BaCO_3微粉原料通常由尺寸较大的棒状颗粒所组成,这些棒状颗粒在一次球磨过程中由于不容易粉碎,从而对经预烧、二次球磨所得到的BaTiO_3陶瓷微粉的化学组分的均匀性和颗粒度产生影响,进而影响后序烧结制备的BaTiO_3陶瓷的微观组织结构...BaCO_3微粉原料通常由尺寸较大的棒状颗粒所组成,这些棒状颗粒在一次球磨过程中由于不容易粉碎,从而对经预烧、二次球磨所得到的BaTiO_3陶瓷微粉的化学组分的均匀性和颗粒度产生影响,进而影响后序烧结制备的BaTiO_3陶瓷的微观组织结构和压电性能。本研究重点探讨了以BaCO_3和Ti O_2为原料、通过固相反应途径制备BaTiO_3陶瓷时,实施原料预处理对所制备的BaTiO_3压电陶瓷物性的影响。研究发现,配料前对BaCO_3原料实施球磨预处理可明显地降低棒状颗粒的尺寸,从而可获得颗粒度细化的BaTiO_3陶瓷微粉,进而制备致密度更高和晶粒尺寸更小而压电性能更高的BaTiO_3陶瓷材料。研究中对BaCO_3微粉进行不同时间的球磨预处理,然后制备钛酸钡陶瓷,考察了其压电性能、介电性质、铁电性能和微观结构等物理性质。利用同样的BaCO_3微粉原料,未经球磨预处理所制备的BaTiO_3陶瓷的压电系数d33最高值为410 p C/N,而实施合适的球磨预处理制备的BaTiO_3陶瓷的压电系数d33最高值可达470 p C/N。展开更多
The temperature evolution of dielectric dispersion is examined for a coarse-grained BaTiO_(3)ceramic in the frequency range from 40 Hz to 1 GHz and over the temperature interval between-50℃and 80℃,which thus include...The temperature evolution of dielectric dispersion is examined for a coarse-grained BaTiO_(3)ceramic in the frequency range from 40 Hz to 1 GHz and over the temperature interval between-50℃and 80℃,which thus includes the orthorhombic-tetragonal phase transition and covers the large part of common usage temperature region.We find an important physical phenomenon that the phase transition has a notable influence on the microwave dielectric dispersion.The dielectric permittivityε'shows a maximum,whereas the characteristic frequency fr displays a minimum in the vicinity of orthorhombic-tetragonal phase transition temperature.Also,a large difference in the fr values is observed in the tetragonal phase between the heating process and the cooling process.It seems that the experimentally found phenomenon can be explained by the previously suggested mechanism of the emission of elastic shear waves from ferroelastic domain walls.展开更多
文摘采用传统固相反应法制备了Ba(Ti_(0.96)Sn_(0.04))O_3无铅压电陶瓷,对其压电性能、介电性能、铁电性能和微观结构等进行了研究。研究发现,原料以及制备工艺对Ba(Ti_(0.96)Sn_(0.04))O_3陶瓷的压电性质具有较大的影响。与Ba TiO_3陶瓷相比,Ba(Ti_(0.96)Sn_(0.04))O_3陶瓷的正交–四方相变温度T_(O-T)得到了一定的提高,并且T_(O-T)附近的热滞只有1.8℃。陶瓷的微观形貌呈现出较为复杂的畴结构,主要以90°平行带状畴为主,偶尔有少量不同构型的180°畴。电滞回线呈现为理想的近似矩形饱和形状的曲线,剩余极化强度Pr为18.9μC/cm^2,矫顽场Ec为2.5 k V/cm。此外,非180°畴的翻转是引起陶瓷逆压电常数d_(33)*的主要因素,其值可达550 pm/V。
文摘BaCO_3微粉原料通常由尺寸较大的棒状颗粒所组成,这些棒状颗粒在一次球磨过程中由于不容易粉碎,从而对经预烧、二次球磨所得到的BaTiO_3陶瓷微粉的化学组分的均匀性和颗粒度产生影响,进而影响后序烧结制备的BaTiO_3陶瓷的微观组织结构和压电性能。本研究重点探讨了以BaCO_3和Ti O_2为原料、通过固相反应途径制备BaTiO_3陶瓷时,实施原料预处理对所制备的BaTiO_3压电陶瓷物性的影响。研究发现,配料前对BaCO_3原料实施球磨预处理可明显地降低棒状颗粒的尺寸,从而可获得颗粒度细化的BaTiO_3陶瓷微粉,进而制备致密度更高和晶粒尺寸更小而压电性能更高的BaTiO_3陶瓷材料。研究中对BaCO_3微粉进行不同时间的球磨预处理,然后制备钛酸钡陶瓷,考察了其压电性能、介电性质、铁电性能和微观结构等物理性质。利用同样的BaCO_3微粉原料,未经球磨预处理所制备的BaTiO_3陶瓷的压电系数d33最高值为410 p C/N,而实施合适的球磨预处理制备的BaTiO_3陶瓷的压电系数d33最高值可达470 p C/N。
基金Supported by the National Natural Science Foundation of China under Grant No 51172128the Specialized Research Fund for the Doctoral Program of Higher Education under Grant No 20130131110006.
文摘The temperature evolution of dielectric dispersion is examined for a coarse-grained BaTiO_(3)ceramic in the frequency range from 40 Hz to 1 GHz and over the temperature interval between-50℃and 80℃,which thus includes the orthorhombic-tetragonal phase transition and covers the large part of common usage temperature region.We find an important physical phenomenon that the phase transition has a notable influence on the microwave dielectric dispersion.The dielectric permittivityε'shows a maximum,whereas the characteristic frequency fr displays a minimum in the vicinity of orthorhombic-tetragonal phase transition temperature.Also,a large difference in the fr values is observed in the tetragonal phase between the heating process and the cooling process.It seems that the experimentally found phenomenon can be explained by the previously suggested mechanism of the emission of elastic shear waves from ferroelastic domain walls.
