Crystalline-amorphous Ni3P@Nix(POy)z core–shell heterostructures as corrosion-resistant and high-efficiency microwave absorbents

Abstract The search for high-efficiency and anti-corrosive microwave absorption (MA) materials plays a paramount role in improving the environmental adaptability and survivability of military targets in the harsh chemical conditions. However, it still faces huge challenges and lacks systematic research. Herein, a well-designed heterostructure composed of crystalline Ni3P core and amorphous Nix(POy)z shell was successfully fabricated through a facile annealing and thermal phosphating strategy. Electrochemical analysis demonstrated that the Ni3P@Nix(POy)z heterostructures delivered strong corrosion resistance in acid, alkaline, and salt environment owing to the presence of surface amorphous Nix(POy)z layer. Meanwhile, crystalline Ni3P/amorphous Nix(POy)z interface could trigger intensive interfacial polarization relaxation to strengthen microwave attenuation. Furthermore, abundant lattice defects, polar Ni-P bond, decreased band gap and intrinsic magnetism of Ni3P crystal endowed the Ni3P@Nix(POy)z heterostructures strong reflection loss (−43.1 dB), moderate absorption bandwidth (3.0 GHz) and ultra-thin thickness (1.3 mm). This work may provide an insight into the evaluation and development of corrosion-resistant microwave absorbents.