Preparation and microwave absorption properties of basalt fiber/nickel core–shell heterostructures

Basalt fiber/nickel core–shell heterostructures with different thicknesses of nickel shells are fabricated successfully. The electromagnetic parameters of basalt fiber/nickel-paraffin composites ranging from 8.2 to 12.4 GHz (X band) are measured for investigating the microwave absorption properties. The electromagnetic parameters of basalt fiber/nickel are several times higher than those of naked basalt fibers due to the formation of the core–shell interface. The measured results indicate that effective electromagnetic match is realized in the whole X band. The values of complex permittivity and permeability of basalt fiber/nickel increase monotonically with the increasing thicknesses of the nickel shells. It is interesting that the reflection loss of basalt fiber/nickel do not show the monotonic character with the increasing thicknesses of the nickel shells. The basalt fiber/nickel with the nickel shell thickness about 300 nm shows the strongest reflection loss. The value of reflection loss is more than 15 dB in the whole X band and reaches 40 dB at 8.9 GHz, while the naked basalt fibers hardly exhibit any microwave absorption. The excellent microwave absorption properties of the basalt fiber/nickel core–shell heterostructures are attributed to the good electromagnetic match between the dielectric loss and magnetic loss.