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

Many innovative industrial materials like carbon fibers, metal matrix composites MMC., hypereutectic AlrSi alloys are very hard and difficult to machine with traditional cutting tools. CVD diamond coated inserts seem to be the 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 Co-rich binder phase, however, constitutes a severe obstacle for diamond deposition and adhesion, owing to its catalytic effect for amorphous carbon or soot formation. Several chemical and physical methods have been developed to etch Co from the surface; however, no definite and reliable procedure has been achieved. In our experiments, we treated the WC, xCo hard metal substrates with ArF ls193 nm, hns6.4 eV.and CO2 ls10.6 mm, hns0.12 eV.pulsed lasers, at different fluences and incident angles, to modify both the chemical composition and the structure of the surfaces. The morphological and chemical effects have been studied by SEMrEDAX microscopy and XPS surface analysis. Diamond nucleation and adhesion are compared with results obtained on the plain tool substrates. q1999 Elsevier Science B.V. All rights reserved.