FERROMAGNETIC RESONANCE STUDY OF AMORPHOUS AND NANOCRYSTALLINE Fe81B13.5Si3.5C2 RIBBONS

2009 ◽  
Vol 23 (16) ◽  
pp. 3391-3402
Author(s):  
WEERAPHAT PON-ON ◽  
PONGTIP WINOTAI ◽  
I-MING TANG
Keyword(s):  
Ferromagnetic Resonance ◽  
Resonance Line ◽  
Isothermal Annealing ◽  
Amorphous Matrix ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffusion Controlled ◽  
Nano Grains ◽  
Relative Change ◽  
Kinetics Of

The nanocrystallization process in amorphous Fe 81 B 13.5 Si 3.5 C 2 ribbons caused by isothermal annealing below the crystallization temperature is studied. X-ray diffraction and Mossbauer spectroscopy measurements are used to identify the formation of new Fe containing compounds such as the ribbons annealed at various temperatures. The ferromagnetic resonance measurements for an as-cast ribbon and the 495°, 525°C and 600°C annealed ribbons exhibit a resonance line at 63.64 mT for φ = 0°. The sample annealed at 425°C shows two resonance peaks at 95.45 mT and 295.46 mT. These are due to the nanocrystalline α– Fe(Si) phase. The resonance-line widths are seen to broaden after the ribbons are annealed at 495°C and 525°C, at which time, the amorphous matrix crystallizes into nano-grains of α– Fe(Si) , t– Fe 2 B and t– Fe 3 B phases. The kinetics of the crystallization is discussed in terms of the relative change in the line width of the samples annealed at 495°C for different annealing times. These results yielded an Avrami exponent, n of 0.84 which is consistent with diffusion-controlled growth with a nucleation rate close to zero.

On the Mechanism of Milling Induced Disordering in AlFe

1996 ◽  
Vol 460 ◽  
Author(s):  
M. T. Clavaguera-Mora ◽  
J. Zhu ◽  
M. Meyer ◽  
L. Mendoza-Zelis ◽  
F. H. Sanchez ◽  
...  
Keyword(s):  
Long Range ◽  
Milling Time ◽  
Continuous Heating ◽  
X Ray Diffraction ◽  
Mechanical Grinding ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Diffusion Controlled ◽  
Transmission Mössbauer Spectroscopy ◽  
Kinetics Of

ABSTRACTThe evolution of the B2-AlFe phase during mechanical grinding in Ar has been examined as a function of milling time by X-Ray diffraction, transmission Mössbauer spectroscopy and differential scanning calorimetry. Short and long range disorder was observed to increase with the mechanical treatment up to the attainment of a steady state. The evolution of the long range order parameter and of the local atomic configurations at Fe sites were analyzed in terms of possible mechanisms for milling induced disordering. The kinetics of the thermal reordering was studied under continuous heating and isothermal calorimetrie regimes. Modeling of the reordering processes by diffusion controlled growth of pre-existing ordered grains is presented as well as the estimated values of both the enthalpy and the activation energy of the reordering process. The results are consistent with a non uniform distribution of disorder throughout the sample and will be compared with preceding information on related systems.

Influence of oxygen partial pressure on the kinetics of YBa2Cu3O7−x formation

1994 ◽  
Vol 9 (2) ◽  
pp. 275-285 ◽  
Author(s):  
V. Milonopoulou ◽  
K.M. Forster ◽  
J.P. Formica ◽  
J. Kulik ◽  
J.T. Richardson ◽  
...  
Keyword(s):  
X Ray Diffraction ◽  
Decomposition Products ◽  
Time Resolved ◽  
X Ray ◽  
Formation Kinetics ◽  
Dimensional Diffusion ◽  
Diffusion Controlled ◽  
Gas Atmosphere ◽  
Kinetics Of

The YBa2Cu3O7−x formation kinetics from a spray-roasted precursor powder containing Y2O3, BaCO3, and CuO was followed via in situ, time-resolved x-ray diffraction as a function of gas atmosphere and temperature. In inert atmospheres, BaCO3 and CuO form BaCu2O2 which subsequently reacts with Y2O3 to form YBa2Cu3O6. However, YBa2Cu3O6 decomposes at temperatures exceeding 725 °C with Y2BaCuO5 being one of the decomposition products. In oxidizing atmospheres, YBa2Cu3O7−x formation involves the BaCuO2. At high temperatures (800–840 °C), oxygen increases the yield of YBa2Cu3O6. A nuclei growth model assuming two-dimensional, diffusion-controlled growth with second-order nucleation rate fits the experimental data.

Interdiffusion Kinetics and Magnetic Properties of TA-Permalloy Multilayers

1991 ◽  
Vol 232 ◽  
Author(s):  
I. Hashim ◽  
H. A. Atwater ◽  
K. T. Y. Kung ◽  
R. M. Valletta
Keyword(s):  
Magnetic Properties ◽  
Isothermal Annealing ◽  
Lattice Diffusion ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Short Period ◽  
Interface Roughening ◽  
Interdiffusion Kinetics ◽  
Kinetics Of

ABSTRACTThe interdiffusion kinetics of ultrahigh vacuum deposited Ta/Ni81Fe19 short-period multilayers films have been investigated, and changes in microstructure were related to magnetic properties. Small angle X-ray diffraction and transmission electron microscopy were used to study layer morphology evolution and interdiffusion during post-growth isothermal annealing in the temperature range 300 – 600°C. The kinetic analysis suggests that interface roughening due to grain growth, and grain-boundary mediated diffusion of Ta occurs concurrently at early anneal times in the Ni81Fe19 films. Subsequent grainboundary and lattice diffusion of Ta lead to a reduction of magnetization and increase in coercivity of Ni81Fe19.

Study and Properties of a Steel Microalloyed Hardened Superficially

2015 ◽  
Vol 365 ◽  
pp. 122-127 ◽  
Author(s):  
N. López-Perrusquia ◽  
M.A. Doñu Ruiz ◽  
C. R. Torres San-Miguel ◽  
M. Flores-Báez ◽  
I. Flores-Báez
Keyword(s):  
Growth Process ◽  
Energy Dispersive Spectrometry ◽  
Boride Layer ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffusion Controlled ◽  
Boriding Process ◽  
Kinetics Of ◽  
Over Time ◽  
Scanning Electron

In this study, we present a boronizing treatment on a steel microalloy that was performed according to dehydrated paste-pack boriding. The temperatures conducted were at 1173, 1223 and 1273 K; at various exposure times of 1, 3, 6 and 9 h. As a result of the boriding process, diffusion-controlled growth of the FeB/Fe2B layers was obtained at the surface of the micro-alloy steel, and the kinetics of the growth process changed parabolically over time. The results of these examination properties of the boride layer as revealed by Optical Microscopy (OP) showed the morphology of the boride layer as a saw-tooth with a thickness ranging from 33 μm to 220 μm depending on the boronizing time. The analysis of Scanning Electron Microscopy (SEM-EDS); showed a distribution of the alloying elements that were detected by Energy Dispersive Spectrometry. The X-ray diffraction (XRD) technique indicated that the surface was a mixture of FeB and Fe2B borides. The evaluation of adhesion of the layers was determined by the technique of Rockwell-C hardness. Young’s modulus and hardness of the layer were evaluated by a nanoindentation technique with a load of 250 mN. The paste dehydrate boriding of micro-alloy reveal a change of properties on the surface; also the coatings FeB and Fe2B, to make a sacrificial function in the steels micro alloyed as widely used in pipelines transporting oil.

Kinetic mechanisms for mullite formation from sol-gel precursors

1990 ◽  
Vol 5 (9) ◽  
pp. 1963-1969 ◽  
Author(s):  
Dong X. Li ◽  
William J. Thomson
Keyword(s):  
Activation Energy ◽  
Reaction Kinetics ◽  
Single Phase ◽  
Sol Gel ◽  
Mullite Formation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffusion Controlled ◽  
Kinetic Mechanisms ◽  
Kinetics Of

The reaction kinetics for the formation of mullite (3Al2O3 · 2SiO2) from sol-gel derived precursors were studied using dynamic x-ray diffraction (DXRD) and differential thermal analysis (DTA). The reaction kinetics of diphasic and single phase gels are compared and different reaction mechanisms are found for each gel. Mullite formation in the diphasic gel exhibits an Avrami type, diffusion-controlled growth mechanism with initial mullite formation temperatures of about 1250 °C and an activation energy on the order 103 kJ/mole. On the other hand, mullite formation from the single phase gel is a nucleation-controlled process with an initial formation temperature of 940 °C and a much lower activation energy of about 300 kJ/mole.

scholarly journals Dilatometric and Microstructural Study of Martensite Tempering in 4% Mn Steel

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4442 ◽  
Author(s):  
Adam Grajcar ◽  
Mateusz Morawiec ◽  
Jose Antonio Jimenez ◽  
Carlos Garcia-Mateo
Keyword(s):  
Precipitation Kinetics ◽  
X Ray Diffraction ◽  
High Tempering ◽  
X Ray ◽  
Relative Change ◽  
Mn Steel ◽  
Kinetics Of ◽  
Quenching And Tempering ◽  
Tempering Time ◽  
Tempering Resistance

This paper presents the results of martensite tempering resistance in 4% Mn steel. The material was quenched and tempered at 350 °C for 15, 30, and 60 min. The analysis of the quenching and tempering was carried out using dilatometric and microstructural approaches. The phase composition was assessed using X-ray diffraction. The Ms temperature and tempering progress were simulated using JMatPro software. The dilatometric analysis revealed a small decrease in the relative change in length (RCL) during tempering. This decrease was connected to the precipitation kinetics of cementite within the martensite laths. The microstructure investigation using a scanning electron microscope showed a very small amount of carbides, even for the longest tempering time. This showed the high tempering resistance of the martensite in medium-Mn steels. The hardness results showed an insignificant decrease in the hardness depending on the tempering time, which confirmed the high tempering resistance of martensite.

Reaction Rate Kinetics and Film Textures of Palladium Silicide Formed on Hydrogenated Amorphous Silicon

1993 ◽  
Vol 311 ◽  
Author(s):  
N. R. Manning ◽  
Haydn Chen ◽  
J. R. Abelson ◽  
L. H. Allen
Keyword(s):  
Reaction Rate ◽  
Isothermal Annealing ◽  
X Ray Diffraction ◽  
X Ray ◽  
Resistivity Measurements ◽  
Rate Kinetics ◽  
Palladium Silicide ◽  
Hydrogenated Amorphous ◽  
Kinetics Of

ABSTRACTThe reaction rate kinetics of the thin film solid-state reaction between 120 nm of Pd and 100 or 300 nm of a-Si:H(18at%) to form Pd2Si were studied in situ using x-ray diffraction and four-point probe resistivity measurements during isothermal annealing. These two techniques yielded activation energies and prefactors of Ea=1. 36±:0.11 eV with ko=4.29 cm2/sec for the x-ray diffraction experiments; and Ea=0.97±0.22 eV with ko=3.42x10-4 cm2/sec for the resistivity measurements. The activation energy and prefactor obtained from the c-Si substrate of the resistivity measurements yielded Ea=l.41±0.31 eV and ko=10.6 cm2/sec. Comparisons showed that the silicide formed from the a-Si:H reacted approximately 1.4 times faster than the silicide formed from the c-Si in the same sample, but three times faster than silicide formed on pure c-Si(111). The crystalline texture and grain size of the metal and silicide films were examined.

Experimental Investigation of Interfacial Compounds Evolution in Ultra-Thin Roll Bonded Cu/Al/Cu Strip

2014 ◽  
Vol 622-623 ◽  
pp. 492-500 ◽  
Author(s):  
Hong Wu Song ◽  
Yang Yu ◽  
Yong Xu ◽  
Yan Chen ◽  
Shi Hong Zhang
Keyword(s):  
Intermetallic Layer ◽  
Optical Microscope ◽  
Interfacial Structure ◽  
Tensile Fracture ◽  
X Ray Diffraction ◽  
Roll Bonding ◽  
X Ray ◽  
Diffusion Controlled ◽  
Kinetics Of ◽  
Calculated Activation

Ultra-thin Cu/Al clad strip with 0.12 mm thickness was successfully fabricated by accumulative roll bonding and the interfacial structure of Cu/Al clad strip has been characterized by means of optical microscope (OM), energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM) and also X-ray diffraction (XRD). The intermetallic phases and their formation sequence at the interface was experimentally verified. And the growth kinetics of each phase was also modeled considering the diffusion controlled reaction mechanism. The effect of interfacial compounds on tensile fracture of ultra-thin Cu/Al clad strip was also studied. The obtained results indicate that, intermetallic compounds formed in the interface region of ultra-thin Cu/Al clad strip within the experimental condition are confirmed to be Al2Cu, Al4Cu9 and AlCu in sequence. The calculated activation energies for the growth of Al4Cu9, AlCu and Al2Cu are 101.45、114.30 and 95.15 kJ/mol, respectively. The major cracks propagate through the AlCu intermetallic layer and the Al2Cu / AlCu interface.

The Reaction Kinetics of Liquid 60/40 Sn/Pb Solder With Copper and Nickel: A High Temperature X-Ray Diffraction Study

1984 ◽  
Vol 40 ◽  
Author(s):  
Patrick W. Dehaven
Keyword(s):  
High Temperature ◽  
Reaction Kinetics ◽  
X Ray Diffraction ◽  
Kcal Mole ◽  
Nickel Metal ◽  
X Ray ◽  
Diffusion Controlled ◽  
Solder Reaction ◽  
Kinetics Of

AbstractWith proper sample preparation, high temperature x-ray diffraction can be used to study in-situ the reactions occurring at a solder/metal interface. We have applied this technique to an investigation of the reaction kinetics between copper and nickel metal and 60/40 Sn/Pb solder. The copper and nickel are shown to follow similar pathways, each having a complex reaction profile that involves an initial “hold” of little reactivity, followed by a two-step diffusion controlled reaction. Activation energies were obtained from Arrhenius-type plots, and result in values of 6.8 kcal/mole for the nickel/solder reaction, and 13 kcal/mole for the copper/solder reaction. These results are compared with those obtained by previous investigators, and discussed in terms of the growth of the different intermetallic phases.

scholarly journals Investigation into the Effect of Thermal Treatment on the Obtaining of Magnetic Phases: Fe5Y, Fe23B6, Y2Fe14B and αFe within the Amorphous Matrix of Rapidly-Quenched Fe61+xCo10−xW1Y8B20 Alloys (Where x = 0, 1 or 2)

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 835 ◽  
Author(s):  
Petrica Vizureanu ◽  
Marcin Nabiałek ◽  
Andrei Victor Sandu ◽  
Bartłomiej Jeż
Keyword(s):  
Magnetic Properties ◽  
Crystallization Process ◽  
Isothermal Annealing ◽  
Amorphous Matrix ◽  
Magnetic Phase ◽  
X Ray Diffraction ◽  
Production Methods ◽  
Magnetic Phases ◽  
X Ray ◽  
Injection Casting

The paper presents the results of research on the structure and magnetic properties of Fe61+xCo10−xW1Y8B20 alloys (where x = 0, 1 or 2). The alloys were produced using two production methods with similar cooling rates: Injection casting and suction casting. The alloy samples produced were subjected to isothermal annealing at 940 K for 10 min. The structure of the materials was examined using X-ray diffraction. Isothermal annealing has led to the formation of various crystallization products depending on the chemical composition of the alloy and the structure of the alloy in a solidified state. In two cases, the product of crystallization was the hard magnetic phase Y2Fe14B. However, the mechanism of this phase formation was different in both cases. The magnetic properties of alloys were tested using a vibrating sample magnetometer and a Faraday magnetic balance. It is found that the grain crystallite size of the crystalline phases have a decisive influence on the value of the coercive field (especially in the case of hard magnetic phases). It has been shown that privileged areas can already be created during the production process. Their presence determines the crystallization process.

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