ZnO Varistor Of High Volt-Gradient

The preparation of high volt-gradient ZnO varistor is the main research direction of ZnO varistor recent years. In the actual use of the components, energy absorption capacity has the same rate of raising as the volt-gradient is required. To ensure that other electrical properties do not deteriorate,how to improve the volt-gradient and energy absorption capacity at the same time is the focus of our research.In unit thickness, the more grains and grain boundaries ZnO varistor have, the higher its volt-gradient. So smaller the grains is an important way to increase the volt-gradient. To improve the uniformity consistency of the components micro-structure is the key to improve the energy absorption capacity.First, we discussed the influence of adding related Rare Earth elements (Nd2O3) to the traditional solid-state form of ZnO varistor to the components volt-gradient and energy absorption capacity. The results showed that: Nd2O3 does not only refined the grains which makes the volt-gradient greatly increased, but also makes the grain size distribution more uniform, benefiticial to the increasing of energy absorption capacity in certain extent.Second the main additives of ZnO solid-state formula is prepared by Chemical co-precipitation. The powder made by Chemical co-precipitation can be smaller to the nano-particle size and larger surface area, higher activity and distribution more uniformity, which is the base to improve the electrical properties. The electrical properties test shows: First, the energy absorption capacity increased greatly, close to the traditional solid-state method twice. Second, the volt-gradient raised by 24.1%.Third, co-precipitation method makes the components have higher non-linear coefficientα.It shows that co-precipitation method and adding Rare Earth elements (Nd2O3) to the traditional solid-state form of ZnO varistor can both increase the volt-gradient and energy absorption capacity. But chemical co-precipitation is more conducive to improving the capacity of energy absorption, and adding Rare Earth elements is more conducive to improving the components volt-gradient.