Characterisation of mechanical and wear properties of NiAl and Ni-Al-N thin films deposited by closed field unbalanced magnetron sputter ion plating

NiAl and Ni-Al-N thin films with a thickness of approximately 1 μm have been deposited onto glass and stainless steel 316 substrates using closed field unbalanced magnetron sputter ion platting process. A CSM scratch tester was used to determine the critical load, the coefficient of friction and wear rate of the films. XRD analysis confirmed the presence of β-NiAl phase. EDAX revealed nearly equal atomic composition of Ni and Al at 300 W for Ni and 400 W for Al targets, respectively with the Ni-Al-N thin films showing a nickel rich NiAl phase. AFM indicated a smooth surface finish with surface roughness ≤ 100 nm. Nanoindentation for coatings on glass substrates displayed hardness and elastic modulus of 7.7 GPa and 100 GPa respectively. Hardest coatings obtained were at 10% of N content. Scratch test of coated samples gave critical load, friction of coefficient and wear rate of 24 N, 0.24 and 1×10−6 mm3/m respectively on steel.