كنترل پديده تنزل خواص در برقگيرهاي سراميكي (بررسي تاثير فرايند آنيل )

The primary function of a Zinc Oxide Varistors is to sense and limit transient voltage surges without being destroyed. Their Current (I)-Voltage (V) characteristic is nonlinear similar to that of a Zener diode. Varistor can be used in both AC and DC field and over a wide range of voltage, current and energy absorption capability. The ZnO Varistor shows degradation in I-V characteristic in excess of 10% to 20% when subjected to high current surges. However, each application requires a reliable characteristic of a Varistor and to be remained stable to its original value during usage and after experiencing the oncoming surges. In this study by using Annealing, stability of Varistor will be evaluated and its effect on increasing of energy absorption capability will be studied. The results showed that after annealing at 600 ʹC for 2 hrs, the stability of the system has been increased. The temperature range of formation of yBi2O3 phase was determined to be 600-700 ʹC. The data showed some changes in other properties of the system after this process.