Compositional dependence of microstructure and tribological properties of plasma sprayed Fe-based metallic glass coatings

Gas-atomized powders of three Fe-based glass-forming alloys were sprayed on mild steel substrates by atmospheric plasma spaying using the same spaying parameters. Microstructures, thermal stabilities and tribological properties of the sprayed coatings were analyzed. The coating performances showed a strong dependence on the intrinsic characters of the compositions, i.e., glass-forming ability (GFA) and supercooled liquid region (ΔTx). The coatings tended to exhibit higher amorphous phase fraction for the composition with higher GFA and lower porosity for that with larger ΔTx. All the coatings exhibited superior wear resistance compared with the substrate. Higher wear resistance could be obtained in coatings with higher amorphous phase fraction, i.e. higher GFA of the composition. This study has important implications for composition selecting and optimizing in the fabrication of metallic glass coatings.