| 摘要 |
PROBLEM TO BE SOLVED: To obilain a composition for a thick-filmy negative-characteristic thermistor, which is capable of inhibiting defects such as pin holes or voids from being caused inside the thick film of the resulting thermistor when heating/firing in a production process of the thermistor in performed, to provide a thick-filmy negative-characteristic thermistor produced from the composition and to provide a production process of the thermistor. SOLUTION: The preparation process of this composition comprises: a step 10 for blending prescribed metal oxides each having thermistor characteristics, such as Mn3O4, Co3O4, Fe3O4, and the like, together so as to obtain a blend having a prescribed blend proportion and subjecting the resulting blend to heating /firing under prescribed conditions, to effect a solid phase reaction and to obtain a metal oxide power; a step 12 for adding an electrically conductive substance (RuO2) and a glass powder to the metal oxide powder to obtain a powdery mixture; a step 14 for subsequently subjecting the powdery mixture to wet pulverization with a wet-type ball mill; a step 16 for measuring the average particle size of the pulverized powdery mixture; a step 18 for confirming that the resulting powdery mixture is pulverized into particles having a prescribed particle size; and a step 20 for thereafter adding a thickener and a solvent to the powdery mixture and sufficiently mixing them together by using a three-roll mill, or the like, to prepare a paste for an NTC (negative temperature coefficient) thermistor, which consists of a thick-filmy negative-characteristic thermistor composition 33. |
