Structure and piezoelectric properties of K0.5Na0.5NbO3-AlFeO3 lead-free ceramics by using AlFeO3 as a sintering aid

The (1 - x)K0.5Na0.5NbO3-xAlFeO(3) ((1 - x)KNN-xAF) (x = 0.01-0.08) lead-free piezoelectric ceramics were prepared at low temperature of 1,000 A degrees C by conventional ceramic processing. And AF was used as a sintering aid in order to improve the sintering behavior of KNN. The effect of AF addition on the microstructure, dielectric and piezoelectric properties of the ceramics have been investigated. The results indicate that a small amount of AF can improve the sintering performance and piezoelectric properties of the ceramics effectively. The KNN-AF ceramics for x = 0.03 show the best piezoelectric properties: d (33) = 116 pC/N, k (p) = 32.9 %, Q (m) = 114.8, T (C) = 382 A degrees C, P (r) = 21.8 mu C/cm(2). This also indicates that (1 - x)KNN-xAF ceramics are a promising lead-free piezoelectric candidate material because of its good properties, low-temperature sintering characteristics and plenty of Al2O3 and Fe2O3 resources with low cost.