Efforts to produce microwave absorber materials that
are inexpensive
and environmentally friendly have become a means of greening the environment.
The breakthrough can be focused on industrial waste and natural materials
for functional purposes and how to enhance their performance. We successfully
synthesized nickel slag/laterite soil (NS/LS) and nickel slag/iron
sand (NS/IS) nanocomposites using a simple mechanical alloying technique,
and the electromagnetic (EM) wave absorption capacities of the nanocomposites
were measured using a vector network analyzer. The structural properties
of the nanocomposites were analyzed by X-ray diffraction spectroscopy,
where the results of the analysis showed that NS/IS has the largest
crystallite size (15.69 nm) and the highest EM wave absorption performance.
The optical properties of the nanocomposites were determined from
their Fourier transform infrared spectra using the Kramers–Kronig
relation. As determined through a quantitative analysis of the optical
properties, the distance between the longitudinal and transversal
optical phonon wavenumber positions (Δ(LO – TO) = 65
cm–1) is inversely proportional to the reflection
loss. The surface morphologies of the nanocomposites were analyzed
by scanning electron microscopy, and the particle diameters were observed
by binary image and Gaussian distribution analyses. The nanocomposite
surface exhibits a graded-like morphology, which indicates multiple
reflections of the EM radiation, consequently reducing the EM interference.
The best nanocomposite for an attenuated EM wave achieved a reflection
loss of −39.14 dB at 5–8 GHz. A low penetration depth
has implications for the electrical charge tuning of the storage and
composite magnets. Finally, the EM absorption properties of NS/IS
and NS/LS indicate a 2-mm-thick environmentally friendly nanocomposite
for EM absorption.