Corrosion resistance properties and protective mechanisms of Al2O3-doped Inconel 625 coatings prepared by laser cladding in high-temperature acidic environments

This study investigates the corrosion resistance and protective mechanisms of laser-clad Al2O3-doped Inconel 625 coatings under high-temperature acidic conditions. Inconel 625-xAl2O3 coatings were fabricated via laser cladding and tested in high-temperature acidic environments simulating pipeline conditions. Corrosion media included HCl, H2SO4, HF, HBr (pH=3), and their 1:1:1:1 mixed acid. High-temperature cyclic titration was employed for corrosion testing, while XRD, SEM, EDS, and laser confocal microscopy were used to analyze microstructure, composition, and corrosion products. Results show that increasing Al2O3 content significantly enhances corrosion resistance, reducing rates by 57.9 % in HCl and 46.4 % in HF. Al2O3 forms a stable protective layer, acting as a physical barrier and inhibiting grain growth. A dual-layer oxide film (Al2O3 and Cr2O3) effectively blocks corrosive substance diffusion, further enhancing protection. This study elucidates the pivotal role of Al2O3 in improving the corrosion resistance of Inconel 625 coatings and offers novel insights for the development of high-performance protective coatings tailored for extreme environments.

Duke Scholars

Author Zhaohui Wang Pathology