SURFACE NITRIDING OF TITANIUM AND ALUMINUM BY LASER-INDUCED PLASMA

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, a nd the role of the laser wavelength and pulse time duration is inspect ed 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 nitridin g of aluminium, which is known to be difficult to carry out. Compariso n is made between the nitriding process efficiencies of these two meta ls. (C) 1997 Elsevier Science S.A.