Microstructure and Magnetic Properties of Undercooled Fe-50at%Ni Alloys

2011 ◽  
Vol 695 ◽  
pp. 357-360
Author(s):  
Hui Xie ◽  
G. H. Bai ◽  
Lei Jia ◽  
Zhen Lin Lu ◽  
Sheng Zhong Kou
Keyword(s):  
Magnetic Properties ◽  
Optical Microscope ◽  
Phase Identification ◽  
X Ray ◽  
Ni Alloys ◽  
Ni Alloy ◽  
Chemical Constitution ◽  
Maximum Undercooling ◽  
Two Phases ◽  
Microstructure And Magnetic Properties

Bulk Fe-50at%Ni alloy melts were undercooled using cyclic superheating and glass slag purification. As a result, a maximum undercooling up to 217 K could be achieved. As-solidified microstructures were observed by means of optical microscope. Phase identification of Fe-50at%Ni alloys was performed using the Shimadzu X-ray diffractometer (XRD) system. The chemical constitution revealed using a JEOL Model JSM-6700F scanning electron microscope equipped with energy dispersive X-ray spectroscopy (EDX). The magnetic properties of the alloys were measured by vibrating sample magnetometer (VSM) with a DC M-H analyzer. The results indicated that there were twice grain refinements occurred within an undercooling range of 55-217K, where the first could be ascribed to dendrite-remelting, and the second to recrystallization. The phase composition of undercooled Fe-50at%Ni alloys comprised two phases, i.e., solid solution phases withbccandfccstructure. At various undercoolings, the saturation magnetizationMsandHcrelated closely to the measured grain sizeD, and they were in proportion toD-1by the regression analysis.

Microstructure and Magnetic Properties of Undercooled Fe-80at%Ni Alloys

2009 ◽  
Vol 620-622 ◽  
pp. 327-330
Author(s):  
Hui Xie ◽  
G.H. Bai ◽  
L. Jia ◽  
E.K. Liu ◽  
Zhen Lin Lu
Keyword(s):  
Grain Size ◽  
Magnetic Properties ◽  
Xrd Analysis ◽  
Optical Microscope ◽  
X Ray Diffraction ◽  
Soft Magnetic ◽  
Grain Coarsening ◽  
Ni Alloys ◽  
Purification Technique ◽  
Maximum Undercooling

Bulk Fe-80at%Ni melts were undercooled by using cyclic superheating and glass slag purification technique, and the maximum undercooling 340 K could be achieved. The microstructures of Fe-80at%Ni alloys were observed by means of optical microscope (OM). The phase composition was identified by X-ray diffraction (XRD) analysis. The magnetic properties of Fe-80at%Ni alloys were measured by vibrating sample magnetometer (VSM) with a DC M-H analyzer. The results showed that there was only single γ-(Fe, Ni) phase existing in undercooled Fe-80at%Ni alloys. Two grain refinements and one grain coarsening were observed in the undercooling range from 28 K to 340 K. The first grain refinement could be ascribed to dendrite-remelting, and the second to recrystallization induced by the stress originating from rapid solidification. The grain coarsening could be considered as a result of solid-state grain coalescence. The measurement of soft magnetic properties showed that the grain size D decreases with an increase of undercooling, the maximum Ms is 109.98emu/g, corresponding to minimum grain size 42.9μm or undercooling 210 K, and the coercive force Hc is in proportion to the reciprocal of grain size D-1.

Effect of Nitridation Magnetic Properties of Nanocrystalline Fe-Co Alloy Powders

2010 ◽  
Vol 654-656 ◽  
pp. 1106-1109
Author(s):  
Ya Qiong He ◽  
Chang Hui Mao ◽  
Jian Yang
Keyword(s):  
Grain Size ◽  
Magnetic Properties ◽  
Alloy Powder ◽  
High Energy ◽  
X Ray Diffraction ◽  
Powder Mixtures ◽  
X Ray ◽  
Transmission Electron ◽  
Nitridation Temperature ◽  
Microstructure And Magnetic Properties

Nanocrystalline Fe-Co alloy powders, which were prepared by high-energy mechanical milling, were nitrided under the mixing gas of NH3/H2 in the temperature range from 380°C to 510°C. X-ray diffraction (XRD) was used to analyze the grain size and reaction during the processing. The magnetic properties of the nitrided powders were measured by Vibrating Sample Magnetometer (VSM). The results show that with the appearance of Fe4N phase after nitride treatment, and the grain-size of FeCo phase decreases with the increase of nitridation temperature between 380°C to 450°C.The saturation magnetization of nitrided alloy powder treated at 480°C is about 18% higher than that of the initial Fe-Co alloy powder, accompanied by the reduction of the coercivity. Transmission electron microscope (TEM) was used, attempting to further analyze the effect of Fe4N phase on microstructure and magnetic properties of the powder mixtures.

Synthesis and Magnetic Properties of Nanocrystalline Co-Ni Alloys: A Review

2012 ◽  
Vol 736 ◽  
pp. 229-240 ◽  
Author(s):  
Sudhakar Panday ◽  
P. Jeevanandam ◽  
B.S. Sunder Daniel
Keyword(s):  
Magnetic Properties ◽  
Binary Alloys ◽  
Synthesis Method ◽  
Surface Oxidation ◽  
Alloy Nanoparticles ◽  
Ni Alloys ◽  
Alloy Particles ◽  
Ni Alloy ◽  
Co Concentration ◽  
Potential Applications

This review article deals with the synthesis, characterization and magnetic properties of Co-Ni nanoalloys. The various physical and chemical methods for the synthesis of Co-Ni alloy nanoparticles are discussed. Co-Ni alloy nanoparticles with different size and shape such as spherical, rods, wires chain-like assembly are found to depend on the synthesis method and experimental condition. The structure of Co-Ni alloys is eitherfcc,hcpor mixedfccandhcpphase and found to depends on size, shape and concentration of Co in the Co-Ni alloys. Sodium hydroxide (NaOH) concentration and Co to Ni ratio influence the shape of bimetallic Co-Ni nanoparticles. Pt nucleating agents produced smaller size of Co-Ni alloy particles compared to Ru and Ag. Higher Co concentration in the Co-Ni alloys also influences the size alloy particles. The magnetic properties of Co-Ni nanoalloys depend on the size, shape and composition of the binary alloys. Surface oxidation of Co-Ni alloy nanoparticles decrease the saturation magnetization and increases with Co concentration in the alloys. The shape of Co-Ni alloy nanoparticles has an influence on coercivity. The microwave absorption properties of the Co-Ni alloys found to depend on the shape, size and composition of the binary alloys. The absorbance peaks shifts to higher frequency with decrease in size of the alloy particles. Potential applications of Co-Ni alloys in various fields are highlighted.

Newly Automated EPMA with Phase Identification System

2001 ◽  
Vol 7 (S2) ◽  
pp. 980-981
Author(s):  
S. Notoya ◽  
H. Takahashi ◽  
T. Okumura ◽  
C.H. Nielsen
Keyword(s):  
High Resolution ◽  
Optical Microscope ◽  
Image Display ◽  
Identification System ◽  
Phase Identification ◽  
Analysis Software ◽  
X Ray ◽  
Electron Probe Microanalyzer ◽  
Mouse Pointer ◽  
Live Image

We have developed a new Electron Probe Microanalyzer (EPMA), JXA-8100/8200, with improved basic capabilities such as X-ray intensities of wavelength dispersive spectrometers (WDS), imaging functions, automated functions and analysis software. Fig. 1 shows the appearance of JXA-8200, WD/ED combined microanalyzer. in this session, we report mainly on the improved imaging functions, automated functions and analysis software.The JXA-8100/8200 is the first EPMA in the world to feature 1280 x 1024 pixels high resolution live scanning image display. Regarding scanning image, two or four different signal live images, of course including X-ray images, can be displayed simultaneously. Further, image mixing is also possible to display. On the high resolution image, an operator can choose the probe position or the stage position by mouse clicking. The stage position can also be chosen on the optical microscope (OM) live image. Another new “Swing Mouse” function, which is the seamless movement of mouse pointer between the scanning image display and the computer display, has been developed.Advanced automated functions, such as autofocus, auto astigmatism and auto contrast brightness, are effective to optimize the scanning image.

Effect of Dysprosium Content on the Magnetic Properties of Nanocrystalline (Pr0.25Nd0.75)10-xDyxFe82Co2B6 Alloys

2014 ◽  
Vol 789 ◽  
pp. 28-31 ◽  
Author(s):  
He Wei Ding ◽  
Chun Xiang Cui ◽  
Ji Bing Sun
Keyword(s):  
Magnetic Properties ◽  
Melt Spinning ◽  
Maximum Energy ◽  
Vibrating Sample Magnetometer ◽  
X Ray ◽  
Maximum Energy Product ◽  
Energy Product ◽  
Intrinsic Coercivity ◽  
Electronic Microscope ◽  
Microstructure And Magnetic Properties

(Pr0.25Nd0.75)10-xDyxFe82Co2B6(x=0~0.3) ribbons were prepared by melt spinning at 25m/s and subsequent annealing. The effect of Dy content on the microstructure and magnetic properties of the ribbons has been investigated by X-ray diffractometer (XRD), scanning electronic microscope (SEM) and vibrating sample magnetometer (VSM). The magnetic properties related to the Dy content were characterized. Intrinsic coercivity of 598kA/m, remanence of 0.58T, and the maximum energy product (BH)max of 43kJ/m3 were achieved in (Pr0.25Nd0.75)9.8Dy0.2Fe82Co2B6 after annealing at 700°C for 10 minutes.

Undercooling And X-Ray Structural Studies Of Ti-Zr-Ni Liquids

2002 ◽  
Vol 754 ◽  
Author(s):  
G.W. Lee ◽  
A.K. Gangopadhyay ◽  
K.F. Kelton ◽  
R.W. Hyers ◽  
T.J. Rathz ◽  
...  
Keyword(s):  
Short Range ◽  
Short Range Order ◽  
Icosahedral Phase ◽  
Range Order ◽  
X Ray Diffraction ◽  
Containerless Processing ◽  
X Ray ◽  
Ni Alloys ◽  
Nucleation Barrier ◽  
Maximum Undercooling

ABSTRACTMaximum undercooling results for the icosahedral phase (i-phase), polytetrahedral C14 Laves phase, and solid solution phases are presented as a function of composition in Ti-Zr-Ni liquids. Containerless processing was achieved using the electrostatic levitation facility located at NASA/Marshall Space Flight Center. The maximum reduced undercooling decreases with increasing icosahedral short-range order in the ordered phase. The first synchrotron x-ray diffraction data from aerodynamically levitated liquids of Ti-Zr-Ni alloys suggest an icosahedral short-range order in the liquids, supporting Frank's hypothesis, correlating icosahedral order in the liquid with the nucleation barrier to the crystal phase. The strong negative heats of mixing between Ti/Zr and Ni and their relative atomic sizes likely favor the formation of this local icosahedral order.

Correlation of microstructure and magnetic properties in Cu–Co–Ni alloys

2010 ◽  
Vol 166 (2) ◽  
pp. 174-179 ◽  
Author(s):  
B.N. Mondal ◽  
A. Basumallick ◽  
P.P. Chattopadhyay
Keyword(s):  
Magnetic Properties ◽  
Ni Alloys ◽  
Microstructure And Magnetic Properties

Effect of pH on Composition, Structure and Magnetic Properties of Electrodeposited Co-Ni Alloys

2009 ◽  
Vol 68 ◽  
pp. 52-59 ◽  
Author(s):  
T. Mahalingam ◽  
K. Sundaram ◽  
Subramaniam Velumani ◽  
M. Raja ◽  
S. Thanikaikarasan ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Nickel Content ◽  
Cobalt Content ◽  
Soft Magnetic ◽  
Solution Ph ◽  
Ni Alloys ◽  
Ni Alloy ◽  
Sulfate Baths ◽  
Composition Structure ◽  
Kinetics Of

Co-Ni alloy thin films were electrodeposited from sulfate baths at various solution pH values (1.5-5.5) ±0.1. The deposition kinetics of the films was studied using linear sweep voltametry (LSV). XRD studies exhibited fcc and hcp phases for Co-Ni alloys deposited at low and high pH ranges, respectively. EDAX studies showed that the cobalt content increased and nickel content decreased with increase in solution pH. The surface morphology of Co-Ni films were analyzed by scanning electron microscopy. It is found that the Co-Ni alloys synthesized at low pH exhibited soft magnetic properties and the films deposited at higher values revealed hard magnetic properties and the results are discussed.

EFFECTS OF SPUTTERED Ar PRESSURE AND SUBSTRATE TEMPERATURE ON THE MICROSTRUCTURE AND MAGNETIC PROPERTIES OF Cr/SmCo5/Cr FILMS

2008 ◽  
Vol 15 (01n02) ◽  
pp. 105-109
Author(s):  
CONGMIAN ZHEN ◽  
JINJUAN ZHANG ◽  
LI MA ◽  
DENGLU HOU ◽  
YING LIU ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Substrate Temperature ◽  
Magnetic Measurements ◽  
Body Centered Cubic ◽  
Switching Field ◽  
X Ray ◽  
Atomic Force ◽  
Diffraction Peaks ◽  
Ray Diffusion ◽  
Microstructure And Magnetic Properties

Cr / SmCo 5/ Cr films were fabricated by a DC facing targets magnetron sputtering. The influences of sputtered Ar pressure and substrate temperature on their microstructure and magnetic properties were investigated. Magnetic measurements indicate that the optimal substrate temperature was 450°C, and the film deposited at 2 Pa Ar pressure had the largest in-plane coercivity (2403.54 Oe). No SmCo 5 diffraction peaks except Cr (110) peak with body-centered-cubic structure were seen in all the samples by X-ray diffusion. The Needle-like grains of the film deposited at low Ar pressure were observed by atomic force microscope. The domain pattern of the film fabricated at 2 Pa Ar pressure showed more uniform. When the sputtered Ar pressure was 2 Pa, the narrowest switching field distribution (0.57) was obtained, indicating a narrower grain size distribution. The δM value was nearly zero for the film deposited at 2 Pa Ar pressure, and this indicated that there was almost noninteraction between grains.

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