| The distribution of additives in the zinc oxide varistors is more homogeneous by the process of chemical coprecipitation, which improves the electrical properties of the zinc oxide varistors. In this paper, the method and process were investigated deliberately for preparation of multiplex composite nano-additives, which were characterized by XRD and TEM etc. The electrical properties of ZnO varistors were analyzed and discussed.The experimental results show that electrical propertis almost have not change when the concentration of K+ is less than 40 ppm. So the multiplex composite nano-additives were prepared by the two-step synthesis method with the precipitator of K2CO3 at appropriate pH value. The optimized heat treatment temperature was confirmed within the range of 640-650℃. ZnO varistors with the size of 8.5mm in diameter and 1.0mm in thickness were manufactured by ZnO powders mixed with the nano-additives powders under proper techniques, and high electrical properties were obtained. The surge absorption capability of 8/20μS for varistors exceeds what is 96/97 samples of Panasonic. Its rectangular current pulse(2ms) capability is improved significantly, twice as many as the Panasonic.Due to using cheap inorganic compound of K2CO3 as precipitator, the complex reaction is avoided between ammonia ion and metal ion. The problem of stabilization of coprecipitation is solved. So the present work exceed the conventional technological route, which is available to industrialization and a promising market application. |
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