Selective ablation of titanium nitride film on tungsten carbide substrate using ultrashort laser pulses

Abstract

Many machining tools use coatings on their cutting surface to improve the machining process and increase its useful life. Due to damage or wear on the cutting edge, it is often desirable to remove this film for tool recovery. Doing this without damaging the base material is not easy due to the small thickness of the coating and because its hardness is much greater than that of the substrate. In this work, the removal of titanium aluminum nitride (TiAlN) coating on tungsten carbide (WC) was done with the use of femtosecond laser pulses. Complete film removal was obtained without damage to base material using a fluency far below that of the film ablation threshold for a single pulse. A decrease in this threshold was obtained by applying a high number of overlapping pulses with a low fluency until the incubation effects reduced the film damage threshold to a value slightly below to that of the substrate. With this technique precise and clean results were obtained and are reported in this work.