XPS Analysis of A1/EPDM Bondlines from IUS SRM-1 Polar Bosses
Abstract
A temperature-stress rupture method using partial immersion in liquid nitrogen has been developed for the aluminum/EPDM rubber insulation bondline of the IUS SRM-1 polar bosses in order to investigate a corrosion problem. Subsequent XPS analysis of the ruptured bondline followed changes in the locus of failure as corrosion progressed. Samples from the forward polar bosses had a predominantly noncorroded appearance on the ruptured surfaces. The locus of failure was predominantly through the primer layer, which is distinguished by a high concentration of chlorinated hydrocarbon. The aft polar boss segments analyzed were characterized by the presence of corrosion over the entire mid- section of the ruptured aluminum to insulation bondline. The predominant corrosion product detected was aluminum oxide/hydroxide. The corroded bondline sections had significantly higher concentrations of aluminum oxide/hydroxide than the noncorroded areas, and lower concentrations of primer material. The temperature-stress rupture appeared to progress most readily through areas of thickened aluminum oxide/hydroxide infiltrated into the primer layer. In general there was a very good correlation between the calculated C1:Al atomic % ratio, and the visual characterization of the extent of corrosion. The Cl:Al ratio, which represents the primer to corrosion product ratio at the locus of failure, varied from 0.4 to 47. With only a few exceptions, surfaces with a predominantly noncorroded appearance had Cl:Al ratios > 2, and surfaces with a heavily corroded appearance had Cl:Al ratios < 1.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 10, 1993
- Accession Number
- ADA266851
Entities
People
- Carol S. Hemminger
- Nicholas Marquez
Organizations
- The Aerospace Corporation