EFFECT OF THERMO-MAGNETIC TREATMENT ON MAGNETIC PROPERTIES AND MICROSTRUCTURE OF Fe40.75Cr32.4Co24.6Mo2.0Ti0.25 ALLOY

The microstructure and magnetic properties of Fe-Co-Cr alloys with 15 wt % Co were investigated using transmission electron microscopy and magnetic measurements. The secondary decomposition within both the α2-phase matrix and the α1-phase particles was observed for magnets subjected thermo-magnetic treatment and subsequent stepped aging or continuous-cooling treatments. During high-temperature treatments (630-600оC), when the α2phase is dominant (the volume fraction is more than 50%), the secondary decomposition of this phase takes place (α2→ α1'+ α2'). The deterioration of magnetic insulation of α1-phase particles results in the decrease in the coercive force of alloys. Below 600оC, when the α1phase is dominant (the volume fraction is more than 50%), the splitting of elongated α1-phase particles occurs. When the temperature of stepped-aging decreases in high steps, the secondary decomposition (α1→ α1'+ α2') leads to the splitting of initial α1-phase particles into fine slightly elongated particles and the decrease in the coercive force.

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Effective enhancement of electric and magnetic properties of PMMA/LiFe5O8 nanocomposites via magnetic treatment

Journal of Materials Science Materials in Electronics ◽

10.1007/s10854-021-05668-1 ◽

2021 ◽

Vol 32 (8) ◽

pp. 10101-10111

Author(s):

Emad Mousa ◽

Mariam M. Haroun ◽

Gamal M. Nasr

Keyword(s):

Magnetic Properties ◽

Magnetic Treatment

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Development of Fe-Cr-Co Permanent Magnets by Single Step Thermo-Magnetic Treatment

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.510-511.507 ◽

2012 ◽

Vol 510-511 ◽

pp. 507-512 ◽

Cited By ~ 2

Author(s):

S. Akbar ◽

Z. Ahmad ◽

M.S. Awan ◽

M. Farooque ◽

A. Ali

Keyword(s):

Magnetic Properties ◽

Permanent Magnets ◽

Low Cost ◽

Solution Treatment ◽

Inert Atmosphere ◽

Magnetic Treatment ◽

Single Step ◽

Cooling Rates ◽

Arc Melting ◽

Low Cost Manufacturing

The present work is focused on a new approach for the development of Fe-Cr-Co based permanent magnets. Fe-Cr-Co alloy was prepared by using tri arc melting technique under inert atmosphere of Argon. Solution treatment was done at a temperature of 1250°C for five hours followed by water quenching and then a single step thermo-magnetic treatment (TMT) was applied at predetermined cooling rates. The influence of TMT and cooling rates on the final magnetic properties of the alloy were investigated. The results reveal that microstructure and magnetic properties were sensitive to both cooling rates & TMT and can be optimized by controlling the processing conditions. The optimum magnetic properties in the alloy with two different cooling rates of 1°C per minute and 2°C per minute were obtained as (i) 1010 Oe (Hc), 9400 G (Br), 3.4 MGOe (BHmax) (ii) 810 Oe (Hc), 10590 G (Br), 3.6 MGOe (BHmax) respectively. The above method provides a quick and low cost manufacturing route for the Fe-Cr-Co based permanent magnets with comparable magnetic properties to that of Alnico with added advantage of having high ductility.

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Effect of Thermal and Thermal Magnetic Treatment on Damping Properties of Fe-Cr-Al Alloys

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.265.611 ◽

2017 ◽

Vol 265 ◽

pp. 611-614

Author(s):

M.A. Melchakov ◽

A.I. Scvortsov ◽

A.A. Scvortsov

Keyword(s):

Heat Treatment ◽

Magnetic Properties ◽

Treatment Effect ◽

Alloy System ◽

Magnetic Treatment ◽

Al Alloys ◽

Thermomagnetic Treatment ◽

Damping Capacity ◽

Al Alloy ◽

Damping Properties

The authors studied the effect of the pre–heat treatment and subsequent thermomagnetic treatment on the damping and magnetic properties of the Fe–Cr–Al alloy system. This article reveals the dependences of influence of chromium and aluminum on the thermomagnetic treatment effect. As a result, the study identified the optimal modes of treatment of the alloys to maximize the damping capacity.

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AEM analysis of crystallization in Ti-based amorphous alloys

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100075142 ◽

1983 ◽

Vol 41 ◽

pp. 270-271

Author(s):

A.R. Pelton ◽

A.F. Marshall ◽

Y.S. Lee

Keyword(s):

Magnetic Properties ◽

Amorphous Alloys ◽

Amorphous Materials ◽

Isothermal Annealing ◽

Amorphous Matrix ◽

Nucleation And Growth ◽

Current Interest ◽

Amorphous Films ◽

Electrical And Magnetic Properties

Amorphous materials are of current interest due to their desirable mechanical, electrical and magnetic properties. Furthermore, crystallizing amorphous alloys provides an avenue for discerning sequential and competitive phases thus allowing access to otherwise inaccessible crystalline structures. Previous studies have shown the benefits of using AEM to determine crystal structures and compositions of partially crystallized alloys. The present paper will discuss the AEM characterization of crystallized Cu-Ti and Ni-Ti amorphous films.Cu60Ti40: The amorphous alloy Cu60Ti40, when continuously heated, forms a simple intermediate, macrocrystalline phase which then transforms to the ordered, equilibrium Cu3Ti2 phase. However, contrary to what one would expect from kinetic considerations, isothermal annealing below the isochronal crystallization temperature results in direct nucleation and growth of Cu3Ti2 from the amorphous matrix.

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Microstructure in soft magnetic E3 (S1, Al) (Sendust) alloys

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100105916 ◽

1988 ◽

Vol 46 ◽

pp. 770-771

Author(s):

June D. Kim

Keyword(s):

Electron Microscopy ◽

Magnetic Properties ◽

Ternary Phase Diagram ◽

Vertical Tube ◽

Vacuum Induction Melting ◽

Induction Melting ◽

Soft Magnetic ◽

Quenching Temperature ◽

Thin Foils ◽

Vertical Tube Furnace

Iron-base alloys containing 8-11 wt.% Si, 4-8 wt.% Al, known as “Sendust” alloys, show excellent soft magnetic properties. These magnetic properties are strongly dependent on heat treatment conditions, especially on the quenching temperature following annealing. But little has been known about the microstructure and the Fe-Si-Al ternary phase diagram has not been established. In the present investigation, transmission electron microscopy (TEM) has been used to study the microstructure in a Sendust alloy as a function of temperature.An Fe-9.34 wt.% Si-5.34 wt.% Al (approximately Fe3Si0.6Al0.4) alloy was prepared by vacuum induction melting, and homogenized at 1,200°C for 5 hrs. Specimens were heat-treated in a vertical tube furnace in air, and the temperature was controlled to an accuracy of ±2°C. Thin foils for TEM observation were prepared by jet polishing using a mixture of perchloric acid 15% and acetic acid 85% at 10V and ∼13°C. Electron microscopy was performed using a Philips EM 301 microscope.

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