Directionally solidified calcia stabilised zirconia–nickel oxide plates in anode supported solid oxide fuel cells

We present here a new manufacturing procedure for the anode Ni–zirconia cermet. It is based on the modification of the surface of a NiO–CaSZ (calcia stabilized zirconia) pellet of eutectic composition by surface laser melting and resolidification. A smooth, continuous and dense NiO–CaSZ layer is obtained on top of the ceramic pellet. Its depth can be varied from less than 200 μm to more than 570 μm, depending on the processing conditions. Its microstructure consists mainly of lamellar eutectic grains with interlamellar spacing ranging from 0.4 to 1.6 μm. The interspacing diminishes towards the surface, where a very fine microstructure is developed. Chemical reduction treatment transforms NiO to metallic Ni with the accompanying volume reduction. Complete reduction results into a cermet with 43 CaSZ+33.5 Ni+23.5 pores (%vol). Electrical conductivity is mainly electronic and proceeds along NiO lamellae or through percolating Ni particles.