| 摘要 |
PURPOSE:To attain a sufficiently high nonlinearity index of varistor characteristics in practical use by sintering a mixture of ZnO with an Mn compd. and heat-treating the sintered body at a specified temp. CONSTITUTION:An Mn compd. such as Mn(NO3)2.6H2O is added to ZnO by such an amt. that the amt. of MnO is regulated to 3-7mol.% of the total amt. of ZnO and MnO, and they are mixed in the presence of a solvent which dissolves the Mn compd., e.g., ethanol. After the solvent is evaporated and removed by drying, the mixture is sintered at 1,100-1,350 deg.C and the sintered body is heat-treated at a temp. lower than the sintering temp. by >=50 deg.C and higher than 1,000 deg.C to obtain a varistor material consisting of two crystal phases of ZnO and ZnMnO2 in (3-7)/100 molar ratio of MnO/(ZnO+MnO) and having >=10 nonlinearity index (alpha) of varistor characteristics. |
