SEALING METHODS FOR ENHANCED CORROSION PROTECTION OF ANODIZED MAGNESIUM ALLOY WE43A-T6

摘要

High voltage anodizing processes continue to be developed for providing corrosion protection to magnesium alloys. However, the large pore structure in these coatings represents a barrier to further increases in corrosion resistance. One of the objectives for the work described here was to develop methods of sealing the pores in complex parts where reentrant surfaces preclude the use of spray type top coating systems. A second objective was that the coating not flake off of internal surfaces, thus eliminating a source of foreign object damage for aerospace applications. Salt fog, electrochemical impedance, throwing power and adhesion data will be presented for anodized magnesium alloy WE43A-T6. The anodization was performed using both a commercial and a developmental process. The sealing operations were performed using Parylene grades C and HT. The Parylenes are vapor deposited polymers.