Abstract
An Fe–Al multilayer alloy plate was designed and fabricated using hot-dipping aluminium plating at 800°C for 150 s and the diffusion alloying process at 900°C. A multilayer structure of the Fe–Al intermetallic alloy, including Fe2Al5, FeAl2, FeAl and α-Fe (Al), was formed on the surface of a pure iron substrate. After annealing, Fe2Al5/substrate/Fe2Al5 diffusion couples became Fe2Al5/FeAl2/FeAl/α-Fe(Al)/substrate/α-Fe(Al)/FeAl/FeAl2/Fe2Al5. The Al content decreased from surface to centre and showed a gradient distribution. The geomagnetic shielding factor of the Fe–Al multilayer alloy plate was 23·6, about seven times as high as pure iron. The excellent shielding effectiveness was ascribed to the structure of soft magnetic alloy layer/substrate/soft magnetic alloy layer.