Effect of Nb2O5 doping on low-temperature sintering of TiO2-Al2O3 ceramics

Abstract

This study investigates the effects of Nb₂O₅ as a dopant in TiO₂–Al₂O₃ ceramics to lower sintering temperature and enhance performance, including the physical, mechanical, and dielectric properties of the ceramics at sintering temperatures 1250 °C–1350 °C. Specifically, TiO₂–Al₂O₃ ceramics doped with 1.5 wt% Nb₂O₅ and sintered at 1350 °C exhibit remarkable density 94 %, compressive strength 1372 MPa, and abrasion resistance 1.36 × 10⁻⁴ mm³/N·m, surpassing those of pure alumina ceramics. This improvement is attributed to enhanced grain boundary diffusion and strain energy resulting from Nb⁵⁺ cation substitution. The incorporation of Nb₂O₅ in TiO₂–Al₂O₃ ceramics reduce sintering temperatures by 150–200 °C. The dielectric constant of TiO₂–Al₂O₃ ceramics doped with 1.5 wt% Nb₂O₅ sintered at 1350 °C is found to be 13.4, with a dielectric loss of 2.56 × 10⁻² and insulation resistance 7.3 × 10¹² Ω. Nb₂O₅ is an effective additive for reducing sintering temperatures in Al₂O₃ based ceramic.