| 摘要 |
A simple surface treatment process is provided which offers a high performance surface for a variety of applications at low cost. This novel surface treatment, which is particularly useful for Ti-6Al-4V alloys, is achieved by forming oxides on the surface with a two-step chemical process and without mechanical abrasion. First, after solvent degreasing, sulfuric acid is used to generate a fresh titanium surface. Next, an alkaline perborate solution is used to form an oxide on the surface. This acid-followed-by-base treatment is cost effective and relatively safe to use in commercial applications. In addition, it is chromium-free, and has been successfully used with a sol-gel coating to afford a strong adhesive bond that exhibits excellent durability after the bonded specimens have been subjected to a harsh 72 hour water boil immersion. Phenylethynyl containing adhesives were used to evaluate this surface treatment with a novel coupling agent containing both trialkoxysilane and phenylethynyl groups. The morphology of the interface between the metal surface and the adhesive was investigated using scanning electron microscopy and atomic force microscopy. Lap shear specimen failures were compared for adhesive bonds made with a conventional surface preparation and this new treatment. The test results at hot-wet environment demonstrate an approximately 90% retention of initial strengths. It is expected that this process will establish a low cost and high performance surface for not only high-speed commercial aircraft but also for other commercial applications.
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