PTC Honeycomb heating element with multiple electrode layers
AssigneeTDK Electronics Co., Ltd.
InventorsRyoichi Shioi, Tamotu Yamauchi
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Abstract
In a honeycomb heating element comprising a PTC thermister body, a single electrode layer composed of a silver paste was conventionally used for applying power to the body. In the present invention, two or three electrode layers with improved electrical and chemical properties are used to provide the heating element with a long service life, improved reliability and a high heat generation.
Claims14
A heating element comprising a semiconductor ceramic body of a honeycomb structure, the material of said semiconductor ceramic body having a positive temperature coefficient of resistance over a Curie point and composed of barium titanate, wherein a pair of inner electric conductive layers comprising mainly silver are provided on both end surfaces of said semiconductor ceramic body, electrically connected to a source for supplying power to said semiconductor ceramic body, and wherein an outer electric conductive layer consisting of at least one metal selected from the group, which consists of nickel, zinc and chromium is provided on each of the inner layers.
A heating element comprising a semiconductor ceramic body of a honeycomb structure, the material of said semiconductor ceramic body having a positive temperature coefficient of resistance over a Curie point and composed of barium titanate, wherein a pair of inner electric conductive layers are provided on both end surfaces of said semiconductor ceramic body, electrically connected to a source for supplying power to said semiconductor ceramic body, and wherein an intermediate layer consisting of at least one metal selected from the group, which consists of silver, gold and copper is provided on each of said inner layers, and an outer layer consisting of at least one metal selected from the group consisting of nickel, zinc and chromium is provided on each intermediate layer.
A heating element comprising a semiconductor ceramic body of a honeycomb structure, the material of said semiconductor ceramic body having a positive temperature coefficient of resistance over a Curie point and composed of barium titanate having electrical conductive terminal layers attached by a process comprising a step of screen printing a pair of inner electric conductive layers comprising mainly silver on both end surfaces of said semiconductor ceramic body, wherein said process further comprises the steps of:
- electrolytically depositing an intermediate electric conductive layer, consisting of at least one metal selected from the group which consists of silver, gold and copper, on each of said inner layers, and
- plating on each intermediate layer an outer electric layer consisting of at least one metal selected from the group which consists of nickel, zinc and chromium.
A heating element comprising a semiconductor ceramic body of a honeycomb structure, the material of said semiconductor ceramic body having a positive temperature coefficient of resistance over a Curie point and composed of barium titanate having electrically conductive terminal layers attached by a process comprising a step of screen printing a pair of inner electric conductive layers comprising mainly silver on both end surfaces of said semiconductor ceramic body, wherein said process further comprises the steps of:
- screen printing an intermediate electric conductive layer, consisting of at least one metal selected from the group which consists of silver, gold and copper, on each of said inner layers, and
- plating on each intermediate layer an outer electric conductive layer consisting of at least one metal selected from the group which consists of nickel, zinc and chromium.
A heating element comprising a semiconductor ceramic body of a honeycomb structure, the material of said semiconductor ceramic body having a positive temperature coefficient of resistance over a Curie point and composed of barium titanate having electrically conductive terminal layers attached by a process comprising a step of screen printing a pair of inner electric conductive layers on both end surfaces of said semiconductor ceramic body, wherein said process further comprises a step of:
- plating an outer electrically conductive layer consisting of at least one metal selected from the group which consists of nickel, zinc and chromium, on each of said inner layers.
Dependencies are inferred from the claim text.