Nippon Electric Co., Ltd.

Ohizumi Mfg. Co., Ltd.

Tomeji Ohno

Kazuaki Utsumi

Masatomo Yonezawa

Nobuaki Shohata

Toshio Takada

Masao Kiyama

Shigeru Ikeda

Keizo Iwase

Tomotoshi Nakai

Ryuji Igarashi

Takaki Fukushima

Jyun-Ichiro Yoshida

Toshikazu Akita

A ceramic capacitor is prepared by corting an electrode paste on the opposite surfaces of a green ceramic body. The electrode paste contains an inorganic binder having the same composition as the green ceramic body. Then the green ceramic body is sintered and at the same time the electrode paste is baked to form electrodes for attaching lead wires.

Method of manufacturing ceramic capacitors

A 'varistor' or voltage-dependent nonlinear resistor employs a ceramic base body having a voltage-dependent nonlinearity. First and second lead-out electrode layers are formed on first and second external surfaces, respectively, of the ceramic base body. Within and enclosed by the ceramic base body, a plurality of internal electrodes extend in parallel with each other and connect to the external lead-out electrodes. Also, the invention provides a method of manufacturing the voltage-dependent nonlinear resistor comprising the steps of forming a plurality of raw sheets of material, each having the desired voltage-dependent nonlinearity characteristics, after sintering. Internal electrodes of conducting material are printed on each of these sheets. The sheets are then laminated, cut and formed with external electrodes connecting the internal electrode to each other.

Voltage dependent nonlinear resistor

A ceramic composition consisting essentially of Pb(Fe.sub.1/2 Nb.sub.1/2)O.sub.3, Pb(Fe.sub.2/3 W.sub.1/3)O.sub.3 and Pb(Zn.sub.1/3 Nb.sub.2/3)O.sub.3 which allows low-temperature sintering and has a high dielectric constant and a good dielectric constant temperature coefficient.

Ceramic compositions

Nonohmic ZnO ceramics including the following additives have the voltage nonlinear exponent .alpha. of 30 or more, the dielectric constant .epsilon. of about 1000 or less, the loss factor (tan .delta.) of less than 10%, and small variations caused in the breakdown voltage V.sub.i by load and large current pulses. The additives listed by molecular formulae are given in % by mol. The glass components are given for Nos. 1 through 4 in % by weight, symbols of elements being representative of borosilicate lead and/or zinc glass.

Nonohmic ZnO ceramics including Bi.sub.2 O.sub.3, CoO, MnO, Sb.sub.2 O.sub.

A ceramic composition allowing low-temperature sintering at a temperature below 1000.degree. C and having a high dielectric constant over 5000 essentially contains Pb(Fe 2/3 W 1/3)O.sub.3 and Pb(Fe 1/3 Nb 2/3)O.sub.3, in which the molecular ratio of Pb(Fe 2/3 W 1/3)O.sub.3 to Pb(Fe 1/3 Nb 2/3)O.sub.3 ranges from about 0.2 to 0.5.

Ceramic compositions having high dielectric constant

A ceramic dielectric material according to the present invention has a composition consisting essentially of La.sub.2 Ti.sub.2 O.sub.7, Sr.sub.2 Nb.sub.2 O.sub.7, and 1/2Mg.sub.2x --Ti.sub.2.sub.-2x O.sub.4.sub.-2x, where x lies in a range of 0 to 1.0. This material has a relatively large dielectric constant, a very stable temperature coefficient of the dielectric constant over a wide temperature range, a widely controllable value of the temperature coefficient of the dielectric constant, and a small dielectric loss. The temperature coefficient of the dielectric constant can be determined optionally in a wide range of value by simply changing the ratios among the three constituents of the composition.

Ceramic dielectric material having improved temperature stability

A dielectric material is provided consisting essentially of a composition based on the general formula:

Dielectric ceramic compositions of BaTiO.sub.3 -BaZrO.sub.3 -CaTiO.sub.3

Fine crystalline powder, from 0.02 to 0.2 micron in average particle size, of a composition Pb(Zr.Ti)O.sub.3. Parts of Zr and Ti of the composition may be substituted for with Mn and Sb, Nb, and/or Ta. The powder is produced by preparing an acidic aqueous solution of the constituent metallic ions, neutralizing the solution to provide a suspension of hydroxides of the metals, and subjecting the suspension to hydrothermal reaction at 150.degree.-300.degree.C. The powder provides piezoelectric ceramics of a high sintered density without resorting to hot pressing.

Growing community of inventors

Tokyo, Japan

Tomeji Ohno