Porous Nano-SiC as Thermal Insulator: Wisdom on Balancing Thermal Stability, High Strength and Low Thermal Conductivity

Abstract

We herein show that by integrating nano-scale phonon-scattering mechanisms, such as interfaces and stacking faults thermal resistances in porous nano-SiC, this outstanding material (with intrinsic very high thermal conductivity) could demonstrate promising thermal insulation property. Porous nano-SiC prepared at 1,500°C exhibits a specific balanced mechanical strength (compressive and flexural strength are 26 and 13 MPa, respectively, with 57% porosity) and extremely low thermal conductivity (2 W m−1 K−1 at 300 K); and sample sintered at 1,800°C shows excellent mechanical strength but relatively high thermal conductivity. Our work reports the novel low thermal conductivity of porous nano-SiC for the first time.