scholarly journals Phase Composition of Al-Si Coating from the Initial State to the Hot-Stamped Condition

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1125
Author(s):  
Vojtech Kucera ◽  
Marcello Cabibbo ◽  
Filip Prusa ◽  
Jaroslav Fojt ◽  
Jaroslav Petr-Soini ◽  
...  
Keyword(s):  
Phase Composition ◽  
Electron Diffraction ◽  
Surface Profile ◽  
Thin Layers ◽  
Complex Structures ◽  
Initial State ◽  
Outermost Layer ◽  
Substrate Interface ◽  
Hot Stamped Steel ◽  
Nonuniform Layer

The chemical and phase composition of the coating and the coating/substrate interface of an Al-Si-coated 22MnB5 hot stamped steel was investigated by means of SEM-EDS, XRD, micro-XRD and electron diffraction. Moreover, the surface profile was analyzed by XPS and roughness measurements. The XPS measurements showed that the thickness of the Si and Al oxide layers increased from 14 to 76 nm after die-quenching, and that the surface roughness increased as well as a result of volume changes caused by phase transformations. In addition to the FeAl(Si) and Fe2Al5 phases and the interdiffusion layer forming complex structures in the coating, electron diffraction confirmed the presence of an Fe2Al5 phase, and also revealed very thin layers of Fe3(Al,Si)C, Fe2(Al,Si)5 and Al-bearing rod-shaped particles in the immediate vicinity of the steel interface. Moreover, the scattered nonuniform layer of the Fe2Al8Si phase was identified in the outermost layer of the coating. Despite numerous studies devoted to researching the phase composition of the Al-Si coating applied to hot stamped steel, electron diffraction revealed very thin layers and particles on the coating/substrate interface and outermost layer, which have not been analyzed in detail.

Changes in the structure of a thermal protective aluminum-nickel coating under the influence of a single thermal laser pulse

2021 ◽  
Vol 4 ◽  
pp. 25-30
Author(s):  
O. B. Berdnik ◽  
◽  
P. Yu. Kikin ◽  
V. N. Perevezentsev ◽  
E.N. Razov ◽  
...  
Keyword(s):  
Solid Solution ◽  
Heat Flux ◽  
Phase Composition ◽  
Nickel Coating ◽  
Microstructural Analysis ◽  
Radiation Energy ◽  
Heat Fluxes ◽  
Initial State ◽  
Nial Phase ◽  
Ni3al Phase

The regularities of changes in the structure and phase composition of the thermal protective aluminide-nickel coating (Ni — 45 %; Al — 14 %; Co — 22 %; Cr — 18.9 %; Fe — 0.15 %; Nb — 0.14 %; Y — 0.09 %; Ca — 0.06 %; Mn — 0.01 %; C — 0.15 %; Si — 0.15 %; S — 0.006 %) after exposure to short-term pulsed heat fluxes of various power, created by the radiation of a pulse-periodic laser LRS-150A with a radiation wavelength λ = 1.06 µm and a pulse duration τ = 12·10–3 s. The radiation energy was E = 5, 10, and 15 J. Microstructural analysis and the elemental composition of the resulting coating were carried out as well as analysis of the phase composition. X-ray microanalysis of the coating was also carried out. In the initial state and after irradiation of the coating with a heat flux of power P = 7·103 W/cm2, light microregions are observed in the micrographs of the surface. These regions do not have clearly defined external boundaries and consist of the NiAl phase and a small amount of the Ni3Al phase with the presence of inclusions of particles containing a solid solution of Ni – Co – Cr. After irradiation of the coating with heat fluxes of higher power (P = 1.7·104 W/cm2 and P = 2.2·104 W/cm2), large convex formations appeared on its surface, consisting mainly of Ni3Al and NiAl phases. On micrographs of the surface, they appear as white areas with well-defined outer boundaries. The content of the Ni3Al phase in them in comparison with the initial state increased, and the content of the NiAl phase decreased, while the particles of inclusions of Ni, Co, and Cr disappeared. It can be assumed that an increase in the Ni3Al content is associated with the dissolution of particles of a solid solution of Ni – Co and Cr in the melt and the subsequent diffusion of nickel into the NiAl phase. When exposed to a heat flux of power P = 2.2·104 W/cm2, microcracks appear on the areas of the coating surface covered with aluminum oxide.

scholarly journals Comparison characterization of copper selenide thin layers prepared on polyamide 6 films by sorption-diffusion method

2013 ◽  
Vol 11 (4) ◽  
pp. 636-643 ◽  
Author(s):  
Remigijus Ivanauskas ◽  
Vitalijus Janickis ◽  
Vitalija Jasulaitienė
Keyword(s):  
Phase Composition ◽  
Polyamide 6 ◽  
Copper Selenide ◽  
Thin Layers ◽  
Diffusion Method ◽  
Two Phases ◽  
Xrd Patterns ◽  
Sem Studies

AbstractSome earlier synthesized copper selenide (Cux Se) layers formed on the surface of polyamide 6 by sorption-diffusion method using potassium selenotrithionate (K2SeS2O6) as precursor of selenium were characterized by the XRD, XPS and SEM methods. According to the results of the SEM studies, the most uniform Cux Se layers form at the 2.5 h polyamide seleniumized duration at the temperature of 60°C. The thickness of layers, which dependeds on the duration of seleniumization, changed in the range of 0.8–3.2 µm. The XRD patterns of not previously studied Cux Se layers showed their phase composition of six copper selenides: Cu2Se, two phases of CuSe2, Cu3Se2, berzellianite, Cu2-x Se, and bellidoite Cu2Se. Analysis of the XRD and XPS data shows that the macrostructure and composition of the CuxSe layers depend on the conditions of formation of these layers.

Reduction of Charging in Biological Electron Cryomicroscopy

1997 ◽  
Vol 3 (S2) ◽  
pp. 365-366
Author(s):  
M.B. Sherman ◽  
J. Brink ◽  
W. Chiu
Keyword(s):  
Electron Diffraction ◽  
Ion Beam ◽  
High Energy ◽  
Carbon Layer ◽  
Thin Layers ◽  
Biological Macromolecules ◽  
Electron Cryomicroscopy ◽  
Obvious Effect ◽  
Diffraction Patterns ◽  
The Stability

High resolution imaging in electron cryomicroscopy of biological macromolecules is strongly affected by beam-induced charging1. Charging is often expressed in frozen or glucose-embedded specimens as an increase in apparent mass-thickness of the irradiated area. Another obvious effect of charging is blurring of both the unscattered beam and reflections in electron diffraction patterns recorded from crystalline specimens. Coating of ice-embedded specimens with a carbon layer helps to improve the stability of the ice and probably reduce charging of the specimen. Coating in a Gatan ion-beam coater (model 681) of glucose-embedded specimens with thin layers of various conductive materials did reduce charging but the specimens were damaged by the high energy ions used for the coating. In general, coating resulted in much weaker reflections in electron diffraction patterns obtained from coated crystals and faster resolution fall-off.We modified the Gatan coater by outfitting it with a new chamber that replaced the ion-beam deposition capability for thermal evaporation of carbon rods (Fig. 1).

Investigation of Pulsed Laser Annealing of CdS Layers Designed for Thin-Layer Solar Cells

2010 ◽  
Vol 159 ◽  
pp. 109-112
Author(s):  
Peter Shindov ◽  
Roumen Kakanakov ◽  
Lidiya Bedikyan ◽  
Svetlana Kaneva ◽  
Teodora Anastasova
Keyword(s):  
Surface Layer ◽  
Solar Cells ◽  
Phase Composition ◽  
Thin Layer ◽  
Spray Pyrolysis ◽  
Laser Annealing ◽  
Pulsed Laser ◽  
Thin Layers ◽  
Electrical Measurements ◽  
Pulsed Laser Annealing

The effect of the pulsed – laser annealing on the parameters of CdS thin layers in the medium of oxygen was studied. The CdS thin layers were deposited by spray pyrolysis at different technological conditions. The changes of the layers’ characteristics were studied by SEM, XRD and XPS and electrical measurements were carried out. The results showed that a change in the morphology and the phase composition of the surface occurred; a by-surface layer consisted of CdО with high conductivity was formed in consequence of oxidation of CdS. The parameters of the CdS thin layers were retained in- depth after pulsed laser annealing. These results are discussed in the context of transparent layers in solar cells.

Variations in Magnetic Hyperfine fields for Thin Epitaxial Heterostructures Of (110)Fe ON (111)Ag

1989 ◽  
Vol 151 ◽  
Author(s):  
C. J. Gutierrez ◽  
S. H. Mayer ◽  
Z. Q. Qiu ◽  
H. Tang ◽  
J. C. Walker
Keyword(s):  
Electron Diffraction ◽  
Epitaxial Growth ◽  
Growth Process ◽  
High Energy ◽  
Thin Layers ◽  
High Energy Electron ◽  
Hyperfine Fields ◽  
Iron Films ◽  
Magnetic Heterostructures ◽  
Epitaxial Heterostructures

ABSTRACTWe have made a study of magnetic heterostructures involving the epitaxial growth of (110)Fe on (111)Ag. The flatness and continuity of the films was verified by Reflection High Energy Electron Diffraction during the growth process. A series of structures were made with very thin intervening silver layers with thicker iron layers. The doping of appropriate layers by enriched Fe57 made it possible to examine the magnetic structure of the iron films as a function of depth. Preliminary results indicate that thin layers of silver sandwiched between two very thin Fe layers are able to transmit conduction electron polarization, resulting in iron behavior which resembles that of bulk iron. Implications of these results for understanding the nature of the magnetization of iron will be addressed in the following.

Characterization of CdCrTe Layers Obtained by Pulsed Laser Deposition

2013 ◽  
Vol 203-204 ◽  
pp. 193-197
Author(s):  
Piotr Sagan ◽  
Volodymyr Popovych ◽  
Mariusz Bester ◽  
Marian Kuzma
Keyword(s):  
Solid Solution ◽  
Electron Diffraction ◽  
Lattice Constant ◽  
Pulse Length ◽  
Pulsed Laser ◽  
Thin Layers ◽  
Laser Deposition ◽  
X Ray Diffraction ◽  
X Ray

In this paper we have obtained CdCrTe thin layers by PLD method using the YAG:Nd3+ laser with pulse length 250μs. Synthesized CdCrTe solid solution with 50% at. of Cr has been taken as a target. The layers were deposited on KCl substrate. The target and films were analyzed using X-ray diffraction, TEM microscope and THEED electron diffraction. The morphology of the layers are homogenous. However, we have detected several crystallographic phases: cubic CdTe, hexagonal Cr and hexagonal Te. From the measurements of lattice constant of the layer, their composition was determined to be x=0,14

scholarly journals REDISTRIBUTION OF CARBON ATOMS IN DIFFERENTIALLY CHARGED RAILS FOR LONG-TERM OPERATION

2018 ◽  
Vol 61 (6) ◽  
pp. 454-459 ◽  
Author(s):  
V. E. Gromov ◽  
A. A. Yur’ev ◽  
Yu. F. Ivanov ◽  
V. A. Grishunin ◽  
S. V. Konovalov
Keyword(s):  
Surface Layer ◽  
Phase Composition ◽  
Materials Science ◽  
Rail Steel ◽  
Ferrite Matrix ◽  
Crystalline Lattice ◽  
Initial State ◽  
Term Operation ◽  
Prolonged Operation ◽  
Rolling Surface

Using  transmission  electron  microscopy  methods  at  various  distances from the rolling surface along the central axis, changes in  structure, phase composition, and defective substructure of the head  of differentially hardened rails were studied after passed tonnage of  691.8  million tons of gross weight. It is confirmed that prolonged  operation of rails is accompanied by two simultaneous processes of  transformation of structure and phase composition of plate-pearlite  colonies: cutting of cementite plates and dissolution of cementite  plates. The first process is carried out by mechanism of cutting carbide  particles and removing their fragments, accompanied only by change  in their linear dimensions and morphology. The second process of  dest ruction of the cementite plates of perlite colonies is carried out by  leaving carbon atoms from crystalline lattice of cementite on dislocation, as a result of which phase transformation of rails metal is possible. This is due to a noticeable relaxation of mean energy of carbon  atom  s binding to dislocations (0.6  eV) and to iron atoms in cementite  lattice (0.4  eV). The stages of transformation of cementite plates are considered: enveloping the plates with sliding dislocations and then  splitting them into weakly oriented fragments; penetration of sliding  dislocations from ferrite lattice into lattice of cementite; dissolution of  cementite and formation of nanoscale particles. The presence of nanosized cementite particles in ferrite matrix is noted due to their removal  during dislocation slide. Using expressions of modern physical materials science and X-ray diffraction analysis, influence of content of  carbon atoms on structural elements of rail steel was estimated. It is  shown that prolonged operation of rails is accompanied by a significant  redistribution of carbon atoms in surface layer. In the initial state, the  main quantity of carbon atoms is concentrated in cementite particles,  and after a long operation of rails, along with cementite particles, carbon is located in defects of crystal structure of steel (dislocation, grain  boundaries and subgrains), and in the surface layer of steel atoms carbon is also found in crystal lattice based on α-iron.

scholarly journals DIFFUSIVE AND DISPLACIVE PHASE TRANSFORMATIONS UNDER HIGH PRESSURE TORSION

2019 ◽  
Vol 25 (4) ◽  
pp. 230 ◽  
Author(s):  
Boris Straumal ◽  
Askar Kilmametov ◽  
Andrey Mazilkin ◽  
Olga Kogtenkova ◽  
Brigitte Baretzky ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Plastic Deformation ◽  
Grain Size ◽  
High Pressure ◽  
Phase Composition ◽  
Steady State ◽  
Phase Transformations ◽  
High Pressure Torsion ◽  
Dynamic Equilibrium ◽  
Initial State

<p class="AMSmaintext"><span lang="EN-GB">Severe plastic deformation (SPD) can induce various phase transformations. After a certain strain, the dynamic equilibrium establishes between defects production by an external force and their relaxation (annihilation). The grain size, hardness, phase composition etc. in this steady-state does not depend on the initial state of a material and is, therefore, equifinal. In this review we discuss the competition between precipitation and dissolution of precipitates, amorphization and (nano)crystallization, SPD-induced accelerated mass-transfer, allotropic and martensitic transitions and formation of grain boundary phases.</span></p>

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