摘要
研究了Zn-V-B玻璃料的添加对(Ba,Sr)TiO3 PTC陶瓷微观结构和电性能的影响,并分析了玻璃料增强PTC效应的原因.扫描电镜结果显示,1 240 ℃烧结后玻璃料促进了晶粒长大,但1 280℃烧结后对晶粒生长影响不大.玻璃料一方面有助于晶粒长大和室温电阻率的降低;另一方面高阻的玻璃料存在于晶界增大了晶界电阻.随玻璃料加入量增加,1 240 ℃烧结后室温电阻率先减小后增大;烧结温度高于1 240 ℃,室温电阻率单调增大.通过分析MnO2和V2O5在ZnO压敏陶瓷中的变价以及Mn提高BaTiO3陶瓷PTC效应的机理,初步认为V的变价是玻璃料显著改善PTC效应的原因.
The influence of Zn-V-B glass addition on the microstructure and electrical properties of（Ba, Sr）TiO3 PTC ceramics was studied. Also the reason for the enhancement of PTC effect was analyzed. Scanning electron microscopy （SEM） results show that grain growth is facilitated by the glass at 1 240℃ while this microstructural effect is weak at 1 280℃. Glass promotes the grain growth and thus lowers the room-temperature resistivity. On the other hand, the high-resistance glass increases the grain-boundary resistance. The room-temperature resistivity decreases initially with increasing glass amount and then increases after sintering at 1 240℃, while it monotonously increases after sintering at temperatures higher than 1 240℃. The valence change of V ions is presumably the prime cause for the enhanced PTC effect, by analyzing valence changes of MnO2 and V205 in ZnO varistor and the mechanism of Mn enhancing the PTC effect of BaTiO3 ceramics.
出处
《天津大学学报》
EI
CAS
CSCD
北大核心
2008年第7期828-832,共5页
Journal of Tianjin University(Science and Technology)
基金
中国博士点基金资助项目(20050056055)
