One of the most historically pervasive uses of materials containing chromate is in the treatment of aluminum with chromate conversion coatings (CCC) and chromated primers (CP) (Figure 1). The CCC process prepares aluminum for the application of paint and also provides a corrosion barrier. Chromic acid, from the CCC, accounts for approximately twice the chrome waste as chromate primers while repainting aircraft.2 Environmental, safety and health risks associated with the use of hexavalent chromium are being reduced and eliminated through different systems, using partial chrome or total non-chrome technology.

Testing of the PreKote SP technology included flexibility, filiform corrosion, adhesion and 2000-hour salt spray on painted panels proving performance that surpassed the standard chromated methods (Figure 3).4 The first F-16 was painted in 1997, and the test was completed in 1998 showing excellent results from PreKote SP. In 2000 the Technical Order (TO) for repainting F-16s was changed to include specifications to use PreKote SP as a NCSP. Since that time, over 800 F-16s have been painted with the PreKote SP process. To date not a single aircraft has been returned to depot for a paint- or corrosion-related issue. The early aircraft have completed their six-year cycle and are returning to depot for standard maintenance overhaul. Currently, all F-16s and all training aircraft are engaged in using a NCSP with 16 U.S. Air Force bases. These planes have been deployed all over the world, most recently for utilization during Iraqi Freedom.