• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.120-123
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• 2000

This paper reports a newly developed sol-gel process to synthesize dense YBCO thick films with $BaTiO_3$ additives using electrophoretic deposition and metal alkoxide sol/particle suspension, which we successfully produce dense $YBCO+BaTiO_3$ ceramics at a rather low temperature, compared with the sintering temperature used in conventional methods. The thick films of HTS were prepared by electrophoretic deposition, using pre-sintered powder with barium titanate addition in the form of $BaTi(OR)_6$ solution in suspension for electrophoresis. The conditions for applied voltage and deposition times for electrophoretic deposition of HTS thick films were studied in detail.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.678-679
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• 2006

The effects of particle size on the surface properties of hydro-thermally synthesized barium titanate powders were investigated by means of particle size analysis, specific surface area, SEM, zeta potential and XPS. Particle sizes were measured by laser light scattering and are in the range of 150 to 1100nm. Zeta potential increased with increasing particle size and it was large minus value in the range of particle size from 500 to 900nm, which seems to be related with the dissolution of $Ba^{2+}$ ion in these particle sizes from the analysis of surface properties by XPS.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.35-38
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• 2005

The effect of reduction and re-oxidation firing on the PTCR properties of Sm-doped Barium Titanate ceramics was investigated for the application of multilayered PTC thermistor. The lattice parameter a, c decreases monotonically with increasing oxygen concentration in the reoxidation atmosphere, which seems to be related with the electrostatic Coulomb interaction between oxygen vancancy and nearest other atoms. With increasing oxygen concentration, the resistivity at room temperature and the magnitude of resistivity jump as a function of temperature increased in the region of oxygen concentration of 0 $\sim$ 10%. However, the resistivity at room temperature and the magnitude of resistivity jump is nearly constant and saturated in the region of oxygen concentration of 10 $\sim$ 20%. These phenomena is considered to be related with the variation of oxygen and barium-vancany concentration near the grain boundary.

• Proceedings of the Korean Ceranic Society Conference
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• 2004.10a
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• pp.90.1-90.1
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• 2004

• Proceedings of the Korean Ceranic Society Conference
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• 2004.10a
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• pp.90.2-90.2
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• 2004

• Proceedings of the Korean Ceranic Society Conference
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• 2004.04b
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• pp.44.3-44.3
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• 2004

• Proceedings of the Materials Research Society of Korea Conference
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• 1998.08a
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• pp.114.2-114
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• 1998

• Proceedings of the Materials Research Society of Korea Conference
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• 1998.08a
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• pp.59.4-59
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• 1998

• Journal of the Korean Ceramic Society
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• v.42 no.2 s.273
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• pp.123-126
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• 2005

Barium Titanate (BT) powders were synthesized by solvothermal method with an ethanol as a solvent. The average particle size was increased with the feedstock concentration: the size was 59 nm at $6.25{\times}10^{-2}$ M and 89 nm at 0.5 M. The sample obtained at 0.5 M concentration was analysed by Rietveld refinement and the mole fraction of tetragonal phase was $75.5\%$ and lattice parameter of tetragonal phase was a=0.3999 (nm), c=0.4032 (nm), and cubic phase was a=0.4015 (nm). TEM analysis for the samples with condition of annealing at $500^{\circ}C$ for I h showed that hydroxyl ions on oxygen sites were not found for these experimental conditions.

• Analytical Science and Technology
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• v.10 no.1
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• pp.35-42
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• 1997

The sample pretreatment technique using a high pressure acid digestion bomb for the analysis of ceramic capacitor materials, such as barium titanate and PZT, was studied. When the concentrations of hydrochloric acid were varied with the addition of nitric acid or distilled water, quantitative measurements for those samples were carried out using inductively coupled plasma atomic emission spectrometry. From this experiment the results indicate that most of elements, such as Ba, Mn, Zn, Si, etc., aren't affected by the concentration of hydrochloric acid but Nb and Zr are very susceptable to it. It however turns out that the digestion time relatively gave little effects on the analytical result. In case of Nb the ratio of hydrochloric acid to water should be greater than 3:1(v / v) for the best analytical result. For the Pb determination use of diluted hydrochloric acid compared to the mixture of nitric acid and hydrochloric acid showed a better analytical result.