Glycothermal preparation of potassium niobate ceramic particles under supercritical conditions

Potassium niobate KNbO3 particles were synthesized via a newly developed glycothennal process using isopropanol as the reaction medium in supercritical environment. Increasing the concentration of KOH and the molar ratio of K+/Nb5+ substantially facilitated the formation of KNbO3. When the concentration was 0.5 M and the molar ratio of K+/Nb5+ was greater than 2: 1, well crystallized monophasic, KNbO3 was successfully produced at as low as 250degreesC. In comparison with the traditional hydrothermal process, the supercritical glycothermal process greatly reduced the required concentration of KOH. This supercritical glycothennal process provides a new prospective approach for synthesizing electronic ceramic powders at low temperatures. (C) 2002 Elsevier Science B.V. All rights reserved.