Optimization of low sintering temperature for colossal permittivity and humidity resistance in TiO based ceramics.

This study investigates the colossal permittivity (CP) and humidity resistance of (SnNb)TiO ceramics. Increasing the sintering temperature enhanced both density and grain growth, with the fine-grained structure proving essential for achieving a high dielectric constant (ε' ~ 2.2 × 10) and maintaining low dissipation factors (tanδ ~ 0.011) at a reduced sintering temperature of 1150 °C. At an elevated sintering temperature of 1210 °C, optimal dielectric properties were observed, yielding ε' ~ 1.0 × 10 and an ultra-low tanδ of ~ 0.004, attributed to highly resistive grain boundaries. The CP response is linked to semiconducting grains, supported by the presence of Ti resulting from Ti substitution by Nb. The minimal variation in ε' with temperature suggests suitability for capacitor applications, with ε' exhibiting little dependence on DC bias (0-30 V/mm). Optimized sintering conditions yielded stable CP properties with minimal sensitivity to humidity (30%-90% RH) over a range of temperatures (25-85 °C) and frequencies (10-10 Hz). These findings underscore the potential of (SnNb)TiO ceramics for advanced capacitors in varied environmental and operational conditions.