Electrochemical Behavior of mono- and polycrystalline zirconium electrodes in sulfuric acid solutions

Electrochemical behavior of a Zr electrode in sulfuric acid solutions is studied, at various overpotentials, temperatures, pH values, and concentrations of surfactants, in a cathodic potential range. A mechanism of hydrogen evolution at zirconium electrode is proposed. The supposition that zirconium readily forms a hydride, which essentially changes the electrochemical properties of surface, is confirmed. When heated, this phase readily decomposes yielding hydrogen. Hydrogenation of a Zr monocrystal causes cracking of its surface in a certain crystallographic direction. By x-ray diffraction analysis, indices of a working face of zirconium monocrystal are determined and the variations in the lattice constants under vigorous hydrogenation are calculated.