学术探索
学术期刊
新闻热点
数据分析
智能评审

Grain-boundary segregation and precipitates in La2O3 and Pr2O3 doped SnO2•CoO-based varistors

被引：32
作者：
Oliveira, MM
Soares, PC
Bueno, PR
Leite, ER
Longo, E
Varela, JA
机构：
[1] Univ Fed Sao Carlos, Dept Quim, BR-13565905 Sao Carlos, SP, Brazil
[2] Univ Fed Sao Carlos, Dept Mat Engn, BR-13565905 Sao Carlos, SP, Brazil
[3] Univ Estadual Paulista, Inst Quim, BR-14801907 Araraquara, SP, Brazil
来源：
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY | 2003年 / 23卷 / 11期
基金：
巴西圣保罗研究基金会;
关键词：
CoO; grain boundaries; microstructure-final; SnO2; varistors;
D O I：
10.1016/S0955-2219(02)00445-4
中图分类号：
TQ174 [陶瓷工业]; TB3 [工程材料学];
学科分类号：
0805 ; 080502 ;
摘要：
Structural heterogeneities in SnO2.CoO-based varistors were analyzed by transmission electron microscopy. In SnO2.CoO-based system doped with La2O3 and Pr2O3 two kinds of precipitate phases at grain boundary region were found. Using energy dispersive spectrometry they were found to be Co2SnO4 and Pr2Sn2O7, presenting a defined crystalline structure. It was also identified that such precipitate phases are mainly located in triple-junctions of the microstructure. HRTEM analysis revealed the existence of other two types of junctions, one as being homo-junctions of SnO2 grains and other due to twin grain boundaries inside the SnO2.CoO grain. The role of these types of junction in the overall nonlinear electrical features is also discussed. (C) 2003 Elsevier Science Ltd. All rights reserved.
引用
收藏
页码：1875 / 1880
页数：6
相关论文
共 12 条
[1]   Role of oxygen at the grain boundary of metal oxide varistors: A potential barrier formation mechanism [J].
Bueno, PR ;
Leite, ER ;
Oliveira, MM ;
Orlandi, MO ;
Longo, E .
APPLIED PHYSICS LETTERS, 2001, 79 (01) :48-50
[2]   Nature of the Schottky-type barrier of highly dense SnO2 systems displaying nonohmic behavior [J].
Bueno, PR ;
de Cassia-Santos, MR ;
Leite, ER ;
Longo, E ;
Bisquert, J ;
Garcia-Belmonte, G ;
Fabregat-Santiago, F .
JOURNAL OF APPLIED PHYSICS, 2000, 88 (11) :6545-6548
[3]  
Cerri JA, 1996, J AM CERAM SOC, V79, P799, DOI 10.1111/j.1151-2916.1996.tb07949.x
[4]  
Clarke DR, 1999, J AM CERAM SOC, V82, P485
[5]   GRAIN JUNCTION PROPERTIES OF ZNO VARISTORS [J].
EINZINGER, R .
APPLICATIONS OF SURFACE SCIENCE, 1979, 3 (03) :390-408
[6]   APPLICATION OF ZINC-OXIDE VARISTORS [J].
GUPTA, TK .
JOURNAL OF THE AMERICAN CERAMIC SOCIETY, 1990, 73 (07) :1817-1840
[7]   IMPROVED STABILITY OF THE ZNO VARISTOR VIA DONOR AND ACCEPTOR DOPING AT THE GRAIN-BOUNDARY [J].
GUPTA, TK ;
MILLER, AC .
JOURNAL OF MATERIALS RESEARCH, 1988, 3 (04) :745-754
[8]  
MIYOSH T, 1981, ADV CERAM, P309
[9]   NON-OHMIC PROPERTIES OF ZNO-RARE EARTH METAL OXIDE CO3O4 CERAMICS [J].
MUKAE, K ;
TSUDA, K ;
NAGASAWA, I .
JAPANESE JOURNAL OF APPLIED PHYSICS, 1977, 16 (08) :1361-1368
[10]   Sensitivity of SnO2 non-ohmic behavior to the sintering process and to the addition of La2O3 [J].
Oliveira, MM ;
Bueno, PR ;
Cassia-Santos, MR ;
Longo, E ;
Varela, JA .
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY, 2001, 21 (09) :1179-1185
12