A Novel Composite Material Designed from FeSi Powder and Mn 0.8

A design of the novel microcomposite material composed of spherical FeSi particles and Mn0.8Zn0.2Fe2O4 ferrite is reported together with a characterization of basic mechanical and electrical properties. The sol-gel autocombustion method was used for a preparation of Mn0.8Zn0.2Fe2O4 ferrite, which has a spinel-type crystal structure as verified by XRD and TEM analysis. The final microcomposite samples were prepared by a combination of the traditional PM compaction technique supplemented with unconventional microwave sintering process of the prepared green compacts. The composition and distribution of the secondary phase formed by the spinel ferrite were examined by SEM. It is demonstrated that the prepared composite material has a tight arrangement without any significant porosity, which manifests itself through superior mechanical properties (high mechanical hardness, Young modulus, and transverse rupture strength) and specific electric resistivity compared to the related composite materials including resin as the organic binder

Formation of Effective Non-ferromagnetic Barrier in Fe/MgO Soft Magnetic Composite

Soft magnetic ferromagnetic/insulator composites are complex objects in terms of structure and magnetic properties. They depend on many different parameters, among which one of the main ones is the amount of insulator. In this work, the effect of MgO content on magnetization processes in Fe/MgO composites is studied in detail by using a wide combination of properties and structure analysis methods. Several series of samples with content steps up to 0.1 wt % were prepared using standard powder metallurgy operations such as dry mixing, cold pressing, and sintering. The study demonstrates that the evolution of Barkhausen noise with increasing MgO content is not systematic. The second phase acts as an effective barrier to magnetic interaction between neighboring Fe particles only after reaching a certain point, which was found to be about 0.9% wt. Some other properties (coercivity, permeability, elastic properties) also demonstrate nontrivial composition dependence. To reveal the causes of the observed phenomena, the structure of the composites was studied in detail, and it was shown that with an increase in the MgO content in the range of 0.8–1%, a change in the mechanisms of structure formation occurs, which, in turn, affects the properties. The presented results provide insights into developing advanced soft magnetic composites with an optimal combination of a ferromagnetic powder and an insulator

Make EU trade with Brazil sustainable

Brazil, home to one of the planet's last great forests, is currently in trade negotiations with its second largest trading partner, the European Union (EU). We urge the EU to seize this critical opportunity to ensure that Brazil protects human rights and the environment