The Influence of Air Exposition of the Zr-Mn-Cr-Ni-Al Alloy on Cycle Life

<p><span>It was found by scanning electron microscopy method that the ZrMn</span>_0.5<span>Ni</span>_1.2<span>Cr</span>_0.18<span>А</span>_0.1<span> alloy has a dendritic structure, and the shooting of a typical section of the surface of the metalographic sample in characteristic radiation determined its chemical heterogeneity. The X-ray diffraction method has found that the C</span>₁₅<span> and C</span>₁₄<span> are the main phases of the alloy. In addition, the alloy contains Ni</span>₁₀<span>Zr</span>₇<span> and Ni</span>₁₁<span>Zr</span>₉<span> secondary phases. The method of potentiometric cycling has established that the air exposition of ZrMn</span>_0.5<span>Ni</span>_1.2<span>Cr</span>_0.18<span>А</span>_0.1<span> alloy powder results in an increase in the electrochemical stability of the electrodes pressed from this powder and causes a significant increase of their cycle life. It is important that the cycle life of the AB</span>₂<span> alloy doped simultaneously with chromium and aluminum increased. Such doping is usually carried out in order to increase the cycle life due to the creation of hydrogen penetrating stable oxide films. Alloys with the same content of the Ni</span>₁₀<span>Zr</span>₇<span> phase have the same activation rate of the initial electrodes. The increase in the secondary phase of Ni</span>₁₀<span>Zr</span>₇<span> leads to an improvement in the kinetics of hydrogenation of the initial electrode. Exposition in air of a powder of an alloy with an increased content of the Ni</span>₁₀<span>Zr</span>₇<span> phase does not accelerate the kinetics of hydrogenation, but it leads to a significant improvement in its cyclic stability. By reducing the amount of Ni</span>₁₀<span>Zr</span>₇<span> phase, the improvement of kinetics of hydrogenation occurs as a result of the exposition of the powder of the alloy in the air. The mechanism of origination and distribution of corrosion of the alloy without and with exposition in air for 7 and 15 days with subsequent aging in 30% solution KOH is the same. According to investigations, corrosion of the material originates on the interphase surface and begins to spread along it, indicating its pitting nature, and the surface of the pitting itself has the form of flake. </span></p><p><strong>Keywords: </strong><span>Zr-alloy, hydrogenation, exposition in air.</span></p>