Lead zirconate titanate/tungsten oxide (PZT/WO3) ceramics were prepared from the powders synthesized by a modified triol sol-gel processing method. In this study, the starting materials used for synthesis of PZT-sol were zirconium (IV) propoxide, titanium (IV) isopropxide, lead (II) acetate trihydrate and 1,1,1,- tris (hydroxymethyl) ethane. To prepare PZT/xWO3 powders (where x = 0, 0.5, 1 and 3 wt%), nano-sized WO3 was ultrasonically dispersed and mixed with the PZT sol, dried and calcined at 600°C for 4 h. X-ray diffraction results indicated that fully crystallized powders were obtained. Phase characterization suggested that at high WO3 concentration, the reaction between PZT and WO3 occurred during the calcination process. To prepare PZT/xWO3 ceramics, the powders were pressed and sintered at 1100°C for 6 h. Phase characterization by XRD indicated that the content of WO3 significantly affected tetragonal-to-rhombohedral phase transition. Microstructure of thermally etched samples showed that increasing the content of WO3 decreased grain size of the ceramics.
Extraction and physical characterization of amorphous silica made from corn cob ash at variable pH conditions via sol gel processing