研究目的
The aim of this work was the development of the whole tape-casting technology for production of pyrochlore-free 0.655PMN-0.345PT piezoelectric ceramics at the laboratory scale. Moreover, the phase, microstructure and the electrical properties of the fabricated ceramics were measured. In addition, the properties of the ceramics with the same composition prepared by tape-casting process and the traditional solid state sintering method were also compared.
研究成果
The pyrochlore-free 0.655Pb(Mg1/3Nb2/3)O3-0.345PbTiO3-based piezoelectric ceramics were fabricated by tape-casting process. Through phase and microstructure analyses, temperature played an important role in the performances of the ceramics. The results showed that the ceramics sintered at 1200 (cid:2)C achieved the best overall properties, d33?700 pC/N, kp?0.605, er?4770, tand ? 0.016, Pr?30.68 lC/cm2. Compared to the ceramics with the same composition prepared by solid state sintering method, the piezoelectric constant d33 increased from 632 pC/N to 700 pC/N. Besides, the dielectric and ferroelectric properties both obtained a certain degree of improvement.
研究不足
The technical and application constraints of the experiments, as well as potential areas for optimization, were not explicitly mentioned in the paper.
1：655PMN-345PT by tape-casting in this study is summarized in Figure The whole experimental procedure can be divided into two stages, namely, 1st synthesis of precursor MgNb2O6 and 2nd formation of PMN-PT ceramics by tape-casting. The perovskite-phase powders were synthesized using the precursor method in order to prevent the formation from a pyrochlore phase. Commercial oxide powders of PbO (99%), Nb2O5 (99%), ZrO2 (99%), and MgO (5%) were chosen as the starting materials. The mixture powders of Nb2O5 and MgO were first applied for the processes of mixed ball milling (2 h) and sintering at 1050 (cid:
2)C for 4 h. Then, the mixture was mixed with PhO whose dosage was based on the total weight of the raw materials continued to mill for 8 h. After drying and briquetting, the obtained massive pre-calcined powders were crushed by hand. Finally, the process of pre-calcined in a closed alumina crucible at 925 (cid:2)C (3h) was carried out to fabricate MgNb2O6 ceramic powders. The precursor of MgNb2O6 powder has been synthesized in the first stage. Then, the considered amounts of regent-grade solvents of mixture (30% ethanol and 70% butanone), dispersing (corn oil), binder (polyvinyl butyral PVB), plasticizer (dibutyl phthalate DBP) and MgNb2O6 were wet ball-milled at 200 (cid:3) 300 r/min for 12 h. After that, the synthetic slurry was injected into the casting machine, and then the initial casting substrates were produced. Before sintering, the processes of pressing and excluding glue were carried out to form the final substrates. To limit PbO loss during the high-temperature sintering, ZrO2 powders were added inside the covered alumina crucible. In the sintering process, the temperature was increased from 25 (cid:2)C to 600 (cid:2)C at a heating rate of 100 (cid:2)C/h, and then followed by a heating rate of 100 (cid:2)C/h to 1150 (cid:2)C(cid:3)1250 (cid:2)C. Finally, the temperature was reduced to 600 (cid:2)C at 20 (cid:2)C/h and naturally cooled until to room temperature. According to the above procedures, the final 0.655PMN-0.345PT ceramics were fabricated successfully. In order to test the properties of the samples, adding electrode and polarization processes were executed on both sides of the substrate.
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