Kiichi Minai

High-Dielectric Constant Ceramics for Base Metal Monolithic Capacitors

In order to make the monolithic ceramic capacitors with a base metal internal electrode, the ceramics of {(Ba1-xCax)O}m{(Ti1-yZry)O2} compositions were investigaed, where 0.02x0.22, 0<y0.20 and 1.005m1.030. These ceramic materials are sintered in an atmosphere of low oxygen to yield a high resistivity (1012 Ω-cm), a high dielectric constant (7,000~9,000), and a low dissipation factor of less than 2.5%. The monolithic capacitors of these ceramics with nickel electrode are as reliable as those with precious metal electode.

Influence of agglomeration upon dewaxing properties of greenware for low pressure molding

This paper presents the influence of agglomeration upon the flow property of the slurry and dewaxing properties of the greenware for low pressure molding. (Zr, Sn)TiO4 powder agglomerate was pulverized by a high speed mixer. The agglomeration state was evaluated by tapping density and residual of #350 sieving. The flow property was measured by viscosity and grindmeter scratch. The dewaxing properties were evaluated by pore size distribution, the fraction of residual binder after dewaxing and rejection ratio of greenware due to crack. Pulverization of the agglomerate reduces the thixotoropy of the slurry, contributing to uniform pore size and residual binder distributions. They all contribute to reduce cracks in greenware.