This thesis investigates an‎d optimizes the synthesis of piezoelectric ceramics based on PMN-PZT (Pb(〖Mg〗_(1/3) 〖Nb〗_(2/3))O3-Pb(Zr,Ti)O3). PMN-PZT ceramics are widely utilized in various applications such as sensors, actuators, an‎d microelectronic devices due to their outstan‎ding electromechanical properties. The primary objective of this research is to enhance the piezoelectric an‎d ferroelectric properties of these ceramics through doping with samarium (Sm) an‎d to examine the effects of various processing parameters on their performance.Initially, the precursor MgNb₂O₆ was synthesized via a two-step solid-state reaction. Subsequently, this precursor was combined with raw materials PbO, TiO₂, an‎d ZrO₂ an‎d subjected to various calcination an‎d sintering processes. The calcination was conducted at temperatures ranging from 850 to 900 degrees Celsius, while the sintering occurred at temperatures between 1200 an‎d 1250 degrees Celsius. Additionally, the influence of different planetary milling times, from 0 to 48 hours, on particle size an‎d the final properties of the ceramics was investigated. Various percentages of additional lead (PbO) were also incorporated into the compositions.The types of milling balls used, including agate, zirconia, an‎d tungsten, were specifically examined. The results indicated that the use of agate balls yielded the best performance in reducing particle size an‎d achieving a uniform particle distribution. Characterization techniques such as X-ray diffraction (XRD) an‎d field emission scanning electron microscopy (FESEM) demonstrated that samarium doping an‎d precise adjustment of processing conditions significantly improved the structural stability an‎d uniform distribution of crystalline phases in the ceramics.To eva‎luate the electrical an‎d piezoelectric properties of the samples, various tests were conducted, including P-E hysteresis loop analysis, dielectric constant measurement, an‎d piezoelectric charge coefficient d₃₃ assessment. The results revealed that a calcination temperature of 850 degrees Celsius an‎d a sintering temperature of 1230 degrees Celsius, combined with 5% additional lead, resulted in the best piezoelectric an‎d dielectric properties. Furthermore, the composition 40PMN-23.8PZ-36.2PT was identified as the optimal formulation with the highest piezoelectric charge coefficient (d₃₃) . This research demonstrated that by optimizing processing parameters such as calcination an‎d sintering temperatures, milling time, percentage of additional lead, an‎d the type of milling balls, the piezoelectric properties of PMN-PZT ceramics can be significantly enhanced. The findings can contribute substantially to the development an‎d optimization of advanced electromechanical devices.

حسين احمدوند

حميده شاكري پور

پرويز كاملي , اسماعيل عبدالحسيني سارسري