Inna Andryushina

Solid Solutions of Sodium-potassium-cadmium Niobats: Preparation, Structure, Electrophysical and Thermofrequency Properties Inna Andryushina

The optimal technological regulations (in the limits of the usual ceramic procedure) providing the preparation of impurity- free, high- density samples of solid solutions of the system based on Na, K, Cd niobates were developed. Their structural, piezoelectric and dielectric properties were studied, which enabled one to construct the phase x, T- diagram (at room temperature). At the multiple cycling of a dc electric field the effect similar to phase- transition fatigue was discovered. The interval of critical values of the overall electronegativity of A- elements being a boundary between the traditional reverse dependences of the dielectric permittivity on the homogeneous deformation parameter and the abnormal direct ones was established. Compositions being promising for practical applications were chosen. A conclusion on the necessity to take the results obtained into account in engineering the lead- free Na-, K- , Cd- based materials was made.