Novel low temperature wet chemical processes for the synthesis of gels and ultrafine powders of BaTiO₃ and BaTi₄O₉ were developed. Under acidic conditions a titanyl acylate precursor was obtained by molecular modification of titanium isopropoxide. In the sol-gel process, amorphous BaTiO₃ gels obtained under acidic conditions were heat treated at ≈950-1000°C yielding fine (≈ 1-3 μm), high purity (99.9%) stoichiometric (Ba/Ti = 0.99) BaTiO₃ powders. In the sol-precipitation process, ultrafine (≈ 10 nm) crystalline BaTiO₃ powders were directly precipitated at low temperatures (<100°C) from a stoichiometric titanium acylate- barium acetate sol (pH > 13.5). Precursor powders obtained by hydrolytic decomposition of barium and titanium alkoxides were heat treated at 1100°C to obtain high purity, homogeneous, single phase BaTi₄O₉ powders. Atomistic pathways for the evolution of crystalline phases from amorphous gels and powders were investigated. The microstructure and electrical properties of sintered BaO-TiO₂ ceramics were studied and correlated with the powder processing conditions. The structures of crystalline and amorphous forms of some materials in the BaO-TiO₂ system were simulated using molecular dynamics computer techniques to develop a fundamental understanding of structure-property relationships for BaTiO₃ and TiO₂ containing glasses.
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/184672 |
| Date | January 1989 |
| Creators | Phule, Pradeep Prabhakar. |
| Contributors | Risbud, S. H., Raghavan, S., Deymier, P. A., Pemberton, J. E., Burke, M. F. |
| Publisher | The University of Arizona. |
| Source Sets | University of Arizona |
| Language | English |
| Detected Language | English |
| Type | text, Dissertation-Reproduction (electronic) |
| Rights | Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. |
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