Laser surface treatment of plasma-sprayed yttria-stabilized zirconia coatings

A continuous wave CO2 laser with a defocused beam has been employed to seal the surface layer of plasma-sprayed of 8wt. % yttria-stabilised zirconia coatings on AISI 1045 steel substrate. The effect of laser remelting on microstructure and corrosion resistance of plasma-sprayed layer was investigated. The microstructure of the sealed layer presented a cellular structure which grows perpendicular to the surface. The micrographs have shown small cracks and absence of porosity. The corrosion resistance was analysed by the EIS and polarisation tests by using a 3 % NaCl solution. Laser sealing improved the corrosion resistance of the coating and increased the microhardness.