Akihiro Tsuzuki

Millimeter Wave Spectroscopy of Alumina-Zirconia System

It is important to know the dielectric properties of ceramics at high frequency millimeter wave region as the basis of practicing the millimeter wave sintering of ceramics. For this purpose, dielectric measurements by the millimeter wave spectroscopy were done for alumina-zirconia system compact bodies. The measurements were done using tow measuring systems, a BWO millimeter wave spectroscopy system and a millimeter wave vector network analyzer system. As an example of this study, it was obtained that the relationship between the dielectric constant and the alumina/zirconia ratio was almost linear at W-band.

Dispersion of Barium Ferrite Particles for Slip Casting in Magnetic Field

Water-based slurries containing barium ferrite particles have been prepared and slip cast in magnetic field. This paper presents the characteristics of the suspensions in terms of Iso-Electric Points (IEP) and zeta potential that were evaluated through pH titration and polymer adsorption. Both enlarging the specific surface area of particles by planetary milling and adjusting the pH to low value apparently increase the zeta potentials. Stable slurry was obtained by adding polyethylene glycol (PEG) into the suspension at pH = 2 ~ 3.5. The steric repulsion plays key role in dispersion and PEG films served as insulative layers and mechanically kept particles from contact each other. The barium ferrite particles formed many stacks of plates during slip casting, which either aligned randomly without magnetic field applied or regularly aligned to form textured structure when magnetic field was applied.

INFRARED THERMOGRAPHY: AN INTRODUCTIVE THERMAL HISTORY STUDY IN AEROSOL DEPOSITION

Aerosol deposition (AD) system was set up. An Infrared (IR) Thermal Tracer system was installed and cooperated with AD system to study the temperature variations of substrate influenced by the simulated air jet. While IR camera was focused on the surface of substrate, a live image with colorful temperature profiles was displayed, where spot reading or area averaging was made for temperature sampling. More attention was paid on thermal history of substrate surface under different conditions, in which the time dependence temperatures were collected through re-playing of image sequence file that had been continuously recorded during monitoring.