Accession Number:

ADA305140

Title:

Protective Coatings and Sealants for Solar Applications,

Descriptive Note:

Corporate Author:

SANDIA NATIONAL LABS ALBUQUERQUE NM

Personal Author(s):

Report Date:

1980-09-01

Pagination or Media Count:

47.0

Abstract:

An aging study has been completed which evaluated a number of polymeric materials for potential use as 1 protective coatings for back surfaces of mirrors and 2 solar heliostat edge seals. These investigations were conducted in an artificial weathering chamber that accelerated thermal cycling. We observed the primary mirror failure mode to be silver corrosion resulting from moisture exposure. To increase mirror longevity in current heliostat designs, intimate bonding at all the composite interfaces is essential to minimize moisture pathways to the silvered surface. If any voids or delaminations are present, mirror degradation will eventually occur. Delaminations can also occur as the result of mechanical stresses brought about by mismatches in the various materials coefficients of thermal expansion. If good bonding cannot be achieved or mechanical stresses avoided, then improved moisture barriers must be designed to assure mirror longevity. jg p6

Subject Categories:

  • Coatings, Colorants and Finishes
  • Astrophysics
  • Adhesives, Seals and Binders
  • Astronautics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE