Development of anodization technique on zirconium silicide material for reproducing micro/nanosurface structure: Application to nuclear accident tolerant fuel cladding

Abstract

Zirconium silicide (ZrSi2) surfaces with micro/nanoscale structures were fabricated using an anodization technique with different working solutions. The surface structures evolved depending on the reaction time, and the resulting surface structures were characterized using scanning electron microscopy. For all three solutions, the anodization conditions for producing micro/nano surface structures with the superhydrophilicity were successfully found. The etching rate and thickness were controlled depending on the type of solutions. In the organic bath-based ammonium fluoride (NH4F) solutions, the etching thickness was significantly reduced in comparison to that using a water bath-based hydrofluoric acid (HF) solution. Superior oxidation resistance of ZrSi2 was maintained for all superhydrophilic, anodized ZrSi2 surfaces at 700 °C air oxidation regardless of the type of solution. The superhydrophilic, anodized ZrSi2 surfaces significantly increased the Leidenfrost temperature by inducing liquid-solid contact between the heated surface and coolant. We expect the developed surfaces to be useful in future nuclear fuel cladding material applications for ensuring the safety of nuclear reactors.