Synthesis and characterization of nickel coated exfoliated graphite for microwave absorber applications

Microwave absorbing material of nickel coated exfoliated graphite (Ni-EG) was prepared by electroless deposition in alkaline coating bath.  The coating time, which is an important factor to achieve good coverage of Ni particles over exfoliated graphite (EG), was properly controlled during the process. Morphology and phases of Ni-EG were investigated by means of SEM and XRD, respectively. Electromagnetic (EM) properties of Ni-EG/epoxy composites were recorded using VNA over the frequency range of 2-18 GHz. Ni-EG/epoxy composites exhibit significant microwave absorption properties for coating time 10, 20, 30 and 40 minutes. Specially, reflection loss value reached -23.7 dB at 10.9 GHz with 6.0 GHz (8.1-14.1 GHz) and 2.0 GHz (10.1-12.1 GHz) of -10 and -20 dB absorption bandwidths, respectively for 40 minutes of deposition time. Therefore, the proposed material has a great potential for stealth applications. Copyright © 2016 VBRI Press.