New large-scale production method for C/C-SiC ceramics: Investigating the influence of chopped and nonwoven CF

Abstract

Carbon fibre reinforced carbon and silicon carbide dual matrix composites are a commercially produced using the liquid silicon infiltration (LSI) process. In comparison to the state of the art LSI process, the first production step—the shaping of the carbon fibre reinforced plastic green body—is realised through thermoset injection moulding. Using this method, the complete process can be automated. Simultaneously, the injection moulding technology allows complex geometries with near net shape in short cycle times of about two to five minutes. Thereby, this large-scale process offers a wide range of shot weights from a few mg up to 100 kg, also in multi-component technology. Also, several manufacturing steps can be omitted. This improves the reproducibility, and working in closed environments improves the employees’ health protection. Further process steps, like pyrolysis and silicon infiltration follow the state of the art. Although, this promising approach significantly shortens the fibres, the defined plastic processing is highly reproducible and generates similar mechanical properties like manual processes, due to the better fibre/matrix interaction in the plastic composite. In addition, continuous fibre preforms can be inserted to fulfil higher requirements.