scholarly journals Consideration of Magnetic Measurements for Characterisation of Ferrite–Martensite Commercial Dual-Phase (DP) Steel and Basis for Optimisation of the Operating Magnetic Field for Open Loop Deployable Sensors

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 490
Author(s):  
Mohsen Aghadavoudi Jolfaei ◽  
Lei Zhou ◽  
Claire Davis
Keyword(s):  
Magnetic Field ◽  
Applied Magnetic Field ◽  
Magnetic Measurements ◽  
Initial Permeability ◽  
Open Loop ◽  
Dual Phase ◽  
Dp Steel ◽  
Ferrite Fraction ◽  
Lift Off ◽  
Steel Properties

The magnetic properties of commercial dual-phase (DP) steels (DP600, DP800 and DP1000 grades) were evaluated using initial permeability, incremental permeability and coercivity and correlated with the key microstructural differences between the grades. The ferrite grain sizes and ferrite fractions have been compared with the magnetic parameters obtained from minor and major magnetisation loops within each DP grade. It has been revealed that the incremental permeability increases with the applied magnetic field amplitude to reach a peak and then drops at a higher magnetic field, with the values being different for the three DP grades at a lower field and converging to a similar permeability value at the high field. The effects of ferrite grain size and phase fraction on the incremental permeability are considered, and it has been shown that the influence of ferrite grain boundaries on magnetic permeability is more dominant than the effect of ferrite fraction in commercial DP steel samples. An analysis of the correlation between coercivity and initial permeability with tensile strength shows that the initial permeability provides a slightly better prediction of strength for the steels examined, which is believed to be due to the fact that a combination of reversible and irreversible domain components affect the coercivity value, while the initial permeability is predominantly affected by reversible domain movements. Based on the trend between incremental permeability and applied magnetic field and the commercial EM sensor (EMspec) operating parameters, the effect of lift-off and hence magnetic field strength on the sensitivity to DP steel properties can be assessed.

Hysteresis Loop Shifts in Magnetic Field Cooled FeOOH Nanoparticles

1999 ◽  
Vol 581 ◽  
Author(s):  
M.S. Seehra ◽  
Paromita Roy ◽  
A. Manivannan
Keyword(s):  
Magnetic Field ◽  
Hysteresis Loop ◽  
Spin Glass ◽  
Applied Magnetic Field ◽  
Magnetic Moment ◽  
Open Loop ◽  
Zero Field ◽  
Interparticle Interactions

ABSTRACTMeasurements of the magnetization M as a function of temperature (5K - 300K) and applied magnetic field H (up to 50 kOe) in 30 Å particles of FeOOH are reported. M increases with decreasing T, peaking at TB = 65 K below which the ZFC (zero-field-cooled) and the FC (field-cooled) data separate. Hysteresis loop measured at 10 K for ZFC shows an open loop up to 40 kOe with coercivity = 2 kOe. For the FC case, the loop shifts and the loop-shift increases with the cooling field ItL, approaching saturation above Hc = 20 kOe. From the variation of M vs H above TB, a magnetic moment/particle μp = 300 μB is determined. These results suggest that the FeOOH nanoparticles have an antiferromagnetically ordered core with uncompensated surface spins yielding μp and the surface spins order in a spin-glass-like state below TB, possibly due to interparticle interactions.

scholarly journals Magnetic field frequency optimisation for MFL imaging using QWHE sensors

2020 ◽  
Vol 62 (7) ◽  
pp. 396-401
Author(s):  
J M Watson ◽  
C W Liang ◽  
J Sexton ◽  
M Missous
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Field Strength ◽  
Power Consumption ◽  
Applied Magnetic Field ◽  
Magnetic Particles ◽  
Permanent Magnets ◽  
Low Frequency ◽  
Step Size ◽  
Lift Off

Magnetic particle and other magnetic flux leakage (MFL)-based methods for the detection and evaluation of surfacebreaking flaws in ferromagnetic materials typically use high-strength (∼0.5 T RMS) low-frequency (≤50 Hz) magnetic fields. The rationale behind this is the ready availability of strong permanent magnets and mains power for highstrength electromagnets. This high field strength is needed to saturate the sample and compensate for the insensitivity of magnetic particles, silicon Hall sensors, coils and other magnetic transducers. Consequently, the frequency of the applied magnetic field is typically limited to ≤50 Hz and does not consider the frequency response of the material under test (some MFL applications use this low frequency to detect subsurface or flaws on the backwall). In this study, a probe consisting of a quantum well Hall-effect (QWHE) sensor, an illuminating electromagnet and sensor circuitry was controlled using an automated XYZ scanner with an x-y measurement step size (ie magnetic image pixel size) of 100 microns. This probe was used to apply magnetic fields of various frequencies (DC to 1 kHz) and field strengths (5 mT to 100 mT) to ascertain a frequency and field range best suited to detecting 10 mm- and 11 mm-long longitudinal surface-breaking toe cracks in ground mild steel welds. A lift-off distance of <1 mm was controlled using a proximity laser and a z-direction motor module to autonomously control the probe lift-off and conform to sample geometry. This study found that an applied magnetic field with a frequency of 800 Hz and a field strength of 10 mT RMS was optimal under the constraint of power consumption, based on the ratio of MFL responses from the two flaws and the weld. It was found that other frequency field combinations had comparable or higher detection but were discounted as they had substantially higher power consumption.

Magnetic Properties of the Gd1-xTbxNi3 Intermetallic Compounds

2011 ◽  
Vol 170 ◽  
pp. 109-113 ◽  
Author(s):  
Anna Bajorek ◽  
Grażyna Chełkowska ◽  
Artur Chrobak ◽  
Marzena Kwiecień-Grudziecka
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
Curie Temperature ◽  
Saturation Magnetization ◽  
Intermetallic Compounds ◽  
Applied Magnetic Field ◽  
Magnetic Measurements ◽  
Zero Field ◽  
Zero Field Cooling ◽  
Field Cooling

The paper presents selected magnetic properties of the Gd1-xTbxNi3 intermetallic compounds. Based on the wide-ranging SQUID magnetometer (Quantum Design MPMS, temperature from 1.9K to 300K and magnetic field up to 7T) series of different magnetic measurements were carried out. In studied system the saturation magnetization and the Curie temperature strongly depends of Tb concentration. Moreover, the so-called field cooling - zero field cooling (FC-ZFC) curves reveal a dependence of M(T) on the applied magnetic field. The thermomagnetic curves indicate interesting behaviour which is typical for terbium compounds and can be ascribed to the interaction between different aligned magnetic subblattices.

MAGNETIC MEASUREMENTS OF HIGH QUALITY SINGLE CRYSTAL YBa2Cu3O7-δ

2000 ◽  
Vol 14 (29n31) ◽  
pp. 3697-3702
Author(s):  
A. TIRBIYINE ◽  
A. TAOUFIK ◽  
S. SENOUSSI
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
Single Crystals ◽  
Applied Magnetic Field ◽  
Magnetic Measurements ◽  
Hysteresis Loops ◽  
High Quality ◽  
Flux Lines ◽  
Magnetization Hysteresis ◽  
Irreversible Magnetization

We have investigated the magnetic measurements on high quality single crystals of YBa 2 Cu 3 O 7-δ. Several magnetization hysteresis loops have been obtained for different temperature values, and as a function of the angle θ between the direction of the applied magnetic field and the c-axis of the sample. Measurements were performed at magnetic field up to 6 Tesla and various temperatures between 10 and 90 K. Magnetization hysteresis loops scale and shape are strongly dependent on the temperature values. Our results show that the magnetic properties are profoundly affected by flux lines pinning. The irreversible magnetization decreases as the applied magnetic field deviates from the c-axis (θ increases).

scholarly journals Effect Y substitution on the microstructure, transport and magnetic proprieties of Bi2Sr2Ca1Cu2O8+δ superconducting ceramics

2016 ◽  
Vol 34 (3) ◽  
pp. 582-590
Author(s):  
S. Menassel ◽  
M.-F. Mosbah ◽  
Y. Boudjadja ◽  
S.P. Altintas ◽  
A. Varilci ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Activation Energy ◽  
Applied Magnetic Field ◽  
Magnetic Measurements ◽  
Sol Gel ◽  
X Ray ◽  
Practical Applications ◽  
Field Samples ◽  
Y Substitution ◽  
Dc Current

AbstractIn high Tc superconductors (HTSC) the activation energy gives information about the pinning properties of a sample under applied magnetic field. Pinning of vortices determines the critical current density Jc which is of great importance for practical applications of HTSC. Instead of magnetic measurements, the activation energy may be calculated from resistivity measurements realized under magnetic field. This kind of measurement has been made in this work for yttrium doped samples of Bi2Sr2CaCu2O8+d (Bi-2212) for different values of applied magnetic field. Samples of Bi2Sr2Ca1-xYxCu2O8+d (x = 0, 0.025, 0.1, 0.25) were prepared by a sol-gel method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive analysis of X-ray. The measurements of resistivity were made using a classical four probe method and DC current. The magnetic field was applied with a constant amplitude of 0 T, 1 T, 2 T and 3 T. The obtained results show that the activation energy decreases with introduction of yttrium, but has a relative maximum when x is equal 0.1. The decrease of the activation energy is explained by the granular nature of the samples which promotes 3D transition to 2D of the vortex lattice.

HYMU 80

Alloy Digest ◽  
1971 ◽  
Vol 20 (10) ◽  
Keyword(s):  
Magnetic Field ◽  
Fracture Toughness ◽  
Corrosion Resistance ◽  
Heat Treating ◽  
Initial Permeability ◽  
Nickel Iron ◽  
Technology Corporation ◽  
Carpenter Technology Corporation ◽  
Low Magnetic Field ◽  
Maximum Permeability

Abstract Carpenter HYMU 80 is an unoriented 80% nickel-iron-molybdenum alloy which offers extremely high initial permeability and maximum permeability with minimum hysteresis loss at low magnetic field strengths. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Ni-5. Producer or source: Carpenter Technology Corporation. Originally published May 1953, revised October 1971.

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