This work has for objective to verify the adequateness of the use of rare-earth oxides concentrated to zinc oxide-based varistor ceramics manufacturing. Rare-earth oxides concentrated and mixtures produced in laboratory had been used in the manufacture of zinc oxide-based varistors in accord to conventional ceramic method. Granulometric and thermal analysis, besides X-ray diffraction and fluorescence analysis were used in the characterization of the rare-earth oxides concentrated powders. SEM-EDS analysis and density analysis were used in the microstructural characterization and the electrical characterization was made from voltage-current and voltage-capacitance data. The results obtained show that there are good prospects for the use of rare-earth oxides concentrated in zinc oxide-based varistor ceramics manufacturing, which depend essentially on the nature of the impurities present or on the chemical refine level of the rare-earth oxides concentrated used. Varistor ceramics with non-linearity coefficient between 12 and 40 were obtained, some presenting leakage current values comparable to those presented by commercial varistors.
Varistor ceramics; electroceramics; rare-earth oxides
