The Microstructure, Surface Topography and Wear Resistance of Cold-Sprayed (Cr3C2-25(Ni20Cr))-(Ni-graphite) Composite Coatings Modified by Diode Laser Treatment

Abstract

Cold-sprayed composite coatings have several advantages; however, some properties, such as hardness and abrasion resistance, are lower than those in plasma- or HVOF-sprayed deposits. This work showed that the use of surface diode laser processing allowed the development of (Cr3C2-25(Ni20Cr))-(Ni-graphite) cermet coatings with good adhesion to the steel substrate, and increased properties in the near-surface zone, below which the properties of cold-sprayed coatings were retained. Studies of the microstructure in the micro/nanoscale of the laser-treated coatings showed strong grain refinement after surface treatment. Cr7C3 carbide of various shapes and sizes was formed in the structure; while, a several hundred nanometre layer of Cr2O3 oxide appeared on the coating surface. The changes occurring in the microstructure have resulted in increased mechanical and tribological properties of the laser-treated zone of deposits.