Microstructure Development in -Oriented (K,Na)NbO3-based Ceramics

The development of grain orientation and the factors controlling the degree of orientation in (K,Na)NbO3-based ceramics were examined using two types of platelike NaNbO3 template powders and four types of matrix powders—KNbO3, NaNbO3, and (K0.5Na0.5)NbO3 powders, and a mixture of KNbO3 and NaNbO3 powders. The NaNbO3 template powders were prepared by single- and two-step molten salt synthesis (MSS). In the ceramic specimens, the template NaNbO3 grains changed to (K,Na)NbO3. The direction of material transport in this reaction determined the degree of orientation. The sintering characteristics of the matrix powders also contributed to the control of the degree of orientation.