Bondability of Ti Adherends 2. Humid Environment Effects.
Abstract
We have demonstrated the importance of oxide morphology to the properties of bondments of Al and Ti structures in previous studies. Microrough, porous oxides which provide good mechanical interlocking with the primer/adhesive system were found essential to good bondability. Ability to withstand long-term degradation in humid environments in Al was found to be poor, because the Al oxide was transformed into hydroxide in a relatively short time. On the other hand, Ti oxides are known to be very stable. The purpose of this study was to investigate possible humidity-induced morphological and structural changes on these latter oxides and to relate them to known failure data. We found that both changes occur at temperatures/times relevant to service conditions. Typically, the original oxides are amorphous TiO2. They crystallize into anatase through a dissolution-precipitation process, which is strongly dependent on temperature, oxide porosity and surface contamination. This transformation may be important in the degradation of adhesive bonds to Ti.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 22, 1981
- Accession Number
- ADA307856
Entities
People
- John D. Venables
- Kathleen R. Breen
- Menachem Natan
Organizations
- Martin Marietta