Accession Number:

ADA229600

Title:

Surface and Interface Characterization for High-Temperature Adhesive Systems

Descriptive Note:

Annual rept. 1 Sep 1985-31 Aug 1986,

Corporate Author:

MARTIN MARIETTA LABS BALTIMORE MD

Report Date:

1986-09-01

Pagination or Media Count:

53.0

Abstract:

The structural and bonding properties of Ti-6A1-4V adherends, prepared by chromic acid anodization CAA, were studied as a function of exposure in high-temperature environments such as vacuum, air, boiling and pressurized water, and steam. Subsequent to the environmental exposure, bonds were produced and the adhesive tensile strengths measured. Long-term exposure to high temperature, dry environments did not cause structural changes to the adherend oxide but did result in poor bond strength. The failure mode in these cases was within the oxide, which was apparently weakened by the exposure by the exposure. The water- and steam-exposed oxides underwent a transition from amorphous to crystalline TiO2 with an accompanying change in oxide morphology however, bond strength was maintained for moderate exposures at T 300 deg C. For exposure at T-300 deg C, the bond strength was degraded severely. The latter result can be explained by a lack of porosity in the transformed oxide. SEM and XPS measurements were made on debonded surfaces to determine the loci of failure. The results from investigations of two alternative adherend surface preparation, i.e., anodization in sodium hydroxide for Ti-6Al-4V and the application of an Al alkoxide primer for Al 2024, are also reported. TTL

Subject Categories:

  • Inorganic Chemistry
  • Adhesives, Seals and Binders
  • Metallurgy and Metallography

Distribution Statement:

APPROVED FOR PUBLIC RELEASE