Room and elevated temperature sliding wear of high-velocity oxyfuel sprayed Diamalloy3001 coatings

Co-based alloys used in tribological applications show different friction and wear behaviour that depends on the operational temperature. Here, we deposit Diamalloy3001 coating using high velocity oxy-fuel spray process and study its tribology at room and elevated temperatures. The as-sprayed coating was characterized using scanning electron microscopy (SEM), electron channel contrast imaging and Raman spectroscopy to understand the microstructure, phases formed, whereas indentation was done at different temperatures to determine its hardness. To evaluate the tribology of the coating, dry sliding wear tests were performed at a normal load of 5 N using an Alumina countersphere at temperatures 25oC, 200oC and 350oC respectively. Sliding wear results showed that wear rate increased with increase in test temperature whereas no significant difference was seen in the friction coefficient. SEM imaging of the worn surfaces showed abrasive wear mechanisms and a significant area of the wear track covered with tribolayers at 25oC whereas at elevated temperatures along with abrasion, a decrease in wear track area coverage with tribolayers was seen. The relationship between the coverage of the tribolayers, mechanical properties of the coating and the wear rate and subsurface microstructures will be discussed.