In this paper the preparation, structure and dielectric parameters of ceramics from different powders of pure potassium sodium niobate (KNN) and KNN doped with 1.0 wt% of Li 2 O, CdO, Bi 2 O 3 , MnO 2 , V 2 O 5 and WO 3 have been studied. The dopping of sintering aids did not affect the crystallographic structure of the ceramics significantly; all ceramic samples had a single-phase perovskite structure. Added elements Li 2 O, CdO, MnO 2 , V 2 O 5 effectively decreased the sintering temperature of KNN (50 • -80 • C). All sintering aids influenced sinterability, microstructure and dielectric properties of ceramics. Dielectric constant for doped samples increased from 6000 up to 8000.
Lead-free piezoelectric ceramics (K 0.5 Na 0.5 )(Nb 1−x Sb x )O 3 +0.5 mol.%MnO 2 , where x = 0 ÷ 0.10, with single phase structure and rhombohedral symmetry at room temperature were prepared by conventional ceramic technology. The optimal sintering temperatures of compositions were within 1100 • -1140 • C. MnO 2 functions as a sintering aid and effectively improves the densification. The samples reached density from 4.26 g/cm 3 for undoped (K 0.5 Na 0.5 )NbO 3 to 4.40 g/cm 3 for Mn/Sb 5+ co-doped ceramics. The co-effects of MnO 2 doping and Sb 5+ substitution lead to significant improvement in dielectric and piezoelectric properties: ε at the T c increased from 6000 (KNN) to 12400 (x = 0.04), d 33 = 92 ÷ 192 pC/N, k p = 0.32 ÷ 0.46, k t = 0.34 ÷ 0.48.
Lead-free potassium sodium niobate (K0.5Na0.5)NbO3 (KNN) has been prepared via conventional ceramic processing method. The influence of 0.5 wt% - 1.5 wt% MnO2 and WO3 addition on the sintering, crystallographic structure, microstructure and dielectric properties of KNN has been investigated. Optimal sintering temperatures of KNN ceramics were observed to be in the narrow interval: 1090 °C - 1110 °C for MnO2 doped KNN; 1150 °C - 1170 °C for pure KNN and doped with WO3. XRD patterns showed that all the samples have single perovskite structure with monoclinic structure. Microstructure of ceramics was changed greatly by using dopants.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.