Synthesis and Characterization of Carbon Fiber‐Reinforced Silicon Carbide Composites with an Interlayer of Amorphous Carbon Thin Film Prepared by Precursor Infiltration and Pyrolysis Processes

Abstract

This study conducts a whole precursor infiltration and pyrolysis (PIP) process in order to fabricate carbon fiber‐reinforced silicon carbide matrix (Cf/SiC) composites. Carbon fibers are pre‐treated by depositing a pyrolytic carbon thin film (PyC) via the PIP process, with a phenol‐formaldehyde resin blended with polyvinyl butyral being used as the PyC precursor. Polycarbosilane, the precursor of the SiC matrix, is synthesized via Yajima‐type reaction. Divinylbenzene and SiC powders are used as the crosslinking agent and the additives, respectively, to control the density of the composites and reduce the PIP times. By repeating the PIP process twice in the formation of the PyC interlayer and ten times in the formation of the SiC matrix, a density of ≈1.8 g cm−3 is achieved for the Cf/SiC composite, in addition to a porosity and shrinkage of <5% and ≈10%, respectively. This composite material's bending strength can reach as high as 215.5 MPa, and its minimum coefficient of thermal expansion α is 1.90 × 10−6 K−1. The authors propose a production process in which PIP is used for the entire process, thus making it suitable for use in the production of large‐scale and structurally complex products without using vapor deposition techniques under vacuum.