Papers by Author: Amporn Kamonlert

Abstract: Powder of β-alumina solid electrolyte with general formula Na0.80Li0.20Al5O8 was prepared by solid state reaction according to the ternary systems Li2O-Na2O-Al2O3. All the calcined powders were heated at different temperatures for 1 h. The XRD results indicate that the β-alumina phase started to form at 1100 °C and these consistent with TG/DTA measurements. At constant calcined temperature of 1100 °C, When the dwell times was varied in range 5 h to 15 h, it was found that powder consists of β-alumina as a majority phase with a tiny amount of β-alumina and the β-alumina phase purity is about 82 wt% for dwell time of 10 h. The microstructures of β-alumina particles were seen as a layered structural arrangement with hexagonal shape and strong agglomeration between these particles are clearly seen.

Abstract: PZT-PMN ceramic system with presence of MnO2 contents were proposed and prepared using conventional sintering method as for piezoelectric transformer application. Phase formation and several dielectric and piezoelectric parameters were studied as a function of MnO2 concentration. The x-ray diffraction study revealed the tetragonal symmetry for all samples with MnO2 doping. To determine polarization, the P-E hysteresis loop were produced and the results indicated that entering of Mn4+ ions in the ceramic structure created large amount of oxygen vacancies and the consequent was observed as displacement of the loops to E axis. The obtained optimum parameter are d33 = 119 pC/N, kp = 0.207, Qm = 1669, tan = 0.0101, Pr = 20 μm/cm2 and Ec = 10 kV/cm.