Interdisciplinary Approach to Predictive Modeling of Structural Adhesive Bonding. Factors Affecting the Durability of Titanium/Epoxy Bonds

摘要

Factors influencing the durability of Titanium-6-4 / epoxy and Ti-6-4 / metal alkoxide / epoxy interphases were studied by first determining chemical and physical properties OF Ti-6-4 adherend surfaces; second by characterizing the strength and durability of Ti-6-4 / epoxy bonds; and third by using aluminum and titanium alkoxides as possible adhesion promoters. Ti-6-4 adherend surfaces were oxidized either by chemical etch or anodization. Four principal pretreatments were studied: chromic acid anodization (CAA), sodium hydroxide anodization (SHA), phosphate fluoride acid etch (P/F), and TURCO basic etch (TURCO). The oxides were characterized physically by SEM, STEM, profilometry, and contact angles; and chemically by XPS, AES, SIMS, and indicator dyes. The two anodically produced oxides were porous, with pore diameters of 40 to 50 nm, while P/F and TURCO pretreated adherends showed no porosity. Good reproducibility of oxide composition was seen by XPS. The acidity/basicity of the surfaces was found to be in order of increasing basicity CAA < P/F < TURCO < SHA.