Cold Spray Al-5% Mg Coatings for the Corrosion Protection of Magnesium Alloys

• Published in: Journal of thermal spray technology Vol. 20; no. 6; pp. 1352 - 1358
• Main Authors: DeForce, Brian S., Eden, Timothy J., Potter, John K.
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01.12.2011; Springer; Springer Nature B.V
• Subjects: Adhesion; Alloys; Aluminum; Aluminum base alloys; Analytical Chemistry; Applied sciences; Characterization and Evaluation of Materials; Chemistry and Materials Science; Coatings; Corrosion; Corrosion and Coatings; Corrosion environments; Corrosion prevention; Exact sciences and technology; Hardness; Machines; Magnesium; Magnesium base alloys; Manufacturing; Materials Science; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; Peer Reviewed; Processes; Production techniques; Protective coatings; Sprayers; Sprays; Surface treatment; Surfaces and Interfaces; Thin Films; Tribology; novel materials; corrosion; corrosion and electro-chemical behavior; cold gas dynamic spraying; hardness and (visco-)elastic properties; atomization; Aluminium base alloys; Hot spraying; Mechanical properties; Hardness; Corrosion protection; Coatings; Spray coating; Surface treatment; Corrosion; Magnesium alloy; Elastic properties; Atomization
• ISSN: 1059-9630; 1544-1016
• DOI: 10.1007/s11666-011-9675-4

Poor corrosion resistance is a significant limitation of magnesium alloys as structural materials. To address this problem, the objective of this study was to apply to a magnesium alloy a corrosion-resistant barrier coating that has galvanic compatibility with magnesium and a hardness value no less than that of magnesium. Aluminum coatings were applied to ZE41A-T5 Mg by the cold spray process. A custom-made high-purity Al-5 wt.% Mg powder was produced by spray metal forming for the coating evaluation. In addition, coatings of commercially pure Al (99.5 wt.%), high-purity Al (99.95 wt.%), AA5356, and AA4047 were used for comparison. Coating evaluation included mechanical testing (hardness and adhesion strength) and corrosion testing (salt spray, galvanic coupling, and crevice corrosion). The Al-5% Mg powder resulted in the best overall performance, including a high hardness, 125 H v100 , and an adhesion strength, over 60 MPa, when treated for over 1000 h in a salt spray chamber and with a low galvanic current.