Method of manufacturing a metal-oxide varistor with improved energy absorption capability

摘要

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.