Effect of Microstructure and Phase Evolution on the Wear Behavior of Fe-Based Amorphous/Nanocrystalline Composite Coatings Synthesized by Plasma Spraying

In this work, Fe-10Cr-10Mo-4B-2C-4P (wt.%) amorphous/nanocrystalline multilayered coatings were synthesized using the atmospheric plasma spraying method with different power/heat input to vary the degree of melting. Microstructural and compositional characterization results showed that both amorphicity and porosity decreased with increasing plasma power. Higher hardness was observed at elevated power due to the presence of less porosity and more amount of hard intermetallic phases in the amorphous matrix. Wear behavior of the coatings was investigated under two different modes viz. reciprocating mode and unidirectional rotating mode to reflect the real-life service conditions. Results of dry sliding wear test revealed that improved wear resistance for coatings synthesized at higher plasma power input is attributed to the formation of well-adhered splats and presence of higher amount of intermetallic phases. Interestingly, the specific wear rate and coefficient of friction values obtained by performing the wear test in rotating mode were lower compared to that in reciprocating mode. Most importantly, a transition in wear mechanism was envisaged as mode of wear changes, i.e., fatigue dominated in case of the reciprocating mode to abrasion dominated in the rotating mode.