HYDROTHERMAL SYNTHESIS OF NONLINEAR-OPTICAL POTASSIUM NIOBATE CERAMICPOWDER

Potassium niobate KNbO3 particles having nonlinear optical properties were successfully prepared via a hydrothermal process. When KOH, with a concentration of 8 M, reacted with Nb2O5 particles at 200 degrees C, monophasic KNbO3 was obtained. The high concentration of KOH was foun d to be a critical requisite for the formation of KNbO3. Compared with the traditional solid-state reaction, the hydrothermal process signif icantly lowered the temperature required for synthesizing KNbO3. The a dded amounts of Nb2O5 in the hydrothermal reaction greatly influenced the morphology and particle size of KNbO3, as well as the intensity of the second harmonic generation. (C) 1998 Elsevier Science B.V.