Research and Developpment of a new Material for Metal Oxide Varistors

Metal Oxide Varistors are, from the chemical point of view, ceramics, acting as n-semiconductors and having a poly-crystalline and complex structure. The main application of these power electronic devices is for construction of overvoltage protection equipment (for every voltage level), because of some advantages like: an increased level of non-linearity between the resulting current and the voltage characteristic, a high energy adsorption capacity and an excellent fast response time, which make them ideal for protecting other sensible electronic devices and circuits. This paper presents a new material and some manufacturing technology aspects for a Metal Oxide Varistor based on a new mixture of oxides used in order to obtain a new ceramic with higher non-linear electric properties. The two oxides involved are Cr₂O₃ and MnO₂ as dopants or additives. All measurements of the electrical performances will be carried out in relation with an existing 5 dopants material (three +these two).