Geomagnetic Shielding Property and Mechanism of Fe–Ni Laminated Composite

Xiangyu Ma¹，Qiang Zhang¹，Xiang Chen^1,2，Gaohui Wu¹

1. School of Material Science and Engineering,Harbin Institute of Technology2. Department of Applied Science and Technology,Politecnico di Torino

摘 要：Ni layers were deposited on the two sides of pure Fe substrate by using electroplating to form Ni/Fe/Ni diffusion couple. After diffusion heat treatment, Fe–Ni laminated composite was obtained with Fe–Ni alloy/Fe/Fe–Ni alloy structure. The results indicate that the Fe–Ni layers combine well with the substrate and the Fe–Ni/Fe interface presents an interlocking microstructure with small-size grains. The concentration of element Ni in the Fe–Ni layer decreases from surface to interior exhibiting a gradient distribution. Geomagnetic shielding factor（SF） of Fe–Ni laminated composite can reach as high as 22.6, which is about seven times of that of pure Fe substrate. Mathematical equation of SF for laminated structure was derived according to magnetic circuit and resistance theory. The theoretical expression reveals that parameters such as the thickness and magnetic permeability of the shield material play an important role in the magnetic shielding behavior and the theoretical calculation results of SF coincide well with our experimental values.

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