Effect of Scandium on the Wear Performance of High Entropy Alloy Coatings

Erosion and wear are critical challenges to the longevity and performance of engineering structures, such as airfoils where environmental factors cause gradual degradation of the leading edges. This deterioration leads to decreased aerodynamic efficiency and increased operational costs. High Entropy Alloys (HEAs), characterized by their multielement compositions have exceptional mechanical strength and toughness, making them promising candidates for wear-resistant coatings. This study explores the enhancement of AlCoCrFeMo HEA coatings by incorporating scandium (Sc) dispersoids, known for their micro-strengthening effects in aluminum alloys through precipitate hardening and grain refinement. The impact of Sc addition on HEA powders, however, remains unexplored. The AlCoCrFeMo HEA base coating was fabricated along with 0.1, 0.3, and 0.5 wt. % Sc concentrations using a cost-effective flame spray deposition technique. The Sc-doped coatings formed FCC, BCC and spinel oxide phases, and demonstrated significant improvements in hardness in comparison to the base composition. Notably, erosion testing following a modified ASTM G76 standard revealed a direct correlation between higher Sc content and reduced wear rates. These findings suggest that Sc-doped AlCoCrFeMo HEA coatings offer enhanced wear resistance, making them promising candidates for protective coatings in airfoil applications, potentially reducing maintenance costs and improving the durability of these critical components.