Correlation between electrical and mechanical properties in La1−xSrxGa1−yMgyO3−δ ceramics used as electrolytes for solid oxide fuel cells

•Pure phase La1−xSrxGa1−yMgyO3−δ powders were prepared via ethylene glycol complex solution method.•LSGM ceramics have been characterized by impedance spectroscopy and instrumented indentation techniques.•Both relative density and presence of secondary phases play important roles in hardness and ionic conductivity.•A linear correlation in terms of hardness and ionic conductivity in LSGM ceramics was determined (500–660 °C).•By measuring the LSGM pellet hardness at room temperature, one can achieve an approach to the ionic conductivity.

The relation between the electrical and the mechanical properties in Sr and Mg doped LaGaO3 ceramics, which can be used as electrolyte for solid oxide fuel cells, was investigated in terms of hardness and ionic conductivity. For this purpose, ceramic materials corresponding to the compositions of La1−xSrxGa1−yMgyO3−δ (LSGM), with x = 0.1 and y = 0.2, and x = 0.15 and y = 0.2, were prepared. LSGM powders synthesized by the ethylene glycol complex solution method were shaped into disks by isostatic pressing method. The variation in the microstructure of samples was achieved by varying the sintering temperature between 1300 and 1450 °C. While the effect of the different microstructures on the electrical properties of the LSGM electrolytes was determined by impedance spectroscopy, the influence of the hardness was extracted by instrumented indentation technique. The results showed a linear correlation between the hardness and total ionic conductivity within the temperature range of 500–660 °C, thus indicating that both properties were strongly influenced on the relative density and purity of the samples. It has a potential practical implication: by measuring the LSGM hardness at room temperature, one can achieve an approach to the ionic conductivity within the studied temperature range.

Graphical abstractCorrelation between the hardness and the total ionic conductivity at 660 °C for La1−xSrxGa1−xMgyO3−δ sintered at different temperatures.Figure optionsDownload full-size imageDownload as PowerPoint slide