To avoid exfoliation of electrodes for enhancing the long term reliability of a current-limiting element by forming V2O3 layers having no element A on the end faces of (V1-xAx)2O3 PTC resistor.
Within a current-limiting element 1, a composition having PTC characteristic is provided with a V2O3 base PTC resistor 1a of (V0.9965Cr0.0035)2O3 and V2O3 layers 1b not containing Cr. Mo electrodes and the current-limiting element 1 are brazed with Ag-Cu eutectic brass 3. Furthermore, the thickness of the V2O3 layers 1b is specified to be 0.1-2.5 mm. This current-limiting element 1 is manufactured by blending V2O5 or V2O3, CrO3, Fe2O3 particles, so that the composition after baking step become (V0.9965Cr0.0035)2O3 Fe5 wt.% and V2O3 Fe5 wt.% to be mixed and crushed respectively by wet ball mills for producing particles (1) and (2). Next, after laminating the particles (2), (1) and (2) in this order in a metallic mold to be pressure-molded, the Mo electrodes 2 are brazed to the current-limiting element 1 produced by baking in hydrogen current.
OGINO MASAAKI
SUZUKI TAKUYA
KUNIHARA KENJI
TSUDA KOICHI
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