1999 Volume 107 Issue 1244 Pages 318-321
Polycrystalline samples with nominal compositions K1+xNb4O6 (0≤x≤1.0) were prepared by the solid-state reaction of KNbO3, Nb2O5 and Nb. Powder X-ray diffraction analysis revealed that the KNb4O6-type compound was obtained as the major phase when x≥0.4. Transmission electron microscopy observations showed that when x=0.4, the KNb4O6-type compound contained intergrowth defects. In contrast, when x=1.0, practically no intergrowth defects were observed, although this sample contained KNbO3 as an impurity phase. The relation between the nominal composition and the formation of the intergrowth defects is discussed.