Preparation And Electromagnetic Response Properties Of Barium Titanate@Iron Core Shell Composites

Barium titanate (BaTiO3) particles with high dielectric constant, low dielectric loss and good stability are regarded as the most promising electrorheological materials. In this paper, BaTiO3 particles was used to prepare a new type of composite particle as core material, which was coated with Fe(OH)3 using the homogeneous coprecipitation method. BaTiO3@Fe3O4 and BaTiO3@Fe3O4/Fe core-shell composite particles were made by reducing the shell of BaTiO3@Fe(OH)3 composite particles. The inorganic-inorganic core-shell nanoparticle has excellent magnetic responsiveness and electric responsiveness. The structure, component, morphology, surface chemical elements, dielectric and magnetic properties of the core-shell composite particles have been characterized by SEM, TEM, XPS and impedance analyzer. Particles were dispersed into gelatin hydrogel elastomers cured with/without an electric, magnetic or electromagnetic field, and the difference of storage modulus of the elastomers suggests the particles'electro, magneto or electromagnetic response. Specific content as follows:1. BaTiO3@Fe(OH)3 core-shell structure particles were obtained using the homogeneous coprecipitation method on the surface of the BaTiCh particles with grain diameter of ?500nm. The BaTiO3@Fe3O4 and BaTiO3@Fe3O4/Fe core-shell structure particles were made by hydrothermal synthesis method through reducing the shell (Fe(OH)3) by a specific reducing agent.2. SEM and TEM images of particles showed that that the core and shell of composite particles were ?500 nm and 70 nm respectively. XPS was used tocharacterized the surface chemical elements of the metal on the core-shell composite particles. The magnetic properties of the composite particles were characterized by impedance analyzer, which show how good the magneto response of coated particles.3. In order to compare the response of the electric field, magnetic field, and electromagnetic field of the composite particles, the dynamic viscoelastic spectrum analyzer was used to investigated storage modulus of composite elastomer. The results show that the BaTiO3@Fe3O4/Te composite particles can respond to the electric field, magnetic field, and electro-magnetic field. The response of three particles can change according to the order of BaTiO3@Fe(OH)3< BaTiO3< BaTiO3@Fe3O4<BaTiO3@Fe3O4/Fe. It is indicated that BaTiO3@Fe3O4/Fe core-shell composite particle is a new multifunctional smart material responding to applied electric and magnetic field, and the electromagnetic response performance of BaTiO3@Fe3O4/Fe composite particles is obviously improved compared with bare BaTiO3 and BaTiO3@Fe(OH)3 particles.