Surface protection of magnesium alloys via pack cementation coatings with aluminum powder and chlorides

摘要

Magnesium alloys have been received an attention for structural applications due to their low density compared to other alloys, and intensive studies have been focused for enhancing mechanical strength and surface protection as well. Especially, for environmental reasonings, coating processes in a dry condition have been recently received a great attention. In this study, diffusion coatings via Al powders with an aluminum chloride activator have been investigated in order to examine surface protection effect on magnesium alloys. The commercial AZ31 magnesium alloy has been subjected to diffusion coatings in an Al alloy powder for various time frames. An intermediate layer of Mg_(17)Ag_(12) was successfully synthesized via diffusion annealing. The underlying mechanisms for surface layer formation are discussed together with growth kinetics and microstructural observations