ABSTRACT
Abstract-Silane coatings on aluminum aircraft alloy AA2024-T3 have been proposed as an alternative to toxic chromate conversion coatings for surface pretreatment. The corrosion protection by these silanes is comparable to chromates and in certain cases silanes out-perform them. However, the silane coatings are not visible and do not have the "self-healing" effect that chromates are known for. In this paper we show that silane films can be colored and that a self-healing effect can be achieved by adding optimum amounts of leachable corrosion inhibitors to the silane film which can be released at a controlled rate. We have studied the corrosion protection properties of the colored silane films and have shown that the corrosion inhibition property of the silane film is not hindered by the colorant. We also show that loading silanes with sheared nanoparticles enhances the corrosion protection performance and the mechanical properties of the film. Two different silane systems are described in this paper, viz., a solvent-based system and a completely water-based system.
