Fundamental Investigation of Anodic Oxide Films on Aluminum Alloys as a Surface Preparation for Adhesive Bonding.
Abstract
This study was structured to define the physical, chemical, and mechanical characteristics of anodized films by selecting widely differing anodic processes, systematically varying these processes, and carefully characterizing the resultant surfaces using the most advanced instrumental techniques. After defining the structure and character of the anodic film from the surface to the metal interface, a comparison of the relative stability of these surfaces was made by defining the point at which breakdown or hydration of the film occurred in salt spray and humid environments. Five distinct anodic systems were chosen for study in this program. These represented two porous systems, phosphoric acid and chromic acid, and three barrier layer systems: (1) ammonium chromate, (2) potassium/lithium nitrate eutectic salt, and (3) ammonium pentaborate in ethylene glycol. In each anodic system, electrical properties were recorded during anodization. Surfaces of each anodic coating were analyzed using electron diffraction to determine crystal structure, Auger electron spectroscopy to determine the chemistry, and scanning electron microscopy to characterize the thickness and morphology of the oxide.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1976
- Accession Number
- ADA038068
Entities
People
- R. E. Herfert