An Interdisciplinary Approach to Predictive Modeling of Structural Adhesive Bonding. Characterization of Ti-6Al-4V Oxides and the Adhesive/Oxide Interphase.

Abstract

The hydrothermal durability of adhesive bonds is currently an active area of research. This work focuses on titanium/epoxy bonding using metal alkoxide primers as adhesive promoters. Pike showed that sec-butyl aluminum alkoxide enhances the durability of PAA (phosphoric acid anodized) and FPL (Forest Products Lab) etched 2024 aluminum bonded with the wedge test using epoxy adhesives. No variation in bond performance was observed when the cure temperature of the alkoxide film was varied. Hydrolysis of metal alkoxides occurs readily in the presence of moisture as indicated by the equation. Titanium alkoxide hydrolysis is complex because it involves simultaneous hydrolysis and polymerization. These reactions form polycondensates dependent on the water/alkoxide ratio, hydroylsis medium, temperature, and the nature of the alkyl group. Aluminum alkoxides hydrolyze to monohydroxides initially and later convert to trihydroxides. In hot water, a crystalline boehmite is formed, whereas an amorphous hydroxide is formed in cold water. Both hydroxides will convert to aluminum oxide at 500 C. This report encompasses characterization and adhesive bonding studies of three metal alkoxide primers: tetra n-butyl titanate, TNBT; tetra isopropyl titanate, TIPT; and sec-butyl aluminum alkoxide, E-8385. The films have been characterized by XPS (x-ray photoelectron spectroscopy), STEM (scanning transmission electron microscopy), and FTIR (Fourier transform infrared spectroscopy). Adhesive bonding included the wedge test and the stress durability test to determine time to failure and locus of failure. It was conclude that E-8385 promotes the durability of P/F pretreated adherends, whereas the titanates provide no improvement.

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Document Details

Document Type
Technical Report
Publication Date
Oct 01, 1986
Accession Number
ADA175123

Entities

People

  • J. A. Filbey
  • J. P. Wightman

Tags

Communities of Interest

  • Advanced Electronics

DTIC Thesaurus Topics

  • Adhesion
  • Adhesive Bonding
  • Adhesives
  • Aluminum Oxides
  • Chemistry
  • Chromium
  • Electron Microscopes
  • Electron Microscopy
  • Elements
  • Hydroxides
  • Metals
  • Military Research
  • Predictive Modeling
  • Sodium Hydroxide
  • Spectra
  • Spectroscopy
  • Titanium

Readers

  • Surface Coatings Technology.
  • Thin Film Deposition Science.

Technology Areas

  • Microelectronics