AUGER ELECTRON SPECTROSCOPY STUDIES OF OXIDE FILMS ON AL-ZN-MG ALLOYS,
Abstract
Auger electron spectroscopy and depth profiling have been used to obtain information on the composition of oxide films formed on high purity Al-5.5Zn-2.5Mg alloys as a function of heat treatment, grain size, storage environment and temperature. These studies show that in the as-heat-treated condition the oxide film is predominantly MgO. The Mg/O peak-to-peak height ratio of this oxide is sensitive to the heat treatment temperature and exhibits a maximum at 475 C. During subsequent storage, especially in a moist environment, this film undergoes substantial changes in composition. The Mg/Al ratio of the oxide decreases due to formation of an Al-rich oxide on top of the as-heat-treated oxide. A model is proposed to account for the changes in the oxide film composition during growth of the Al-rich oxide, and possible implications to pre-exposure embrittlement and stress corrosion cracking are discussed. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1979
- Accession Number
- ADA073096
Entities
People
- J. A. S. Green
- R. K. Viswanadham
- T. S. Sun
Organizations
- Martin Marietta