Corrosion Inhibited Pretreatment for Enhanced Corrosion Resistance on Aerospace Alloys

Surface pretreatments are commonly used on aircraft to promote coating adhesion, prevent corrosion, or both.  Pantheon Chemical’s Prekote Surface Preparation (SP) or 3M’s AC-131 (also known as Boe Gel) are two surface pretreatments that work well for adhesion promotion; however, they do not contain a corrosion inhibitor.  Henkel’s Bonderite, more commonly and formerly known as Alodine, is another approved pretreatment qualified to MIL-DTL-81706; however, Bonderite faces consistent pressure from environmental and occupational health regulatory agencies because it contains hexavalent chromium.  Thus, there is a need to demonstrate a corrosion inhibited pretreatment on USAF aircraft that does not contain chromium compounds. For this effort, ES3 will conduct validation testing of corrosion inhibiting pretreatment AC-131 to satisfy airworthiness requirements.  The intent of this program is to leverage previous work funded internally by our subcontractor, Boeing to show equivalence to MIL-DTL-81706 qualified products to provide a corrosion inhibited pretreatment that will qualify to MIL-PRF-32239 and become part of a complete, non-chrome system stack-up.  After demonstration of effectiveness through testing, results will be communicated with aircraft System Program Offices (SPOs) for on aircraft demonstration on non-critical aerospace parts.  Follow on efforts will address additional testing to further use the technology on flight critical components.