Magnetic Properties Of Metals Research Articles

Nondestructive Testing of Metal Cracks: Contemporary Methods and Emerging Challenges

There are high demands for the early and reliable detection of metal components used in safety-critical structures. Nondestructive testing (NDT) is a pivotal technique used across industries to assess a material’s integrity without causing damage and has been used in early crack detection of metals, mainly based on changes in the crystal structure and magnetic properties of metals. This review provides an overview of internal and external detection technology based on nondestructive testing methods such as ultrasonic, electromagnetic, ray, magnetic particle, etc. Especially, the integration of advanced methodologies such as machine learning and artificial intelligence deserves a place in NDT methods. Furthermore, the multifactorial detection method is promoted to enhance the sensitivity and detection range due to advantage integration but still has emerging challenges for safer equipment and applications. The review aims to compare these methods and outline the future challenges of NDT technologies for metal crack detection.

Magnetic control of structural changes in structural steels during plastic deformation

The analysis and consideration of the influence of the main factors on the damage of welded metal structures during long-term operation. The relationship between the strength of the magnetic field of the Hр scattering and structural changes in structural steels that occur during cold plastic deformation to different degrees is established. It is shown that at small degrees of deformation, the change in the magnetic parameter Hр is large. As they increase, the HP value decreases and tends to the values of the Earth's magnetic field. The data of microstructural analysis of the metal of structural steels are in good agreement with the results of the passive ferrosonde method of control. A method for evaluating the effect of cold plastic deformation on the magnetic properties of metal in structural steels has been developed.

Effect of lattice vibrations on magnetic properties of metals at finite temperatures

We investigate the effect of electron-phonon interaction in the dynamic spin-fluctuation theory of metallic magnetism. Electron-phonon interaction is represented by fluctuations of the crystal lattice potential. We illustrate the theoretical results in the example of Fe and Ni. We show that the effect of phonons on temperature dependence of magnetic characteristics is appreciable in Fe, but not as large as in the static single-site spin-fluctuation theory and spin dynamics using classical Hamiltonians. On the contrary, in Ni the effect of phonons is small in agreement with the results of the spin dynamics.

Cu phthalocyanine, Cu and Fe@Au nanoparticles grafted polyethylene: From structural to magnetic properties

Structural and magnetic properties of metal (Cu and Fe@Au) nanoparticles and phthalocyanine grafted on plasma activated ultra-high-molecular weight polyethylene (PE) are reported. Plasma treatment alters surface morphology, charge and creates polar groups on PE surface, which affects values of contact angle. X-ray photoelectron spectroscopy and electrokinetic analysis proved successful binding of all grafted magnetic compounds. Morphological changes after each modification step were monitored by atomic force and scanning electron microscopies. SEM images revealed homogeneous distribution of BPD and agglomerates of Fe@AuNP-BPD on plasma treated PE surface. Electron paramagnetic resonance spectra captured at 300 K confirmed successful binding of the CuPc and NPs at the radicals or BPD sites with a specific signal shape for each type of the grafted material.

Magnetic Properties of Metal - Polymer Composites for Ac Applications at High Frequencies

This paper presents the soft magnetic properties of the Fe-, Ni-, Co- and Fe-Co-Ni polymer composites. The composites were ob-tained with Fe, Ni and Co powders (99.9% purity) with particle sizes of 150, 10 and 2 mm, respectively. Ring-shaped samples were ob-tained using uniaxial compaction at 91 MPa. The Fe-Co-Ni-polymer composite has the highest value of the magnetic permeability (μ=54) at 107 Hz and saturation magnetization (Ms=10000 Am2Kg-1) higher than the Ni-polymer composite (4100 Am2Kg-1).

Alumina Composites with Metal Particles in Ceramic Matrix

Ceramic–metal composites are an important group of materials for many applications due to their unique properties. The combination of the hardness, strength at high temperatures, chemical inertness of ceramics with ductile, electrical or magnetic properties of metal are not achieved in single-phase materials. However, the brittleness of ceramics is the main disadvantage, which is limiting the under stress performance of ceramics and ceramic matrix composites. Theoretical and experimental research is still concentrated on improving the fracture toughness by tailoring the microstructure of composites. The study of metal particles embedded into ceramic particles, their distribution, size, and the interfaces and their influence on mechanical properties of the composites are presented. The important role of production techniques is emphasized. Based on experimental results, the Al2O3–Ni system is discussed.

Experimental and theoretical study of photoluminescence and magnetic properties of metal–organic polymers based on squarate and tetrazolate moieties containing linkers

Cd2+, Zn2+ or Co2+ based luminescence and magnetic properties of isostructural metal organic chains.

Effect of the structure and stress state on the magnetic properties of metal in different zones of welded pipes of large diameter

The existence of an extensive network of main pipelines, both already operating and being constructed, which are exploited under complex climatic conditions, specifies the need for the development of methods of a nondestructive control for testing the current state of both the pipes themselves and the welded joints in the process of manufacture and subsequent service. In this work, we give the results of microstructural studies, as well as the mechanical and magnetic properties of different zones of welded joints (base metal, heat-affected zone, and the weld) of pipe steels of the strength classes X70 and X80 produced using the method of controlled rolling. The influence of different modes of loading on the magnetic characteristic of the metal of all three zones of welded joints has been investigated. The magnetic parameters that unambiguously characterize changes in the stress-strain state of the separate zones of the welded joint (weld, heat-affected zone, base metal) have been determined in certain ranges of the applied stresses.

Effect of surface modification on dielectric and magnetic properties of metal powder/polymer nanocomposites

Metal nanopowder (Co and Fe)/polymer composites, both with and without surface modification by behenic acid, were fabricated and their dielectric and magnetic properties were measured at 1 GHz to study the effect of surface modification on the electromagnetic properties. The relative permittivity and the real part of the permeability of the composites with surface modified powders were higher than those with unmodified powders. Related dielectric losses remained at almost the same level, but magnetic losses were somewhat increased. The increase of relative permittivity could result from the increased volume fraction of interphase with a slightly higher relative permittivity at the particle/polymer interface than that of the bulk polymer. The increase in the real part of the permeability may be caused by suppression of the induced demagnetizing field due to suppression of eddy currents by a better particle distribution and a decrease in effective agglomerate size because of the surface modification.

Electronic and Magnetic Properties of Metal−(4,4′-bipyridine) Sandwich Complexes and Their Nanowires

Using calculations based on density functional theory, we have investigated the geometric, energetic, and magnetic properties of complexes of 4,4'-bipyridine (BPY) with metal atoms M (= Li, V, and Ti). The systems of interest include BPY-M(2) and BPY(2)-M(2) complexes and (BPY-M(2))(x) nanowires in which the sandwich structure is stacked infinitely along one direction. For each of these systems, a detailed analysis was performed on the electronic structure. First, we found that BPY-M (M = V and Ti) binding is stronger than BPY-Li binding because of the covalent nature of the former interaction. The difference in the magnetic properties of BPY-M(2) and BPY(2)-M(2) (M = V and Ti) complexes can be understood in terms of the different strengths of the M-M interactions mediated by d(M) or sd(M)-hybridized orbitals. Second, we found that the (BPY-Li(2))(x) nanowire is a semiconductor, whereas (BPY-V(2))(x) and (BPY-Ti(2))(x) nanowires are magnetic metals due to the spin-polarization in d(z)2(M)-derived bands.

Syntheses, Crystal Structures, and Magnetic Properties of Metal−Organic Hybrid Materials of Cu(II): Effect of a Long Chain Dicarboxylate Backbone, and Counteranion in Their Structural Diversity

Eight new metal-organic hybrid materials of Cu(II) have been synthesized by using flexible glutarate/adipate as a bridging ligand, 2,2'-bipyridine/1,10-phenanthroline as a chelating ligand, and BF4-/ClO4-/Cl- as a counteranion. These materials are characterized by single-crystal X-ray diffraction analyses and variable temperature magnetic measurements. Out of them, complexes 1, 3, 5, and 8 crystallize in the triclinic system with space group P. Complexes 2, 4, 6, and 7 crystallize in the monoclinic system with space group P21/n (2, 4), P21/c (6), and C2 (7). The structural analysis reveals that bridging glutarate gives rise to dinuclear and tetranuclear species, whereas the adipate dianion leads to octanuclear, one-dimensional and two-dimensional polymeric complexes, although they have been prepared under similar conditions. Supramolecular architectures of higher dimensionality have been achieved through H-bonding and pi-pi interaction. In all the complexes, the bridging and/or counteranions as well as chelating ligand have a vital role in directing the solid-state structure. A variable temperature (2-300 K) magnetic susceptibility study discloses the antiferromagnetic coupling for all of the complexes.

Scrap stainless steel detection using a pulsed electromagnetic field

A pulsed electromagnetic sensor (PEMS) utilising the difference in electrical and magnetic properties of metals was designed for automatic sorting of scrap stainless steel (SS). Experimental results for the identification and separation of stainless steel are presented. The design of a prototype being developed at Delft University of Technology and the results obtained in the laboratory are also discussed.

The effect of cold plastic deformation and subsequent annealing on the magnetic properties of metals with different initial structures

The effect of the degree of cold plastic deformation (CPD) and the temperature of subsequent annealing on the coercive force, relaxation magnetization, and relaxation magnetic susceptibility of iron and nickel is studied. The effect of the degree of CPD on steels with different initial structures in the annealed state (such as ferrite (Э10 steel), pearlite (ШX15 steel), and ferrite-pearlite (50Γ steel) structure), as well as on 50Γsteel with different initial structures obtained after quenching and tempering at different temperatures, is also studied. The dependences obtained are analyzed based on modern theories of magnetic hysteresis for magnetically soft materials. Recommendations for the use of nondestructive testing of the degree of CPD of articles (semifinished items) made from steels with different initial structures are given.

The Effect of Cold Plastic Deformation and Subsequent Annealing on the Magnetic Properties of Metals with Different Initial Structures

The Effect of Cold Plastic Deformation and Subsequent Annealing on the Magnetic Properties of Metals with Different Initial Structures

Column: Nanostructured Materials

Conductive polyisoprene/silver microcomposite films were prepared and electrically stabilized by a photochemical crosslinking treatment. The films showed a very stable and reproducible conductor-insulator transition at a temperature of ca. 55¡C. In addition, crosslinking removed the negative coefficient temperature (NTC) effect and hysteresis phenomena. These photochemical treatment results are applicable for thermoelectric devices manufactured in the form of supported films. Metal/polymer microcomposites (i.e., fine metal powder dispersions in polymeric matrices) combine low cost, easy processing, and excellent mechanical properties of plastics with thermal, electric, and magnetic properties of metals [1,2]. In addition, novel physical characteristics are observed, e.g., these materials strongly absorb microwave producing heat, they show temperature-dependent electrical properties, and absorb all types of nuclear radiations.

Image enhancement in photoemission electron microscopy by means of imaging time-of-flight analysis

Photoemission electron microscopy (PEEM) is widely used in combination with synchrotron sources as a powerful tool to observe chemical and magnetic properties of metal and semiconductor surfaces. Presently, the resolution limit of these instruments using soft-X-ray excitation is limited to about 50 nm, because of the chromatic aberation of the electron optics used. Various sophisticated approaches have thus been reported for enhancing the spatial resolution in photoemission electron microscopy. This work demonstrates the use of a simple imaging energy filter based on electron time-of-flight (ToF) selection. The spatial resolution could be improved dramatically, even though the instrument was optimized using a rather large contrast aperture of 50 μm. A special ( x, y, t)-resolving delayline detector was used as the imaging unit of this ToF-PEEM. It is operated in phase with the time structure of the synchrotron source, cutting time intervals from the raw image-forming data set in order to reduce the electron energy width contributing to the final images.

On the role of spin-orbit splitting in magneto-optics (abstract only)

The interaction of photons with spins is mediated through spin-orbit coupling.Therefore, magneto-optics of magnetic materials depends crucially on the spin-orbitinteractions in either the initial and/or the final state of the optical transition considered and this makes magneto-optics a very powerful tool for the study of spin-orbit coupling in 3d, 4f and 5f materials. This paper will review some of themost striking results obtained over the last 30 years(For the data up to 1990 see: Schoenes J 1991 Materials Science and Technology Vol 3A Electronic and Magnetic Properties of Metals and Ceramics eds. R W Cahn, P Haasen and E J Kramer (Weinheim: VCH)p147).The largest ever reported Faraday rotations exceed 2×10 6 deg cm-1. They have beenobserved in thin films of the europium monochalcogenides EuS, EuSe and EuTe, which have a 4f 7( 8S7/2) groundstate, i.e. no spin-orbit splitting in the initial state.The occurrence of the large magneto-optical signal is therefore clear evidence for a largespin-orbit interaction in the final state of the responsible transition. A line shape analysis shows that this final state consists of a coupling of the excited 5d electronwith the remaining 4f 6 state. Nd3S4 is an example of a system with spin-orbitcoupling in the initial as well as in the final state. The diamagnetic line shape helps toidentify the coupling in the final state and the spin-orbit parameter can be determined.While the intrinsic value of the Kerr rotation of CeSb is still debated, agreement exists that inany case CeSb has the largest Kerr rotation. Of particular interest is the transition froma paramagnetic line shape to a diamagnetic line shape, when the magnetization is reduced from saturation.LaSe presents another archetypical example. Here the initial state is a non-magnetic 5d1state and the magneto-optical experiment allows one to study empty 4f states.In all these lanthanide compounds Russel-Saunders coupling could be applied to the initialand final states. This is no longer the case for the final state in actinide compounds.Magnetic circular dichroism and Faraday rotation measurements on UO2 films evidence that the final state for the excitation of an f electron out of the 5f 2 initial stateis near to a j-j coupled 5f 1-6d1 state. A different approach has to be made to interpretmagneto-optical data for uranium monochalcogenides. In the case of US, for example, 5fdelocalization and f-d hybridizations are too large to apply atomic models and sophisticated band structure calculations are needed to account for the spectra.Besides interband transitions, magneto-optics has also proven to be powerful for studying free carriers. Two different types of frequency dependencies have been predicted by theory.Examples of these two kinds will be presented in the form of data for TmSe and U3P4. Thespecial case of CrPt3 will be discussed in a separate paper.

Magnetic phase transition and hydrogen solubility in Fe, Co, and Ni

It was observed experimentally that hydrogen affects strongly the magnetic properties of metals and alloys. Recently, we performed a series of first-principles calculations to study the effect of hydrogen on the magnetism of magnetic metals, and we found that the strong hybridization among the orbitals of hydrogen and nickel atoms suppresses the ferromagnetism completely. On the basis of this first-principles calculation, we developed a statistical thermodynamic model and analyzed the experimental results of hydrogen solubility in transition metals Fe, Co, and Ni using the model. We found that our model can describe the temperature dependence of hydrogen solubility in a wide range of solid phase in the stated magnetic metals.

Börner, Ehlers, Meier: Vom Urknall zum komplexen Universum/Wheeler: At Home in the Universe/Buschow: Materials Science and Technology: Vol. 3B: Electronic and Magnetic Properties of Metals and Ceramics Part II/Wiedemann: Particle Accelerator Physics: Vol.1: Basic Principles and Linear Beam Dynamics/Haug: Quantum Theory of the Optical and Electronical Properties of Semiconductors/Henneberger, Schmitt‐Rink, Göbel: Optics of Semiconductor Nanostructures/Ott: Chaos in Dynamical Systems/Thaller: The

Physikalische BlätterVolume 50, Issue 7-8 p. 717-722 BuchbesprechungOpen Access Börner, Ehlers, Meier: Vom Urknall zum komplexen Universum/Wheeler: At Home in the Universe/Buschow: Materials Science and Technology: Vol. 3B: Electronic and Magnetic Properties of Metals and Ceramics Part II/Wiedemann: Particle Accelerator Physics: Vol.1: Basic Principles and Linear Beam Dynamics/Haug: Quantum Theory of the Optical and Electronical Properties of Semiconductors/Henneberger, Schmitt-Rink, Göbel: Optics of Semiconductor Nanostructures/Ott: Chaos in Dynamical Systems/Thaller: The Dirac Equation/Shinitzky: Biomembranes/Donoghue, Golowich, Holstein: Dynamics of the Standard Model/Kaye: Chaos and Complexity R. Durrer, R. Durrer ZürichSearch for more papers by this authorW. Schleich, W. Schleich UlmSearch for more papers by this authorH. Warlimont, H. Warlimont DresdenSearch for more papers by this authorR. Brinkmann, R. Brinkmann HamburgSearch for more papers by this authorR. Zimmermann, R. Zimmermann BerlinSearch for more papers by this authorJ. Kuhl, J. Kuhl StuttgartSearch for more papers by this authorH. Kantz, H. Kantz WuppertalSearch for more papers by this authorA. Schirrmacher, A. Schirrmacher München/BerkeleySearch for more papers by this authorR. Lipowsky, R. Lipowsky Jülich/PotsdamSearch for more papers by this authorK. Goeke, K. Goeke BochumSearch for more papers by this authorF. Theunert, F. Theunert WittlichSearch for more papers by this author R. Durrer, R. Durrer ZürichSearch for more papers by this authorW. Schleich, W. Schleich UlmSearch for more papers by this authorH. Warlimont, H. Warlimont DresdenSearch for more papers by this authorR. Brinkmann, R. Brinkmann HamburgSearch for more papers by this authorR. Zimmermann, R. Zimmermann BerlinSearch for more papers by this authorJ. Kuhl, J. Kuhl StuttgartSearch for more papers by this authorH. Kantz, H. Kantz WuppertalSearch for more papers by this authorA. Schirrmacher, A. Schirrmacher München/BerkeleySearch for more papers by this authorR. Lipowsky, R. Lipowsky Jülich/PotsdamSearch for more papers by this authorK. Goeke, K. Goeke BochumSearch for more papers by this authorF. Theunert, F. Theunert WittlichSearch for more papers by this author First published: Juli/August 1994 https://doi.org/10.1002/phbl.19940500724AboutPDF ToolsExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Volume50, Issue7-8Juli/August 1994Pages 717-722 RelatedInformation

Book Review: Volume 3 A: Electronic and Magnetic Properties of Metals and Ceramics (Part I). Edited by K. H. J. Buschow

Book Review: Volume 3 A: Electronic and Magnetic Properties of Metals and Ceramics (Part I). Edited by K. H. J. Buschow