Ein keramischer,spannungsabhaengiger Widerstand und ein Verfahren zu dessen Herstellung

摘要

1,268,385. Semi-conductor devices. MATSUSHITA ELECTRIC INDUSTRIAL CO. Ltd. 19 June, 1969 [19 June, 1968; 20 June, 1968; 25 Sept., 1968; 8 Oct., 1968], No. 31167/69. Heading HlK. An asymmetrical voltage-dependent resistor comprises a semi-conductive titanate body 1 provided with an ohmic electrode 3 and a non- ohmic electrode 2, the latter consisting of, by weight, 55-93% of an Ag component (e.g. pure Ag or a mixture of Ag and Ag 2 O), 6À5-25% of a combined addition of Pb 3 O 4 and Bi 2 O 3 , and 0À5-38À5% of a further addition of one or more metal oxides based upon B, Cu, Cd, Zn, Ni, Co, Fe, Ti, Nb or Ta. The body 1 may be of sintered barium titanate or strontium titanate, the former material containing aluminium oxide, silicon dioxide and silver oxide as dopants incorporated into an initial mixture of barium carbonate and titanium dioxide prior to pressing, calcining and sintering. The ohmic electrode 3 may be of Al, Zn, Cu or Cu on Al, vacuum deposited, spray metallized or electroplated on to the body 1. Various preferred compositions for the non-ohmic electrode 2 are specified, the mixture being provided with a polyester binder, applied to the body 1 as a paint, fired at 600-920‹ C. in an oxidizing atmosphere and finally allowed to cool in the firing atmosphere.