Optimization of Processing Variables Which Affect Adhesion of Organic Coatings to Anodized Aluminum Alloys.

摘要

The report describes the results obtained in a study program to improve adhesion between anodized aluminum and presently used organic coating systems. The blister test method was used which uses fluid pressure under the coating through a hole in the substrate to cause adhesive failure. Specimens were evaluated in both the 'as prepared' condition and after being subjected to 30 day alternate salt water immersion conditioning. Several anodizing processes were compared for adhesion characteristics. Special emphasis was placed on determining the anodizing variables which affect adhesion and in the determination of optimum processing parameters for both chromic acid and sulfuric acid anodizing. These evaluations used 2024 and 7075 aluminum alloy which were anodized, contaminated and cleaned prior to coating with epoxy polyamide primer.