Nanosized BaTiO₃ powders with crystallite size about 20 nm were synthesized by chemical precipitation, in which, Titanic acid (H₄TiO₄) and barium nitrate [Ba(NO₃)₂] were used as the raw materials, and hydrogen peroxide (H₂O₂) and ammonia (NH₃•H₂O) were used as solvents. The influences of species of raw materials, calcination temperatures, feeding sequence, reaction temperatures on BaTiO₃ were studied in detail. The results show that the good dissolution properties, the small particle size and high purity of BaTiO₃ could be obtained at the conditions of H₄TiO₄ (g)∶H₂O₂ (mL)∶NH₃•H₂O (mL)＝1∶5∶3 and adding the solution of H₄TiO₄ dissolved in H₂O₂ and NH₃•H₂O into Ba(NO₃)₂ aqueous solution slowly. Moreover, the crystal structure, crystallization transfer mechanism, and crystallite size were researched by X-ray diffraction (XRD) and scanning electron microscope (SEM). The results show that the beginning crystallization temperature of barium titanate is approximately 500 ℃ and the particles obtained at 800 ℃ exhibited integral crystal structure and spherical morphology. However, the crystal structure of BaTiO₃ obtained at 900 ℃ was changed from cubic into tetragonal phase.

Key words: nanosized BaTiO₃ powders, titanic acid, calcination temperature, chemical precipitation