The influence of laser treatment on the properties of electro-spark deposited coatings

The aim of the study is to determine the influence of the laser treatment process on the properties of electro-spark deposited coatings. The properties were assessed by analysing the coating microstructure, microhardness, residual stresses, bonding strength and corrosion resistance. The tests were conducted for Mo, Ti and Cu coatings (the anode), which were electro-spark deposited over the C45 steel substrate (the cathode) and melted with a laser beam. The coatings were deposited by means of an ELFA-541. The laser processing was performed with an Nd:YAG, BLS 720 system. The tests show that the laser-treated electro-spark deposited Cu-Ti and Cu-Mo coatings are characterized by higher microhardness, higher adhesion and higher resistance corrosion. It is also reported that in laser-treated coatings tensile stresses occur deeper. The laser treatment process causes the homogenization of the chemical composition, the structure refinement and the healing of microcracks and pores of the electro-spark deposited coatings. The coatings, whether laser-treated or not, exhibit very good performance properties, and this makes them suitable for use in sliding friction pairs.