Zinc oxide varistor, a method of preparing the same, and a crystallized glass composition for coating

摘要

PCT No. PCT/JP90/01442 Sec. 371 Date Jun. 26, 1991 Sec. 102(e) Date Jun. 26, 1991 PCT Filed Nov. 7, 1990 PCT Pub. No. WO91/07763 PCT Pub. Date May 30, 1991.The present invention relates to a zinc oxide varistor as a characteristic element of an arrestor for protecting a transmission and distribution line and peripheral devices thereof from surge voltage created by lightning, and more particularly a highly reliable zinc oxide varistor excellent in the non-linearity with respect to voltage, the discharge withstand current rating properties, and the life characteristics under voltage, a method of preparing the same, and PbO type crystallized glass for coating oxide ceramics employed for a zinc oxide varistor, etc. A zinc oxide varistor of the present invention includes a sintered body (1) and a high resistive side layer (3) consisting of crystallized glass with high crystallinity containing the prescribed amount of SiO2, MoO3, WO3, TiO2, NiO, etc., formed on the sides of the sintered body (1) to enhance the strength and the insulating property thereof, thereby improving the non-linearity with respect to voltage, the discharge withstand current rating properties and the life characteristics under voltage. The crystallized glass composition for coating of the present invention includes PbO as a main component and additives such as ZnO, B2O3 , SiO2, MoO3, WO3, TiO2, and NiO to enhance the crystallinity and the insulating property thereof.