Phenolic polymer infiltration and pyrolysis process for additively manufactured carbon/PEEK composites to produce carbon-carbon composites

Carbon-carbon composites are carbon fibers reinforced with carbon matrix and are classified as advanced materials well suited for high-temperature structural applications. Carbon-carbon composites are characterized by maintaining excellent mechanical properties and structural stability at high temperatures and have been used in aerospace application as nozzles, heatshields, and leading edge. However, conventional methods to manufacture carbon-carbon composites are costly and time-consuming. The aim of this work is to develop a method for creating additively manufactured (AM) carbon-carbon composites using a high-pressure re-infiltration process. In doing so, less infiltration cycles are required compared to a low-pressure re-infiltration, reducing the total manufacture time. Samples were fabricated using a traditional vacuum assisted resin transfer molding (VARTM) technique, as well as the new high-pressure system developed for this work. For both techniques, AM carbon fiber/PEEK composite parts were used for the composite preform, and SC-1008 phenolic resin was used as the polymer matrix. Pyrolysis cycles were performed between infiltration stages to convert the phenolic resin into the desired carbon matrix. The two techniques were compared to each other, analyzing the porosity resulting from each technique. Compared to a traditional VARTM technique, the high-pressure re-infiltration system developed in this work has less porosity after pyrolysis stages and required fewer re-infiltration and pyrolysis cycles to achieve the desired porosity. (: .)