Improvement of solar absorbing property of Ni-Mo based thermal spray coatings by laser surface treatment

摘要

Ni-Mo and Ni-Mo-Co high velocity oxy-fuel (HVOF) sprayed coatings were treated by Nd:YAG laser source, for the purpose of improving the solar absorbing effect. The coatings after laser treatment showed increment on solar absorptance (alpha) as the Ni-Mo sample increased from 0.84 to 0.88 and Ni-Mo-Co sample from 0.75 to 0.83. To elucidate the mechanisms for the improvement, microstructures of the coatings before and after laser treatment were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM) and laser scanning confocal microscope (LSCM). The results demonstrated that the enhanced cc was attributed to multiple mechanisms including the decrease in nickel oxide content, the increase in metallic volume fraction, the reduction of micro-defects as well as the greater surface roughness. (C) 2015 Elsevier Ltd. All rights reserved.