Microstructure and Conductivity of La1−xSrxGa0.8Mg0.2O3−δ Electrolytes Prepared Using the Freeze-Drying Method

• Published in: Journal of the American Ceramic Society Vol. 94; no. 4; pp. 1031 - 1039
• Main Authors: Marrero-López, David, Martín-Sedeño, Maria Carmen, Peña-Martínez, Juan, Ruiz-Morales, Juan Carlos, Núñez-Coello, Pedro, Ramos-Barrado, Jose Ramón
• Format: Journal Article
• Language: English
• Published: Malden, USA Blackwell Publishing Inc 01.04.2011
• Subjects: Agglomeration; Ceramics; Densification; Electrolytes; Evolution; Low level; Microstructure; Strontium
• ISSN: 0002-7820; 1551-2916
• DOI: 10.1111/j.1551-2916.2010.04233.x

Polycrystalline powders of La1−xSrxGa0.8Mg0.2O3−δ (LSGM) (x=0.05, 0.10, and 0.20) were synthesized using an alternative freeze‐drying method. Precursors and sintered pellets of LSGM were characterized by X‐ray diffraction and scanning electron microscopy, paying special attention to the temperature dependence of phase formation and microstructure evolution. The results of this study indicate that dense LSGM samples with a low level of Sr doping x≤0.1 can be prepared as a single phase at 1300°C, although a temperature of 1400°C is required for samples with a higher Sr content (x>0.1). The phase formation and densification processes take place in a short time due to the small particle size and the low degree of agglomeration of the synthesized powders. Dense samples of La0.8Sr0.2Ga0.8Mg0.2O3−δ without secondary phases are obtained after sintering at 1400°C for only 15 min with ionic conductivity values of 0.1 S/cm at 800°C.