Yoichiro Yokotani

Maltilayer Ceramic Capacitor with Copper Electrode

Dielectric material of (PbaCab){(Mg1/3Nb2/3)Ti(Ni1/2W1/2)}O2+a+b, where a+b>1, has been investigated. This composition has been proved to be fired under low oxygen partial pressure of less than 10-1 Pa with high resistivity. To make multilayer ceramic capacitor, the dielectric material was co-fired with copper electrode in an atmosphere of intermediate oxygen pressure. The obtained capacitor met to Z5U specification and had low dissipation factor and small change of capacitance under a d.c. bias voltage.

Dielectric Properties of Pb(Mg1/3Nb2/3)Ti(Ni1/2W1/2)O3 Ceramic

Dielectric properties of Pb(Mg1/3Nb2/3)O3–PbTiO3–Pb(Ni1/2W1/2)O3 pseudo-ternary ceramics were studied. The ceramics could be sintered at 1050°C, exhibited high dielectric constant (15000~20000) and high resistivity (1013Ωcm, 27000 ΩF). A small addition of MnO2 to these ceramics decreased the dissipation factor and caused a peculiar temperature dependence of dielectric constnt. The characteristics of multilayer chip capacitors made of these ceramics with Ag–Pd electrode are described.

Dielectric Properties of Pb(Mg1/3Nb2/3)(Zn1/3Nb2/3) (Fe2/3W1/3O3) Ceramics

Dielectric ceramics with the compositions of Pb(Mg1/3Nb2/3) O3–Pb(Zn1/3Nb2/3)O3–Pb(Fe2/3W1/3)O3 pseudo-ternary system were studied. The ceramics were sintered at 900°C, had high dielectric constant (6500) and small change of dielectric constant with temperature (+3%~-26% relative to 20°C between -25°C to 85°C). The powder processing of these compositions was studied. Pb2Nb2O7 phase remained in the ceramics with low calcining temperatures. Multilayer chip capacitors with Ag–Pd internal electrodes were fabricated.