| 摘要 |
<p>PURPOSE:To stabilize varistor voltage and surge resistance characteristics by a method wherein a baking sheath having one or more penetrating hole in the bottom surface is used, a zinc oxide type varistor is mounted on the bottom surface of the baking sheath and baked, thereby uniformizing bismuth partial pressure in the baking sheaths of the upper and the lower parts. CONSTITUTION:A baking sheath 2 provided with one or more penetrating holes 3 on the bottom surface is used, and a zinc oxide type varistor 1 is mounted on the bottom surface of the baking sheath 2 and baked. For example, a molded body 1 formed by using powder wherein zinc oxide exhibiting varistor characteristics by baking is used as main component and bismuth oxide is contained as additive material. The molded body whose thickness and diameter are 1.2mm and 15mm, respectively, are stacked by 20 stages. The baking sheath 2 is provided with penetrating holes, whose diameters are 10mm, at four corners of the bottom surface. Two stages of the baking sheaths 2 are stacked. A sheath lid 4 is put on the upper stage sheath 2; a spacer 5 is arranged under the lower sheath 2, in order that gas in the sheath and atmosphere in a furnace may be able to sufficiently circulate; the molded body 1 is baked at a maximum temperature 1300 deg.C.</p> |
