| 摘要 |
PURPOSE: To provide a manufacturing method of a ZnO varistor which has no irregularity in electric characteristics and instability in life characteristics and also dielectric loss can be suppressed. CONSTITUTION: Al2 O3 of 10 to 100ppm is added to ZnO base material, and heat treatment is conducted at 800 deg.C to 1200 deg.C. Then, the ZnO base material is granulated, powdered by adding Bi2 O3 and other additional material, and calcined. Also, Al2 O3 of 30 to 120ppm is contained in the ZnO base material after heat treatment. |
