High-Temperature Wear Behavior and Mechanisms of Self-Healing NiCrAlY-Cr3C2-Ti2SnC Coating Prepared by Atmospheric Plasma Spraying

In engineering applications, it is crucial to extend service life by reducing the coefficient of friction (COF) and wear rate to improve dry wear resistance. This work investigates the tribological properties of NiCrAlY-Cr3C2-Ti2SnC coatings with different Ti2SnC additions over a wide temperature range. Composite coatings with varying Ti2SnC concentrations were deposited onto TC4 titanium alloy substrates using atmospheric plasma spraying. Pin-on-disk wear tests were utilized to evaluate the tribological performance of the coatings, including the friction coefficient and wear rate, from room temperature to 800 degrees C. The wear mechanism of the coating was determined using SEM and a 3D profiler. The results demonstrate that the coating containing 30 wt.% Ti2SnC (NC-30TSC) exhibits the lowest friction coefficient (0.29) and wear rate (4.89 x 10(-5) mm(3)<middle dot>N-1<middle dot>m(-1)) at 800 degrees C. The composite coatings containing Ti2SnC exhibited a decreased coefficient of friction and wear rate due to the high-temperature decomposition products of Ti2SnC, such as TiO2 and TiC. The wear mechanisms of the NC-30TSC coating were adhesive and fatigue wear at 300 degrees C, adhesive and oxidation wear at 600 degrees C, and oxidation wear at 800 degrees C. Additionally, the prefabricated cracks on the surface of the NC-30TSC coating healed after isothermal treatment, demonstrating excellent self-healing performance.