Accession Number:

ADA279963

Title:

Surface Contamination on LDEF Exposed Materials

Descriptive Note:

Corporate Author:

AEROSPACE CORP EL SEGUNDO CA TECHNOLOGY OPERATIONS

Personal Author(s):

Report Date:

1992-06-15

Pagination or Media Count:

25.0

Abstract:

X-ray photoelectron spectroscopy XPS has been used to study the surface composition and chemistry of Long Duration Exposure Facility LDEF exposed materials. In each set of samples, silicones were the major contributors to the molecular film accumulated on the LDEF exposed surfaces. All surfaces analyzed have been contaminated with Si, 0, and C most have low levels l atom of N, S, and F. The contaminant overlayer is thought to be patchy, with significant areas covered by less than 100 A of molecular film. For most materials analyzed, Si contamination levels were higher on the leading-edge surfaces than on the trailing-edge surfaces. It is probable that the return flux associated with atmospheric backscatter resulted in enhanced deposition of silicones and other contaminants on the leading-edge flight surfaces relative to the trailing edge. XPS analyses, however, did not conclusively show different relative total thicknesses of flight-deposited contamination for leading- and trailing-edge surfaces. Unlike other materials, exposed polymers, such as Kapton and FEP-type Teflon, had very low contamination on the leading-edge surfaces. SEM evidence showed that undercutting of the contaminant overlayer and damaged polymer layers occurred during atomic oxygen erosion, which would enhance loss of material from the exposed surface. LDEF, Contamination, XPS.

Subject Categories:

  • Aircraft
  • Physical Chemistry
  • Laminates and Composite Materials
  • Atomic and Molecular Physics and Spectroscopy

Distribution Statement:

APPROVED FOR PUBLIC RELEASE