A novel magnetic-field-driving method for fabricating Ni/epoxy resin functionally graded materials

A uniform magnetic field was applied to prepare Ni-epoxy resin functionally graded material (FGM) with gradient and anisotropy both in microstructures and resulting properties. By moving a magnetic field imposed on the green sample perpendicular to the field direction from one end to the other, Ni particles were driven by the field and distributed gradually in epoxy resin matrix. The gradient of light transmittance and electrical resistivity reflected the graded structures in Ni-epoxy resin composite. Furthermore, Ni particles aggregated to form chain clusters along the field direction, which produced anisotropic electrical properties in direction along and perpendicular to the chains. It has been clearly proved that the magnetic-field-driving method is a facile and effective attempt to prepare FGMs.