Effect of Impact Angles and Temperatures on the Solid Particle Erosion Behavior of HVOF Sprayed WC-Co/NiCr/Mo and Cr3C2-CoNiCrAlY Coatings

Abstract

Extreme erosion wear from elevated temperature caused by the impact of entrained solid particles in the fluid stream primarily affects aerospace components and marine parts. This work focuses on increasing the base material erosion resistance by applying thermally sprayed carbide-based coatings. A high-temperature Solid particle erosion behavior of WC-Co/NiCr/Mo and Cr<inf>3</inf>C<inf>2</inf>-CoNiCrAlY coatings deposited by the HVOF process on a titanium-31 was evaluated using an air-jet erosion tester. The erosion test was conducted utilizing alumina erodent of grit size 35-50 µm. The effects of impact angles (30°, 60°, and 90°) and temperatures (200-800 °C) on the erosion performance of two coatings are compared. The feedstock powder and as-sprayed coatings were characterized for micro-structure phase composition, porosity, density, micro-hardness, and adhesion strength. SEM/EDS and a 3D optical profilometer were used to examine eroded samples further to determine the erosion mode. The Cr<inf>3</inf>C<inf>2</inf>-CoNiCrAlY coating shows a brittle mode behavior of erosion at 200-400 °C and ductile mode behavior of erosion at 600-800 °C. In contrast, the WC-Co/NiCr/Mo coating shows brittle mode behavior of erosion at 200-400 °C and 600-800 °C, a mixed mode behavior of erosion. The erosion loss in volume of Cr<inf>3</inf>C<inf>2</inf>-CoNiCrAlY is lower than WC-Co/NiCr/Mo for all temperatures and impact angles. The development of carbide and oxide phases on the eroded surfaces demonstrates increasing erosion resistance at high temperatures. The optical profilometer measures the volumetric erosion loss, compares it with the weight loss method, and finds consistency between them. © 2023, ASM International.