Study On Synthesis Of Barium Titanate Electronic Ceramics

Ferroelectric particles BaTiO3, a kind of electronic ceramics with high dielectric constant at room temperature, have been used as raw materials for the manufacture of multilayerceramic capacitors, positive temperature coefficient resistivity (PTCR) thermistors and other electro-optic components. The properties and microstructure of barium titanate ceramics are highly dependent on the ratio of barium to titanium.Preparation of fine ceramic powders has become an important part of modern ceramic research. There is a strong trend toward the application of chemical method for powder synthesis in electronic ceramics. Recently, with the miniaturization of electronic devices, the thickness of dielectric layers in MLCC has been reduced to 2μm, and it can be expected that this thickness will become less than 1μm in the future. Consequently, with the reduction of thickness of the dielectric layers in MLCC, BaTiO3 particles with sizes from a few hundred nm to a few tens of nm are required. Besides, The super-fine BaTiO3 ceramic powders lower sintering temperature, achieve fine ceramic grain size uniformly and save energy.To begin with, BaTiO3 nanoparticles were synthesized with the diameter about 16nm using Ba(OH)2·8H2O and tetrabutyl titanate as the raw materials by hydrothermal method in this paper. The effect of the synthesis temperature and concentration of reactants on the particles size, the effect of the molar ratio of barium hydroxide to tetrabutyl titanate on the ratio of barium to titanate in products, and the effect of different anneal temperature on the crystal lattice parameter were studied. The products were characterized by FT-IR, TEM and XRD. The results show that the products are single cubic system nanoparticles, the molar ratio of barium to titanium of products is 1.0 from chemical analysis.furthermore, Nanisized BaTiO3 particles were synthesized in reverse microemulsion consisting of water, Trition-10, n-hexanol and cyclohexane. The reaction conditions were optimized on the basis of the study of the influence of the molar ratio of water to surfactant, the concentration of reactants and ageing time on the shape and size of BaTiO3 particles. The prepared BaTiO3 samples were characterized by XRD and TEM. The results show that the spherical BaTiO3 nanoparticles with an average size of 20～80nm belong to single tetragonal system, The molar ratio of barium to titanium of products is 1.0 from ICP analysis.Finally, BaTiO3 nanorods were synthesized by adoping water/OPE-10/ n-hexanol/cyclohexane reverse microemulsion system in this paper. The reaction...