Surface nitriding of titanium and aluminium by laser-induced plasma

摘要

In this work we study a nitriding technique for titanium and aluminium by means of laser-induced plasma. The synthesised layers are composed of a nitrogen concentration gradient over several mu m depth, and are expected to be useful for tribological applications with no adhesion problems. The method is tested on the synthesis of titanium nitride, and the role of the laser wavelength and pulse time duration is inspected by comparing layers obtained with two kinds of pulsed laser: a CO2 laser (lambda = 10.6 mu m) and an XeCl excimer laser (lambda=308 nm). The laser-plasma treatment is then applied to the superficial nitriding of aluminium, which is known to be difficult to carry out. Comparison is made between the nitriding process efficiencies of these two metals. (C) 1997 Elsevier Science S.A.