Effect of degree of crystallinity on elastic properties of silicon carbide fabricated using polymer pyrolysis

In this study, silicon carbide (SiC) is fabricated using polymer infiltration and pyrolysis (PIP). Allylhydridopolycarbosilane (AHPCS) is used as the preceramic polymer. Final processing temperatures are varied to observe the change in microstructure as well as physical and mechanical properties. Density, porosity and thermal conductivity are determined as a function of processing temperatures. Microstructural characterization, done using atomic force microscopy (AFM) and X-ray diffraction (XRD), has revealed the presence of nanocrystalline domains with grain sizes in the range of 5-20 nm. The degree of crystallinity is determined using non-contact mode atomic force microscopy. The degree of crystallinity follows an increasing trend with processing temperature. Hardness and modulus are determined using nanoindentation, and are found to be influenced by the degree of crystallinity.