Structure of laser cladded tungsten carbide composite coatings

Carbide-metal matrix composite materials are used in applications were high wear resistance is critical. The laser surface cladding technique offers new advantages in depositing composite materials wear resistant coatings. Layers of WC in Co and Ni-based alloys matrix composites have been laser cladded on a low carbon steel substrate. Due to the right selection of the laser processing parameters during laser surface cladding porosity and crack free WC-metal composite coatings have been produced. The results of optical and SEM microstructure observations, X-ray phase, and EDS chemical composition analysis as well as cross-sectional microhardness distribution have been presented. The longer the laser beam-composite material interaction time, the higher level of the dissolution of primary carbide phase in metal matrix is to be expected. The primary WC particles dissolution degree depends also on their mesh size and volume fraction in composite material. The processing conditions should be optimized to keep the primary carbides dissolution at minimum. (C) 2001 Elsevier Science B.V. All rights reserved.