| 摘要 |
An inorganic-metal composite body exhibiting PTC behavior at a trip point temperature ranging from 40° C.-300° C., including an electrically insulating inorganic matrix having a room temperature resistivity of at least 1x106 OMEGA.cm, and electrically conductive particles uniformly dispersed in the matrix and forming a three-dimensional conductive network extending from a first surface of said body to an opposed second surface thereof, wherein the composite body has a room temperature resistivity of no more than 10 OMEGA.cm and a high temperature resistivity of at least 100 OMEGA.cm. Preferably, the electrically conductive particles are made of a Bi-based alloy containing at least 50 wt % Bi, and have an average diameter, phiave, of 5-50 mum and a 3sigma particle size distribution of 0.5 phiave-2.0 phiave. Also disclosed is an inorganic PTC device including an intermediate electrode layer to insure adhesion of outer termination electrodes to the PTC composite body, and a method of forming the composite body, which method effectively deals with the volatility of the electrically conductive particles.
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