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Silicon carbide (SiC) is known for sustaining its durability at high temperatures. Highly dense SiC can be fabricated via reactive liquid silicon infiltration (LSI) of porous carbon (C) preforms. This study aims to prepare porous C via direct ink writing (DIW), a method of 3D printing, and thermal treatment for LSI, leading to SiC in complex shapes. This has many high temperature applications including use for hypersonic aircrafts.

LSI success is dependent on the porosity of controlled C preforms. As a continuous filament technique, DIW parameters, such as printing speed, layer height, and nozzle diameter, influence filament packing and may affect pore size distribution after heat treatment. The mass ratio of the carbon precursors (microcrystalline cellulose and phenolic resin) and the volume fraction of water in the ink are known to influence porosity as well. Additionally, in consideration that uneven mixing may increase the potential for trapped gasses, which leads to large pores, the total mixing time and the number of intervals the carbon precursors are added in will be explored for their effects on the pore size distribution. This study aims to explore the effects of DIW printing parameters and ink composition on the variance of C preform pore size distribution after DIW and thermal processing, as measured by mercury porosimetry. Minimization of C preform pore size distribution variance will increase control over LSI, leading to highly uniform SiC.