| Piezoelectric ceramics have been widely used in communication, aerospace, detection and computer, etc. However, with the rapid development of science and technology, the requirements of the application of piezoelectric materials under high temperature become increasingly higher. Such as piezoelectric materials can work wellly above200℃even900℃. In general, in order to ensure the stability of the piezoelectric properties, the operating temperatures is usually limited half of its Curie temperature(tc). Commercially available piezoelectric materials are used at approximately for most PZT formulations, wich have not satisfy the Commercial application. The bismuth base perovskite structure piezoelectric material such as (1-x)Bi(Mg1/2Ti1/2)O3-xPbTio3possess higher Curie point and good piezoelectric properties wich have become hot spot in research. In this work,(1-x)Bi(Mg1/2Ti1/2)o3-xPbTiO3ceramics were prepared by conventional solid state reaction method. The structure, sintering behavior, microstructure, dielectric and ferroelectric properties of ferroelectric ceramics with adding PbTio3were studied respectively. And analyzed the relation between the sintering temparature and the structure, electrical properties of the0.64Bi(Mg1/2Ti1/2)O3-0.36PbTio3ceramics samples systematacially.(1) Experiment selected the (1-x)Bi(Mg1/2Ti1/2)O3-xPbTiO3(x=0.31～0.39) ceramics samples sintered at1050℃. Analyzed the change of structure and properties with the variation of content proportion between Bi(Mg1/2Ti1/2)03and PbTio3. Room-temperature XRD pattern confirms the formation of single perovskite structure for all components which indicates that the PbTio3has been totally in the crystal lattice, and with the increase of the PbTiO3-content, the sample experienced phase transition from rhombohedral to tetragonal phase, the morphotropic phase boundary exists in x=0.36and0.37. SEM photographs exhibit the uniform distribution of grains with less porosity. There are two dielectric peaks in dielectric-temperature spectra which exist in250℃～400℃and～630℃respectively, combining with the high temperature X-ray diffraction explain why the dielectric peak appeared from a phase-structure angle. The morphotropic phase boundary composition (x=0.37) possess the excellent piezoelectric property (d33=215pC/N). The saturation of hysteresis loops indicate the addition of PbTio3affected the ferroelectricity of materials to a large extent, and with the PbTio3-content increase, the residual polarization Pr value first increases and then decreases, the maximum Pr is16.7μC/cm2for x=0.36.(2) In order to study the relationship between material structure, electrical properties and sintering temperature, the0.64Bi(Mg1/2Ti1/2)O3-0.36PbTiO3which possess excellent piezoelectric properties prepared by the above mentioned reaction method and were sintered at three sintering temperatures (1000℃,1050℃and1075℃). The sintering temperature influence on the phase structure and electronic properties of components were discussed. It turned out that the sintering temperature has a great influence on the ceramic phase structure, the grain size increases with the increase of sintering temperature; As for the electrical properties, at1000℃, samples have the best dielectric and piezoelectric properties (d33-213pC/N), but with the increase of sintering temperature, the piezoelectric constant decrease quickly, and the reduction in dielectric peaks also abnormal rapidly, sample weight loss during sintering process about0.58%at1000℃and2.34%at1075℃, it is the volatilization of PbO result in the weakened dielectric performance.In conclusion, above two experiments have done basic work for further study on (1-x)Bi(Mg1/2Ti1/2)O3-xPbTiO3system. |
PDF Full Text Request