Influence of Sintering Temperature on Densification, Structure and Microstructure of Li and Sb Co-Modified (K,Na)NbO₃-Based Ceramics

Abstract

Polycrystalline samples of Lead free (K_0.5Na_0.5)_1-x(Li)_x(Sb)_x(Nb)_1-xO₃ ceramics with nominal compositions (x = 0.040 to 0.060) have been prepared by high temperature solid state reaction technique. X-ray diffraction (XRD) pattern shows that the crystal structure transforms from orthorhombic to tetragonal as Li and Sb content increases. Normal sintering process yield compounds with density ~98.2% of the theoretical value. Densification of the Li and Sb co-doped KNN ceramics might be explained by the liquid-phase sintering. This may be attributed to the low melting temperature of Li compounds that appears to promote the formation of a liquid phase during sintering.