Microstructure and hydrogenation thermokinetics of ZrTi0.2V1.8 alloy

✍ Scribed by X.W. Yang; T.B. Zhang; R. Hu; J.S. Li; X.Y. Xue; H.Z. Fu

• Book ID: 103832721
• Publisher: Elsevier Science
• Year: 2010
• Tongue: English
• Weight: 944 KB
• Volume: 35
• Category: Article
• ISSN: 0360-3199
• DOI: 10.1016/j.ijhydene.2010.08.065

✦ Synopsis

The microstructures and phase composition of the pseudobinary ZrTi 0.2 V 1.8 alloy were examined by scan electron microscope (SEM) and X-ray diffraction (XRD). Before hydrogenation, the hypoeutectic structure accompanied with ZrV 2 þ (ZrV 2 þ Zr) spherical-like texture has been observed in ZrTi 0.2 V 1.8 and the dominant phase could be ascribed to the C15 Laves phase. Hydrogen absorption pressureecomposition isotherms (PeC isotherms) and hydriding kinetics of ZrTi 0.2 V 1.8 were investigated by pressure reduction method using Sievert apparatus from 673 to 823 K. At hydrogen concentration 0.65 (H/A), the relative partial molar enthalpy and entropy calculated by Van't Hoff equation are À60 AE 1 kJ mol À1 and À119 AE 1 J mol À1 K À1 , respectively. In addition, two stages in the hydrogen absorption reaction between 673 and 823 K could be attributed to the different hydrogen absorption mechanisms including redistribution of the hydrogen atoms in the hydride phase and the diffusion of hydrogen in the b-phase. The activation energy E a of the alloy is w3.6 kJ mol À1 for the first absorption stage and w61.9 kJ mol À1 for the second one.