Russian Journal of Inorganic Chemistry ( IF 1.8 ) Pub Date : 2020-09-10 , DOI: 10.1134/s0036023620080045 A. V. Egorysheva , A. S. Kraev , O. M. Gajtko , A. E. Baranchikov , A. V. Agafonov , V. K. Ivanov
Abstract
A comparative analysis has been made for the dielectric and electrorheological properties of suspensions of highly dispersed powders of bismuth ferrites BiFeO3 and Bi2Fe4O9 in polydimethylsiloxane PMS-300. Dielectric characteristics (dielectric constant, dielectric loss tangent) for the suspensions in frequency range 2.5–106 Hz have been determined and non-Debye character of relaxation processes in these systems has been revealed. The measured values of dielectric constant for the disperse bismuth ferrites at zero and infinite frequency (ε0 and ε∞) are 150 and 59 for BiFeO3, 22 000 and 14 for Bi2Fe4O9, respectively. Electrorheological properties of bismuth ferrite suspensions in static electric field (up to 5 kV) in tension, compression, and shear modes have been analyzed. It has been found that the values of electrorheological effect for BiFeO3 suspensions in polydimethylsiloxane PMS-300 are small even at high concentrations of disperse phase (60 wt %). On the contrary, the suspensions of highly disperse Bi2Fe4O9 exhibit distinct electrorheological effect. For 80 wt % Bi2Fe4O9 suspension, the tensile yield point reached ~7 kPa in electric field of 5 kV, while compressive stress was 12 kPa.
中文翻译:
基于铋铁氧体BiFeO 3和Bi 2 Fe 4 O 9的电流变流体
摘要
已对聚二甲基硅氧烷PMS-300中高分散性铋铁氧体BiFeO 3和Bi 2 Fe 4 O 9的悬浮液的介电和电流变特性进行了比较分析。已经确定了频率范围为2.5–10 6 Hz的悬浮液的介电特性(介电常数,介电损耗正切),并且揭示了这些系统中弛豫过程的非德拜特性。在零和用于分散铋铁氧体介电常数的测量值无限频率(ε 0和ε ∞)为150和59,用于的BiFeO 3,22 000和14的Bi 2铁4 O 9。分析了铋铁氧体悬浮液在静电场(高达5 kV)中的拉伸,压缩和剪切模式下的电流变特性。已经发现,即使在高分散相浓度(60重量%)下,聚二甲基硅氧烷PMS-300中的BiFeO 3悬浮液的电流变效应值也很小。相反,高度分散的Bi 2 Fe 4 O 9的悬浮液表现出独特的电流变效应。对于80 wt%的Bi 2 Fe 4 O 9悬浮液,在5 kV电场中的拉伸屈服点达到〜7 kPa,而压缩应力为12 kPa。