Kruae, Vergleichende Analyee der Rd. filicie maris. littheilnngen ans dem pbarmacentischen Institnt zn Dorpat. 4. V e r s u c h e i n e r v e r g l e i c h e n d e n A n a l y s e d e r i n d e n M o n a t e n A p r i l , J u l i u n d O c t o b e r 1874, i n d e r U m g e g e n d W o l m a r s g e s a m m e l t e n Rd. f i l i c i s m a r i s .

Barium zirconium titanate powders with a composition of Ba (Zr0.3Ti0.7)O3 were synthesized by a conventional mixed oxide and vibro-milling method. Ba (Zr0.3Ti0.7)O3 ceramics were fabricated from the synthesized powders. The effects of milling technique on the physical and mechanical properties of the prepared samples were investigated. Compared to conventional samples, the samples prepared by the vibro-milling method showed a higher densification. The vibro-milling methods also produce a higher degree of crystallinity. The microstructure results were correlated with the characteristics of the milling process. The measurement results indicated that the milling technique affected both of physical and mechanical properties of the lead-free BZT ceramics.

This research reports the physical and mechanical properties of (1-x) Bi0.5(Na0.81K0.19)0.5TiO3-xKNbO3 (x=0.00-0.06) ceramics. The Modified Bi0.5(Na0.81K0.19)0.5TiO3 ceramics were synthesized by solid state reaction technique. The mixed oxides powders were calcined at 850 °C, 4 h and sintered at 1120 °C, 2 h to form pure phase perovskite and the optimum bulk density, respectively. The phase formation of the modified ceramic samples was determined by X-ray diffraction technique. All of the modified Bi0.5(Na0.81K0.19)0.5TiO3 ceramics exhibited a single perovskite phase. The bulk densities of the modified ceramic samples were 5.41±0.27-5.75±0.28 g/cm3 using the Archimedes’ method. The microstructure was revealed by the scanning electron microscope. The rectangular-like shape was found of all studied ceramics which had the grain size between 1.31±0.02-1.56±0.03 mm. The mechanical properties were studied by both Vickers and Knoop microhardness tester. The results are discussed in term of the relation among hardness properties, Young’s modulus, and fracture toughness.

Lead-free powders of Bi(Na0.81K0.19)O3 doped 0.3 wt.% CoO were prepared by a conventional mixed oxide technique. The sintering process was controlled with various rate up and down temperature. The samples were sintered at 1,050 °C for 4 h which difference heating rate controlled i.e. 100, 300, and 600 °C/h. The XRD pattern analysis of all studied samples showed a single phase perovskite structure Dielectric and ferroelectric properties of the ceramics were investigated as a function of rate controlled sintering temperature. The sample heating rate at 600 °C/h showed maximum dielectric constant (~5961) at Tm. In addition, the ferroelectric properties were analyzed and discussed.