Synthesis and Characterization of Mg-Based Coatings for Sacrificial Cathodic Protection of Mg Alloy AZ31B
Abstract
Magnesium (Mg) alloys are becoming increasingly popular for weight reduction in the automotive industry due to their low density and nominal specific strength [1]. However, the deleterious intrinsic corrosion rates of Mg alloys have hindered their widespread application. To date, protection strategies for Mg alloys has consisted primarily of barrier coatings such as Rockhard™ and Tagnite™ which have not demonstrated the ability to protect bare Mg at scratches, cracks, and other defects [2] while conversion coatings have not been shown to survive harsh working conditions and do not provide sacrificial cathodic protection or inhibitor release [3]. The drawbacks of these coating strategies provide motivation for additional research. In addition, sacrificial cathodic protection of Mg alloys has not been widely studied and presents opportunities of high interest. Recent studies have shown that sacrificial cathodic protection of Mg and its alloys is possible and shows some promise albeit complicated by cathodic corrosion of Al rich phases and large local cathodic reaction rates [4]. However, an optimal sacrificial coating has not been produced to date. As such, the overall goal of this research is to design a tunable coating which acts as (1) a corrosion barrier, (2) provides sacrificial cathodic protection, and (3) functions as a reservoir for ionic inhibitor release. Such a coating has been designed recently for aluminum alloy AA2024 using an amorphous Al-Co-Ce alloy [5].
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Sep 01, 2017
- Source ID
- 10.1149/ma2017-02/10/735
Entities
People
- James M. Fitz-gerald
- John R. Scully
- Michael A. Melia
- Taylor W. Cain