US 5,497,129 AGranted

Filter elements having ferroelectric-ferromagnetic composite materials

AssigneeGeneral Motors Corporation

InventorsJoseph V. Mantese, Adolph L. Micheli, Dennis F. Dungan, Norman W. Schubring, Clyde M. Callewaert

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Abstract

A material which possesses both capacitive and inductive properties for suppressing electromagnetic interference is provided, wherein the material is a composite of a ferroelectric material and a ferromagnetic material. The ferroelectric-ferromagnetic composite material is formulated and processed so as to retain the distinct electrical properties of the individual constituents according to the relative quantities of the constituents present in the ferroelectric-ferromagnetic composite material. As a unitary composite element, the ferroelectric-ferromagnetic composite is readily formable to provide a compact electrical filter whose filtering capability is highly suitable for suppressing electromagnetic interference from sources internal and external to an automotive environment. The sintered composite has a very low porosity; interconnectivity between the ferroelectric and ferromagnetic phases; and has no chemical reaction between the ferroelectric and ferromagnetic phases to produce a third phase.

Claims20

Dependent claims

A filter/connector comprising:

at least one connector pin;
a first and a second component layer;
the first component layer including a first ferroelectric-ferromagnetic composite layer having a clearance hole formed in the first composite layer for each connector pin;
a metallization pad deposited on a top surface of the first composite layer in an area immediately adjacent each clearance hole but not entirely across the top surface of the first composite layer;
said first ferroelectric-ferromagnetic composite layer consisting essentially of two phases wherein each phase is interconnected to the other phase throughout the first composite layer;
the second component layer comprising a second ferroelectric-ferromagnetic composite layer having a clearance hole formed therein for each connector pins;
and a metallization plane deposited on a top surface of the second composite layer everywhere except for a pin isolation area formed immediately adjacent each clearance hole in the second component layer where no metallization is deposited, said second ferroelectric-ferromagnetic composite layer consisting essentially of two phases wherein each phase is interconnected to the other phase throughout the second composite;
and said component layers being sintered together to form a single block;
wherein each of said ferroelectric-ferromagnetic composite layers comprises about 30 to about 70 percent by volume of a ferromagnetic material, and about 30 to about 70 percent by volume of a ferromagnetic material, and wherein the ferromagnetic material comprises a AB.sub.2 O.sub.4 type material where A is at least one selected from the group consisting of Cu, Mg, Zn, Ni and Mn;
and B includes primarily Fe.

7 more elements

Dependencies are inferred from the claim text.