Microstructure, magnetic properties and empirical electron theory calculations of laser cladding FeNiCr/60%WC composite coatings with Mo additions

Abstract

FeNiCr/60%WC coatings were deposited by laser cladding with direct injection of FeNiCr+60%WC powder premixed with different amounts of Mo powder (0–4wt.%) onto the N1310 nonmagnetic steel. The morphology was characterized using a scanning electron microscope (SEM), the phase analysis was performed using an X-ray diffractometer (XRD), and the magnetic properties were examined using a vibrating sample magnetometer (VSM). The empirical electron theory (EET) of solids and molecules was used to calculate magnetic moments of Fe3W3C and Ni3Mo3C. The relative permeability of FeNiCr/60%WC composite coatings containing different amounts of Mo ranged from 1.008 to 1.052, which was significantly lower than that without Mo addition (1.104). The relative permeability decreased with increasing Mo content until a minimum was reached, and then increased with further increasing Mo content. Ni3Mo3C phase was formed initially at high Mo addition (≥2.5%) due to the metallurgical reaction between the Mo particles and the Fe-based alloys. Both Ni3Mo3C and Fe3W3C phases were weakly ferromagnetic with a magnetic moment of 0.6816 and 0.9018 respectively, which seemed to be the main factors affecting the non-magnetic properties of the cladding coatings.