Laser Surface Melt Treatment and Galvanic Protection of 5XXX

Exfoliation corrosion of 5XXX series aluminum alloy is an issue related to the sensitization of the aluminum substrate typically occurring at end-grains. The Navy is interested in preventing this corrosion to decrease lifetime costs on Littoral Combat Ships, Ship-to-Shore Connector vessels, and Ticonderoga class ships. Luna will investigate surface modification using laser surface melt processing (LSM) of the 5XXX aluminum alloy to reverse localized sensitization in problem areas followed by application of a galvanic primer to prevent additional future corrosion. Luna will assess the 5XXX using a number of techniques, including but not limited to traditional accelerated corrosion testing (ASTM B117, ASTM G85-A5, GMW 14872), ASTM G66 (ASSET Test), SEM/EDS analysis, goniometry, and corrosion modeling. Luna will investigate the as-received, sensitized, and post-treatment conditions for coated and uncoated systems to show that a galvanic primer is required post-treatment to further prevent and mitigate future corrosion initiation of the treated area. Luna’s developed solution will feature the LSM treatment paired with a galvanic primer as a spot treatment system for known corrosion hotspots.