Premium
The Effect of Bi 2 O 3 /SiO 2 Molar Ratio and Annealing on the dc Degradation of ZnO Varistors
Author(s) -
Meng Lei,
Li Guorong,
Zheng Liaoying,
Cheng Lihong,
Zeng Jiangtao,
Huang Hualing
Publication year - 2011
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2011.04654.x
Subject(s) - annealing (glass) , materials science , varistor , microstructure , grain boundary , molar ratio , electrical resistivity and conductivity , oxygen , chemical engineering , composite material , voltage , chemistry , electrical engineering , biochemistry , organic chemistry , engineering , catalysis
The dc electrical stability of ZnO varistors was effectively improved by controlling the composition proportion of Bi 2 O 3 and SiO 2 as well as annealing condition. The microstructure, current–voltage ( I – V ) property, and dc degradation characteristics are significantly affected by the molar ratio of Bi 2 O 3 to SiO 2 in composition. It is found that a phase transition from β‐Bi 2 O 3 (with dissolved Si ) to Bi 12 SiO 20 , with a volume contraction of 5.88%, occurred after annealing at 850°C. The formed Bi 12 SiO 20 plays an important role in improving the electrical stability by inhibiting the oxygen‐desorption at the grain boundary.