Annealing effects on Laves phase-related body-centered-cubic solid solution metal hydride alloys

摘要

Effects of thermal annealing (between 800 and 1100 degrees C) on the structural, gaseous phase and electrochemical hydrogen storage properties of a Laves phase-related body-centered-cubic (BCC) alloy, Ti15.6Zr2.1V40.0Cr11.2Mn6.9Co1.4Ni22.5Al0.3, were studied. Only BCC, TiNi, and C14 phases appeared in the as-cast sample. Annealing at 800 and 900 degrees C increased the main hydrogen storage BCC phase abundance and reduced C14 and TiNi catalytic phases. Annealing at 1000 degrees C promoted the formation of Ti2Ni phase. A sigma-VNi phase appeared after annealing at 1100 degrees C. In addition, the annealed samples also contained Zr and TiO2 debris. Electrochemical results suggested optimized annealing conditions of 900 degrees C for 12-h to optimize the storage capacity, high-rate performance, and activation due to a favorable balance in abundance between storage phase (BCC) and catalytic phases (C14 and TiNi). (C) 2015 Elsevier B.V. All rights reserved.