Carbon tolerance of Ni–Cu and Ni–Cu/YSZ sub-μm sized SOFC thin film model systems

Thin films of YSZ, unsupported Ni–Cu 1:1 alloy phases and YSZ-supported Ni–Cu 1:1 alloy solutions have been reproducibly prepared by magnetron sputter deposition on Si wafers and NaCl(001) single crystal facets at two selected substrate temperatures of 298K and 873K. Subsequently, the layer properties of the resulting sub-μm thick thin films as well as the tendency towards carbon deposition following treatment in pure methane at 1073K has been tested comparatively. Well-crystallized structures of cubic YSZ, cubic NiCu and cubic NiCu/YSZ have been obtained following deposition at 873K on both substrates. Carbon is deposited on all samples following the trend Ni–Cu (1:1)=Ni–Cu (1:1)/YSZ>pure YSZ, indicating that at least the 1:1 composition of layered Ni–Cu alloy phases is not able to suppress the carbon deposition completely, rendering it unfavorable for usage as anode component in sub-μm sized fuel cells. It is shown that surfaces with a high Cu/Ni ratio nevertheless prohibit any carbon deposition.