© Woodhead Publishing Limited, 2013 414 15 Cold spray coatings to improve the corrosion resistance of magnesium (Mg) alloys V. K. CHAMPAGNE and B. GABRIEL, US Army Research Laboratory, USA and J. VILLAFUERTE, CenterLine (Windsor) Ltd, Canada DOI: 10.1533/9780857098962.3.414 Abstract: Magnesium alloys are widely used in aircraft and automotive components because of their inherent light weight compared to other engineering metals. However, premature corrosion is one of the challenges associated with magnesium. In the aerospace industry, many expensive castings cannot be reclaimed adequately because current methods are often inappropriate due to excessive porosity, oxidation and thermal damage. Cold spray is a solid-state coating process that uses a supersonic gas jet to accelerate small particles against a substrate to produce metal bonding by rapid plastic deformation of the impacting particles. Significantly, magnesium components can be repaired, restored and protected by cold spray deposition of pure aluminum which has thus already been specified by some aerospace users as a standard technique for magnesium repair. In this chapter, the state of the art of commercial cold spray technologies for magnesium repair will be discussed, as well as their advantages and limitations compared to traditional thermal processes. Key words: cold spray, high velocity deposition, supersonic spray, magnesium alloys, powder spray, corrosion protection, commercial equipment. 15.1 Introduction Magnesium is the lightest of all structural metals, being approximately 35% lighter than aluminum and 78% lighter than steel with exceptional stiffness and damping capacity (Yamauchi et al., 1991). Magnesium’s low density and good castability are ideal for mass-production and weight sensitive applica- tions, such as automobile and aircraft components.