Multilayered gradient Ti2AlC0.5N0.5 prepared by crystal/amorphous C diffusion for efficient electromagnetic absorption and thermal shielding

The unique advantages of surface/interface engineering are pivotal in advancing the design and development of high-performance electromagnetic wave (EMW) absorption materials. We present a universal microwave molten salt carbon (C) diffusion control strategy based on surface/interface engineering. This method leverages microwaves to promote the amorphous transformation and rapid diffusion of C on the carbon fiber surface, allowing for the rapid and controlled formation of three-dimensional multilayered gradient core-shell structures, primarily consisting of Ti₂AlC_0.5N_0.5 MAX. This unique structure with cavities contributes to the incident and multiple EMW losses. TACN-1 exhibited an efficient reflection loss of -83.4 dB at a thickness of just 1.9 mm and effectively isolates internal radiant heat, making it a promising material for stealth applications. This study not only advances the application of diffusion-controlled surface/interface engineering but also introduces a universal approach for modulating multilayered gradient structures in MAX phase ceramics.