Plasma-Sprayed Coatings as Surface Treatments of Aluminum and Titanium Adherends
Abstract
Thermal sprayed coatings were evaluated as environmentally benign pretreatments for aluminum and titanium adherends. The thermal spray process allows a wide variety of coatings to be deposited onto different substrates and, hence, the coatings can be engineered for different applications. Because there are no liquid or vapor wastes for disposal, the process has several environmental advantages to conventional treatments that use strong chemicals. Scanning electron microscopy showed that the best performing treatments exhibit an irregular, rough surface over wide dimensional scales. This roughness provides excellent opportunity for mechanical interlocking or physical bonding and allows a complex interphase to be formed as the adhesive penetrates into the coating. Wedge tests prepared using the best thermal spray coatings (titanium and, in some cases, an aluminum-polyester blend) on aluminum adherends preformed better under humid conditions than those prepared by the Forest Products Laboratory (FPL) process and similar to those prepared by the phosphoric acid anodized (PA) process for some adhesives. Bonds prepared using plasma sprayed titanium coatings on titanium perform equivalently to the best chemical treatments with failure within the adhesive for some adhesives.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1996
- Accession Number
- ADA365478
Entities
People
- B. S. Wenner
- G. B. Groff
- G. D. Davis
- P. L. Whisnant
- R. Zatoarski