Yoshizumi Tanaka

Properties of Si-Zr-C-O fibre/S1ZrC composites dispersed ZrSiO4 particles in the matrix

Si-Zr-C-O fibre (Tyranno ZMI®fiber)/SIZrC mincomposites dispersed ZrSiO4 particles in the matrix were fabricated by the PIP (Polymer Impregnation and Pyrolysis) method. The minicomposites with 30wt% ZrSiO4 particles in the matrix showed extremely high tensile strength up to 1573K in air than when otherwise. From the observation of microstructures of the minicomposites with dispersed ZrSiO4 particles, it is found that any fibre did not contact each other within a distance of a few micrometers in the matrix. In addition, the matrix included fewer cracks and was of apparently higher density than those of the matrix without ZrSiO4 particles. ZrSiO4 particles dispersed matrix was applied to the 2D composites.

Synthesis And Characterization Of Ceramic Powders By Dual Irradiation Of CO2 And Excimer Lasers

Ultrafine SiC and Si/C/N powders were prepared by photochemical reactions of SiH4, C2H4 and NH3 under dual irradiation of CO2 and excimer laser beams. Effects of process variables on the characteristics of these powders were studied. Enhanced crystallization and size reduction of SiC particles were observed by irradiation of excimer laser. Growth of the particles proceeded by CO2 laser irradiation, whereas refinement of the particles occurred by ablation of the initially formed particles under excimer laser irradiation. Uniformly mixed state of silicon, carbon and nitrogen atoms in the Si/C/N composite particles was confirmed by transition electron microscopy and x-ray photoelectron spectroscopy analyses. Sintering behavior of the Si/C/N powders was examined by microwave sintering and conventional hot-pressing, and the resultant Si3N4-SiC composites were consolidated into highly dense bodies with fine grain size and high hardness. It was found that the vapor- phase reaction using dual-type CO2 and excimer lasers offered a feasible method for controlling composition, crystallinity and particle size in the synthesis of ultrafine sinterable single- and multi-component powders

Synthesis and characterization of SiCSi3N4 composites by dual irradiation of CO2 and excimer lasers

Abstract Ultrafine SiC and Si/C/N powders were prepared by photochemical reactions of SiH 4 , C 2 H 4 and NH 3 under dual irradiation of CO 2 and excimer laser beams. Effects of process variables on the characteristics of these powders were studied. Enhanced crystallization and size reduction of SiC particles were observed by irradiation of excimer laser. Growth of the particles proceeded by CO 2 laser irradiation, whereas refinement of the particles occurred by ablation of the initially formed particles under excimer laser irradiation. Uniformly mixed state of silicon, carbon and nitrogen atoms in the Si/C/N composite particles was confirmed by TEM and XPS analyses. Aerosol particles of SiCSi 3 N 4 with yttrium and aluminum compounds were directly transferred and impinged on a substrate to form green compacts in a closed apparatus. It was found that the vapor-phase reaction using dual-type CO 2 and excimer lasers offered a feasible method for controlling composition, crystallinity and particle size in the preparation of ultrafine single- and multi-component powders.