Laser treatment of vacuum plasma sprayed CoCrAlY alloy

The coatings of an alloy Co + 17 wt.% Cr + 12.5 wt.% Al + 0.45 wt.% Y were vacuum plasma sprayed onto steel substrates. The CO: high power, continuous wave (c.w) laser with a Gaussian-rectangular beam was applied to treat these coatings after spraying. The treatment was made with a 7.5 kW cm(-2) power density and the relative beam scan speed was in the range of 0.7 to 1.3 m min(-1) and resulted in a melting of the coatings. The microstructure of treated alloy as well as the heat affected zone were analysed using optical and scanning electron microscopes. Finally, the wear resistance of the coatings was tested using: sliding wear, oscillating wear and scratch tests.