• Proceedings of the Korean Magnestics Society Conference
• /
• 2007.05a
• /
• pp.22.2-22.2
• /
• 2007

• Analytical Science and Technology
• /
• v.12 no.3
• /
• pp.230-234
• /
• 1999

Barium titanyl oxalates (BTO) has been homogeneously prepared by thermal decomposition of dimethyl oxalate (DMO) in hydrochloric solution containing $Ba^{2+}$ and $Ti^{4+}$. Particles of BTO settled on the bottom of the beaker were collected at the aging time of 120 min using hydroxy propyl cellulose (HPC) as a dispersant. The reaction temperature, the concentration ratio of $[DMO]_0/([Ba^{2+}]_0+[Ti^{4+}]_0)$ and the existence of HPC were found to influence on morphologies of BTO, chemical yields and characteristics of barium titanates formed from their precursors.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.7 no.1
• /
• pp.163-166
• /
• 1997

• Proceedings of the Korean Vacuum Society Conference
• /
• 1994.06a
• /
• pp.45-46
• /
• 1994

• Proceedings of the Korean Ceranic Society Conference
• /
• 2003.10a
• /
• pp.48.2-48
• /
• 2003

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2004.05a
• /
• pp.54-54
• /
• 2004

• Proceedings of the Materials Research Society of Korea Conference
• /
• 1998.08a
• /
• pp.87.3-87
• /
• 1998

• The Korean Journal of Ceramics
• /
• v.1 no.2
• /
• pp.69-74
• /
• 1995

The optimal condition for minimal agglomeration of barium titanyl oxalate tetrahydrate, the precipitate on preparing barium titanate by oxalate process, was investigated. Burette-dropping and dual-nozzle-spraying were used as adding methods. pH of washing water for precipitates was changed, and sodium pyrophosphate solution, methanol, ethoanol, and acetone were used as washing agents for precipitates, as well as distilled water. Drying temperature was changed from $50^{\circ}C$ to $120^{\circ}C$. Spraying, methanol-washing, and drying at $60^{\circ}C$ showed the most dispersed distribution, Below $70^{\circ}C$, the crystalline phases were observed.

• Bulletin of the Korean Chemical Society
• /
• v.14 no.1
• /
• pp.38-42
• /
• 1993

Factor analysis was applied to study the thermal decomposition of barium titanyl oxalate (BTO) which is used as the precursor of barium titanate. BTO was synthesized in $H_2O$ solvent and calcined at various temperatures. The X-ray diffraction patterns were obtained to make the data matrix of peak intensity vs. 2${\theta}$. Abstract factor analysis and target transformation factor analysis were applied to this data matrix. It has been found that the synthesized BTO consists of the crystals of $BaC_2O_4{\cdot}0.5H_2O\;and\;BaC_2O_4{\cdot}2H_2O$ as well as the amorphous solid of TiO-oxalate. The results also indicate that the BTO was transformed via $BaCO_3\;to\;BaTiO_3\;and\;Ba_2TiO_4$ during the thermal decomposition.

• Bulletin of the Korean Chemical Society
• /
• v.16 no.12
• /
• pp.1180-1184
• /
• 1995

The precursors of Ba1-xSrxTiO3(x=0.0-0.3) were prepared by the rapid addition of aqueous solution of titanyl oxalate to the mixed aqueous solution of barium and strontium at room temperature. The optimum pH was theoretically calculated from the equilibrium constants and solubility products. The chemical formula of the precursors obtained corresponded to Ba1-xSrxTiO(C2O4)2·4H2O(x=0.0-0.3) as determined by thermal gravimetric analysis. The precursors were converted to stoichiometric Ba1-xSrxTiO3(x=0.0-0.3) with a particle size of 0.01-0.04 μm. As increasing the amount of strontium substituted to barium sites, the structure of crystal changed from the tetragonal phase to the cubic and the unit cell volume was decreased.