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.