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.