Heat insulation materials are an important part of the thermal protection system (TPS) of hypersonic aircraft.
In recent years, high-entropy ceramics have low thermal conductivity due to their phonon scattering caused by multi-component and twisted lattice, which has attracted great attention in the field of thermal insulation.
Among the various options available, porous high-entropy carbide (PHEC) ceramics have become promising candidates for TPS due to their inherent characteristics such as high melting point, excellent high temperature stability, low density and excellent thermal insulation properties.
, Photo source: The journal Advanced Ceramics.
Generally, porous high-entropy carbide ceramics are manufactured using various methods, such as templating, direct foaming and partial sintering.
In order to synthesize these ceramics, metal carbides or oxides are usually used as starting materials, using a solid-state method.
This requires a lot of grinding to disperse the various components and extremely high processing temperatures to accelerate the diffusion of atoms.
, However, this method consumes a lot of energy, and impurities will be introduced during the ball milling process, destroying stoichiometry and affecting the configuration entropy.
high-temperature sintering leads to grain growth and the disappearance of nanopores, making it difficult to control the porosity and pore structure of PHEC ceramics.
in addition, this solid phase method also limits the formation and processing of high-entropy carbides.
Return to the first electric network home page>,.
