Book Description

Coating systems on Navy aircraft perform a variety of functions, but clearly the most critical of these is the protection of aircraft structures from environmental degradation. Protective coatings serve as the primary defense against corrosion of aircraft metallic alloys, as well as degradation of other materials such as polymeric composites. Traditional coatings for aircraft include inorganic pretreatments, epoxy primers, and polyurethane topcoats. Pretreatments provide some corrosion protection and prepare the surface for subsequent organic coatings. Primers normally Contain high concentrations of corrosion inhibitors, such as chromates, and are designed to provide superior adhesion and corrosion protection. Polyurethane topcoats are formulated to enhance protection and durability; they also provide desired optical effects including aesthetics and camouflage. More recently, alternative coatings have been developed, such as nonhexavalent chromate pretreatments and primers, self-priming topcoats, flexible primers, low volatile organic compounds (VOC) Content coatings, temporary and multifunctional coatings. These new developments reflect trends in protective coatings technology, changes in aircraft operational requirements/capabilities, and most dramatically, concerns over environmental protection and worker safety. These environmental issues have created a drive toward coatings protection and worker safety. These environmental issues have created a drive toward coatings with ultra low/zero concentrations of VOC and nontoxic corrosion inhibitors. In turn, these changes have led to concerns over long-term performance, especially protection against corrosion. This report reviews current protective coatings technology for Navy aircraft structures and discusses future needs and trends based on advancing technology, environmental concerns, and operational requirements.