HARD AND TOUGH NANOCOMPOSITE TiN-Ni COATINGS DEPOSITED BY REACTIVE ION BEAM ASSISTED DEPOSITION

Abstract

A new category of hard nanocomposite coatings with adjustable improved hardness or enhanced toughness consisting of nanocrystalline (nc-) titanium nitride grains embedded in an amorphous (a-) metallic intergranular nickel phase i.e. nc - TiN / a - Ni type has been produced and investigated. Coatings were deposited at 573K on different substrates using a reactive dual ion beam sputtering (RDIBS) technique. A composite Ti - Ni target was sputtered with 1.2 keV Ar + ions and the growing films were bombarded with a mixture of 50 eV Ar ++ N 2++ N + ions. XRD, nanoindentation, high load indentation and pin-on-disk tests were used to characterize structural and mechanical properties. By adjusting Ni content enhanced hardness or toughness is obtained with an important improvement in wear resistance corresponding to the coatings exhibiting the highest toughness than highest hardness.