Estimation of Magnetic Anisotropy in Ferromagnetic Elements and Their Alloy Powders by the Law of Approach to Saturation (LAS)

Abstract

This thesis work proposes to characterize the magnetic properties of elemental ferromagnetic powders (Fe, Ni, and Co) and their alloys, evaluate them by the law of approach to saturation, and establish correlations between magnetic anisotropy constant (K) of the alloy powders and their constituent elemental powders. The characterization of their magnetic properties, their dependence on temperature and milling time, the effect of shape anisotropy will be investigated.

The curve fitting of experimental data of magnetization (M) vs. the applied field (H) to several variants of the law of approach to saturation will be analyzed. The dependency and effect of different parameters in the equations and their fit based on statistical linearity, variations to the known MS values from the M-H curves as well as known trends based on variations in temperatures are studied to infer the behavior of the material in the high field region.

The first order magnetocrystalline anisotropy constant (K1) was estimated for the elemental powders and their alloys. A correlation between the anisotropy constant (K1) of the elemental powders and their alloys was established. The dependence of magnetic anisotropy on composition, temperature and milling time is studied. The findings are likely to establish quality control of magnetic alloy powders in additive manufacturing.