Accelerated Corrosion Analysis of Nonchromate Conversion Coatings on Aluminum Alloys 5083, 7039, and 6061 for DoD Applications

摘要

This study examines the effectiveness of six nonchromate conversion coatings on aluminum alloys 5083, 7039, and 6061. Evaluation methods included ASTM B117 (American Society for Testing and Materials. 'Standard Method of Salt Spray Fog Testing'. ASTM B117-90, 1990) salt fog, General Motors 9540P (General Motors. General Motors Engineering Standard, Accelerated Corrosion Test. GM 9540P, July 1991) cyclic salt spray, wet adhesion, and dry adhesion on painted test panels. Conversion-coated panels without paint were also screened to assess quality and pretreatment characteristics. Differences in behavior were noted between the salt fog data and the cyclic salt spray data obtained on scribed panels. How these data may relate with implementation of nonchromate pretreatments for military vehicles is discussed.