The tribological applications of WC-Co electro-spark coatings modified via laser treatment

Electro spark alloying (ESA) technique is a well established method. However, new lasers are becoming available on the market that can make this technique more attractive for various industry applications, e.g.: surface texturing technology, which has significant advantages for the wear decreasing into sliding friction. The work reported here concentrates on electro-spark coatings properties under laser treatment. The quality of coatings was proved via microstructure analysis, microgeometry measurement, hardness and tribological tests. These tests were carried out on WC-Co coating (the anode) obtained by electro spark deposition over carbon steel 45 (the cathode) and molten via laser beam (Nd:YAG). It was noticed that electro-spark deposited WC-Co coatings after laser treatment are characterized by lower microhardness, friction force and higher seizure resistance. Also, the laser treatment post-process produced homogeneous chemical composition, refinement of structure, healed microcracks and pores of the electro-spark deposited coatings. Direct application of WC-Co electro-spark coatings modified via laser treatment can be used in sliding friction pairs. The wear resistance protection should significant extend the final product durability, which will be investigated in future tests.