Laser surface treatment of S235JRC carbon steel with Co 2 B nanocrystals

In this study, Co 2 B nanocrystals, which were synthesized in a planetary type mill by using the mechanochemical method, were pre-coated on the surface of S235JRC low carbon steel substrates, and then the surfaces were clad using a CO 2 laser. In the experiments, laser scan speed was kept constant and laser power was specified as the variable parameter. The microstructure and phases of the coatings were investigated by using X-ray diffractometry, scanning electron microscopy, and optical microscopy. The mechanical properties of the coatings were characterized using micro-hardness, ball-on-disc wear, and scratch testing. The thickness of the coatings depending on the laser power was measured in the range 35–71 μm. The hardness and the wear resistance of the coatings were approximately 3 times higher compared to the base metal due to FeN 0.0760 , Fe 15.1 C, FeCo, and B 2 C 5 N 2 phases of the coatings. The most durable coatings against wear were obtained at 174 W and 220 W laser powers.