Effects of Fuel Contents and Surface Modification on the Sol-gel Combustion Ce0.9 Gd0.1O1.95 Nanopowder

Sol-gel combustion was employed for the synthesis of Ce0.9 GD0.1O1.95or10GDCnanopowder. Optimum fuel ratio and surface modification were closely examined. The fuel/metal molar ratios were ranged from 0.78, 0.83, 1.5 and 2.0. The results showed that increasing the fuel/metal ratio to above 0.78, which was the stoichiometric molar ratio, resulted in combustion of the gel at higher temperatures with a greater amount of residue ash content. Crystallite size of the sample was almost 2-fold larger when the fuel ratio was increased from 0.78 to 2.0. The density of the sintered samples were found to decrease with an increase of the fuel/metal molar ratios.The 0.78 composition was thus used in the latter part. Additions of ammonium dispex (Dispex A40), a surface modifier, at different ratios was found to affect the degrees of particle agglomeration and was found to be optimum at 0.4wt%. The compacted powder with this Dispex A40content could be fully densified at around 1350 C, mainly due to the extremely fine particles with a lesser degree of agglomeration.