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

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.