Room-Temperature and High-Temperature Wear Behaviors of As-Sprayed and Annealed Cr3C2-25NiCr Coatings Prepared by High Velocity Air-Fuel Spraying

Cr3C2-25NiCr coatings were deposited on stainless steel substrates by high velocity air-fuel (HVAF) spraying. Friction and wear behaviors of as-sprayed and annealed coatings were investigated both at room-temperature (RT) and 600 degrees C (high-temperature, HT). The results show that annealing at 600 degrees C in air is effective to enhance the wear performances of the coating both at RT and HT. The enhanced wear resistance of annealed coatings is discussed from the oxide growth and the microstructural evolution of the coatings. The wear behavior of the annealed coating follows the abrasive mechanism at RT and changes to an oxidative wear at HT, in which formation of a tribo-oxide layer plays a critical role to reduce the friction coefficient and to protect the underlying coatings from abrasive damage. The findings of this work reveal the significance of oxide-scale growth and microstructural evolution on the HT wear behaviors of the Cr3C2-25NiCr coating, which provides strategies for enhancing the wear properties of such coatings for HT applications.