Study of the replacement of Nb₂O₅ by Sb₂O₃ in SnO₂ varistors

Brazil is struck by around 100 million lightning bolts every year so the development of new varistor systems for use in electrical power distribution networks is of great interest to industry. Varistors are materials that exhibit non-linear behavior between current and voltage and can be referred to as variable or non-ohmic resistors. They act as electrical power transmission and distribution systems protecting them from possible defects caused by overvoltage. They are used as protection devices for high voltage (lightning rods) or low voltage (electronic devices) performing an important function of limiting the voltage level and protecting equipment. Thus the SnO2-based varistor system can also have a high number of effective barriers (85%) compared to the traditional ZnO-based system which has about 30%. Another advantage is its simpler chemical composition requiring fewer dopants to obtain properties similar to those of multicomponent ZnO varistors. In addition they have greater resistance to chemical and electrical degradation.