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I am working on tuning thermal conductivity of porous SiC ceramics with additives for thermal energy application. SiC ceramics have been applied as high temperature structural material for decades due to its superior thermal stability, corrosion resistance and so on. Generally, SiC is a material with high thermal conductivity of 100-350 W/(m・K) depending on the fabrication process and purity. However, by introducing pores or additives, the thermal conductivity of SiC ceramics will become more adjustable. Porous SiC ceramics with high thermal conductivity are potential candidate for heat exchanger and solar receiver, and those with low thermal conductivity are expected to be applied as thermal insulators, thermal energy storage material and thermoelectric material. Therefore, porous SiC ceramics have received great attention for thermal energy application.

So far, my work has been focusing on investigating the effect of aluminum and boron additives on porous SiC ceramics. There are several factors that will affect the thermal conductivity of ceramics: porosity, grain size, crystalline defects, grain boundary phases etc. I am trying to clarify what is the main factor that will dominate the thermal conductivity of porous SiC ceramics with aluminum and boron additives. Porosity might seem like an important factor to dominate the thermal behavior of porous SiC ceramics, but the unique morphology of hexagonal platelets produced by aluminum and boron addition must provide some degree of impact on the thermal conductivity. Besides, the addition of aluminum and boron themselves may also serve as crystalline defects in SiC lattice by forming solid solution. By clarifying the main factor, the mechanism of thermal conductivity of porous SiC ceramics with additives can be establish and expand the range of thermal energy application.

Ying CHUNG

chung.y.aa@m.titech.ac.jp 

Department of Materials Science and Engineering

School of Materials and Chemical Technology

Tokyo Institute of Technology

Japan