Fabrication of silicon carbide fiber-reinforced silicon carbide composite by hot-pressing

Continuous SiC fiber-reinforced SiC composites (SiC/SiCf) are one of the most attractive structural materials for future fusion reactors. To date, the only successful manufacturing process of SiC/SiCf composites is the chemical vapor infiltration technique, which is a very delicate and expensive process. In this study, therefore, a new method to fabricate the composite with higher density is developed using a conventional 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°C under 40 MPa applied stress in Ar. The matrix SiC sheet consists of fine, β-SiC powders and Al, B and C sintering aids. A sheet of SiC was formed using the doctor blade technique. The relative density of sintered bodies was 66–99%. The load–displacement behavior of the composites with Nicalon cloth showed a slightly ductile load–displacement behavior with low maximum strength, whereas the composite with Hi-Nicalon cloth showed brittle fracture with high maximum strength at room temperature.