Preparation of creep-resistant Ni–5 wt.% Al anodes for molten carbonate fuel cells

Ni–5 wt.% Al anodes for molten carbonate fuel cells (MCFCs) are fabricated using relatively cheap elemental powders instead of expensive alloy powders. The tape-cast green sheets are sintered in various atmospheres: reduction, full oxidation–reduction, and partial oxidation–reduction atmospheres. The anode sintered in a reduction atmosphere shows a morphology of a network structure of an Ni---Al solid solution with its surface covered with thin Al2O3 films, and has relatively low creep resistance. On the other hand, the anode sintered in a full oxidation–reduction atmosphere or the one sintered in a partial oxidation–reduction atmosphere has a morphology of small Al2O3 particles dispersed in a network structure. In the former, however, a large number of micropores are created during sintering. The latter does not have the micropore problem and generally exhibits high creep resistance. The highest creep resistance is shown by the anode sintered in a partial oxidation–reduction atmosphere with an oxidation time of 2.5 h.