Electrical Properties and Grain Growth Kinetics of PZN-based Ceramics Using Microwave Sintering

Effectiveness of microwave sintering process through investigation of microstructural characteristics and electrical properties of x(0.94PbZn_ 1/3Nb_ 2/3O_3 + 0.06BaTiO_3)+(1-x)PbZr_yTi_ 1-yO_3(PBZNZT)ceramics with x=0.6 and y=0.52 was evaluated.The relative density of 95% was achieved with sintering at 800℃ for 2 h.The small grain growth exponents indicate how easy the grain growth in these materials sintered using microwave radiation.Grain growth rate increases abruptly and is higher than that of conventional sintering at a temperature higher than 1050℃.This is attributed to the lower activation energy and higher grain boundary mobility.The activation energy required for the grain growth is found to be 132kJ/mol.Higher remanent polarization(Pr=50.1μC/cm2)and increase in remanent polarization with sintering temperature are observed in microwave sintering process when compared to that of conventional sintering process,due to fast increase in grain growth rate and homogeneity in the specimen.The results indicate lower sintering energy and reduction of PbO pollution in the working environment by microwave sintering process.

SYNTHESIS,CHARACTERIZATION AND ELECTRICAL PROPERTIES OF Nd/Zr CO-DOPED NANO BaTiO_(3) CERAMICS

Ceramic samples of composition Ba_(1-3)xNd_(2x)Ti_(1-y)ZryO_(3)(x=0.025;y=0.025 and 0.05)were synthesized by modified sol-gel technique.Phase confirmation,surface morphology and electrical properties of the samples were studied using XRD,FESEM,impedance spectroscopy and DC conductivity.Impedance,AC and DC conductivities of the samples were recorded in the temperature range room temperature(RT)-500℃.From impedance data,various parameters like bulk resistance(R_(b)),bulk capacitance(C_(b)),grain resistance(R_(g)),grain boundary resistance(R_(gb)),grain capacitance(C_(g))and grain boundary capacitance(Cgb)T were determined.These parameters were found to be function of both temperature and frequency.Grain and grain boundary relaxation times(τ_(g),τ_(gb))were also evaluated as a function of temperature.From AC and DC conductivity plots activation energies for conduction were obtained.Results obtained lead to improved understanding of conductivity and charge transportation kinetics in the present system of samples.