Influence of Chromate Conversion Coating and Its Corrosion on Electrical Contact Resistance of Alclad AA2024-T3

In this study the effect of CCC on ECR of Alclad AA2024-T3 was investigated. CCCs were applied on sheet samples of Alclad AA2024-T3 through dipping in a chromating bath having pH 1.41 in various times of 10,20,30,60 and 90 sec. The salt spray testing according to ASTM B-117 was employed to evaluate corrosion performance of bare and CCC-coated samples. The ECR values of the coatings before and after 168 hrs exposed to salt spray environment were measured using a laboratory designed and mSD1Jfactured device based on MIL-C-81706. Su.rfilce morphologies of CCCs were characterized using the atomic force microscope (AFM). Based on ECR. results, it was concluded that the increase in the coating time, results in the increase of the coating ECR. It was, however, found that only the coatings applied in times equal and less than 30 sec meet the stringent ECR requirements of military specifications MIL-C-81706.

کلیدواژه ها:

AA2024-TI ، conversion coating. corrosion. electrical contact resistance. Satellite