Title: Design and fabrication of SiC or IrSi3 composites for use in highly oxidizing environments

Abstract

Currently, MMCs with SiC as reinforcement emerge as ideal candidates for long-term stable devices withstanding high temperatures and harsh operating environments which are typical for many industrial sectors, such as energy, aerospace, electronics, catalysis, etc. However, the costly manufacture of such composites is the major restraint to make them marketable. In this paper, the design and fabrication of highly-dense, nearly-shaped SiC/IrSi3 composites, effortless produced at T = 1250°C under a vacuum by reactive melt infiltration of liquid Si-62 wt%Ir eutectic alloy into bimodal SiCp-C porous preforms, are presented. The replacement of unreacted detrimental Si by a tougher and less oxidizing intermetallic phase (IrSi3) was successfully obtained. As it will be introduced during the talk, the know-how gained from preliminary fundamental studies performed on liquid Si-Ir thermo physical properties, thermodynamic properties of Si-Ir-C, as well as on the reactivity at the liquid Si-rich Si-Ir alloys/C and Si-Ir alloys/SiC interfaces, was crucial for optimizing the reactive infiltration process. Finally, a high compatibility of IrSi3- silicide with SiC and an improved oxidation resistance of the SiC-Si based composites by the presence of the Ir-silicide phase were observed during thermo-mechanical characterization, as expected.