Diffusional Growth Kinetics of Boride Layers on Iron-Chromium Alloys

2008 ◽  
Vol 138 ◽  
pp. 181-188 ◽  
Author(s):  
Vasil I. Dybkov ◽  
L.V. Goncharuk ◽  
V.G. Khoruzha ◽  
K.A. Meleshevich ◽  
A.V. Samelyuk ◽  
...  
Keyword(s):  
Experimental Data ◽  
Growth Kinetics ◽  
Reaction Times ◽  
Layer Growth ◽  
Diffusional Growth ◽  
Chromium Alloys ◽  
Layer Growth Rate ◽  
Linear Differential ◽  
Kinetics Of ◽  
Iron Chromium

Two boride layers were found to form at the interface of iiron-chromiium alllloys (10 and 25% Cr) or an industrial 13% Cr steel and boron at 850-950 oC and reaction times in the range 1-12 h. In the case of a Fe-10% Cr alloy and the steel, the layers are based on the FeB and Fe2B compounds. With a Fe-25% Cr alloy, the constituent phases are FeB and CrB for the outer layer and Fe2B and Cr2B for the inner layer. Both layers are characterized by a pronounced texture. Diffusional growth kinetics of boride layers are close to parabolic and can alternatively be described by a system of two non-linear differential equations, producing a good fit to the experimental data. The temperature dependence of the layer growth-rate constants obeys a relation of the Arrhenius type.

Diffusional Growth Kinetics of Boride Layers at the 13% Cr Steel Interface with Amorphous Boron

2007 ◽  
Vol 263 ◽  
pp. 183-188 ◽  
Author(s):  
Vasil I. Dybkov
Keyword(s):  
Experimental Data ◽  
Differential Equations ◽  
Growth Kinetics ◽  
Reaction Times ◽  
Average Content ◽  
Amorphous Boron ◽  
Diffusional Growth ◽  
Fe2b Phase ◽  
Linear Differential ◽  
Kinetics Of

Two borides FeB and Fe2B were found to form as separate layers at the interface between a 13% Cr steel and boron at 850-950 oC and reaction times up to 12 h. The chromium distribution within the boride layers is rather irregular. Its average content is 8 at. % in the FeB layer and 9 at. % in the Fe2B layer. Both layers are characterized by a pronounced texture. The strongest reflections are {002} and {020} for the orthorhombic FeB phase and {002} for the tetragonal Fe2B phase. Diffusional growth kinetics of boride layers are close to parabolic and can alternatively be described by a system of two non-linear differential equations, producing a good fit to the experimental data.

Diffusional Growth Kinetics of Boride Layers on Iron-Chromium Alloys

2008 ◽  
pp. 181-188 ◽  
Author(s):  
V.I. Dybkov ◽  
L.V. Goncharuk ◽  
V.G. Khoruzha ◽  
K.A. Meleshevich ◽  
A.V. Samelyuk ◽  
...  
Keyword(s):  
Growth Kinetics ◽  
Diffusional Growth ◽  
Chromium Alloys ◽  
Kinetics Of ◽  
Iron Chromium

Precipitation of Oxygen and Mechanism of Stacking Fault Formation in Czochralski Silicon Bulk Crystals

1982 ◽  
Vol 14 ◽  
Author(s):  
Kazumi Wada ◽  
Naohisa Inoue ◽  
Jiro Osaka
Keyword(s):  
Growth Model ◽  
Growth Kinetics ◽  
Stacking Faults ◽  
Diffusional Growth ◽  
Czochralski Silicon ◽  
Self Diffusion ◽  
Diffusion Limited ◽  
Silicon Bulk ◽  
Precipitate Growth ◽  
Kinetics Of

ABSTRACTThis paper describes recent progress on nucleation and growth of oxide precipitates and stacking faults in Czochralski silicon. Conclusions on the growth kinetics of oxide precipitates are drawn from the experiments and analysis of growth kinetics of two-dimensional precipitates: The experimentally obtained growth kinetics, three-quarter power law is theoretically derived and the precipitate growth is demonstrated to be diffusion-limited by oxygen interstitials. The formation mechanism of stacking faults is the Bardeen-Herring mechanism. Based on diffusional growth model, the growth kinetics of stacking faults are analyzed, assuming a coexistence of self-interstitial supersaturation and vacancy undersaturation. It is found that the growth is driven by vacancies in undersaturation. Vacancy component of self-diffusion has been determined and found to be predominant at low temperature. The possibility of growth model proposed for increase of oxide precipitate density during annealing has been excluded. Both processes, homogeneous and heterogeneous nucleation, have been taking place during annealing.

Modelling the Nitriding Kinetics of Iron-Chromium Alloys

2003 ◽  
Vol 426-432 ◽  
pp. 1047-1052 ◽  
Author(s):  
R.E. Schacherl ◽  
P.C.J. Graat ◽  
Eric J. Mittemeijer
Keyword(s):  
Chromium Alloys ◽  
Kinetics Of ◽  
Iron Chromium

Structural Relaxation by Precipitation in Al-Li I. Growth Kinetics of Precipitates

1991 ◽  
Vol 229 ◽  
Author(s):  
R. Kamel ◽  
N. K. Gobran ◽  
M. M. Danial
Keyword(s):  
Growth Kinetics ◽  
Structural Relaxation ◽  
Electrical Resistance ◽  
Physical Property ◽  
Diffusional Growth ◽  
Solvus Line ◽  
Structure Sensitive ◽  
Δ Phase ◽  
Two Phases ◽  
Kinetics Of

AbstractChanges in electrical resistance measured by the four probe method was adopted as a structure sensitive physical property used to trace changes in the atomic microstructure below and above the δ'-solvus line in the Al-Li binary alloys. The kinetics of the growth and dissolution of δ' phase (Al3Li) and the formation of δ phase (AlLi), below and above δ'-solvus line, during the coarsening process were studied by isochronal and isothermal investigations. The diffusional growth of δ'-phase, below the δ'-solvus line, was found to be activated by 0.24 eV. Interpretation of the results showed that this energy involved two events during the coarsening process. The first event seemed to be a breakdown of the bonding between the vacancy-Lithium pair and the second event involved the transport of Li atoms to Al-particles to coarsen δ'; (Al3Li) particles. Furthermore, the study of the temperature dependence of electrical resistance of the stable phases δ' and δ of Al-Li alloys was found to be accompanied by difference in the temperature coefficient of the electrical resistance and was attributed to the change in structure of the two phases considered.

Growth kinetics of MgB2 layer and interfacial MgO layer during ex situ annealing of amorphous boron film

2004 ◽  
Vol 19 (10) ◽  
pp. 3081-3089 ◽  
Author(s):  
Hyun-Mi Kim ◽  
Sung-Soo Yim ◽  
Ki-Bum Kim ◽  
Seung-Hyun Moon ◽  
Young-Woon Kim ◽  
...  
Keyword(s):  
Growth Kinetics ◽  
Interfacial Layer ◽  
Surface Reaction ◽  
Layer Growth ◽  
Ex Situ ◽  
Amorphous Boron ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Kinetics Of ◽  
Rough Surface Morphology

This paper describes the growth kinetics of an interfacial MgO layer as well as those of an MgB2 layer during ex situ annealing of the evaporated amorphous boron (a-B) film under Mg vapor overpressure. A thin MgO layer is formed at the interface between a-B and Al2O3 substrate before the formation of crystalline MgB2 layer and the interfacial layer is epitaxially related with Al2O3 substrate (MgO (111)[110] // Al2O3 (0001)[1100]). The interfacial MgO layer continues to grow during the annealing, and its apparent growth rate is about 0.1 nm/min. The analysis of MgB2 layer growth kinetics using cross-sectional transmission electron microscopy reveals that there exist two distinct growth fronts at both sides of an MgB2 layer. The growth kinetics of the lower MgB2 layer obeys the parabolic rate law during the entire annealing time. The growth of the upper MgB2 layer is controlled by the surface reaction between out-diffused boron and Mg vapor up to 10 min, resulting in a rough surface morphology of MgB2 layer. By considering the mass balance of Mg and boron during ex situ annealing, we obtained the diffusivities of Mg and boron in MgB2 layer which were in the same order range of approximately 10−12 cm2/s.

Kinetics of Growth of Gas-Saturated (Embrittled) Layers on Titanium during Vacuum Annealing

2021 ◽  
Vol 316 ◽  
pp. 821-826
Author(s):  
Alexey B. Bulkov ◽  
Vladimir V. Peshkov ◽  
Vladimir F. Selivanov
Keyword(s):  
Experimental Data ◽  
Titanium Alloy ◽  
Growth Kinetics ◽  
Annealing Temperature ◽  
Vacuum Annealing ◽  
Surface Cracks ◽  
Brittle Crack ◽  
Parabolic Relationship ◽  
Kinetics Of ◽  
Annealing Mode

The influence of the parameters of the vacuum annealing mode on the thickness of the embrittled layers, formed on the surface of titanium as a result of its interaction with the residual gases of the vacuumed space, is studied. The thickness and structure of the layers were determined on samples made of VT6 alloy obtained from sheet metal with a thickness of 3 mm. Annealing of samples in the temperature range of 500-750 °C was performed with air dilution from 10 to 3∙10-2 PA. The dimensions of the embrittled layers were determined by measuring the zone of brittle crack propagation in the fracture of the samples, and measuring the distance between the surface cracks in the embrittled layers, formed during bending deformation. To quantify the effect of vacuum annealing modes of sheet titanium alloy VT6 on the depth of the embrittled part of the formed oxide layer, it is proposed to use a parabolic relationship, characterized by the degree of growth and the constant of the embrittled layer. By processing experimental data, the effect of annealing time, temperature, and air dilution on the growth kinetics of the embrittled layers was established. Based on the obtained kinetic regularities of the growth of the embrittled layers, nomograms are constructed, to determine the size of the embrittled layer formed at the heating stage at different speeds up to the specified annealing temperature.

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