Influence of temperature and chloride ion concentration on the corrosion behaviour of Mg–4Al–3Ca–0.5RE alloy

Abstract

The influence of temperature and chloride ion concentration on the corrosion behaviour of Mg−4Al−3Ca−0.5RE alloys were studied in this paper. Corrosion rates of the alloys were measured by weight loss test and electrochemical measurement. The results revealed that a shorter incubation period to the onset of corrosion, a more negative corrosion potential, and a higher corrosion rate was correlated with a higher temperature in 3% NaCl solution and a higher chloride ion concentration at 30°C. The corrosion behaviour of the alloys was affected by surface film and the corrosion mainly occurred at the breaks or defects in surface films. K E Y W O R D S chloride ion concentration, corrosion behaviour, magnesium alloys, microstructure, temperature F I G U R E 1 1 X-ray diffractometer pattern of corrosion products of the Mg-4Al-3Ca-0.5RE alloy XIONG ET AL. | 1221

Corrosion Behavior of Al2O3-40TiO2 Coating Deposited on 20MnNiMo Steel via Atmospheric Plasma Spraying in Hydrogen Sulfide Seawater Stress Environments

“…The declining corrosion rate of the Al 2 O 3 -40TiO 2 coating in the simulated environment was attributed to the blocking of metal sulfides such as FeS. Chloride ions have a small radius and strong penetration and, in artificial seawater environments, they are able to destroy the oxide film of corrosion products at the interface of the substrate and coating and weaken the protective effect of these products [33,34]. Unlike corrosion products in artificial seawater, corrosion products in a simulated environment might be more chemically stable, leading to a longer blocking effect [14,15].…”