锡钛酸钡BaSnxTi1–xO3厚膜陶瓷的大电卡效应

Large Electrocaloric Effect in BaSnxTi1–xO3 Thick Film Ceramics

对无铅铁电材料锡钛酸钡（BaSnxTi1-xO3（BSnT））（x=5%,10%,15%,20%,摩尔比）陶瓷进行了研究,利用流延法得到锡钛酸钡膜带,采用X射线衍射技术对烧结后的厚膜陶瓷进行结构分析,利用扫描电子显微镜分析了样品形貌,测量了样品介温关系和电滞回线,并利用Maxwell关系对电卡效应进行了计算。结果表明：厚膜陶瓷BSnT在不同的Sn4＋掺杂量下的电卡效应有明显的差异,在x=0.05及外加电场10 MV/m时,绝热温变（△T）可达到2.1 K,且x=0.05的样品在5 MV/m的电卡效率最高达到0.24×10^6 K·m·V–1。无铅铁电陶瓷拥有大的电卡效应可望在制冷器件上作为制冷剂使用。

Lead-free ferroelectric materials of Sn4＋ ions doped barium titanate （BaxSnlxTiO3 （BSnT）） with Sn4＋ ionic contents of 5%, 10%, 15%, and 20% （in mole fraction） were prepared, and the thick film ceramics were fabricated by a tape casting method. The microstructure of the BSnT ceramics after sintering was characterized by X-ray diffraction. The morphologies of the ceramics were analyzed by scanning electron microscopy. The dielectric constant and loss as a fimction of temperature, and the hysteresis loop as a function of electric field and temperature were measured. The electrocaloric effect （ECE） was calculated based on the Maxwell equations. The results indicate that the electrocaloric effect of the thick film ceramics is affected by Sn4＋ ionic content. As x=0.05, AT can reach 2.1 K when E=10 MV/m. The maximum elctrocaloric efficiency is up to 0.24×10^6 K·m·V-1 when E=5 MV/m for the composition as x=0.05. The lead-free ceramics with the great ECE have a promising potential application as a refrigerant in the future cooling devices.