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Using Fe nanoparticles as raw material, we manufactured Fe16N2 nanoparticles by hydrogen reduction and ammonia nitriding process. X-ray diffractometer (XRD) and Mössbauer spectroscopy analyses show that the prepared nanoparticles are composed of Fe16N2 and $\alpha $ -Fe. The proportion of the Fe16N2 phase could reach 75%, and the saturation magnetization of the nanoparticles reaches 197 emu/g. The Fe16N2 nanoparticles are mixed with paraffin, and the microwave absorption properties of the composites are measured. The reflection loss (RL) of the Fe16N2/paraffin composite can reach −18.3 dB at 4.8 GHz, with a thickness of 2.2 mm. The ratios of the magnetic loss and dielectric loss are 40% and 59%, respectively. Only 1% (100%–40%–59%) of the incident microwave energy is reflected, which shows Fe16N2/paraffin composite is a potential candidate for microwave absorbing materials. [ABSTRACT FROM AUTHOR]

• The loss of electromagnetic energy in absorbers can be strictly classified into only two types: magnetic and dielectric loss. • The ratios of the two losses with respect to incident microwave intensity can be accurately evaluated. • The dependence of reflection loss on absorber thickness can be well explained with this method. • The proper coordination between dielectric loss and magnetic loss can enhance absorption and widen bandwidth With the increasing demand for high-frequency electronic devices in wide applications, microwave absorption materials of GHz have attracted extensive attention. In this paper, a new method is provided for quantitative analysis of energy dissipation in the microwave absorption materials. The loss of electromagnetic energy in absorbers can be strictly classified into only two types: magnetic and dielectric loss, and the ratios of the two losses with respect to incident microwave intensity can be accurately evaluated. Moreover, different materials were analyzed with the new method. Notably, both magnetic loss and dielectric loss were found to be important in Sm 1.5 Y 0.5 Fe 16.5 Si 0.5 /paraffin composite, which can consume up to 88% and 78% of the incident microwave energy under certain conditions, respectively. The fascinating combination of the magnetic loss and the dielectric loss well explained the peculiar two or three peaks in the reflection loss (RL) curves. This analysis method can be a powerful supplement for current theories to explain the microwave absorption property of materials, thus providing a new perspective for the design of high-performance absorption materials. [ABSTRACT FROM AUTHOR]