| 摘要 |
PURPOSE:To contrive improvement in surge resistivity characteristics, reduction in variation of element characteristics and electric charge characteristics by a method wherein prescribed quantity of zinc oxide raw material, adding material and borosilicate bithmuth glass frit containing silver are mixed, and especially, the compounding ratio of boron and silver is specifically prescribed. CONSTITUTION:Borosilicate bithmuth glass frit of 0.01 to 0.2wt.% is blended to the total quantity of zinc oxide raw material and an additive ingredient. If the quantity of silver oxide, to be blended to the mixture formed by adding silicon oxide of 5 to 15 wt. % and boron oxide of 1 to 10wt.% to the above-mentioned frit, is 10wt.% or smaller, the flatness rate in the large current region in V-I characteristics of an element is aggravated, and if the above-mentioned blending quantity is 35wt.% or exceeds it, silver oxide is not solidified uniformly, and vitrification becomes difficult. As a result, the reaction of the element to other components becomes non-homogenous. The blending of bismuth oxide forms low- homogenous. The blending of bismuth oxide forms low-melting point glass which can be vitrificated easily by forming it into bismuth glass frit, and its reactivity with other adding material is also enhanced. With B2O3/Ag2O of 0.07 or less, the effect of of boron oxide is reduced extremely, electric charge life is deteriorated, and when the B2O3/Ag2O exceeds 1.0, the effect of addition of silver oxide is reduced, and the charging rate of lightning surge is deteriorated. |
