Because of their superior properties, titanium aluminium nitride (TiAlN) films are increasingly
applied as protective layers on cutting and forming tools and turbine compressor blades and as
biocompatible barriers. TiAlN films were deposited on AISI 316L stainless steel substrates by
reactive magnetron sputtering using a target consisting of equal segments of titanium and
aluminium. X-ray diffraction characterisation showed that the coating structure was face centred
cubic. AFM and SEM studies indicated that the coatings are regular with dense shpherical
granular structure. The coatings were also characterised using photoluminescence spectroscopy
and Raman microscopy to elucidate the optical and acoustic phonon modes of the cubic lattices.
Characteristic peaks were observed at 250, 620 and 1180 cm21 in laser Raman studies.
Polarisation and impedance spectroscopy studies on TiAlN and TiN coated specimens were
conducted in Fusuyama simulated body fluid. The charge transfer resistance Rct increased in the
order: uncoated 316L substrate; 2 mm TiN film; 3 mm TiN film; 2 mm TiAlN film. Thus, the TiAlN
coating has the highest corrosion resistance, and was also found to have the most noble
corrosion potential and lowest corrosion rate in the polarisation tests