Low fire X7R dielectric compositions and capacitors made therefrom

Abstract

Abstract Multi-layer ceramic capacitors are made from novel low temperature fired ceramic dielectric compositions which may have dielectric constants of over 3200 at room temperature, and which do not vary in value by more than 15 percent over a temperature range of -55° C. to +125° C., with the value at +25° C. being the reference point. The compositions comprise a base ceramic formulation or host material, a ceramic sintering aid, and a low melting point glass formulation, each derived from metal oxides or precursors thereof. The host material is made from 97.89 to 98.19 weight percent barium titanate and from about 1.81 to 2.11 weight percent neodymium oxide, the sintering aid from Bi 2 O 3 ·2TiO 2 , and the the glass formulation from 86.0 wt. % PbO, 9.0 wt. % B 2 O 3 , 1.58 wt. % SiO 2 , 0.13 wt. % TiO 2 and 3.29 wt. % Al 2 O 3 . Manganese dioxide or a precursor is added in an amount of about 0.205 wt. % as the dioxide based on the combined weight of the ceramic formulation, the Bi 2 O 3 ·2TiO 2 and the glass formulation. The mixture, when made into a multi-layer capacitor is fired at or below 1100° C.

Inventors

• 👤 James M. Wilson
• 👤 Walter J. Symes, Jr.

Bibliographic Details