| 摘要 |
<p>PURPOSE: To obtain a working voltage not more than 30V and a nonlinear coefficientαnot less than 30 with high reproducibility, by formingαlaminated structure having one resistance material layer containing a ceramic sintered body as a resistance mate rial on a zinc oxide-based barrier layer having higher electrical conductivity than the resistance material has. CONSTITUTION: A multilayered varister has a resistance material layer 3, a carrier layer 5, and metallic-layer electrodes 9 and 11 composed of a silver-based contact metal. The varister preferably has a coating layer 7 between the layer 3 and 9. When a relatively thin resistance material layer 3 exists, the number of grain boundaries can be maintained within a relatively narrow range. Although the specially uniform particle growth in the relatively thin resistance material layer indicates the same particle growth as that of the resistance material in a sintering process, it is recognized that the uniform particle growth can be accomplished when the resistance material layer is covered as wide as possible with the layer of a material which does not give any influence on the resistance characteristic of a produced varister. When the resistance material layer is coated with the coating layer 7 of a material having higher electrical conductivity by a larger surface area, the working voltage UA becomes a reproducible value not more than 10V (UA<=10V).</p> |
