Pre-ceramic polymer-derived open/closed cell silicon carbide foam: microstructure, phase evaluation, and thermal properties

摘要: The presented article describes a simple technique to fabricate open/closed cell silicon carbide (SiC) foams. SiC foams, especially pyrolyzed either at 1200 °C (PSiC_12) or 1500 °C (PSiC_15), offered the best thermophysical properties suitable for advance thermal management systems. Both PSiC_12 and PSiC_15 possessed almost equal concentrations of open closed pores (~22–24 vol%). On contrary, 1800 °C-pyrolyzed specimen (PSiC_18) had 40 vol% only ~9 vol% pores. X-ray Micro-CT observation also revealed that significant concentration having pore volume in range (2–20) × 10−4 mm3. While contained small β-SiC crystallites ~13-nm size, PSiC_18 ~55 nm α-SiC. From room temperature 1000 °C, conductivity values varied from 0.5 1.6 W/m K. these specimens outstanding oxidation resistance 1000 up 100 h. Extremely low conductivity, presence restricted inward diffusion oxygen even elevated temperatures, formation impervious oxide scale initial stage were key factors behind obtaining such excellent resistance. due much higher channel relatively (~3 W/m K), was found be exaggerated resulting few orders magnitude weight gain compared those obtained PSiC_15.