Optimization of Y Addition in a Tribaloy‐Type Alloy for Improved Oxidation Resistance

ABSTRACT While Tribaloy alloys such as T‐400C and T‐900 have shown promising high‐temperature oxidation and wear performance, additional compositional optimization is needed to further enhance their corrosion resistance for protecting high‐temperature components in corrosive environments. In this paper, the amount of the reactive element Y was varied in the Co‐20Cr‐18Mo‐2.6Si‐xY (wt.%) alloy system (x = 0–1.1) and its effect on the oxidation resistance at 800°C in air was evaluated. Based on specific mass change data together with surface and cross‐sectional microstructural observations, the optimal Y content was determined to be approximately 0.6–0.7 wt.%. Partial replacement of Co with Ni in the Y‐containing alloy further enhanced its oxidation performance.