Design Parameters for Nanostructured Soft Magnetic Alloys

Improving soft magnetic properties in FINEMET-like alloys. A study

“…Our studies are based on an average anisotropy model that takes into account the random anisotropy model for the magnetocrystalline anisotropy [2] and the uniaxial anisotropies such as magnetoelastic and field-induced ones. A greater understanding of the subject can be found in [2,3] and a brief summary in [1]. Here, we write the equations used in the present work and the corresponding constants without going into details.…”

“…A small grain size, of the order of tens of nanometers, is the key to their good properties and, often, the addition of these elements was conducted for this purpose neglecting other important features. In a previous work [1], we have discussed the parameters to design nanocrystalline soft magnetic materials such as FINEMET, NANOPERM, HITPERM and NANOMAT types and the effect of some alloy elements on them. In order to do this, we have modeled the theoretical behavior of the coercive force, H c , with the crystalline fraction, m cr , of the nanocomposite materials taking into account some material parameters, like the grain diameter, D, the magnetocrystalline constant, K 1 , the crystalline and amorphous magnetostriction constants, k am and k cr , respectively, the internal stresses, r i , and m cr , which act in magnetocrystalline and uniaxial anisotropies according to models in literature.…”

“…5 Si 13.5 B 9 Cu 1 Nb 3 ), they present a clear minimum in the H c (m cr ) curve that can be exploited to soften the material. In this work, we go deeper into previous research focusing our attention on FINEMET-like nanocrystalline systems, analyzing the origin of this minimum, studying the magnetic effect of some solutes on the crystalline phase (compiling several charts from literature) and the behavior of the magnetostriction constant of the amorphous matrix with the crystallized fraction, which improving the results obtained in [1]. The theoretical results are first compared with a whole series of a Fe 73.5 Cu 1 Nb 3 Si 22.5Àx B x alloys from literature validating the model, and the effect of Ge, Al, Co and Ge + Al on the a-Fe (Si) phases are discussed.…”

Влияние температуры продолжительного отжига на структуру и магнитные свойства нанокристаллического сплава FeSiNbCuB

“…2. Увеличение коэрцитивной силы при увеличении температуры отжига наблюдалось ранее, например, в работах [8,44,60].…”

A simple method for determining the lattice parameter and chemical composition in ternary bcc-Fe rich nanocrystals

“…In some other works, having the necessary data to determine the chemical composition, it is not reported due perhaps to the lack of a tool for this purpose (for example, [8] in bcc Fe-Si-Al and [9] in bcc Fe-Si-Ge nanocrystals). In previous works [10][11][12], we already employed these two techniques to approach the chemical composition of Fe-Si-Ge and Fe-Si-Al nanocrystals. In this work, we present some theoretical lattice parameter charts in the Fe-rich regions of the Fe-Si-Al, Fe-Si-Ge, Fe-Al-Ge, Fe-CoSi, Fe-Co-Al, and Fe-Co-Ge ternary systems in order to validate the work previously performed by analyzing their structure based on phase diagrams and comparing the results obtained from these charts with experimental results in literature.…”