Direct Electrolysis Process of Hydrogen absorbing alloy films from Molten Salts and Film Characterization

点击翻译按钮获取中文摘要

Hydrogen absorbing. alloy, HAA, consists of element A (La, Mg, Ca, Ti, etc) and element B (Ni, Fe, Cu, etc). The elements A, which are generally very active metals, were electrodeposited on substrate B in molten salts and diffused each other to make intermetallic compounds with hydrogen absorbing property. This process for HAA production has an advantage to produce directly from resources of active element A and film type.Lanthanum was electrodeposited on nickel substrate in chloride bath. The phase formed on the substrate depends on electrolysis conditions such as temperature, current density, electrolysis duration, etc. The HAA film, LaNi_5, can be obtained by controlling the electrolysis condition. The charge-discharge property for the HAA films were estimated electrochemically in an alkaline solution at ambient temperature. In La electrolysis, LaNi_5 layer with 25 μm formed on Ni substrate during 0.4 ks under the current density of 0.1 Acm^<-2> at 1023 K.This film showed better cyclic charge-discharge property for hydrogen adsorption/disorption than commercial LaNi5 ingot. The Ni substrate inhibited the embrittlement of HAA film on the surface during charge-discharge test. On the other hand, co-electrodeposition of La and Co on Ni sheet gave LaNi_<5-x>Co_x (X<1%) layer. This Co addition also improved cyclic property.