Magnetic Properties of Nickel‐Plated Carbon Fiber Composites and Equivalent Model for the Magnetic Permeability Tensor

ABSTRACT With the development of magnetic multifunctional composites, precise control of material magnetic properties has become increasingly important. Relative magnetic permeability is the most fundamental and critical parameter for evaluating magnetic materials. The equivalent magnetic permeability of fiber composites is typically estimated based on the volume fraction of components and their physical properties. Existing classical models often rely on assumptions such as uniform fiber distribution and the absence of magnetic interactions, thereby exhibiting certain limitations. Currently, there is no suitable model for predicting the equivalent magnetic permeability of nickel‐coated carbon fiber composites. This study investigated the magnetic behavior of nickel‐coated carbon fibers and two types of composites. The effects of magnetic anisotropy, fiber volume fraction, and fiber crimping on the magnetic properties of nickel‐coated carbon fiber composites are analyzed. Based on this, a modified mixture rule model considering fiber crimping and demagnetization factors was proposed. The results indicate that this model can accurately predict the magnetic anisotropy behavior of the composite, with prediction accuracy higher than that of the commonly used mixture rule and Maxwell–Garnett theory models.