Preparation and Corrosion Phenomena of Self-Healing Multi-Layered Coating by Silica and Swelling Clay

Abstract

Ceramics coating for substrate provides high-level protection because of stability or toughness. However, once the coatings are degraded by cracks or pinholes, both the coating and the substrate are severely damaged by corrosion. We have investigated the feasibility of self-healing coatings which automatically repair the damaged, and focused on the swelling clay. The swelling property of clay mineral is known to come off hydration of cation in the interlayer space. By swelling, the clay minerals shows thixotropy and it have blocking effect for the water or dissolved ions in the water. In this study, we tried to synthesize the built-up coating of SiO2 layer and swelling clay layer by spin coating under various conditions. As the results, 2 or 3 clay layers successfully were interposed in the coating. Furthermore surface condition and the corrosion phenomena were studied.