Corrosion behavior of ultra-high strength steel 23Co14Ni12Cr3Mo in simulated seawater environment

The corrosion behavior of ultra-high strength steel 23Co14Ni12Cr3Mo was investigated by three accelerated corrosion methods, alternating immersion corrosion, neutral salt spray and full immersion tests, and electrochemical impedance spectroscopy in simulated seawater environment. The morphology of corrosion products was observed by SEM and the composition was analyzed by X-ray diffraction. The results show that the corrosion product layer is composed of outer rust layer γ-FeOOH and inner rust layer α-FeOOH. The corrosion process begins with pit corrosion, then the corrosion area expands and the uniform corrosion forms with the corrosion time. The corrosion of extend is worst alternating immersion corrosion test, simulated alternation of wetting and drying seawater environment.