Effects of Oxide Additives Coating on Microstructure and Dielectric Properties of BaTiO3

Effects of mixing methods (mechanical mixing, chemical coating) on microstructure and dielectric properties of Ho, Mg and Mn doped BaTiO3 have been studied. BaTiO3 particles coated with Ho, Mn and Mg were prepared by a homogeneous precipitation method using urea, and then silica was coated by the sol-gel technique. The adsorption of additives on the BaTiO3 surface was confirmed. Temperature characteristics of capacitance were satisfied by mechanical mixing and chemical coating techniques, both of which yield different sintering and microstructure behaviors. Pyrochlore phase (Ho2Ti2O7) was observed on the mechanically mixed sample, whereas none of pyrochlore phase was observed at the coated sample after thermal etching. Those different behaviors caused by the degree of homogeneous distribution of the additives in BaTiO3 matrix were confirmed by EDS analysis.