Study on abnormal hot corrosion behavior of nickel-based single-crystal superalloy at 900 °C after drilling

Abstract

The hot corrosion behavior of nickel-based single-crystal superalloy after drilling is investigated at 900 °C. The characteristics of hot corrosion after drilling which are different from normal hot corrosion are reflected in the formation of a more stable oxide layer and less severe spallation. The change of microstructure around the hole is the main reason for the formation of a stable oxide layer during hot corrosion by changing the diffusion process of alloying elements. Subsequently, the formation of a stable oxide layer can reduce the effect of spalling by optimizing surface stress.

A Study of the Hot Salt Corrosion Behavior of Three Nickel-Based Single-Crystal Superalloys at 900 °C

“…These O 2− molecules preferentially react with Al, Mo, and Cr to form oxides, followed by reactions with Ni and Ti [12]. While the reaction of Ni with the molten salt may facilitate the formation of an Al 2 O 3 layer, the loose and easily exfoliating nature of NiO reaction products can compromise their protective role, potentially accelerating the degree of melted salt corrosion [13].…”