Influence of sintering profile on the microstructure and electronic transport properties of Sr(Ti,Nb)O3 tapes for solid oxide cell applications

• Published in: Solid state ionics Vol. 335; pp. 164 - 169
• Main Authors: Sudireddy, B.R., Blennow, P., Agersted, K., Hansen, K.V., Mogensen, M.B.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.07.2019; Elsevier BV
• Subjects: Backscattering; Conductivity; Dilatometry; Electron imaging; Electron transport; Electronic properties; Mapping; Microstructure; Nb-doped strontium titanate; Niobium; Pretreatment; Resistance; Shrinkage; Sintering; Sintering (powder metallurgy); Solid oxide cells; Solid oxide fuel cells; Strontium oxides; Strontium titanates; Tape casting; Temperature effects; Transport properties; Conductivity; Solid oxide cells; Nb-doped strontium titanate; Sintering
• ISSN: 0167-2738; 1872-7689
• DOI: 10.1016/j.ssi.2019.01.030

Nb-doped strontium titanate (Sr0.99Ti0.9Nb0.1O3, STN) tapes were fabricated by tape casting and used for investigating the influence of pre-treatment temperature on the sintering behavior, microstructure and electronic properties. The pre-treatment temperature was varied between 500 °C and 800 °C. Phase analysis of the powder from the pre-treatment step showed a single phase up to 700 °C and a Sr-enriched secondary phase beyond 700 °C. Sintering dilatometry showed similar sintering behaviour with little variation in the final shrinkage with different pre-treatment temperatures. Backscattered electron imaging confirmed the presence of Sr enriched secondary phase for pre-treatment at 700 °C or above. Conductance mapping on samples pre-treated at 800 °C and sintered at 1450 °C exhibited regions of low conductance. Conductivity measurements of pre-treated and sintered, at 1300 °C, samples showed decrease in conductivity with increasing pre-treatment temperature. These observations enhance the understanding of processing STN materials for solid oxide cells applications significantly. •Investigation of Nb-doped SrTiO3 fuel electrode materials in different atmospheres•Segregation of SrO phase along grain boundaries and triple-point junctions•Formation of SrO phase results in reduction of electronic conductivity.•Results provide understanding of processing of Nb-doped SrTiO3 materials.