Fe-based metallic glass composite coatings by HVOF spraying: Influence of Mo on phase evolution, wear and corrosion resistance

Developing Fe-based metallic glass (MG) composite coatings with exceptional amalgamation of enhanced mechanical and corrosion properties have attracted wide interests recently. In this work, Fe-based MG composite coatings were developed from two distinct compositions of Fe63Cr9B16C7P5 and Fe57Cr9Mo5B16C7P6 (at. %). The coatings were prepared using optimized parameters of high velocity oxy-fuel (HVOF) spraying for eliminating the porosity effect and to only investigate the influence of minor Mo addition on phase evolution, wear and corrosion resistance. Microstructural and compositional characterization results exhibited lower and similar porosity content for both the MG composite coatings and higher level of amorphicity for Mo-containing coating compared to the other one. The Mo-containing coating displayed superior wear resistance, because of increment in amorphous content and minor amount/absence of softer alpha-Fe phases, and this was correlated with higher hardness (H) and ratios of H/Er and H3/Er2. Moreover, an enhanced corrosion resistance was also observed in case of Mo-containing coating, ascribed to the improved passivation ability resulting from increased fraction of protective and stable Cr- and Mo-oxides in passive film due to incorporation of Mo in the alloy. Thus, the addition of a minor amount of Mo was observed to be advantageous for improving the wear and corrosion properties of this Fe-Cr-based MG composite coating. Interestingly, both composite coatings showed improved wear and corrosion properties than that of SS316L coating synthesized with industrially optimized parameters.

Automated summary

Fe-based metallic glass composite coatings with added minor amount of Mo exhibited improved wear and corrosion resistance due to the increase in amorphous content and incorporation of Mo, which resulted in higher hardness and enhanced passivation ability of the coatings.