Analyses on Structure and Magnetic Properties of Nanocrystalline Fe_(72)Si_(17)Al_(11) Alloy Powders

摘要

Fe_(72)Si_(17)Al_(11) ribbons prepared through melt-quenching were milled for 30, 70 and 90 h respectively. This process produced nanocrystalline powders with non-equilibrium solid solution of bcc a-Fe (Si, Al) and DO3 superlattice. The powders milled for 90 h were annealed at 300 °C for 1 h. Powders' profiles were analyzed by Scanning Electron Microscope (SEM). Microstructures were studied by analyzing the X-ray Diffraction patterns. Complex permeability in the frequency band of 0.5 to 8 GHz was measured by microwave vector network analyzer. Aspect ratios (>10:1) of as-milled powders were evaluated. DO_3 superlattice ordered phase appears in as-quenched ribbons. Grain size decreased from 27.2 to 7.9 nm with the time prolonged and internal strain decreased after annealing drastically. Imaginary part of complex permeability maintains high level near 4 GHz after annealing.