|
ИСТИНА |
Войти в систему Регистрация |
Интеллектуальная Система Тематического Исследования НАукометрических данных |
||
Mechanism of BaTiO3 formation in hydrothermal conditionsтезисы доклада
- Авторы: Kholodkova Anastasia A., Danchevskaya Marina N., Ivakin Yurii D.
- Сборник: 4th International Solvothermal and Hydrothermal Association Conference
- Том: 1
- Тезисы
- Год издания: 2014
- Место издания: Bordeaux, France
- Первая страница: 123
- Последняя страница: 124
- Аннотация: Hydrothermal synthesis of barium titanate is of high industrial importance for the opportunity to produce pure, uniform, fine-crystalline particles with narrow size distribution. Powder with these properties is most suitable in manufacturing of ceramics for MLCCs, PTCRs, piezoelectric transducers and electro-optic devices. To further control of the product characteristics it is necessary to understand the mechanism of its formation in hydrothermal reaction. For BaTiO3 this problem has been under consideration for few decades. Nevertheless it is still not quite clear which of two proposed mechanisms - in situ or dissolution-precipitation - occurs during hydrothermal synthesis of BaTiO3. Current work continues the investigations devoted to solution of this problem. Set of BaTiO3 samples was synthesized in hydrothermal conditions at 130°C and 0,4 MPa for 0-48 hours from mixture of TiO2 (rutile) and Ba(OH)2•8H2O. From XRD patterns of samples, formation of crystalline BaTiO3 starts after 20 minutes of process and the conversion completes in 4,5 hours. During this period the appearance and growth of new spherical BaTiO3 particles on the TiO2 surface were observed by means of SEM. Mostly intensive growth of these particles from about 63 to 97 nm occurred at 20-60 minutes of synthesis, after that the mean size changed insignificantly. The appearance of notable amount of spherical nanoparticles was detected by SEM also in samples synthesized for 0-20 minutes. However, XRD doesn't show any BaTiO3 peaks during this early period of process. Presumably, nanoparticles are generated in amorphous form and then crystallize. New crystals always located on the rutile surface and never separately from it. SEM images show gradual transformation of rutile crystals into BaTiO3 (Figure 1).These facts support the in situ mechanism of BaTiO3 formation in hydrothermal process. Final BaTiO3 powders synthesized for 24-48 hours consist of spherical aggregated crystals with the mean size of 85-95 nm and show pseudocubic modification at XRD. The powders are perspective as raw material for dense ferroelectric ceramics.
- Добавил в систему: Данчевская Марина Николаевна
Прикрепленные файлы
| № | Имя | Описание | Имя файла | Размер | Добавлен |
|---|---|---|---|---|---|
| 1. | Полный текст | Kholodkova_CV-Abstract.pdf | 106,4 КБ | 23 декабря 2014 [khol] |