Mechanisms and kinetics during reactive infiltration of molten silicon in porous graphite
Language
EN
Article de revue
This item was published in
Ceramics International. 2019-05-01, vol. 45, n° 7, p. 8690-8699
English Abstract
Liquid silicon Infiltration (LSI) is a fast and economical process to manufacture SiC-based ceramics. For a better understanding of reactive melt infiltration of liquid silicon, the wetting and infiltration of porous ...Read more >
Liquid silicon Infiltration (LSI) is a fast and economical process to manufacture SiC-based ceramics. For a better understanding of reactive melt infiltration of liquid silicon, the wetting and infiltration of porous graphite by molten silicon were investigated at 1450, 1500 and 1550 °C for duration comprised between 10 s and 1 h. Infiltrations tests were performed in an argon atmosphere with an inductively heated furnace operating with heating and cooling rates of 300 °C.min−1. The formation and growth of SiC grains were investigated at the outer surface and within graphitic carbon substrates with 11% porosity and a narrow pore size distribution centered at 2 μm. The length of the infiltrated zone and the SiC crystals growth were determined from scanning electron microscopy. Rapid spreading and infiltration of molten silicon are observed from the first 60 s. The growth rate of the interfacial SiC layer obeys a fourth-power law with an activation energy of 260 ± 30 kJ mol−1. Pore filling by SiC is limited by volume diffusion with an activation energy equal to 320 ± 40 kJ mol−1.Read less <
English Keywords
Grain growth
Composites
Electron microscopy
Carbon
SiC
Refractories