Kabushiki Kaisha Toshiba

Yoshikazu Tanno

Hironori Suzuki

Toshiya Imai

Hiroyoshi Narita

Yoshiyasu Itoh

Hideyasu Ando

Yoshiyasu Ito

Hideyasu Andoh

Takeshi Udagawa

Koji Higashibata

Kiyokazu Umehara

Yoshlyasu Ito

A current/voltage non-linear resistor comprises a sintered body having a main component of ZnO, an electrode applied to a surface of the sintered body and an insulation material applied to another surface of the sintered body. The main component containing, as auxiliary components, Bi, Co, Mn, Sb, Ni and Al, and the contents of the auxiliary components are respectively expressed as Bi O , Co O , MnO, Sb O , NiO and Al , of Bi O : 0.3 to 2 mol %, Co O : 0.3 to 1.5 mol %, MnO: 0.4 to 6 mol %, Sb O : 0.8 to 7 mol %, NiO: 0.5 to 5 mol % and Al : 0.001 to 0.02 mol %; a Bi O crystalline phase in the sintered body including an &agr;-Bi O phase representing at least 80% of the total Bi O phase.

Current/voltage non-linear resistor and sintered body therefor

A sintered body which can be formed into a resistor having a non-linear resistance includes zinc oxide is the principal composition and bismuth, cobalt, antimony, manganese and nickel respectively converted to expressed Bi,O,, Co,O,, Sb,O,, MnO and NiO as auxiliary compositions. The compositions contains 0.05 to 10 mol % of Bi,O,, 0.05 to 10 mol % of Co,O,, 0.05 to 10 mol % of Sb,O,, 0.05 to 10 mol % of MnO and 0.05 to 10 mol % of NiO; the content ratio of the Bi,O,to the NiO is in a mole ratio of 0.5 or more but 1.5 or less, and the content ratio of the MnO to the Sb,O,is in a mole ratio of 1.0 or less. Preferably, the composition contains at least one of 0.5 to 500 ppm of aluminum, converted to Al,, and 10 to 1000 ppm of at least one or the other of boron and silver, converted respectively to B,, and Ag,. The composition may also contain 0.01 to 1000 ppm of at least one of sodium, potassium, chlorine and calcium, converted respectively to Na,, K,, Cl,and Ca,.

Sintered body having non-linear resistance characteristics

A high resistivity layer is disclosed for a medal oxide voltage-nonlinear resistor (varistor) for arrestors and surge absorbers of the type having a sintered body containing zinc oxide as a major component and two spaced electrodes attached to the surface of the body wherein the electrodes are insulated from one another by the high resistivity layer. The high resistivity layer of the invention consists essentially of at least zinc ferrate (III). The high resistivity layer is formed by sintering a slurry containing ferric oxide (Fe.sub.2 O.sub.3) as a major component.

Zinc oxide varistor and method of making it

Growing community of inventors

Ebina, Japan

Yoshikazu Tanno