Abstract: The present invention relates to a varistor material for a surge arrester with target switching field strength ranging from 250 to 400 V/mm comprising ZnO forming a ZnO phase and Bi expressed as Bi2O3 forming an intergranular bismuth oxide phase, said varistor material further comprising a spinel phase, characterized in that the amount of a pyrochlore phase comprised in the varistor material is such, that the ratio of the pyrochlore phase to the spinel phase is less than 0.15:1.

Abstract: The present invention relates to a varistor material for a surge arrester with target switching field strength ranging from 250 to 400 V/mm comprising ZnO forming a ZnO phase and Bi expressed as Bi2O3 forming an intergranular bismuth oxide phase, said varistor material further comprising a spinel phase, characterized in that the amount of a pyrochlore phase comprised in the varistor material is such, that the ratio of the pyrochlore phase to the spinel phase is less than 0.15:1.

Abstract: A varistor including a varistor body with two parallel end faces made of a material that contains one or more metal oxides, and at least one electrode made of an electrically conductive electrode material arranged on any of the end faces of the varistor body. The electrode includes a layer of electrode material coated on the end face by means of an ion- or atom-transferring method, whereby the layer has a thickness within the interval of from 5 micrometers to 30 micrometers.

Abstract: A method of manufacturing a metal-oxide varistor with improved energy absorption capability. Electrodes are arranged making contact with the end surfaces of the varistor, these end surfaces being coated with metal. The envelope surfaces are supplied with a high-resistance material so as to form a zone with enhanced resistivity close to the envelope surface. According to the invention, a metal-oxide powder is formed into a cylindrical body. The envelope surface of the cylindrical body is coated by spraying, dip-painting, rolling, or some other equivalent method, with a paste or a dispersion of a high-resistance material. After the coating, the coated cylindrical body is sintered at 1100-1300° C. for 2-10 h. During the sintering, the high-resistance material penetrates, by diffusion, into the surface zone of the envelope surface to a depth of 2-6 mm.