Patent ID: 6802116
Filing Date: 2004-10-12
Classification: H01C,Y10T

Abstract:
A method of manufacturing a cylindrical metal-oxide varistor with improved energy absorption capability, wherein electrodes are arranged making contact with the end surfaces of the metal-oxide varistor, the end surfaces of the varistor are coated with metal, and the envelope surface is supplied with a high-resistance material so as to form a zone with enhanced resistivity close to the envelope surface, the method comprising:forming a metal-oxide powder into as unsintered cylindrical varistor body; coating envelope surfaces of the unsintered varistor body with a paste or a dispersion of a high-resistance material comprising SiO2 spraying, dip-painting, rolling, or spraying painting; and sintering the coated varistor body, wherein during sintering the high-resistance material diffuses into the surface of the varistor body to a depth of 2-6 mm.