Fuji Electric Co., Ltd.

Fuji Electric Corporate Research and Developement Ltd.

Ikuo Nagasawa

Kazuo Mukae

Koichi Tsuda

Satoshi Maruyama

Takashi Ishii

Toyoshige Sakaguchi

Masaharu Namba

A method of manufacturing a voltage nonlinear resistance element comprising the steps of providing a mixture of main component ZnO and auxiliary components of at least a rare earth element, Co and B in a mold, placing the mold in a sheath box having openings in the surfaces thereof, and baking the mold in the sheath box. The preferred ratio of the area of the openings in the sheath box to the total surface area of the sheath box is 10-90% to produce the voltage nonlinear resistance elements having favorable long wave tail surge withstanding data and an acceptable ratio of a voltage developed across the terminals of the element when a current of 1 mA flows in the element.

Method of manufacturing voltage nonlinear resistance elements

A zinc oxide voltage-nonlinear resistor is described. The resistor is produced by sintering a zinc oxide mixture containing 0.08 to 5.0 atomic % of at least one rare earth element, 0.1 to 10.0 atomic % of cobalt, 0.01 to 1.0 atomic % of at least one member of potassium, cesium, and rubidium, 0.01 to 1.0 atomic % of chromium, and 5.times.10.sup.-4 to 1.times.10.sup.-1 atomic % of boron, the balance being zinc oxide. This resistor has superior voltage nonlinearity and is greatly improved in the short duration discharge current withstand capability and the life performance under application of electricity.

Zinc oxide voltage nonlinear resistors

A voltage non-linear resistor in the form of a sintered body is disclosed. The sintered body is comprised of 0.08 to 5.0 atomic % of a rare earth element, 0.1. to 10 atomic % of cobalt, 5.times.10.sup.-4 to 1.times.10.sup.-1 atomic % of boron and an additional component which may be 0.01 to 5.0 atomic % of magnesium or calcium and/or 1.times.10.sup.-4 to 5.times.10.sup.-2 atomic % of aluminum, gallium or indium. The remainder of the sintered body is comprised of zinc oxide. The sintered body provides a small voltage non-linear resistor with high discharge current withstand capability and good life performance.

Zinc oxide non-linear resistor

A voltage-dependent nonlinear resistor containing ZnO as a main component and six auxiliary components, i.e., (1) a rare earth element; (2) Co; (3) at least one of Mg and Ca; (4) at least one of K, Rb and Cs, (5) as well as Cr; and (6) B which may be combined with at least one of Al, Ga and In. Alternatively, the auxiliary components may be (1) a rare earth element; (2) Co; (3) at least one of K, Rb and Cs; (4) Cr; (5) B; and (6) at least one of Al, Ga and In. The voltage-dependent nonlinear resistor of the present invention has high resistance to both long and short wave-tail surge currents and has an extended service life without sacrificing good nonlinearity.

Voltage-dependent nonlinear resistor

A surge absorber of a construction having a voltage non-linear resistive element composed of an oxide, a pair of electrodes attached to both surfaces of the resistive element, a lead wire connected to one of the electrodes, and a terminal plate fastened to the other electrode and having a plurality of fitting holes formed in one part thereof, the combination of the resistive element, the electrodes, and a part of the terminal plate and the lead wire being covered with a resin coating layer.

Surge absorber

Voltage non-linear resistance ceramics

Ceramics having nonlinear voltage characteristics in which (1) zinc oxide is used as a main component and (2) praseodymium, (3) one or more of magnesium or calcium, and (4) cobalt are added thereto as subcomponents, in elemental form or as a compound thereof, in an amount of from about 0.08 to about 10.0 atomic % for praseodymium, from about 0.08 to about 10.0 atomic % for the one or more of magnesium or calcium, and from about 0.1 to about 8.0 atomic % for the cobalt, each calculated as praseodymium, magnesium or calcium and cobalt.

Ceramics having nonlinear voltage characteristics

A ceramic having non-linear voltage characteristics, comprising the product obtained on mixing (a) zinc oxide, as a principal component, and (b) (1) cobalt and (2) one of neodymium, samarium or dysprosium, either in an elemental form or as a compound thereof, each in an amount of 0.1 to 10 atomic % for the cobalt, neodymium, samarium and dysprosium, calculated as cobalt, neodymium, samarium and dysprosium as subcomponents, and calcining the mixture at a temperature of from about 1150.degree. to about 1400.degree. C.

Ceramics having non-linear voltage characteristics and method of

Ceramics having nonlinear voltage characteristics comprising the product obtained on preparing a mixture of zinc oxide as a main component, and, as subcomponents, cobalt plus one of praseodymium or terbium, either in an elemental form or as a compound thereof, in an amount of from 0.1 to 8.0 atomic % for the cobalt, from 0.08 to 8.0 atomic % for the praseodymium and from 0.1 to 8.0 atomic % for the terbium, each calculated as cobalt, praseodymium and terbium, and calcining the mixture at a temperature in the range of from about 1150.degree. to about 1400.degree. C and a method for preparing the ceramics. An embodiment includes, as an additional subcomponent, lanthanum, either in an elemental form or as a compound in an amount of from 0.08 to 8.0 atomic %, calculated as lanthanum, with the zinc oxide, cobalt and praseodymium.

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Kanagawa, Japan

Ikuo Nagasawa