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

Abstract

Effects of mixing methods (mechanical mixing, chemical coating) on microstructure and dielectric properties of Ho, Mg and Mn doped BaTiO 3 have been studied. BaTiO 3 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 BaTiO 3 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 (Ho 2 Ti 2 O 7 ) 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 BaTiO 3 matrix were confirmed by EDS analysis.

Spherical pellets of BaTiO3 and Ba0.67Sr0.33TiO3 perovskite-type compounds made by a sol–gel oil drop process for non-thermal plasma applications

“…5(c), reveals two types of grains. Some are very compact with important grain boundaries due to sintering, while others close to macropores appear to display a wrap on the surface such as that described by Park and Han (2006). It seems that the decomposition of additives during the sintering affects the grain morphology notably close to the pores.…”

Effects of multi-doping of rare-earth oxides on the microstructure and dielectric properties of BaTiO3

“…The mixture was sonicated in a water bath and heated to 80 • C for 2 h in a thermostatic under stirring. The suspension was then aged in an electric oven at 90 • C for 12 h and calcination was conducted at 700 • C [5,11]. The powders were pulverized into fine particles and formed into a disk shape under a uniaxial pressure of 200 MPa.…”

“…The chemical coating on ceramic powders has been attempted to investigate the doping effects and the surface characteristics of particles through various coating processes [5][6][7][8][9][10][11][12]. Chemical coating can produce a very homogeneous additives shell, regardless of particle size.…”

“…Additives coating on BaTiO 3 powders have been carried out for X7R temperature characteristics, revealing the performance on the dielectric properties and microstructure [10]. The effects of additives coating on the powder characteristics, dielectric properties, and sintering behavior of BaTiO 3 system were also studied [11,12].…”

Two-step sol–gel method for preparing MgO–MnO2–B2O3–Li2O co-added core-shell structural Ba0.55Sr0.40Ca0.05TiO3 powders and the dielectric properties of the composite ceramics

“…And the sintering temperature of the core-shell powders was 1,100°C [12]. The method that used for MZO or MgO coating that had been mentioned above was homogeneous precipitation which had intimate relationship with the relative particle size and the surface charge of the powders [13]. Mornet et al [14] had represented a sol-gel method that based on the hydrolysis and condensation of the tetraethoxysilane (TEOS) for preparing SiO 2 coated Ba 0.6 Sr 0.4 TiO 3 powders.…”