Sintering Mechanism of CuO-doped Ce0.8Gd0.2O2 Ceramics

Gadolinia doped Ceria (Ce0.8Gd0.2O2, GDC) is considered to be one of the most promising alternatives to yttria stabilized zirconia (YSZ) for application in solid oxide fuel cells operating at intermediate temperatures. Although several transition metal oxides can be used to lower the sintering temperature of GDC only CoO has been deeply studied. This paper considers the less toxic and less expensive CuO and reports its effect on the sintering mechanism of GDC through dilatometric and microstructural analyses. The addition of 2% CuO into GDC greatly improves its sinterability lowering the sintering temperature of more than 300°C and increasing the maximum shrinkage rate. The early stage of sintering has been modelled showing a mechanism substantially different from the one generally accepted for CoO.