Tamotsu Ueyama

Evaluation of ferroelectric/ ferromagnetic composite by micro-composite designing

Abstract Composite of ferroelectric (PZT)/ferromagnetic (ferrite) material has been fabricated by fast sintering. The dielectric and magnetic properties can be considered by the logarithmic mixing low. As an application, a microwave absorber has been proposed. An absorbing condition of microwave is theoretically derived and designed with a central frequency of 470 MHz and a thickness of 11.5 mm.

Ferroelectric Properties of Pb(Zr0.53Ti0.47)O3 Ceramics Synthesized by Partial Oxalate Method (Using Zr0.53Ti0.47O2 Hydrothermal Produced Powder as a Core of Pb(Zr0.43Ti0.47)O3)

Pb(Zr0.53Ti0.47)O3 ceramics were produced using powders synthesized by partial oxalate method. Dielectric and piezoelectric properties were investigated and discussed with grain size dependence. Highly electromechanical copling factors, kp and kt modes in disk sample, were obtained even by the low sintering temperature of 900°C, where the grain size was 0.5 µm.

Microstructure of Pb(Zr0.53Ti0.43)O3 Ceramic Synthesized by Partial Oxalate Method (Using Zr0.53Ti0.47O2 Hydrothermal Produced Powder as a Core of Pb(Zr0.53Ti0.47)O3)

Pb(Zr0.53Ti0.47)O3 powder was produced by partial oxalate method using Zr0.53Ti0.47O2 powder which was derived by hydrothermal processing. The Pb(Zr0.53Ti0.47)O3 ceramics was sintered at fairly low temperature. This synthesized process was discussed with microstructures of powder and ceramics. The Zr0.53Ti0.47O2 hydrothermal produced powder was estimated to be a core of reaction.

Fabrication of high Tc superconductor, Ba2Y1Cu3O7-x ·Ag metal composite thick film and their evaluation

Abstract High Tc superconductor, Ba2Y1Cu3O7-x thick film including Ag metal has been developed by the sintering of Ba2Y1Cu3O7-x single phase powder and Ag2O powder. In general, Ag2O varies to metal Ag around 400°C, which does not react with Ba2Y1Cu3O7-x and metal Ag melts around 800°C. The resistivity in the normal conductance region depends greatly on the content of metal Ag in this composite thick film and decreases with increasing the content of metal Ag. Superconducting temperature was 85–90 K. Current density of 132 A/cm2 was the most highest measured value in this study.

Sintering Properties of BaTiO3 Green Sheets with High Packing Density

The sintering properties were discussed in two kinds of BaTiO3 green sheets, in which packing densities were 48 vol% and 60.4 vol%, respectively. The sintering temperature reduced as the packing density increased ;and the number of internal void in the sintered body decreased considerably and its bending strength increased from 120 MPa to 150 MPa.

Advanced manufacturing process of dielectric ceramic gwen sheet

Abstract New manufacturing technique of ceramic slurry has been developed, making agglomerated particles of ceramic powder pulverized to primary particles without mechanical destruction. This technique has been applied for manufacturing alumina green sheets and barium titanate green sheets by the doctor blade method. The density of green sheets depends largely on the average agglomerated particle diameter rather than on the average primary particle diameter. The smaller the diameter of agglomerated particles is the higher density of green sheets becomes. The maximum density of green sheet manufactured by this technique is almost equal to the most closed packing density of primary particles.

Influence of W Particle Size and Co-firing Temprature on the Bonding Strength of the W Metallized Alumina Substrates

This paper treats the influences of the W-particle size and the firing temperature on the metallization bonding strength of the W-metallized alumina substrate co-fired in the wet reduced atmosphere. As the result, it has been revealed that there is an optimum firing temperature at which the metallization bonding strength becomes the maximum and that this temperature increases with the increase of the W-particle size.