The Effect of Mechanical Activation on the Synthesis and Properties of Multiferroic Lead Iron Niobate
The present work studies the effect of high-energy mechanical activation using the planetary-centrifugal ball mill AGO-2 and subsequent annealing on the synthesis and magnetic properties of PbFe0.5Nb0.5O3 (PFN). This technique enables one to perform the mechanically activated synthesis of PFN at much shorter time. The results of X-ray phase analysis, electron microscopic studies and transmission Mossbauer 57Fe spectra measurement are presented and discussed. Mossbauer studies show that the temperature of magnetic phase transition in PbFe0.5Nb0.5O3 powders can be changed by mechanical activation and subsequent annealing.
Formation of Perovskite and Pyrochlore Phases during Mechanochemical Synthesis of Lead Ferroniobate
We have studied the effect of mechanical activation in lead ferroniobate synthesis on the formation of perovskite and pyrochlore phases during both mechanochemical synthesis and subsequent firing. It has been shown that, during mechanical activation, the first to form is the perovskite structure. During subsequent sintering of the material, the pyrochlore structure begins to form as well. As the firing temperature is raised to 650–750°C, the perovskite structure is again formed. We provide explanation for this process.
Barium titanate-based actuator with ceramic internal electrodes
Abstract Electrostriction and mechanical properties of multilayer ceramic actuators with ceramic internal electrodes were investigated. Insulative BaTiO3 and La-doped semiconductive BaTiO3 were laminated by means of a conventional green sheet method and co-fired into the multilayer structure. The strain induced by an electric field in the multilayer was measured using a differential transformer method. The 4 × 10−4 magnitude of strain at 15 kV/cm is sufficiently applicable to fine movement control devices. Mechanical strength obtained was 50 MN/m2, about three times larger than that for a conventional multilayer ceramic actuator with Pd internal electrodes.