlN coatings are receiving increasing attention for use as hard coating materials because of their unique combination of wear and oxidation resistance. In this work, boron ion implantation has been used to further improve the wear resistance of TiAlN coatings. TiAlN coatings were implanted with boron ions at 75 keV with a dose range of 1.0x10(17)-1.0x10(18) cm(-2). The composition and crystallographic structure of as-deposited and implanted TiAlN coatings were characterized by X-ray photoelectron spectroscopy (XPS) and glancing angle X-ray diffraction. XPS results revealed that boron ions showed a near-Gaussian distribution over a depth range of approximately 300 nm. Boron ion implantation led to formation of two new phases, TiB2 and BN, in the implanted region. The microhardness of TiAlN was increased by boron ion implantation. The friction coefficient of TiAlN was found to decrease with increasing dose of boron ions. Wear loss of TiAlN was significantly reduced by a high dose of boron ion implantation. The improved wear resistance of TiAlN was attributed to the hardening effect and formation of TiB2 and BN. (C) 2002 Elsevier Science B.V. All rights reserved.