| Abstract |
| The corrosion behavior and oxide properties of HANA-3, HANA-6 and Zircaloy-4 alloys have been investigated. HANA-3 and HANA-6 alloys showed an excellent corrosion resistance when compared to the Zircaloy-4 alloy in a PWR-simulation loop condition without a neutron flux. In HANA alloys, the corrosion rate was increased with an increase of the final annealing temperature. Oxide microstructure observation showed that the oxides formed on all the alloys had a layer structure regardless of the alloy composition. HANA-6 which was annealed at 470℃ showed the best corrosion resistance among the tested alloys and it had the highest thickness of the fully developed oxide layer even though the total oxide thickness was the smallest. The oxides were consisted mainly of columnar grains in the interface region and equixed grains in the outer surface region. The size of oxide grains was increased with an increase of the corrosion resistance and the grain morphology was changed periodically from the interface to the outer surface, which was well correlated the layer structure and the transition behavior in the corrosion kinetics. The lateral cracks were observed only in the regions where the equiaxed grains are dominant. The precipitates incorporated into the oxide of HANA alloys maintained the crystallite in the interface region but transformed to the amorphous state by oxidation when apart from the interface. |
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| Key Words |
| Zr alloys, corrosion, oxide |
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