Protection of Cu components with Mg and Al coatings deposited by pack cementation

Abstract

The growth of Mg and Al coatings on copper by pack cementation is examined in this work by investigating the mechanism of the process, the effect of temperature and heating time on the coating structure. The experiments were undertaken at temperatures ranging from 550 to 600°C, while the duration of the process varied from 30 min to 3 h. It was found that the magnesium coatings consist of two phases corresponding to MgCu₂ and CuMg₂. These phases appeared as distinguished layers or mixed with each other, depending on the deposition temperature and duration. On the other hand, the aluminium coatings consist of a single Al₄Cu₉ phase whose thickness increases with deposition time and temperature. Finally, the oxidation resistance was also evaluated by thermogravimetric measurements, which revealed that the coated samples have superior resistance to bare copper, while Al coated coupons had the best performance when exposed in high temperature environment.

Keywords:

• Chemical vapour deposition
• Coatings
• Oxidation
• XRD
• SEM
• TG