Preparation of LaNi₅ by FFC Cambridge Process

Abstract

A new technique was proposed for preparation of LaNi5 powder by direct electrolytic deoxidation of solid La2O3–NiO mixture oxides in molten CaCl2–NaCl. Oxides pellets was sintered and used as cathode. High – density graphite was used as anode. Electrolysis was performed. Current change during electrolysis was recorded. XRD was used to analyse the composition of products. SEM was used to analysis surface and cross section of pellets before sintering, after sintering and after electrolysis. The preparation mechanism and the influences of sintering temperature and cell voltage on electrolytic deoxidation was studied. Results show that the optimum conditions to prepare LaNi5 are：NiO-La2O3（Ni:La=5:1）pellets are formed at 30MPa, sintered at 850°C for 5h, electrolyzed under 3.2V in CaCl2–NaCl melt at 850°C for more than 12 hours.

DC Voltammetry of Electro-deoxidation of Solid Oxides

“…It was claimed that the formation of the metallic phase is possible at 2.5 V in eutectic NaCl–CaCl 2 , with the reduction pathway initiated by metallising NiO to Ni, which then reacts with CeOCl to produce CeNi 5 . Zaho et al reported the preparation of CeNi 5 and LaNi 5 under 3.2 V in molten CaCl 2 at 1023 K. Zhang et al, prepared La 0.5 Ce 0.5 Ni 5 using the same conditions and electrolyte. Song et alused eutectic KCl–LiCl to produce CeNi 4 Cu alloy powders by electro-deoxidation of oxide precursors at 923 K. At such low temperature, no CeOCl was detected as an intermediate phase .…”

Investigation on the thermodynamic analysis, preparation and characterization of LaNi5 - hydrogen storage alloy by magnesiothermic reduction diffusion process

“…The AB 2 's seem to be more sensitive to gaseous impurities than the AB 5 's [7] hence the advantage of LaNi 5 intermetallic compound is that they exhibit low hysteresis, are moderate to gaseous impurities and are effortlessly hydrogenated in the initial cycle after manufacture [8]. Conventionally, the metal hydride materials have been prepared by arc melting [9][10][11] , induction melting [12], mechanical alloying [8,[13][14][15] electro chemical synthesis [16,17], solid state reduction method [18].The preparation of Rare Earth metals and alloys production from its ores has not yet full-fledged in India .Therefore the production processes of Rare Earth based functional materials are found to be considered as a insightful area of research. The Reduction-Diffusion (R-D) process involves reduction of cheaper raw materials such as lanthanum oxide (La 2 O 3 ) by calcium and simultaneous diffusion in nickel [19][20][21] forming the intermetallic compound.…”