Preparation and Microwave Absorbing Properties of an Electroless Ni-Co Coating on Multiwall Carbon Nanotubes Using [Ag(NH3)‎2]+ as Activator

Abstract EN

Ni-Co-coated carbon nanotubes (CNTs) composites with different molar ratios of Ni/Co were synthesized using [Ag(NH3)2]+ as activator and H2PO2- as reductant, thereby replacing the conventional noble metal Pd salt activator and Sn2+ reductant.

Scanning electron microscopy, X-ray diffraction, and X-ray energy dispersive spectrometry analyses demonstrated that the CNTs were deposited with a dense, uniform Ni-Co coating.

The possible mechanism of the electroless method was studied, which indicates that pure Ag0 acted as a nucleation site for subsequent Ni-Co-P deposition.

Network vector analyzer measurements indicated that the composite with only Ni coated had an absorbing value of −12.6 dB and the composite with a Ni/Co ratio of four had the maximum wave absorption (−15.6 dB) and the widest absorption bandwidth (800 MHz, RL < −10 dB), while the saturation magnetization (Ms) was 4.28 emu·g−1 and the coercive force (Hc) was 31.33 Oe.