Ternary borides Cr3AlB4: A novel material of layered structure for efficient broadband microwave-absorption

In this study, a novel MAB phase Cr3AlB4 was successfully synthesized and is, characterized by a layered microstructure that is created via a two-step reaction process. The Cr3AlB4 powders exhibit superior electromagnetic absorption performance, showcasing a minimum reflection loss of - 35.80 dB at a thickness of 1.4 mm, along with an effective absorption bandwidth spanning 5.6 GHz. The excellent electromagnetic wave (EMW) absorption properties of Cr3AlB4 can be ascribed to the synergistic interplay of dielectric and magnetic losses, which is determined by material attributes such as electrical conductivity, inherent defects, and paramagnetic qualities. Notably, the existence of a heterogeneous interface between Cr3AlB4 and Al2O3 impurities significantly promotes impedance matching and improves the microwave-absorption properties. Consequently, Cr3AlB4 emerges as a promising candidate in the realm of EMW absorption materials, offering substantial potential for achieving broad absorption profiles even at a small material thickness. This research expands the realm of possibilities for advanced broadband wave-absorbing materials.