Magnesium Composites With Corrosion and Wear Resistant Coatings

The project concerns the development of magnesium composites with advanced anodized coatings for improved corrosion and wear resistance. Coating production and the properties obtained are significant improvements over previous surface treatments for magnesium. In Phase I, over eighty experiments were conducted in the anodization of magnesium alloys and composites. Variables examined through these experiments include: voltage, electrolyte, temperature, magnesium alloy, cathode geometry, and time. Comparison of the coatings was conducted using microscopy, chemical analysis, and corrosion and wear tests. Four magnesium composites were obtained containing two different base alloys and four reinforcement phases (B4C, SiC, Al2O3, and carbon fiber). Anodization of two composites produced excellent coatings. The other two composites were shown to be incompatible with coating methods to resist corrosive environments. These results justify the goals of the project to identify appropriate magnesium composites and make them corrosion and wear resistant and eliminate from contention inappropriate materials. On completion of Phase II, the goals and objectives met will include a database will exist of known and tested anodized magnesium composites. The deliverables include anodized magnesium composite components produced and tested to NASA specifications for use in the reusable launch vehicle program.