Laser ablation and micropatterning of thin TiN coatings

Laser ablation of thill TIN films deposited on steel substrates has been studied under wide-range variation of irradiation conditions (pulsewidth, wavelength, energy density and spot size). It has been demonstrated that both picosecond (150-300 Ds) and nanosecond (5-9 ns) laser pulses were suitable for controllable ablation and microstructuring of a 1-mum-thick TiN film unlike longer 150-ns pulses. The ablation rate was found to be practically independent of the wavelength (270-1078 nm) and pulsewidth (150 ps-9 ns), but it increased substantially when the size of a laser spot was reduced from 15-60 mum to 3 mum. The laser ablation technique was applied to produce microstructures in the thin TiN films consisting of microcraters with a typical size of 3-5 mum in diameter and depth less than 1 mum Tests of lubricated sliding of the laser-structured TiN films against a steel ball showed that the durability of lubricated sliding increased by 25% as compared to that of the original TiN film.