| 摘要 |
PROBLEM TO BE SOLVED: To provide a laminated varistor of superior static electricity suppression effect and static electricity resistance which has varistor voltage and voltage non-linearity of equivalent level to the case where firing is performed in atmosphere by using an electrode of a noble metal such as a Pd even when an non-fired varistor material and a Cu electrode are integrally fired.SOLUTION: An electrode contains Cu as a main component, and the varistor material contains ZnO as a main component and contains a perovskite compound of a general formula ABOas a sub-component, an A site is at least one kind of Sr, Ca and Ba, a B site is Co simple substance or one kind selected out from Co, Mn and Cr. Ceramic green sheets of the varistor material and Cu conductive paste layers are alternately laminated to form a laminate, and for the laminate, a first heat treatment performed in a Cu reducing atmosphere where a temperature is 980°C or above and below 1,080°C and an oxygen partial pressure is 10-10Pa and a second heat treatment for performing oxidation treatment in the atmosphere of 500-900°C are performed in this order to form a ceramic sinter and then an external electrode is formed. |
