Tunable microwave absorption properties of Ni particles/carbon composites by calcination temperature

The problem of electromagnetic pollution is becoming more and more serious with the coming of the 5G era. The development of high-performance electromagnetic absorbing materials is an effective way to solve that problem. In this study, disposable gauze masks are used as raw materials to prepare Ni particles/carbon composites by impregnation process and subsequent calcination for microwave absorption application. Ni particle/carbon composites consist mainly of lamellar carbon and Ni particles. Ni particles in Ni particles/carbon composites are surrounded by graphite phase to form Ni/C core–shell structure. The strong RL of − 42.8 dB at 1.5 mm thick and an effective absorption bandwidth of 3.63 GHz are obtained from Ni particle/carbon composites calcined at 850 °C. This work provides a new idea for the application of disposable gauze masks.