Abstract
The potential of atmospheric plasma spraying (APS) technology has been investigated for the manufacture of anode, electrolyte and cathode of a solid oxide fuel cell. As substrates tape-casted or commercial available porous plates both made of a FeCr-alloy were used. The functional layers were applied by atmospheric plasma spraying, however, it turned out that screen printed LSCF cathodes performed better than thermally sprayed versions. Anode layers with high electrochemical activity could be produced by APS using separate injections of NiO and YSZ powders. The manufacturing of gas-tight electrolyte layers was a key-issue of the present development. With adequate processing conditions and advanced gun technology it was possible to produce highly dense ceramic coatings with a very low amount of micro-cracks and pores. These electrolytes gave high open cell voltages above 1 V corresponding to the low measured leakage rates (<10-3 mbar*l/s) of the rather thin (<50 µm) coatings. Additional layers have been applied to reduce the interdiffusion especially of species from the metallic substrates into the anode. These layers could significantly reduce degradation of the cells. SOFCs with a power density at 800°C well above 0.7 W/cm² could be produced by the developed technology.
