Electrochemical Conversion of Oxide Precursors to Consolidated Zr and Zr-2.5Nb Tubes

Porous tubular oxide precursors have been fabricated from the ZrO2 powder and its mixture with the Nb2O5 powder, and directly metallised to pure Zr or the Zr-2.5Nb Zircaloy tubes through electrochemical reduction and deoxygenation that induces in situ consolidation or sintering of the metallized tubes in molten CaCl2 at similar to 900 degrees C. This new process is simple, fast, and low in energy consumption, promising a new technology for the fabrication of zirconium/Zircaloy tubes, which are the crucial materials in nuclear reactors and chemical plants. Also reported in this paper is the mechanism of the electrochemical process, correlating the cyclic voltammogram of ZrO2 powder in a metallic cavity electrode with the morphological and compositional analyses of the products from potentiostatic electrolysis of porous ZrO2 pellets.