i ELUWNATION OF CICROMATE COXVERSION COATINGS FROM ARMY TACTICAL VEHICLE MANUFACTUFUNC PROCESSES

Many United States Army light tactical vehicles are fabricated from armor-grade aluminum. Aluminum-hulled tactical vehicles are coated with the Army's standard Chemical Agent Resistant Coating (CARC) system. The CARC system includes chemical pretreatments, epoxy primers, and polyurethane topcoats. The MTL-C-5541 chromate conversion coating pretreatment process included in the CARC specification contains hazardous chromic acid. Chromic acid is a SARA Title Ill extremely hazardous substance and air emissions of the material will be regulated by the 1990 Clean Air Act Amendments. In 1989, Red River Army Depot (RRAD) staff investigated replacing the hazardous chromate conversion coating with a more environmentally acceptable production process. The Army Acquisition Pollution Prevention Support Office reviewed the RRAD results and tasked Ocean City Research Corporation (OCRC) to conduct a comprehensive coating performance assessment and develop appropriate non-chromate production process control documents. The evaluation program demonstrated that chromate conversion coatings may be eliminated from aluminum-hulled tactical vehicle painting operations without degrading overall coating system performance. KEY WORDS: coatings, abrasive blasting