SERVICE EVALUATION OF AIRCRAFT EXPERIMENTAL FASTENERS.
Abstract
An investigation was made of the degree of protection against corrosion provided to aircraft fasteners by high purity aluminum coatings versus the normal treatments - cadmium plating on steel and anodize on aluminum. Fasteners included aluminum and titanium rivets, titanium hi-loks, and steel lockbolts. Coating included cadmium plating, anodizing, aluminum (applied by two processes), zinc chromate primer (wet and encapsulated), and aircraft fuel tank sealant. The aircraft had been in service for approximately 24 months at the time of the final inspection. Three field inspections were conducted. The report contains the details of the third, and final, inspection, and also is the final summary technical report of the entire Phase II field service evaluation. Some of the results are very significant. Toward the primary purpose they showed conclusively that aluminum coatings protect steel fasteners and prevent damage to adjacent structure much more completely than conventional cadmium plating. Titanium fasteners also perform much better than cadmium plated steel fasteners. These results showed no significant trends as far as aluminum rivets are concerned. These results did show a very significant advantage for zinc chromate primer over fuel tank sealant in protecting cadmium plated steel fasteners and in preventing corrosion of the adjacent structure. Further, two important trends seemed to be indicated: encapsulated zinc chromate primer seems to be even more effective than normal wet applied zinc chromate primer, and titanium fasteners must be insulated from the adjacent aluminum structure to prevent galvanic corrosion which had begun to develop. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1967
- Accession Number
- AD0825191
Entities
People
- W. C. Herron