Project Objectives

The nanocrystalline/nanostructured soft magnetic materials, as well as the methods used to their synthesis are very intensively studied in last decade. By anocomposite materials we try to combine materials with very different properties in order to obtain a new material which can cover the empty space uncovered by both component materials. Soft ferrites have low core loss in the high frequency region, but due to their low magnetic flux density, they have the drawback of requiring a large core. Electrical steel sheets and permeability alloys have high flux density and high permeability, but they cannot be used in the high frequency region due to excessive core losses. So, the nanocomposite powder cores are magnetic materials which cover the region where the former two magnetic materials cannot be used. The similar goal (but in other permeability-frequency region) could be obtain by combine high permeability of Supermalloy with higher resistivity of Rhometal composition in core-shell t
ype powders.

The proposed research aims to optimize the magnetic coupling and electrical resistivity by experimental researches on the structure and microstructure obtained in nanocomposite powders and sintered compacts. The realization of these objectives is the fruit of an interdisciplinary scientific work between specialists in physics and materials science and engineering.
The proposal project aim to answer to two objectives:

OBJECTIVE 1: Nanocrystalline/nanostructured powders and sintered compacts like Permalloy (Supermalloy)/Rhometal type.
This objective assumes the elaboration and study of: (i) the core-shell type powder, where core is a nanocrystalline Permalloy or Supermalloy particle surrounded by a thin layer (shell) of Rhometal, and (ii) the sintered compacts obtained from such powders by SPS. The results expected are the particles and compacts with a good permeability and higher resistivity compared to the Permalloy (Supermalloy) powders and compacts. This objective will be attained by three work packages, WP, each package being realized by different complementary tasks.

OBJECTIVE 2: (Me1Me2)Fe2O4/(Fe, Fe-Ni alloy) nanocomposite powders and compacts.
The main goal of the project will focus on the development of nanocomposite soft magnetic materials which could be used like magnetic cores at medium and high frequencies, but with higher magnetic properties than soft magnetic ferrites (see fig. 1). These activities will be fulfilled by four work packages with different complementary tasks: the WP 1 and 2 are dedicated to obtaining the (Me1Me2)Fe2O4/(Fe, Fe-Ni alloy) nanocomposite powders by two different ways and the other WP to obtain sintered compacts from powders and to study the magnetic coupling and electrical conduction in correlation with the structure and microstructure of the powders/compacts.