Microstructural, mechanical and high-temperature tribological performance of Fe-based fully amorphous and amorphous/crystalline coatings

In this research, fully amorphous and amorphous/crystalline (A/C) Fe-based coatings were explored for high-temperature tribological applications. The commercially available gas atomized feedstocks were sprayed using high velocity oxygen fuel (HVOF) processes. The microstructural, mechanical and tribological behaviour of the coatings were investigated and compared. The fully amorphous Fe-based amorphous coating exhibited higher wear resistance at 600 °C than room temperature (RT) with high thermal stability and performed superior to A/C coatings at both temperature conditions. Detailed analysis of worn surfaces demonstrated that fully amorphous coatings were dominated by abrasive wear and oxidative wear at RT and oxidative and adhesive wear at 600 °C, whereas A/C coating suffered abrasive, surface fatigue wear and minor oxidation at both RT and 600 °C. A thick oxide glaze layer formed onto the worn surface of fully amorphous coatings, which enhanced the high-temperature mechanical properties and prevented severe wear loss. The Fe-based amorphous coating exhibited superior wear resistance and retained its phase structure, which established it as a potential high-temperature protective coating for tribological applications.