Effect of nickel shell thickness of Ni-microsphere on microwave absorption properties of Ni-microsphere@MWCNTs hybrids

Magnetic nickel microspheres with core–shell structure were synthesized via depositing nickel metal on the polystyrene (PS) microspheres surface by the method of chemical platting, which were used to assemble a multiple-loss absorbers hybrids of Ni@MWCNTs. The nickel shell thickness of Ni-microspheres was controlled via regulating the platting solution concentration of nickel sulfate solution. XRD analysis indicated that the Ni@MWCNTs hybrids still retained the crystal structure of MWCNTs and nickel metal. The SEM results showed that the nickel shell thickness of Ni-microspheres was effectively regulated by altering the plating solution concentration. When the plating solution was 24 g/L, 12 g/L and 6 g/L, the nickel shell thickness of Ni-1, Ni-2 and Ni-3 microspheres were 55 nm, 45 nm and 20 nm, respectively. While the nickel shell thickness of Ni-2 microspheres was 45 nm, the Ni-2@MWCNTs hybrids presented the best microwave absorption (MA) property. At 11.20 GHz, the minimum reflection coefficient (RC_(min)) value was −40.65 dB and the bandwidth of RL < -10 dB was 3.6 GHz, while the RC_(min) of Ni-1@MWCNTs and Ni-3@MWCNTs were −17.83 dB and −27.52 dB, respectively. The results demonstrated that the nickel shell thickness of Ni-microspheres had a meaningful influence on the MA performance of Ni@MWCNTs hybrids.