Effect of Silanization on the Magnetic and Microwave Absorption Properties of SrFe12O19 Nanostructure Particles

Strontium ferrite nanostructure particles (SrFe12O19), which have a ferrimagnetic nature, were synthesized by a co-precipitation process of chloride salts using a sodium hydroxide solution. The resulting precursors were heat-treated in a furnace at 1100°C for 4 h. After cooling in the furnace, the nanostructure particles were silanized using 3-methacryloxypropyltrimethoxy silane molecules. After applying the silane pretreatment to the surface of the nanoparticles, we studied the effects of the most influential silanizing parameters, including the silane concentration and hydrolyzing time, on the magnetic and microwave absorption properties of the samples. The hysteresis loops showed an optimum saturation magnetization of 0.065T for 1 h hydrolyzing time at 1.25 wt.% silane concentration; however, no change was detected in the coercivity by varying the two factors. The powders with optimum magnetic properties were used to manufacture the samples in order to study the microwave absorption properties. Employing silanized nanostructures resulted in a significant increase in the reflection loss (at the resonance frequency) from − 16 dB up to − 72 dB.