Dynamical Behavior of the Subsurface Region in Alloys Under Ion Bombardment at High Temperatures

1981 ◽  
Vol 7 ◽  
Author(s):  
N. Q. Lam ◽  
H. Wiedersich
Keyword(s):  
Alloy Composition ◽  
Dynamical Behavior ◽  
Alloy System ◽  
Model Alloy ◽  
Model Calculations ◽  
Enhanced Diffusion ◽  
Preferential Sputtering ◽  
System A ◽  
Radiation Enhanced Diffusion ◽  
Different Temperatures

ABSTRACTModifications of subsurface alloy composition by bombardment with ions of several keV energy were investigated theoretically, using a phenomenological model which includes the effects of various processes, such as preferential sputtering, displacement mixing, Gibbsian adsorption, radiation-enhanced diffusion, and radiationinduced segregation. The nonuniformity of damage rates, resulting from slow-down of the incoming ions, was also taken into account. The alloy composition evolution in time and space was calculated numerically for different temperatures, using concentrated Ni-Cu as a model alloy system. A good qualitative agreement between the present model calculations and recent experimental measurements was obtained.

Prediction of High Dose Ion Implantation Profiles as Influenced by Radiation Induced Transport and Sputtering

1985 ◽  
Vol 45 ◽  
Author(s):  
M. Rangaswamy ◽  
D. Farkas
Keyword(s):  
Probability Distributions ◽  
Practical Interest ◽  
High Dose ◽  
High Fluence ◽  
Enhanced Diffusion ◽  
Preferential Sputtering ◽  
Radiation Enhanced Diffusion ◽  
Defect Probability ◽  
Radiation Induced ◽  
Effects Of Radiation

ABSTRACTVarious models for predicting high fluence ion collection profiles are reviewed. Recent calculations based on the diffusion approximation are described. The solute and defect probability distributions are calculated by a MONTECARLO code, TRIM. The method takes into account the effects of sputtering, including preferential sputtering of one of the components, and lattice dilation. In addition, the effects of radiation enhanced diffusion and radiation induced segregation are also considered. The calculations include the coupling of solute and defect fluxes. The described formalism can account for observed maximum attainable concentrations and distributions in high fluence implantation conditions of practical interest.

scholarly journals Ion Implantation At Elevated Temperatures

1985 ◽  
Vol 51 ◽  
Author(s):  
Nghi Q. Lam ◽  
Gary K. Leaf
Keyword(s):  
Present Model ◽  
Elevated Temperatures ◽  
Synergistic Effects ◽  
Concentration Profiles ◽  
Enhanced Diffusion ◽  
Preferential Sputtering ◽  
Radiation Enhanced Diffusion ◽  
Spatial Redistribution ◽  
Radiation Induced ◽  
Effects Of Radiation

ABSTRACTA kinetic model has been developed to investigate the synergistic effects of radiation-enhanced diffusion, radiation-induced segregation and preferential sputtering on the spatial redistribution of implanted solutes during implantation at elevated temperatures. Sample calculations were performed for Al+ and Si+ ions implanted into Ni. With the present model, the influence of various implantation parameters on the evolution of implant concentration profiles could be examined in detail.

Mechanisms and kinetics of ion implantation

1986 ◽  
Vol 1 (2) ◽  
pp. 251-267 ◽  
Author(s):  
Nghi Q. Lam ◽  
Gary K. Leaf
Keyword(s):  
Ion Implantation ◽  
Elevated Temperatures ◽  
Synergistic Effects ◽  
Implantation Rate ◽  
Host Lattice ◽  
Ion Energy ◽  
Enhanced Diffusion ◽  
Preferential Sputtering ◽  
Radiation Enhanced Diffusion ◽  
Radiation Induced

The evolution of the implant distribution during ion implantation at elevated temperatures has been theoretically studied using a comprehensive kinetic model. In the model foreign atoms, implanted into both interstitial and substitutional sites of the host lattice, could interact with implantation-induced point defects and with extended sinks such as the bombarded surface. The synergistic effects of preferential sputtering, radiation-enhanced diffusion, and radiation-induced segregation, as well as the influence of nonuniform defect production, were taken into account. The bombarded surface was allowed to move in either direction, − x or + x, depending on ion energy, i.e., on the competition between the rates of ion deposition and sputtering. The moving surface was accounted for by means of a mathematical technique of immobilizing the boundary. The ion implantation process was cast into a system of five coupled partial differential equations, which could be solved numerically using a suitable technique. Sample calculations were performed for two systems: Si+ and Al+ implantations into Ni. It has been known from previous studies that in irradiated Ni, Si atoms segregate in the same direction as the defect fluxes, whereas Al solutes migrate in the opposite direction. Thus the effects of different segregation mechanisms, as well as the influence of target temperature, ion energy, and implantation rate on the evolution of implant concentrations in time and space, could be examined with the present model.

DYNAMIC PROCESSES OF ALTERED LAYER FORMATION IN Cu-Pt ALLOYS UNDER ION BOMBARDMENT

1996 ◽  
Vol 03 (05n06) ◽  
pp. 1811-1821 ◽  
Author(s):  
CHUNFEI LI ◽  
TATSUYA ASAHATA ◽  
RYUICHI SHIMIZU
Keyword(s):  
Steady State ◽  
Ion Bombardment ◽  
Cooling Effect ◽  
Layer Formation ◽  
Transient Stage ◽  
Enhanced Diffusion ◽  
Preferential Sputtering ◽  
Radiation Enhanced Diffusion ◽  
Initial Stage ◽  
Altered Layer

Three different experimental approaches have been developed to study the dynamic process of subsurface altered layer formation in a Cu-Pt alloy under Ar + ion bombardment: (1) sputter neutral mass spectrometry by multiphoton ionization (MPI-SNMS) for the study of preferential sputtering caused by the collision cascade process in the very initial stage of sputtering; (2) ion scattering spectroscopy (ISS)-Auger electron spectroscopy (AES) sequential measurements for investigating radiation-enhanced Gibbsian segregation in the transient stage of sputtering; (3) an approach based on ISS monitoring by prompt switching of the ion bombardment with ( He ++ Ar +) ions to that with He + ions, for revealing the cooling effect in radiation-enhanced diffusion in the final steady state of sputtering. For this we have developed a specific coevaporating device for depositing Cu and Pt simultaneously on a substrate at constant deposition rate. The coevaporating device was attached to both of the specimen chambers of the Auger microprobe, JAMP-3, and of the MPI-SNMS apparatus. The results have clearly revealed: (i) ion bombardment causes a preferential sputtering of Cu atoms in the very initial stage of sputtering, (ii) followed by gradual formation of an altered layer as ion sputtering proceeds in the transient stage, and (iii) finally the alloy system approaches a steady state where the composition profile is controlled by cascade mixing, radiation-enhanced Gibbsian segregation and radiation-enhanced diffusion to satisfy the mass balance law. In the steady state the approach (3) has, first, revealed that the cooling effect does exist in radiation-enhanced diffusion.

scholarly journals Spectroscopic investigations of polycrystalline InxSb20−xAg10Se70 (0 ⩽ × ⩽ 15) multicomponent chalcogenides

2016 ◽  
Vol 34 (4) ◽  
pp. 794-799 ◽  
Author(s):  
Rita Sharma ◽  
Shaveta Sharma ◽  
Praveen Kumar ◽  
Ravi Chander ◽  
R. Thangaraj ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Physical Properties ◽  
Solid Solutions ◽  
Composition Dependence ◽  
Alloy Composition ◽  
Alloy System ◽  
Indium Content ◽  
Structural Modifications ◽  
System A ◽  
Phase Quantification

AbstractThe composition dependence of physical properties of chalcogenides has recently been studied for their phase change properties and energy conversion. In the present work, we report the structure, composition, optical and Raman spectroscopy results for bulk polycrystalline InxSb20−xAg10Se70 (0 ⩽ × ⩽ 15) samples. The phase quantification and composition have been studied by using XRD and EDX techniques. The alloy composition up to 5 at.% of indium resulted in crystallization of AgSbSe2, while further increase in In content favored the formation of another chalcopyrite AgInSe2 phase yielding the solid solutions for this alloy system. A decrease in band gap up to x = 5 followed by its increase with an increase in indium concentration has been observed. The variations in shape and position of characteristic Raman bands has been used for understanding the structural modifications of the network with the variation in indium content.

The Study of the Interaction of the Components of Imitator-Glasses of Glassified Radioactive Wastes With Various Surrounding Rocks

1981 ◽  
Vol 6 ◽  
Author(s):  
V. I. Spitsyn ◽  
A. A. Minaev ◽  
L. I. Barsova ◽  
P. Ya. Glazunov ◽  
V. N. Vetchkanov
Keyword(s):  
Gamma Irradiation ◽  
High Temperatures ◽  
Phosphate Glass ◽  
Phosphate Glasses ◽  
Radioactive Wastes ◽  
X Ray ◽  
Enhanced Diffusion ◽  
Radiation Enhanced Diffusion

ABSTRACTThis work is one of the first attempts to work out a proper technique for the determination of the diffusion of the phosphate glass components into various rocks by using X-ray microanalysis. Under study was thermal and radiationenhanced diffusion of phosphorus, chromium from phosphate glasses into the samples of basalt, metagabbro, metadunite and quartz at high temperatures (to 600°) during gamma irradiation. Radiation enhanced diffusion of ions into rocks.

Measuring Radiation Enhanced Diffusion Through in situ Ion Radiation Induced Sintering of Oxide Nanoparticles

2021 ◽  
Author(s):  
Nathan J. Madden ◽  
Samuel A. Briggs ◽  
Diana Perales ◽  
Timothy J. Boyle ◽  
Khalid Hattar ◽  
...  
Keyword(s):  
Oxide Nanoparticles ◽  
Enhanced Diffusion ◽  
Radiation Enhanced Diffusion ◽  
Radiation Induced

scholarly journals Influence of Drying in Hyptis pectinata Essential Oil

2018 ◽  
Vol 10 (4) ◽  
pp. 96
Author(s):  
Núbia Angélica de Ávila Branquinho ◽  
Fabiano Guimarães Silva ◽  
Osvaldo Resende ◽  
Luiz Cláudio Almeida Barbosa ◽  
Daniel Emanuel Cabral de Oliveira ◽  
...  
Keyword(s):  
Essential Oil ◽  
Anhydrous Sodium Sulfate ◽  
Fixed Bed ◽  
Chemical Characterization ◽  
Automated System ◽  
Caryophyllene Oxide ◽  
System A ◽  
Different Temperatures ◽  
Drying Conditions

The present study assessed the effects of drying at different temperatures (35, 45 and 55 °C) and air velocities (1 and 2 m s-1) on the content and chemical characteristics of Hyptis pectinata essential oil. Drying was conducted in a fixed-bed dryer, and the temperatures and air velocities were controlled and recorded by an automated system. A 350±0.12 g quantity of fresh leaves was used for each of the four repetitions in each dryer. From the material obtained after drying, 60 g of each repetition was used to extract essential oil by the hydrodistillation method. Dichloromethane was used as the solvent, and anhydrous sodium sulfate was used as the desiccating agent. Gas chromatography in the forms of GC-MS and GC-FID were used for the chemical characterization of the essential oil compounds. Decreasing drying times and decreasing concentrations of essential oils were observed with increasing temperatures. A GC-MS analysis of the essential oil from H. pectinata leaves led to the identification of 19 compounds. A sesquiterpene called caryophyllene oxide was the most abundant compound under all drying conditions, with the highest concentration at a temperature of 55 °C, ranging from approximately 42 to 53%.

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