COG dielectric composition for use with nickel electrodes
AssigneeFerro Corporation
InventorWalter J. Symes, Jr.
Life of this patent
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Abstract
Multilayer ceramic chip capacitors which satisfy COG requirements and which are compatible with reducing atmosphere sintering conditions so that non-noble metals such as nickel and nickel 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 comprise a barium strontium zirconate matrix doped with other metal oxides such as TiO2, CaO, B2O3, and MgO in various combinations.
Claims21
A composition comprising a mixture of precursors that, upon firing, forms a dielectric material comprising:
- from about 26.5 wt % to about 34.0 wt % BaO;
- from about 18.0 wt % to about 24.5 wt % SrO;
- from about 41.0 wt % to about 50.0 wt % ZrO2;
- from about 0.50 wt % to about 1.50 wt % CaO;
- and
- from about 0.70 wt % to about 2.50 wt % TiO2.
A lead-free and cadmium-free dielectric composition comprising:
- from about 47.8 wt % to about 61.3 wt % BaZrO3;
- from about 39.4 wt % to about 53.6 wt % SrZrO3;
- from about 1.2 wt % to about 3.6 wt % CaTiO3;
- from about 0.1 wt % to about 2.14 wt % Mg(OH)2;
- and
- from about 0.1 wt % to about 1.78 wt % H3BO3.
A lead-free and cadmium-free dielectric paste comprising a solids portion wherein the solids portion comprises:
- from about 47.8 wt % to about 61.3 wt % BaZrO3;
- from about 39.4 wt % to about 53.6 wt % SrZrO3;
- from about 1.2 wt % to about 3.6 wt % CaTiO3;
- from about 0.1 wt % to about 2.14 wt % Mg(OH)2;
- and
- from about 0.1 wt % to about 1.78 wt % H3BO3.
Dependencies are inferred from the claim text.