The Role of Silane Sol-Gel Coatings on the Corrosion Protection of Magnesium Alloys

Abstract

Magnesium alloys, as the lightest structural metallic material with promising physical, mechanical, and biodegradable properties, have become very attractive for different technical applications, especially for industrial and biomedical fields. However, rapid corrosion is the most critical obstacle that limits its use to play a major role in large-scale applications. The simplest way to control the corrosion rate is to prevent a direct contact of the magnesium substrate with the environment by using surface modification technologies. Silica sol-gel coatings are considered a promising solution to enhance the corrosion resistance of magnesium alloys because sol-gel-based coating systems form very stable chemical bonds with the metallic surface. In this chapter, an insight about the advances in silica sol-gel coatings as an alternative method to control the corrosion of Mg and its alloys will be exposed. A wide overview of the most relevant aspects and their current applications, specifically for aerospace, automobile, and biomedical applications will be described. The modification of silica sol-gel matrix by the incorporation of different types of inhibitors to achieve an active barrier property on Mg alloys has been also considered. Finally, the future perspective based on the development of new silica sol-gel coatings on Mg alloy will be presented.