Accession Number:

ADA048756

Title:

Characterization of Chromic-Acid Anodized 2024-T3 Aluminum Adherends

Descriptive Note:

Technical rept.

Corporate Author:

ARMY ARMAMENT RESEARCH AND DEVELOPMENT CENTER DOVER NJ LARGE CALIBER WEAPON SYSTEMS LAB

Report Date:

1977-09-01

Pagination or Media Count:

43.0

Abstract:

The topography of 2024-T3 aluminum-alloy surfaces has been characterized by using high-magnification transmission electron microscopy TEM at various stages during the chromic-acid anodizing procedure used to prepare aluminum surfaces for adhesive bonding. The surface structure characteristic of the unsealed chromic-acid anodized alloy was found to form during the first 6 minutes of the 37-12-minute anodizing cycle the surface characteristic of the sealed anodized alloy was found to form during the last half of the 8-minute sealing cycle. The surface structure of FPL deoxidized and of unsealed anodized surfaces consists of a repeating pattern of close-packed depressions 200 to 800 angstrom units in diameter. The structure of the sealed surface consists of crevices 500 to 2,000 angstrom units wide between mounds of material formed during sealing. The chemical composition of the surfaces was determined after anodizing and also after sealing the surface, using electron spectroscopy for chemical analysis and auger electron spectroscopy. These surfaces were found to consist of aluminum, oxygen, carbon, and nitrogen with traces of silicon and maganese. Copper and magnesium, two of the major alloying elements in the alloy used, were not detected.

Subject Categories:

  • Adhesives, Seals and Binders
  • Metallurgy and Metallography

Distribution Statement:

APPROVED FOR PUBLIC RELEASE