Microstructural and high-temperature performance evolution of Al-doped lamellar porous Ti3SiC2 using freeze casting

To enhance high-temperature oxidation resistance, Al was introduced into lamellar porous Ti3SiC2, reducing wall porosity from 16% to 7%, signifying wall densification. DFT calculations revealed that Al substitution for Si in the silicon layer caused lattice distortion, raising lattice parameter (d) from 0.2278 to 0.2289 nm, and disrupting energy, weakening bonds and reducing fracture energy absorption. Consequently, diffusion activation energy dropped from 370 kJ/mol to 230 kJ/mol, significantly impacting high-temperature stability. Yet, Al doping improved wall and oxide film densification, lowering the oxidation rate from 0.0097 to 0.0073 mg2/cm4 & sdot;h, leading to remarkable high-temperature electromagnetic shielding with SSE of 71.1 dB.