양극 산화법을 통한 나노구조물을 갖는 초친수성 지르칼로이-4 표면의 제조 및 젖음성 변화에 관한 연구

Abstract

This thesis presents fabrication and wettability study about superhydrophilic Zircaloy-4 surface. Anodic oxidation in dilute hydrofluoric acid formed self-organized micro/nano structures on Zircaloy-4 surface. Morphology of the surface evolved as a function of anodization time and nanotube layer and “barnacle” structures were found as the result. Both structures made micro/nano scale rough surface and siginificantly enhanced wetting behavior of the surface. Especially barnacle structure was a dual-scale structure and contact angle converged into near zero as this structure appeared on outermost surface. Wetting properties were characterized in both contact angle measurement and spreading experiment. Barnacle structure made near-zero contact angle as well as a large spreading. The barnacle structures were fabricated on Zircaloy-4 tube surface then. Since zircaloy is used in tube shape in real applications (i.e., nuclear fuel rod), barnacle structures on tube specimen demonstrates feasibility for real applications. Application of this research on nuclear reactor will make great advantages, both enhancement of safety and economic profit.