Fuel cell e.g. solid oxide fuel cell, has support substrate which is made of iron and/or iron group

The cell (30) has a solid electrolytic layer (33) made of zirconium oxide, to cover a fuel electrode layer (32) formed on a support substrate (31). The support substrate is made of iron and/or oxides of iron group metals and rare earth oxides. - An INDEPENDENT CLAIM is also included for a fuel cell assembly.