| 摘要 |
<p>PURPOSE:To increase crystal grain diameter because, in the case where varistor voltage is lowered for a low voltage circuit use, the thickness of a resistor must be 0.1-0.2mm, and the strength is insufficient when zinc oxide crystal grain diameter is 10-20mum. CONSTITUTION:By reducing the quantity of admixture forming the grain boundary of zinc oxide crystal grain, the crystal grain diameter can be made large without deteriorating voltage nonlinearity. That is, the following values are set; the total loadings of at least one of Pr and La is 0.08-2.0atomic%, the total loadings of at least one of Mg and Ca is 0.001-2.0atomic%, the total loadings of at lest one of K, Cs, and Rb is 0.001-0.5atomic%, and the loading of Cr is 0.001-0.5atomic%. By performing baking in the atmosphere wherein oxygen partial pressure is 40% or higher, the baking temperature is lowered and the irregularities of characteristics are reduced.</p> |
