Chemical Conversion Coatings on Magnesium Alloys (Part 1)

There is growing demand for light metal alloys components in aerospace and automobile fields primarily to save fuel cost. Magnesium alloys promise a great potential for various applications as lightweight structural materials. This advantage stems from their low densities and high specific strength/weight ratio. Other advantages are good electrical and thermal conductivity, good impact strength, ability to dampen shockwaves, ease of forming at room temperature, weldability, buckling resistances, ductility and pressure tightness. Despite sounding like a designers‘ dream metal, magnesium has two grave drawbacks that limit their widespread applications: poor corrosion resistance and the relatively frail surface mechanical properties. Owing to the exceptional engineering properties of magnesium alloys ample attempts have been made in last few decades to develop suitable surface protection techniques. In this article the advances of chemical conversion coatings on the magnesium alloys are discussed.