Preparation and properties of carbonyl iron/Al_2O_3 core-shell composite particles

The carbonyl iron/Al_2O_3 core-shell composite particles with different morphologies of nanoshells were prepared and the influences of the Al_2O_3 nanoshell morphologies on the properties of the carbonyl iron/Al_2O_3 core-shell composite particles were investigated.The results show that the shell morphologies of the carbonyl iron/Al_2O_3 core-shell composite particles strongly depend on the species of acid and pH value.Compared to the carbonyl iron particles,the anti-oxidation property,microwave electromagnetic parameters and mechanical properties of the composite particles are significantly improved, and the particles,uniform,compact and grain-like Al_2O_3 nanoshells are beneficial to improving the anti- oxidation property and decreasing permittivity with the retention of permeability,while fiber-like Al_2O_3 nanoshells are more advantageous to improving the interface compatibility between the particles and the matrix of the polymers,resulting in obvious increase of mechanical properties of their based absorbing coatings.