Speaker
Description
Currently, composite materials 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 aerospace, energy production, electronics, catalysis, etc. However, the costly manufacture of such composites is the major restraint to make them marketable.
In this paper, 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 main conclusion, both the reactivity and infiltration kinetics were driven by the presence of free C as bonding phase and additional SiC was produced at the infiltration front.
Taking into account that: a) the infiltration kinetics is well described by a linear law; b) the resulting activation energy is 300 ± 100 KJ/mol; c) highly consolidated SiC particles are observed by the appearance of SiC type II, as preliminarly confirmed by wettability studies,the mechanisms governing infiltration are essentially driven by reactivity and less influenced by viscous forces
Finally, if compared with the SiC-Si materials, a good thermo-mechanical response and a substantial improved oxidation resistance for the as produced SiCp-IrSi3 composites are observed, as expected.
| Speaker Country | Italiy |
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