Preparation of graphite/silicon carbide based on SLS/LSI and study of properties

In this paper, graphite/silicon carbide composites with an integrated structure-function were prepared by selective laser sintering (SLS) and liquid silicon infiltration (LSI). The study investigated the influence of different factors on the microstructure, mechanical properties, and thermal conductivity of graphite/silicon carbide composites. The results demonstrated that the open porosity of the precast body gradually decreased with an increase in the content of mesocarbon microbeads (MCMB), while the carbon content gradually increased. The density, mechanical strength, and thermal conductivity (TC) of the composites initially increased, followed by a subsequent decrease. In the absence of MCMB, micropores and a significant amount of free silicon were observed within the composite after LSI, leading to reduced density and mechanical properties. Conversely, the inclusion of 20 wt% MCMB led to the elimination of micropores and free silicon within the composite, resulting in the highest density and TC values of 2.52 g/cm(3) and 73.22 W/m center dot K, respectively. The measured TC values were consistent with those calculated by the Effective Medium Theory Model (EMT). At a 40 wt% addition, micropores and free silicon reappeared within the composites, leading to a decrease in density and properties. Furthermore, the calculated values of the five thermal conductivity models were found to be higher than the measured values. This paper presents a further improvement in the process of preparing graphite-ceramic composites with a complex structure, achieved by controlling the amount of MCMB added. This contributes to the subsequent research.