Wyniki wyszukiwania - BazTech

1

Influence of production technology on magnetic properties of nanocrystalline stacked and block magnetic cores

Świeboda C., Leszczyński J.

Przegląd Elektrotechniczny

|

2016

|

R. 92, nr 11

281--285

EN

Nanocrystalline soft magnetic materials are more and more commonly used in power electronic industry. New production techniques and different treatment methods are still developed and as a result new solutions are available. Two types of large nanocrystalline magnetic cores are proposed in the paper. First, nanocrystalline magnetic stacked core (NMSC) with distributed air gap. Second, nanocrystalline magnetic block core (NMBC) with a specific number of air gaps. Differences in cores construction and magnetic properties are presented.

PL

Materiały nanokrystaliczne są coraz bardziej powszechne w przemyśle energoelektronicznym. Opracowywane są co raz to nowsze technologie produkcji, czego rezultatem są nowe rozwiązania. W artykule przedstawiono dwa typy nanokrystalicznych rdzeni magnetycznych o dużych masach. Nanokrystaliczne rdzenie pakietowane (NMSC) z rozproszoną szczeliną powietrzną oraz nanokrystaliczne rdzenie blokowe (NMBC).

2

Transmission electron microscope studies on carbon nanostructured materials

Pawlyta M.

Archives of Materials Science and Engineering

|

2013

|

Vol. 63, nr 2

58--67

EN

Purpose: Carbon nanostructured materials are important and still not satisfactorily recognised products. Structure can be investigated with sufficient resolution using transmission electron microscopy but main difficulties are connected with low scattering of electrons by carbon atoms and destruction by knock-on damage caused by collisions of high energy electrons with specimen atoms. Design/methodology/approach: Scanning/transmission electron microscopy (S/TEM) deliver a chance to improve the quality of performed investigations. BF, DF and HAADF detectors were applied for various carbon materials: carbon nanotubes, nano-onions, nanodiamonds and graphitized carbon black. Findings: Obtained results confirmed the usefulness of applied microscopy techniques. Research limitations/implications: Sample preparation is crucial for performed investigations. Because of ionization damage caused by collisions of high energy electrons, results obtained with high-voltage TEM have to be analysed with caution, hence low-voltage electron microscopy is strongly recommended. Originality/value: New and not commonly used techniques were applied for carbon nanostructured materials studies. Advantages and disadvantages of them were compared.

3

Molecular Modelling of Stresses and Deformations in Nanostructured Materials

Szefer G.

International Journal of Applied Mathematics and Computer Science

|

2004

|

Vol. 14, no 4

541-548

EN

A molecular dynamics approach to the deformation and stress analysis in structured materials is presented. A new deformation measure for a lumped mass system of points is proposed. In full consistency with the continuum mechanical description, three kinds of stress tensors for the discrete system of atoms are defined. A computer simulation for a set of 105 atoms forming a sheet undergoing tension (Case 1) and contraction (Case 2) is given. Characteristic microstress distributions evoked by a crack propagation illustrate the mechanical problem considered.

4

Partially devitrified metallic glasses

Lachowicz H. K., Zaveta K., Ślawska-Waniewska A.

Journal of Technical Physics

|

2002

|

Vol. 43, no 4

527-542

EN

The paper presents a review of selected experiments which have been carried out using partially devitrified Fe- and Co-based metallic glasses as the research objects. It is shown that by a suitable choice of the composition of the metallic glass and also by the conditions of annealing, a variety of magnetic phases can be created in these systems. It is also shown that by controlled processes of annealing, the coercivity of metallic glass can be altered by several orders of magnitude, giving a possibility to produce materials with the extremely soft magnetic properties, up to the magnetically semi-hard ones. The magnetostriction of nanocrystalline materials of the FINEMET-type is discussed as well, showing that the size-dependent phenomena and the symmetry restriction at the particle boundaries create the surface contribution to the effective magnetostriction. Finally, the magnetic interactions between particles in partially devitrified samples are considered and the observed effects of temperature and hydrostatic pressure discussed.