Synergistic Strategy of Oxidation and Coordination for Removing Post-Service Silicon-Modified Diffusion Aluminum Coating on Turbine Blades

Engine blade maintenance can extend engine service life, with coating removal being the initial step in the regeneration process. Silicon-modified diffusion aluminum-silicon coating (AlSi coating) is well-established as a protective coating for nickel-based superalloys due to its excellent oxidation and corrosion resistance, and is widely used in applications such as aero-engines and gas turbines. This study proposes a synergistic strategy combining oxidation and coordination to remove AlSi coating from nickel-based superalloy surfaces. The results demonstrate that this formulation effectively removes the coating while controlling substrate corrosion, avoiding detrimental effects such as intergranular corrosion and over-etching that compromise product quality. Mechanism analysis based on Density Functional Theory Simulations indicates that oxidizing elements such as Ni and Al into nickel oxide and aluminum oxide, followed by electronic structure modulation via a chelating agent, promotes efficient and uniform removal of the post-service AlSi coating by the acid solution.