Correlation between microstructure and electrical properties of A-site substituted YAlO3 ceramics

Abstract

The effect of microstructural parameters on the electrical properties of Y1−xCaxAlO3−δ (x = 0.10, 0.20) synthesized by Pechini and solid state routes was studied. A study on the phases formed was conducted using the X-ray diffraction method. Microstructural analyses were performed by scanning electron microscopy coupled energy dispersive X-ray spectroscopy and electron backscatter diffraction techniques. Electrochemical impedance spectroscopy over the temperature range 200–800 °C and frequency range 5 Hz–15 MHz was used to separate the grain interior and grain boundary contributions of the total conductivity. Brick layer model was used to interpret the impedance data. A correlation between the microstructural features and the impedance measurements was attempted to understand the effect of preparation route on the electrical conductivity. The role played by microstructural elements such as grain size, grain boundary area, grain orientation and grain boundary thickness on the electrical behaviour of doped YAlO3 ceramics was investigated.