液相Y、Nb共掺杂BaTiO_3基PTC陶瓷的制备与性能

Preparation and Properties of Liquid Y,Nb-codoped BaTiO_3-based PTC Ceramics

本文以Ba(OH)2.8H2O、Sr(OH)2.8H2O、TiCl4、NbCl5、YCl3和Mn(Ac)2为原料,采用室温研磨、低温固态反应合成了一系列的纳米钛酸钡基PTCR陶瓷粉,首先实现了Y和Nb双施主以离子的形式共掺杂。采用XRD,TEM对样品进行了表征。研究表明,产品为立方晶系的完全互溶取代固溶体。粒子基本成球形,分布均匀,粒径大约60 nm。通过优化Y和Nb的掺杂量,使材料的室温电阻得到了进一步降低,并提高了材料的升阻比。当Y、Nb和Mn的用量分别为0.2 mol%、0.18 mol%和0.04 mol%时,加入定量的AST烧结助剂,控制最高烧结温度为1310℃,制备出了室温电阻17.6Ω,正温度系数为18.6%/℃,升阻比为6.5×104的性能优异的PTCR电阻材料。另外还就烧结条件对材料PTC性能的影响进行了讨论。

A series of nano-Ba0.92-xSr0.08YxTi0.9996-yNbyMn0.0004O3-based PTCR powders were synthesized via solid-state reaction at low temperature using Ba（OH）2·8H2O,Sr（OH）2·8H2O,TiCl4,NbCl5,YCl3 and Mn（Ac）2 as raw materials.In this paper,the Y3＋ and Nd5＋ donors were firstly codoped into the host lattice in their ionic form.XRD patterns demonstrated that the compounds were mutually miscible in the solid solutions.TEM iamge showed that the as-obtained powder was composed of uniform spherical particles with an average particle size of 60 nm in diameter.The PTC measurements indicated that the room temperature resistance could decrease and the resistance jump could increase by adjusting the doping concentrations of Y and Nb.It was found that the room temperature resistance is near 17.6 Ω,temperature coefficient of resistance（α） is 18.6%/℃,and the ratio of Rmax/Rmin is 6.5×104 when the doping concentrations of Y,Nb and Mn were 0.2 mol%,0.18 mol%,and 0.04 mol%,respectively.Furthermore,the sintering conditions of the PTCR materials were investigated in detail.