Friction and wear behavior of suspension plasma sprayed tantalum oxide coatings at elevated temperatures

Tantalum oxide-based coatings have recently become potential candidates for high-temperature tribological applications due to their high thermal stability and ionic potential. This study focuses on developing suspension plasma sprayed (SPS) tantalum oxide coatings and evaluating their tribological behavior at elevated tempera-tures. The coating morphology, oxide phases, and mechanical properties were characterized using Scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and microhard-ness. Microstructural observations showed uniform and dense nanostructure coatings with no phase trans-formation after deposition. The tribological results illustrated that the friction coefficient of the tantalum oxide coating slightly decreased from 0.9 at 25 degrees C to 0.8 at 300 degrees C. On the other hand, the wear rate at 300 degrees C decreased by >50 % compared to 25 degrees C. Ex-situ analysis indicated the brittle-fracture behavior of the coating during sliding at 25 degrees C, which resulted in higher friction and wear. However, the friction and wear decreased at 300 degrees C, which was attributed to the formation of a smeared or continuous smooth layer on the wear tracks with a stable transfer film on the counterface.