Influence of Mn additions on the microstructure and magnetic properties of FeNiCr/60% WC composite coating produced by laser cladding

• The FeNiCr/60%WC coatings with different Mn additions were fabricated by laser cladding.
• Nonmagnetic properties of laser clad FeNiCr/60%WC coatings were improved by Mn additions.
• The magnetic mechanism of FeNiCr/60%WC coatings with different Mn additions was investigated.
• The main factor affecting the non-magnetic properties of FeNiCr/60%WC coatings was clarified.

The influence of Mn additions on the microstructure and magnetic properties of FeNiCr/60%WC composite coatings produced by laser cladding was investigated. The microstructure of FeNiCr/60%WC coatings was characterized using SEM, TEM and XRD. The magnetic properties of the composite coatings were examined by a vibrating sample magnetometer (VSM). The valence electron structure and magnetic moments of Fe3W3C and Fe-based solid solution were calculated according to the empirical electron theory (EET) of solids and molecules. The results showed that FeNiCr/60%WC composite coatings had a high metallurgical quality, and that Mn can stabilize the austenite region and promote the formation of Cr0.19Fe0.7Ni0.11. The relative permeability decreased significantly with increasing the addition of Mn, indicating that Mn had the potential to improve the non-magnetic properties of the composite coatings. EET results revealed that Fe3W3C was a weakly ferromagnetic phase with a magnetic moment of 0.9018, which appeared to be the main factor affecting the non-magnetic properties of the coatings. In addition, given a constant amount of Ni in the Fe-Ni-Cr alloy, the average magnetic moment of the alloy decreased with increasing Mn.