| To develop the advanced Zr alloy for nuclear fuel cladding, the microstructure and corrosion characteristics of Zr-xNb binary alloys were studied of Nb addition. Microstructural observation and corrosion behavior of Zr-xNb alloys with niobium content were carried to develop an advanced nuclear fuel cladding materials. Niobium addition results in refining the final grain size, increasing precipitation in matrix and reducing corrosion resistance of the alloy in 360℃, 18.9㎫ water. The alloy with 0.2 wt.% Nb, especially, showed the highest corrosion resistance in this study which was related to columnar structure of the oxide and relatively high content of tetra-ZrO₂. This supports that the corrosion behavior of the Zr-Nb alloy significantly depended on the microstructure and composition of the oxide. mom the XRD analysis, SEM study and TEM observation on the oxide having equal oxide thickness, the 0.2 wt.% Nb alloy showing the best corrosion resistance had higher fraction of tetra-ZrO₂ and columnar structure than other alloys. Therefore, it is considered that the corrosion of Zr-xNb binary alloy would be controlled by the oxide characteristics like tetra-ZrO₂ and equiaxed structure. |
|
