On military aircraft chromates have long been used as corrosion inhibitors for the aluminum alloy body. Along with the chromate inhibitors, solvent based epoxypolyamide primers compliant with MIL-P-23377 are used as an intermediate layer between the topcoat and substrate for corrosion protection. In addition, hexavalent chromate pretreatment is used for further corrosion inhibition and adhesion promotion.