Magnesium alloys are advanced light structural and functional materials being increasingly used in the automotive, aerospace, electronic, and energy industries. However, their corrosion performance at the current stage of development is still not good enough for increasingly diverse practical applications. The Cooperative Research Centre for Cast Metals Manufacturing (CAST) in Australia is one of the most active research organizations in the world established to cope with the problems associated with the development and application of advanced light metals. Corrosion and prevention of magnesium and its alloys is an important part of CAST'S research program. This paper presents a brief summary of recent research achievements by CAST and relevant research work in this area in the world. This overview covers "anodic hydrogen evolution", estimation of corrosion rate, corrosion of aluminum- and non-aluminum-containing magnesium alloys, influences of composition and microstructure on corrosion, corrosion of a die-cast magnesium alloy, galvanic corrosion, coolant corrosion, and an aluminum-alloyed coating. The aim of this overview is to deepen the current understanding of corrosion and protection of magnesium and its alloys and to provide a base for future research work in this field.

Recent Progress in Corrosion and Protection of Magnesium Alloys

This review aims to provide a foundation for the safe and effective use of magnesium (Mg) alloys, including practical guidelines for the service use of Mg alloys in the atmosphere and/or in contact with aqueous solutions. This is to provide support for the rapidly increasing use of Mg in industrial applications, particularly in the automobile industry. These guidelines should be firmly based on a critical analysis of our knowledge of SCC based on (1) service experience, (2) laboratory testing and (3) understanding of the mechanism of SCC, as well as based on an understanding of the Mg corrosion mechanism.

A Critical Review of the Stress Corrosion Cracking (SCC) of Magnesium Alloys

An innovative specimen configuration for the study of Mg corrosion

The opportunity to give an invited presentation to the Gordon Research Conference - Aqueous Corrosion in 2006 and reflections on the discussion at the conference were used to review our understanding of Mg corrosion mechanism, to generate new insights, to identify gaps in our knowledge and to identify research opportunities.

Recent Insights into the Mechanism of Magnesium Corrosion and Research Suggestions

Validated numerical modelling of galvanic corrosion for couples: Magnesium alloy (AE44)–mild steel and AE44–aluminium alloy (AA6063) in brine solution

The boundary element method (BEM) was used to study galvanic corrosion using linear and logarithmic boundary conditions. The linear boundary condition was implemented by using the linear approach and the piecewise linear approach. The logarithmic boundary condition was implemented by the piecewise linear approach. The calculated potential and current density distribution were compared with the prior analytical results. For the linear boundary condition, the BEASY program using the linear approach and the piecewise linear approach gave accurate predictions of the potential and the galvanic current density distributions for varied electrolyte conditions, various film thicknesses, various electrolyte conductivities and various area ratio of anode/cathode. The 50-point piecewise linear method could be used with both linear and logarithmic polarization curves.

J. Baynham

Papers

Evaluation of the BEASY program using linear and piecewise linear approaches for the boundary conditions