80 Theory and the Effective Parameters in Making Varistors Ceramic Nano-Structured Zinc Oxide in the Range of 31 Volts
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Published:2011
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Doping with other metal oxides are ZnO varistors. ZnO varistors ceramic pieces are more complex than solids, includes Characteristics of the voltage — current are highly nonlinear the same anti-parallel Zener diodes are[2]. The threshold voltage (breakdown voltage) with a high resistance and then, voltage and resistance severely reduced so varistors act as a conductor[3]. Zinc oxide alone is an N-type semiconductor, the voltage behavior various metal oxides as additives for non-linear characteristic of a voltage - current use. Absorbing them as fast unstable voltages and high voltage transient, Stabilizing voltage in electric systems and electronic circuits are used as a sudden transient voltage regulator is used. To protect the electronic equipment, due to low prices and access are very important. Bi2O3 and TiO2 oxides of zinc oxide added to them. Then we double sintering. Because the random orientation of crystals during a sintering causes, ceramics have characteristics that are homogeneous in all directions. This feature can be homogenous with specific procedures during sintering or cool to room temperature changed[4, 5]. The small crystals with random orientation are grain to say so. Grain boundary area between the so-called thin layer is depleted the electrical conductivity of this layer is less than the grains themselves. As a result, there is an inverse relationship between resistivity and grain size[2]. In other words, the grain structure of zinc oxide is surrounded by a thin insulating dams have. The nano-powder with zinc oxide and additives (including oxides of bismuth, antimony, chromium, cobalt, nickel, etc.) synthesized zinc oxide made tablets lightning rods.Tablets of the surge arrester made Microstructure under test and Electrical measurement and underwent X-ray and SEM. After the final sintering nonlinear coefficient and breakdown voltage were investigated.