1987 Fiscal Year Final Research Report Summary
Control and Functional Utilization of Ferroelectric Powder Surfaces
| Project/Area Number |
61550580
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
無機工業化学
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| Research Institution | Tokyo Metropolitan University |
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Principal Investigator |
CHIKAZAWA Masatoshi Faculty of Technology, Tokyo Metropolitan University, 工学部, 教授 (90087289)
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| Project Period (FY) |
1986 – 1987
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| Keywords | Barium Titanate / Oriented Adsorption / Chloromethanes / Isosteric Heat of Adsorption / 表面電場強度 |
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| Research Abstract |
Sample powder (ca.7 m^7/g) of BaTiO_3 was prepared by wet process using BaCl_2 and TiCl_4 reagent. The control of adsorption force by applying electric field to the ferroelectric powders is main theme in this study. Chloromethanes, such as CCl_4, CHCl_3 and CH_2Cl_2, were used as adsorbates. The powder characteristics were investigated from x-ray diffraction pattern, IR spectra, SEM observation, temperature programmed desorption spectra and density measurement of sample particles. Then, the surface properties were examined by H_2O and CH_3OH adsorption. The suface of BaTiO_3 powder particles were clarified to be covers with chemisorbed H_2O and CO_2. These impurities were removed by evacuation under reduced pressure of 10^<-6>mmHg at 1000 ゜C for 13hr and heat treatment at 800゜C for 1hr in atmosphere of O_2. In the cases of chloromethanes adsorption, the isosteric heats of adsorption increased lineary with the increment of dipole moment of the adsorbate. Adsorption potential due to London dispersion force is equal each other, and interaction between solid surface and induced dipole of the adsorbate is very small. Therefore, the difference of the adsorption heats is concluded to be ascribed to the orientation force of the dipole of the adsorbates to the solid surface. Subsequently, the sample powder was spontaneously polarized by applying electric field of 5kv/ cm at room temp., and adsorption amounts of chloromethanes were measured under applying electric field of 2kv/cm. The isosteic heat of adsorption increased about 15 -20%. From these results, the electric field of the adsorption sites on the solid surface was calculated as follows. Applying electric field : 0kv/cm 1.2x10 c.g.s.e.s.u.; 2kv/cm 2.3x10 c.g.s.e.s.u.
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