Reaction-Bonded Silicon Carbide by Reactive Infiltration

Abstract

Exothermic reactions between a porous matrix and an infiltrating melt provide a more economic alternative for synthesizing many ceramics, intermetallics, and composites. It has recently been demonstrated that infiltration of cast microporous carbon preforms by silicon melt can be used to fabricate high-density, nearly net-shaped silicon carbide components at significantly reduced cost. This paper describes the synthesis of reaction-bonded silicon carbide by reactive infiltration of microporous carbon preforms. The kinetics of unidirectional infiltration of silicon melt into microporous carbon preforms as a function of pore morphology and melt temperature is investigated in this paper. Qualitative agreement between experimental data and a mathematical model for capillarity-driven fluid flow through cylindrical pores is demonstrated. Experimental evidence of high parametric sensitivity is also presented. A simplified model relating fluid flow, transport, and reaction phenomena is formulated to interpret experimental evidence of pore closing and free silicon entrapment. A robust numerical formulation is also described.

Reactive Processing in Ceramic‐Based Systems

“…Typically, RBSC has a larger grain size than sintered or hot‐pressed SiC, which results in higher thermal conductivity, but lower strength. The major advantage of reactive processing, in this case, is that it is the lowest cost production process for dense SiC components 60 . Other reactive processes have been commercialized, but most tend to be low‐volume processes such as the reactive deposition of thin films for microelectronic applications.…”

Biomorphic SiC: A New Engineering Ceramic Material

“…The reactive infiltration of microporous C preforms, both artificial and natural, has been the matter of a number of studies 13,16,19,35,36,46–51 . Literature is also available on the fabrication of cellulosic‐based porous oxides 23 .…”

“…8, high‐temperature crushing strength results of reaction‐formed SiC (RFSiC) are also included. RFSiC is fabricated by reactive melt infiltration of artificial porous carbon preforms 47,48,50 . Higher SiC partial densities are achieved, and the materials present isotropic mechanical properties.…”

Simulation of capillary infiltration into packing structures for the optimization of ceramic materials using the lattice Boltzmann method

“…For more general porous systems, the radius of the channel is replaced with the effective radius. Relevant studies on reactive infiltration based on dynamics can be found in Asthana Asthana, Singh, and Sobczak (2005), Gern and Kochendörfer (1997), Martins, Olson, and Edwards (1988), Messner and Chiang (1990), Sangsuwan, Orejas, Gatica, Tewari, and Singh (2001), and Yang and Ilegbusi (2000). The simulation output is in model units.…”