Thin Film Corrosion of Anodized High-Strength Aluminum Alloys.
Abstract
Progress is reported in the development of a procedure for measuring the susceptibility of alloys to marine atmospheric corrosion. The availability of a variety of aluminum alloys, tempers, and protection methods necessitates a test method which is rapid, reproducible, quantitative, and representative of the atmosphere corrosion experienced by Naval components. A testing apparatus is herein described as are the specimen preparation techniques, test environment, and data reduction method. The corrosion cell is designed to subject the specimen both to a thin, salty film of moisture and to a controlled electrical potential. The resulting current through the specimen is recorded as a function of this potential and as a function of time. To minimize the effects of random variations, both the order in which tests are run and specimen selection are randomized. Preliminary times-to-failure from aluminum alloy 7075-T73 specimens with sulfuric acid anodizing, with sulfuric acid anodizing plus sealing, and with chromic acid anodizing, corroborate the validity of the procedure. As some specimens survived more than 200 hours before onset of pitting corrosion, planned methods for shortening the test are given. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 23, 1978
- Accession Number
- ADA054424
Entities
People
- C. R. Crowe
- H. M. Dejarnette
Organizations
- Naval Ordnance Laboratory