The dc electrical stability of ZnO varistors was effectively improved by controlling the composition proportion of Bi2O3 and SiO2 as well as annealing condition. The microstructure, current–voltage (I–V) property, and dc degradation characteristics are significantly affected by the molar ratio of Bi2O3 to SiO2 in composition. It is found that a phase transition from β-Bi2O3 (with dissolved Si) to Bi12SiO20, with a volume contraction of 5.88%, occurred after annealing at 850°C. The formed Bi12SiO20 plays an important role in improving the electrical stability by inhibiting the oxygen-desorption at the grain boundary.
If you can't find a tool you're looking for, please click the link at the top of the page to "Go to old article view". Alternatively, view our Knowledge Base articles for additional help. Your feedback is important to us, so please let us know if you have comments or ideas for improvement.