Preparation and Thermal Insulation Property of BCN-TiN Composite Aerogels by In-Situ Carbothermal Reduction/Nitridation Method.

Non-oxide ceramic aerogel draws increasing attention in area of thermal insulation because of its low density, high temperature resistance and good chemical/thermal stability. Here, a BCN-TiN composite aerogel was prepared by an in-situ carbothermal reduction/nitridation method, using melamine (C₃N₆H₆), boric acid (H₃BO₃), chitosan ((C₆H₁₁NO₄)_n) and titanium dioxide (TiO₂) as raw materials. The aerogel prepared at 1473 K showed a porosity high up to 97.6 pct with a density of 0.05 g/cm³. When testing at a temperature of 673 K, the thermal conductivity value of as-obtained composite aerogel was as low as 0.135 W/(m K). Moreover, the lightweight BCN-TiN aerogel had the high-temperature stability (at least 1473 K) and good compression strength, which ensures it a potential high-temperature insulation material in inert atmosphere. [ABSTRACT FROM AUTHOR]