在还原气氛烧结过程中施主掺杂量对(Bam-xSmx)TiO3基热敏材料PTC特性的影响  

Influence of Donor-doped Contentration on PTC Effect of (Ba_(m-x)Sm_x)TiO_3 Based Ceramics in Reducing Atmosphere

作　　者：程绪信[1] 范杰轩 李晓霞[1] 赵肇雄[1] 

机构地区：[1]肇庆学院电子信息与机电工程学院,肇庆526061

出　　处：《硅酸盐通报》2016年第10期3172-3177,共6页Bulletin of the Chinese Ceramic Society

基　　金：国家自然科学基金(51402258);广东省自然科学基金(2015A030313706);广东省科技计划项目(2014A010105056);广东省普通高校特色创新项目(2014KTSCX189);肇庆市科技计划项目(2015B010402003)资助

摘　　要：正温度系数(PTC)热敏陶瓷常用于低压集成电路的过流保护,为了适应市场对该样品低阻化的要求,人们一般采用还原再氧化的烧结工艺来制备片式PTC热敏陶瓷。本文主要研究了(Ba_(m-x)Sm_x)TiO_3(BST)基陶瓷在还原气氛中1300℃烧结30 min并在850℃再氧化热处理后其化学计量比和施主掺杂浓度对该样品的电性能及其PTC效应的影响。结果表明,BST基陶瓷样品的化学计量比和施主掺杂量都对该样品的电性能和PTC效应产生影响。随着施主掺杂含量的增加(0.2~0.5mol%Sm^3+)不同化学计量比样品的室温电阻率均呈现出先减小后增加的变化趋势,其中Ba过量样品的室温电阻率比Ti过量的和满足化学计量比样品的一般要高一些。m=1且施主掺杂0.3mol%Sm^3+的BST基陶瓷可以获得较好的PTC效应,它的室温电阻率(ρRT)和升阻比Lg(ρmax/ρmin)分别为383.1Ω·cm和3.1个数量级。此外,化学计量比和施主掺杂量对样品的平均晶粒尺寸有较大的影响,再氧化热处理对施主掺杂BST基PTC陶瓷的电性能以及PTC特性也有明显影响。In order to adapt to the market requirement of the lowering resistance for the positive temperature coefficient(PTC) thermistor,whose was used for the low voltage integrated circuit as function of the overcurrent protection. The chip-type PTC ceramics were prepared by reduction reoxidation method.The stoichiometry and the donor-doped contentration on the electrical properties and PTC effect of the(Bam-xSmx) TiO3(BST) based ceramics reoxidized at 850 ℃ for 1 h in air after sintering at 1300 ℃ for30 min in a reducing atmosphere were investigated in this paper. The results showed that the stoichiometry and the donor-doped content affected the electrical properties and PTC characteristics of the BST ceramics,whose room temperature resistivity firstly reduced and then increased with increasing of the donor-doped content in the range from 0. 2mol% to 0. 5mol%. The room temperature resistivity of the Baexcess ceramics is higher than that of the Ti-excess and the stoichiometry samples. The BST specimens exhibited a remarkable PTC effect,with a resistance jump greater by 3. 1 orders of magnitude,along with a low room temperature resistivity of 383. 1 Ω·cm at the donor-doped content of 0. 3mol%. In addition,theinfluence of the donor-doped concentration and the stoichiometry on the mean grain size of the as-fired samples has been investigated. Moreover,the effect of the reoxidated heat treatment on the electrical properties and PTC characteristics of the BST ceramics has also been studied.

关 键 词：BATIO3陶瓷 PTC效应 热敏陶瓷 施主掺杂剂 

分 类 号：TB34[一般工业技术—材料科学与工程]