Effects of silicon content on properties of gas-atomized Fe-Si-Cr powders
Fe-Si soft magnetic composites, SMC have some advantages such as excellent dc current superimposed permeability and low core loss over ferrite and Fe-Si bulk cores.
Effects of Ordering on the Magnetic Properties of Gas-Atomized Fe–Si–Cr Powders
Fe–9%Si–2%Cr powder was gas-atomized and then annealed in order to investigate the effects of DO3 and B2 ordered phases on high-frequency permeability of the powder. The B2 phase is formed during the atomization process. The DO3 phase began to form at 450 °C and grew rapidly when annealed at higher temperature as confirmed by X-ray diffractometer, whereas the existence of the DO3 phase in the as-atomized powder could be confirmed by electron transmission microscope. With the increase in the temperature, the average lattice parameter and the coercivity decreased. There was an abrupt increment of the coercivity in the powder annealed at 450 °C. Highest permeability could be obtained in the powder annealed at a relative low temperature of 150 °C and then the permeability real decreased with the temperature. The behavior of the coercivity and the permeability with the temperature could be successfully explained by the formation of the DO3 ordered phase and the change of the electrical resistivity.
Kinetics of antiphase domain growth
Abstract The antiphase boundary, APB, energy was recalculated, indicating that, in the B2 superlattice, it is even more isotropic than previously believed. High vacancy concentrations at APB were also analyzed with respect to their positional energy at the boundaries as compared to that in the perfectly ordered crystal. Finally, the motion of APB in β brass has been analyzed with particular emphasis placed upon the geometrical constraints imposed on atom movement by the superlattice. Two cases were considered, the shrinking of an isolated spherical domain, and the flattening of wavy APB. The former is associated with a parabolic rate law similar to that of grain growth in pure metals. The latter is extremely sensitive to the amplitude and period of the boundary.