Formation of porous Fe3O4/Ag composite by self-propagating combustion for lightweight and efficient microwave absorption

Due to the growing demands for radar stealth and electromagnetic pollution prevention, EM-waves absorbing materials with lightweight, broad bandwidth, thin thickness and strong strength are in high need nowadays. However, the achievement of both lightweight and efficient absorption still remains a challenge. In this work, the porous Fe3O4/Ag composites are successfully synthesized by a self-propagating combustion method, which has the advantages of simplicity, green and high yield. The magneto-electric synergy components and porous microstructure not only effectively reduces the density of the composites, but also significantly reinforces the absorption of EM waves. The sample with Fe3O4/Ag molar ratio of 4:1 attains the maximum reflection loss of −45.01 dB at the matching thickness of 1.85 mm and it can realize dramatical reduction of RCS signal by coating on the perfect electric conductor. The findings shed light on the promising application of the porous Fe3O4/Ag composites in the fields of environmental protection and military stealth.