摘要：

Plasma spraying of polymers has been investigated as a surface treatment for titanium in preparation for adhesive bonding. Polymeric materials were plasma sprayed on titanium and the plasma-sprayed materials were characterized using solid state NMR, and surface sensitive analytical methods. The chemical nature of plasma-sprayed polymers is equivalent to that for powdered materials. The durability of titanium adherends, plasma-sprayed with polymeric coatings, and bonded with a second plasma-sprayed polymeric coating or a polyimide adhesive film has been studied. Durability was investigated using a wedge-type specimen by exposing the specimens to several different environments: immersing the samples in toluene, methyl ethyl ketone, jet fuel, and ethylene glycol at room temperature, and testing the specimens in boiling water. Systems exhibiting durability comparable to that for adherends treated using standard solution methods (chromic acid anodization) included: 1) titanium adherends grit-blasted with alumina, plasma-sprayed with LaRC TPI-2000; 2) titanium plasma-sprayed with TPI-2000 and then LaRC PETI-5, and bonded directly with or without an adhesive film. For the samples that were grit-blasted with alumina and were bonded by contacting the two polyimide plasma-sprayed layers, failure during exposure to room temperature and the solvents occurred in the adhesive, indicating a favorable adherend-plasma-sprayed coating interaction. The systems exhibiting poor durability, included titanium adherends grit-blasted with alumina/chromia particles, plasma-sprayed with LaRC TPI-2000, and bonded with a polyimide adhesive film, and titanium adherends grit-blasted with alumina/chromia particles, plasma-sprayed with LaRC TPI-2000 and PETI-5, and bonded directly with no adhesive film.

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