Nanosized spinel ferrites MFe2O4 (M = Mn, Co, Ni, Cu, Zn)-coated flaky FeSiAl alloy composites were synthesized successfully. Nano-ferrites preferentially grow into nanoplatelets due to induced or restricted growth on the flaky surface of FeSiAl. With annealing temperature increasing, the ferrites' nanosheets thicken gradually and then grow into irregular particles. The annealing temperature not only affects the nanosized morphology and coating but also the magnetic properties of flaky FeSiAl composites. The saturation magnetization of CuFe2O4- or NiFe2O4-coated FeSiAl is approximate 69 emu/g, where the value of MnFe2O4-, CoFe2O4- and ZnFe2O4-coated FeSiAl show a decreasing trend generally from 64 emu/g to 55.7 emu/g annealing at 800 °C, respectively. The saturation magnetization of flaky FeSiAl composites was improved with the increased annealing temperature, except for those coated with ZnFe2O4 and NiFe2O4. These results are useful for improving the comprehensive properties of ferrite-coated flaky FeSiAl alloy composites.
Keywords: co-precipitation; flaky FeSiAl; magnetism; nanosheet; spinel ferrite.