materials Article The Effect of Laser Beam Processing on the Properties of WC-Co Coatings Deposited on Steel Norbert Radek 1, *, Janusz Konstanty 2 , Jacek Pietraszek 3 , Lukasz J. Orman 4 , Marcin Szczepaniak 5 and Damian Przestacki 6   Citation: Radek, N.; Konstanty, J.; Pietraszek, J.; Orman, L.J.; Szczepaniak, M.; Przestacki, D. The Effect of Laser Beam Processing on the Properties of WC-Co Coatings Deposited on Steel. Materials 2021, 14, 538. https://doi.org/10.3390/ ma14030538 Received: 16 December 2020 Accepted: 19 January 2021 Published: 23 January 2021 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). 1 Faculty of Mechatronics and Mechanical Engineering,KielceUniversity of Technology, Al. 1000-lecia P.P. 7, 25-314 Kielce, Poland 2 Faculty of Metals Engineering and Industrial Computer Science, AGH University of Science & Technology, 30 Mickiewicz Avenue, 30-059 Cracow, Poland; konstant@agh.edu.pl 3 Faculty of Mechanical Engineering, Cracow University of Technology, Al. Jana Pawla II 37, 31-864 Cracow, Poland; jacek.pietraszek@mech.pk.edu.pl 4 Faculty of Environmental, Geomatic and Energy Engineering, Kielce University of Technology, Al. 1000-lecia P.P. 7, 25-314 Kielce, Poland; orman@tu.kielce.pl 5 Military Institute of Engineer Technology, Obornicka 136 Str., 50-961 Wroclaw, Poland; szczepaniak@witi.wroc.pl 6 Faculty of Mechanical Engineering, Institute of Mechanical Technology, Poznan University of Technology, Piotrowo 3 Str., 61-138 Poznan, Poland; damian.przestacki@put.poznan.pl * Correspondence: norrad@tu.kielce.pl; Tel.: +48-691-123-940 Abstract: The main objective of the present work is to determine the effects of laser processing on properties of WC-Co electro-spark deposited (ESD) coatings on steel substrates. Tungsten carbide coatings have been applied to steel substrates using a manual electrode feeder, model EIL-8A. The laser beam processing (LBP) of electro-spark coatings was performed using an Nd:YAG fiber laser. The microstructure and properties of laser treated/melted coatings were evaluated by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), surface geometric structure (SGS) and roughness measurements and adhesion, microhardness, residual stresses, corrosion resistance and application tests. The obtained experimental data were subjected to statistical analysis and multidimensional numerical and visual exploratory techniques. It has been shown conclusively that the laser-treated ESD WC-Co coatings are characterized by lower microhardness, higher resistance to corrosion, increased roughness and better adhesion to the substrate. LBP homogenizes the chemical composition, refines the microstructure and heals microcracks and pores of ESD coatings. The laser treated ESD WC-Co coatings can be used in frictional sliding nodes (e.g., on the front seal rings used in pumps) and as protective layers. Keywords: WC-Co coating; ESD method; laser beam processing; pulse plasma sintering; perfor- mance characteristics 1. Introduction Surface layers with a specific structure and properties are usually produced on ma- chine elements in various processes before they are used in practice. The variety of tech- nological possibilities leading to the products’ intended operational features is very large. Bond techniques are among the new generation of antiwear coatings. They create great technical and technological possibilities to control the parameters of surface layer manufac- turing processes. Introducing them into industrial practice promises great development prospects, which in the era of globalization significantly improves the competitiveness of products. Carbide coatings have numerous industrial applications. Characterized by high abra- sion, sliding and erosion resistance, they can be used as a substitute for hard chrome plating. Cemented carbides are cermets containing between 70 and 97 wt % of refractory metal Materials 2021, 14, 538. https://doi.org/10.3390/ma14030538 https://www.mdpi.com/journal/materials