Studies on preparation and chemical stability of reduced iron particles encapsulated with polysiloxane nano-films

The soft magnetic composite of reduced iron particles encapsulated with polysiloxane shell was prepared by hydrolysis–condensation polymerization of tetraethylorthosilicate (TEOS) on the surface of iron particles. The structure, morphology, magnetic properties, and chemical stability of the polysiloxane coated iron particles were studied. The thickness of the shell was about 60 nm according to the results of transmission electron microscopy (TEM) and laser particle size analysis, while the mean diameter of the iron particle was 4.45 μm. The chemical stability of the soft magnetic composites was greatly improved, though its magnetic properties were declined a little. However, encapsulated iron particles are still useful in MR fluids as its magnetic properties are much better than other soft magnetic particles like Fe3O4, etc.