Effects of the penetration temperature on structure and electrical conductivity of samarium modified BaTiO₃ powders

Gaseous penetration technique was adopted to improve the electrical conductivity of BaTiO₃ powders and the effects of penetration temperature on the structure and electrical conductivity of Sm-modified BaTiO₃ powders were studied. It was observed that the penetration of Sm made the resistivity of BaTiO₃ powders decrease with the increase in the penetration temperature and decreased to the lowest point of 4.20×10² Ω·m when the penetration temperature was 950 °C. The relationship curve of the temperature and resistivity of the samples was also established preliminarily to get the mathematical expression by the fitting method. Through X-ray diffraction (XRD) analysis, the new phases of Sm₂O₃ and Ba₄Ti₂O₂₇ were detected. It was indicated that intricate reactions related to Sm took place during the penetration process and led to the Ti-rich state of the system. The Fourier transform infrared (FTIR) spectrum illustrated that the bonds of Ti-O octahedron was strengthened by substitution of Sm³⁺ at Ti ⁴⁺ sites, which led to the growth of Ti: Ba ratio. The analysis results of scanning electron microscopy (SEM) indicated that the particle size of Sm-modified BaTiO₃ powders progressed with the penetration temperature increasing.