Sintering process optimization for multi-layer CGO membranes by in situ techniques

• Published in: Journal of the European Ceramic Society 2013-03, Vol.33 (3), p.549-556
• Main Authors: Kaiser, A., Prasad, A.S., Foghmoes, S.P., Ramousse, S., Bonanos, N., Esposito, V.
• Format: Article
• Language: English
• Subjects: Activation energy; Asymmetry; Cobalt oxides; Densification; Dilatometry; Doped ceria; Membranes; Multi-layer sintering; Multilayers; Optical dilatometry; Sintering (powder metallurgy); Sintering aid; van der Pauw
• ISSN: 0955-2219; 1873-619X
• DOI: 10.1016/j.jeurceramsoc.2012.09.021

The sintering of asymmetric CGO bi-layers (thin dense membrane on a porous support; Ce0.9Gd0.1O1.95−δ=CGO) with Co3O4 as sintering additive has been optimized by combination of two in situ techniques. Optical dilatometry revealed that bi-layer shape and microstructure are dramatically changing in a narrow temperature range of less than 100°C. Below 1030°C, a higher densification rate in the dense membrane layer than in the porous support leads to concave shape, whereas the densification rate of the support is dominant above 1030°C, leading to convex shape. A flat bi-layer could be prepared at 1030°C, when shrinkage rates were similar. In situ van der Pauw measurements on tape cast layers during sintering allowed following the conductivity during sintering. A strong increase in conductivity and in activation energy Ea for conduction was observed between 900 and 1030°C indicating an activation of the reactive sintering process and phase transformation of cobalt oxide.