Improving impedance matching of flaky carbonyl iron based on the surface modification by binary coupling agents

Abstract

In this paper, the impedance matching of the flaky carbonyl iron was improved by surface modification with binary coupling agents. The microstructure, phase and electromagnetic parameters were detected by scanning electron microscope (SEM), X-ray diffraction (XRD) and Agilent vector network analyzer, respectively. After binary coupling agent applied, the shape and particle size of the flaky CIP have changed significantly, whereas the phase remained α-Fe phase.On the other hand, with the addition of binary coupling agents, the complex permittivity of flaky CIP is reduced, which is beneficial to impedance matching. The doping with 2wt% calcium stearate and 2ml titanate to flaky CIP has a minimum reflection loss peak of −13 dB at the thickness of 2 mm. It is noted that the effective absorption bandwidth (RL<-10dB) is up to 0.8GHz (1.8~2.6GHz). Moreover, the magnetic tangent loss of the samples can be significantly improved by the addition of binary coupling agents. Therefore, the surface modification of binary coupling agent can make flaky CIP get better impedance matching and absorbing performance in S