Tribological performance analysis of Stellite and Cr ₃ C ₂ coatings on Inconel 625

Inconel 625 alloy is widely recognized for its excellent performance in corrosive and abrasive environments, making it a preferred material in challenging applications. To further enhance its resistance to corrosion and wear, this study investigates the application of plasma-sprayed coatings using Chromium Carbide Cr 3 C 2 and Stellite. Both coated and uncoated Inconel 625 specimens were subjected to high-temperature sliding wear tests using a pin-on-disc tribometer. The wear behavior was evaluated by examining the worn surfaces through scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy. Additionally, the hardness of all specimens was measured using a Vickers hardness tester. Results from microhardness tests revealed a significant increase in hardness due to the coatings. The Cr 3 C 2 -coated sample showed an increase in Vickers hardness (HV) by 42.6%, while the Stellite-coated sample exhibited a 32.7% rise in HV, compared to the uncoated Inconel 625 specimen, which recorded a hardness of 505 HV. SEM analysis confirmed a strong adhesive bond between the coating materials and the substrate, indicating good coating integrity. Furthermore, wear tests conducted at varying temperatures demonstrated different wear behaviors. Notably, the Stellite-coated samples performed better under high-temperature conditions, showing improved wear resistance compared to both the Cr 3 C 2 coated and uncoated samples. These findings suggest the potential of such coatings for enhancing the durability of Inconel 625 in extreme working environments.