Korea Institute of Science and Technology

In J Chung

Myung Seop Kim

Myung Hwan Oh

Kyung Jae Lee

Nam Yoon Lee

A method of producing a zinc oxide varistor for high voltage which is a voltage-current non-linear type of resistor including zinc oxide as the major ingredient and bismuth oxide or manganese dioxide as additives for use with a circuit protector and gapless arrester. The method of the invention includes sintering a zinc oxide composition lacking bismuth oxide at 1200.degree.-1350.degree. C. under conditions and for a period of time effective to form a primary sintered body, heat-treating a primary sintered body coated with an amount of metal oxide paste containing mostly bismuth oxide at a temperature of 1000.degree.-1200.degree. C. for a period of time effective to diffuse the metal oxide paste to the grain boundaries of the zinc oxide grains.

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Seoul, South Korea

In J Chung