Effect of Cr content on microstructure and oxidation resistance of laser-clad Cu-Ni-Fe-Mo-xCr alloy coating

Cu-Ni-Fe-Mo-xCr type alloy coatings with different Cr content were produced on a medium carbon steel substrate by laser cladding in this investigation. The effect of Cr content on macro-quality, microstructure, phase structure and high temperature oxidation resistance of the coatings was revealed by macro photography, optical microscopy (OM), environmental scanning electron microscopy (ESEM) incorporating with EDX microanalysis, X-ray diffraction (XRD) analysis, respectively. Results showed that, the coatings with Cr content ranging from 0 to and 5 wt% are smooth and crack free while the coatings with Cr content ranging from 7.5 to and 10 wt% are smooth but cracked. The volume content of second phase (Fe,Ni,Si,Cr)(2) Mo and the high temperature oxidation resistance of the coatings are both increased with an increase in Cr content.