Low-temperature synthesis of BiNbO4 ceramics using reaction-sintering process was investigated. Orthorhombic BiNbO4 phase together with
minor triclinic BiNbO4 phase were found in the pellets. The phase transition temperature in BiNbO4 with 0.5 wt% CuO addition was lowered from
960 8C via traditional route to 880 8C when the reaction-sintering process was used. After 920 8C sintering for 4 and 6 h, densities 6.8–6.85 g/cm3
(94% of the theoretical value) were obtained. The abnormal grain growth in BiNbO4 via traditional route was not observed in this study.