稀土掺杂无铅铁电陶瓷的电卡效应

Electrocaloric effect of rare earth doped free-lead ferroelectric ceramics

以稀土Sm掺杂无铅0.88(Na 0.5 Bi 0.5)TiO 3-0.12(Ba 1-x Sm x)TiO 3(NBT-BST)铁电陶瓷为研究对象,研究Sm掺杂含量对陶瓷材料的相结构、微观结构及其铁电行为和相变过程的影响规律.利用麦克斯韦理论公式系统研究了不同Sm掺杂含量陶瓷的电卡性能.结果表明:在不同相变过程中,绝热温变、等温熵变及电卡系数均呈现出不同的变化规律,在Sm掺杂摩尔分数为0.25%时实现了连续的电卡制冷行为,即正负电卡在30~180℃范围内共存.实现的连续电卡行为有益于提高电卡材料的工作效率,从而推动铁电陶瓷材料在可集成、高效率、高可靠性室温致冷领域的应用进程.

Sm doped 0.88(Na0.5Bi0.5)TiO3-0.12(Ba1-xSmx)TiO3(NBT-BST)lead-free ferroelectric ceramics were prepared.The effect of doping content of Sm on the phase structure,microstructure,ferroelectric behavior and phase transition of the ceramic materials was studied.In addition,the electrocaloric properties of the ceramics with different Sm content were studied by using Maxwell’s theoretical formula system.The results show that the adiabatic temperature change,isothermal entropy change and electrocaloric coefficient had different behaviors in phase transition processes,and continuous electrocaloric cooling behavior was achieved when the doping mole fraction of Sm is 0.25%.That is,the positive and negative electrocaloric behaviors coexist in 30~180℃.The continuous electrocaloric behavior realized herein is beneficial to improving the working efficiency of electrocaloric materials,which will promote the application process of ferroelectric ceramic materials in the field of integrative,high efficient and high reliable room temperature cooling.