Cemented carbide surface modifications using laser treatment and its effects on hard coating adhesion

A pulsed HyBrID copper laser (510 nm, 30 ns, 13.8 kHz) was used for the treatment of cemented carbide substrate before deposition of TiCN/Al2O3/TiN coating by the MT-CVD process. The influence of the laser treatment on the surface morphology, surface structure and coating adhesion was investigated based on the laser irradiation dynamics used here. The experimental results showed that a large variety of cemented carbide surface textures could be obtained, depending on the laser intensity and number of applied laser pulses. Moreover, this laser process was found to produce some less carbon non-stoichiometric WC phases such as β-WC1 − x and α-W2C. Finally, using the Rockwell C adhesion test as output criteria, two sets of laser parameters were identified that produced a surface with adhesion strength comparable to that of commercial tools pretreated by micro-sandblasting.