Preparation and properties of strontium hexaferrite/polyurethane magnetic coatings

Strontium hexaferrite nanoparticles (NPs) were prepared by co-precipitation of strontium and ferric ions in sodium hydroxide solution. The SrFe12O19 NPs were characterized by X-ray powder diffraction, transmission electron microscopy and vibrating sample magnetometer. SrFe12O19 NPs with perfect crystal structure, nanometer size, high saturation magnetization and coercivity were obtained. Afterwards, strontium hexaferrite nanoparticles were dispersed in polyester–polyurethane solution to prepare magnetic coatings (MCs) via solution blending. The magnetic and rheological properties of magnetic coatings were measured by Gouy magnetic balance and rotational rheometer, respectively. Furthermore, the mechanical, thermal properties and physical properties of magnetic films were also investigated. The results showed that magnetic films with superior mechanical properties could be obtained with the addition of 27 wt% magnetic powders.

► SrFe12O19 NPs with high saturation magnetization and coercivity were obtained.
► The magnetic coatings have good stability under magnetic field and gravity field.
► The thermal and mechanical properties of magnetic films were improved.