A study on synthesis of fine size cobalt powder from fluoride compounds

Research studies were carried out to prepare extra fine and high purity cobalt powder from synthetic cobalt chloride solutions without the use of hydrogen. The two major steps involved in the process were, first, precipitation of an appropriate ammonium cobalt fluoride salt and second, its thermal decomposition to cobalt powder. The optimum conditions for precipitation of NH4CoF3 were found to be, temperature of 30 oC, 100% excess NH4F and a solution pH of 5. Cobalt metal powder was prepared from NH4CoF3 in a closed reactor and decomposition cum reduction temperature and time were optimized to 550 oC and 6 h, respectively. Detailed XRD studies identified all the intermediate and final products. The powder was further characterised by Chemical and SEM analysis. SEM analysis revealed the formation of 100-500 nm cobalt powder having spherical/round morphology