ISSN:
1573-4846
Keywords:
barium titanate
;
sol-gel method
;
transparent
;
partially-crystallized xerogel
;
low temperature densification
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract Transparent, partially-crystallized nanostructured barium titanate (BaTiO3) monolithic xerogels (dried at 90°C) have been successfully synthesized via hydrolysis of Ba, Ti alkoxide precursor solutions in a concentration range of ≥1.0 mol/l with addition of water with a molar ratio of H2O/Ba ≥ 6.3. Transparent monolithic xerogels obtained from a precursor solution of 1.0 mol/l remained transparent even after firing at 500°C in oxygen, although the degree of their transparency was considerably decreased. Firing at temperatures above 500°C yielded translucent ceramics of BaTiO3, and ultimately, firing above 600°C resulted in normal opaque ceramic bodies. Those obtained from a more concentrated precursor solution of 1.2 mol/l were, on the other hand, still transparent after firing at 600°C in oxygen, and turned opaque at 700°C. The results demonstrate that the materials retained their transparency even after pyrolysis of organic compounds involving exothermic oxidation at temperatures in the range of 200 to 400°C. The densification behavior of transparent BaTiO3 monolithic xerogels obtained was found to be excellent; for example, those derived from a 1.0 mol/l precursor solution could be sintered to form monolithic BaTiO3 ceramics with a relative sintered density of about 94% and an average grain size of ≈1 μm by firing at 1100°C for 2 h in oxygen.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1008662904874
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