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【答案】应助回帖
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浮云翳月: 金币+140, 翻译EPI+1, ★★★★★最佳答案, 多谢多谢 2013-11-30 22:17:21
TiO2 varistor ceramics is a semiconductor functional material with excellent electrical behaviours such as low varistor voltage, large nonlinear coefficient and high dielectric constant. In low voltage field, it has found ever increasing applications in over voltage protection, noise reduction as well as surge suppression. This paper studies the varistor characteristics of TiO2 based ceramics doped with TA2O5, based on a review of the history, current status and future perspectives of varistor ceramics in China as well as abroad.
In this design a series of samples are prepared using solid state sintering. The focus has been on the impact of Ta2O5, with different dopants, and different temperatures on the varistor voltage and nonlinear coefficient and comparisons are made accordingly. The main experimental work and results are as follows:
1. Impacts of Ta2O5 doped within a range of 0.01mol%--1.0mol% on the nonlinear V-A characteristics and dielectric properties of TiO2 varistor ceramics. The results demonstrate that with the gradual increase of Ta2O5 dopant, the nonlinear coefficient of the samples first increases and then decreases, with the maximum being 6 obtained when the Ta2O5 dopant is close to 0.1 mol%; sample dielectric constant (measured at 1kHz frequency) first decreases and then increases, with its minimum occurring when the Ta2O5 dopant is close to 0.1 mol%.
2. Impacts of different temperatures on the varistor characteristics of the samples. The study shows that within a range of 1250℃~1400℃, as the temperature rises, varistor voltage and nonlinear coefficient gradually increase and at 1350℃, the samples have the best pressure sensitivity （V1mA~ 6 ，α~ 6）.
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