A Study of the Influence of Alloying Additions on the Passivity of Aluminum
Abstract
The corrosion behavior of nonequilibrium Aluminum tantalum and Aluminum Tungsten alloys produced by either dynamic compaction or sputter deposition has been evaluated. Dynamical compacted material showed no enhanced passivity as a result of precipitates formed during powder formation. No new precipitates were found that originated during the dynamic compaction process when water was used to reflect the shock wave. Sputter-deposited AlW and AlTa alloys exhibited considerable enhanced resistance to pitting corrosion over a range of pH's extending from pH 9.6 to pH 0. Surface analysis showed that although very little oxidized W is found in the passive film at near-neutral pH's, the passive film at pH3 consists of comparable amounts of oxidized W and Al. A review of the different mechanisms that have been proposed to explain the passivity of this class of alloys suggests that the pitting resistance of Al-W is likely to result from a repassivation of metastable pits due to the stability of oxidized W in low pH environments.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1992
- Accession Number
- ADA248339
Entities
People
- B. A. Shaw
- B. J. Rees
- G. D. Davis
- M. Ferry
Organizations
- Martin Marietta