In order to examine the effect of Cr on the microstructure and hardness behaviour of WC cermet, coatings have been obtained by laser surface alloying technique. WC-9Co-4Cr particulate was injected into the surface of AISI 304L stainless steel under different processing variables. The morphologies and microstructures of the composite coatings were investigated using optical microscopy and high resolution scanning electron microscopy, while the phase changed were observed using x-ray diffraction. The surface hardness was determined using the Vickers microhardness tester. The excessive heat from the laser beam partially melt the WC-Co which results in carbon deficiency and precipitation of carbon as graphite to form CO2 pores within the coatings. 4% Cr has been added to compensate for the precipitation of graphite to form Cr3C2. A considerable increase in hardness value from 246 to 1331 Hv0.1 was achieved when alloying was carried out at high laser power and speed, the pores being completely eliminated.
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