FABRICATION OF SILICON-CARBIDE FIBER-REINFORCED SILICON-CARBIDE COMPOSITE BY HOT-PRESSING

Continuous SiC fiber-reinforced SiC composites (SiC/SiCf) are one of t he most attractive structural materials for future fusion reactors. To date, the only successful manufacturing process of SiC/SiCf composite s is the chemical vapor infiltration technique, which is a very delica te and expensive process. In this study, therefore, a new method to fa bricate the composite with higher density is developed using a convent ional hot-press procedure. Matrix SiC sheets and Nicalon or Hi-Nicalon two-dimensional cloths without any coatings were stacked alternately and then this stacked green body was hot-pressed at 1750 degrees C und er 40 MPa applied stress in Ar. The matrix SiC sheet consists of fine, beta-SiC powders and Al, B and C sintering aids. A sheet of SiC was f ormed using the doctor blade technique. The relative density of sinter ed bodies was 66-99%. The load-displacement behavior of the composites with Nicalon cloth showed a slightly ductile load-displacement behavi or with low maximum strength, whereas the composite with Hi-Nicalon cl oth showed brittle fracture with high maximum strength at room tempera ture. (C) 1998 Published by Elsevier Science S.A. All rights reserved.