WC-Co cutting tool surface modifications induced by pulsed laser treatment

Many innovative industrial materials like carbon fibers, metal matrix compo sites (MMC), hypereutectic Al/Si alloys are very hard and difficult to mach ine with traditional cutting tools. CVD diamond coated inserts seem to be t he most promising system to overcome the problem. The WC.xCo hard metal. a widespread used and cheaper bulk material, could be a convenient substrate for diamond film coatings. The Go-rich binder phase, however, constitutes a severe obstacle for diamond deposition and adhesion, owing to its catalyti c effect for amorphous carbon or soot formation. Several chemical and physi cal methods have been developed to etch Co from the surface: however, no de finite and reliable procedure has been achieved. In our experiments, we tre ated the WC.xCo hard metal substrates with ArF(lambda = 193 nm, hv = 6.4 eV ) and CO2 (lambda = 10.6 mu m, hv = 0.12 eV) pulsed lasers, at different fl uences and incident angles, to modify both the chemical composition and the structure of the surfaces. The morphological and chemical effects have bee n studied by SEM/EDAX microscopy and XPS surface analysis. Diamond nucleati on and adhesion are compared with results obtained on the: plain tool subst rates. (C) 1999 Elsevier Science B.V. All rights reserved.