Hyperwide band electromagnetic wave absorbing Al2O3 coating boosted with in-situ generated nano TiO1.81

Abstract No choice but to choose the dielectric loss type materials for realizing the high temperature electromagnetic (EM) wave dissipation is well acknowledged, as the magnetic EM wave absorbing materials generally have functional failure above 600°C ¹. However, the electromagnetic wave absorption bandwidth (EAB) of current dielectric loss type materials is too narrow. Here, we invented one TiO1.81/Al₂O₃ coating characterized with the twice of the widest EAB reported among all the current dielectric loss type materials. The simple fabrication process is composed of the supersonic atmospheric plasma spraying (SAPS) of Ti₂AlC/Al₂O₃ powders and following oxidation at 950°C for 2 h in air. The occurred in-situ double decomposition mechanism transformed Ti₂AlC (45 µm) into O-vacancy-defected TiO1.81 (30 nm). The interfacial polarization contribution was suddenly boosted due to the appearance of a huge amount of nano hetero-interfaces. The continuous outwards diffusion of Ti and Al elements further endows our coating self-protective capacity through the formation of covered TiO1.81 and Al₂O₃. As MAX phase contains more than 90 categories, our work supports one open window for fabricating superior EM wave absorbing coatings used in high temperatures.