| 摘要 |
Multilayer ceramic chip capacitors which satisfy X7R requirements and which are compatible with reducing atmosphere sintering conditions so that non-noble metals such as nickel, copper, and alloys thereof may be used for internal and external electrodes are made in accordance with the invention. The capacitors exhibit desirable dielectric properties (high capacitance, low dissipation factor, high insulation resistance), excellent performance on highly accelerated life testing, and very good resistance to dielectric breakdown. The dielectric layers preferably contain BaTiO3 as the major component and CaTiO3, BaO, CaO, SrO, Si02, MnO2, Y2O3, and CoO as minor components in such proportions so that there are present 0.1 to 4 mol % CaTiO3, 0.1 to 2 mol % BaO, 0 to 1 mol % CaO, 0 to 1 mol % SrO, 0.1 to 5 mol % SiO2, 0.01 to 2 mol % MnO2, 0.1 to 3 mol % Y2O3, and 0.01 to 1 mol % CoO. The preferred form of the invention may be sintered in the temperature range 1,250 to 1,400° C. in a reducing atmosphere having a humidified mixture of nitrogen and hydrogen. Additionally, a re-oxidation procedure may be utilized during the sintering cycle to optimize the resistance of the ceramic to dielectric breakdown.
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