Interdiffusion in Nb-Mo, Nb-Ti and Nb-Zr Systems

2012 ◽  
Vol 323-325 ◽  
pp. 491-496 ◽  
Author(s):  
Soma Prasad ◽  
Aloke Paul
Keyword(s):  
Activation Energy ◽  
Diffusion Coefficient ◽  
Diffusion Couple ◽  
Impurity Diffusion ◽  
Impurity Diffusion Coefficient ◽  
Different Temperatures ◽  
Diffusion Couple Technique ◽  
Interdiffusion Coefficients

Diffusion couple technique is used to study interdiffusion in Nb-Mo, Nb-Ti and Nb-Zr systems. Interdiffusion coefficients at different temperatures and compositions are determined using the relation developed by Wagner. The change in activation energy for interdiffusion with composition is determined. Further, impurity diffusion coefficient of the species are determined and compared with the available data in literature.

Diffusion in Co-Ni System Studied by Multifoil Technique

2011 ◽  
Vol 312-315 ◽  
pp. 466-471 ◽  
Author(s):  
V.D. Divya ◽  
U. Ramamurty ◽  
Aloke Paul
Keyword(s):  
Activation Energy ◽  
Binary System ◽  
Diffusion Couple ◽  
Diffusion Coefficients ◽  
Impurity Diffusion ◽  
Intrinsic Diffusion ◽  
Exponential Factor ◽  
Temperature Range

Diffusion couple experiments were performed in the Co-Ni binary system for determining inter-, impurity- and intrinsic-diffusion coefficients in the temperature range of 1050 - 1250°C. The activation energy and pre-exponential factor estimated for interdiffusion do not vary significantly with composition. The activation energy calculated for impurity diffusion experiments shows is higher than . Intrinsic diffusion coefficients estimated from the multifoil experiment show that Ni is the fastest diffusing species in this system.

Study on the Growth of Nb3Sn Superconductor in Cu(Sn)/Nb Diffusion Couple

2010 ◽  
Vol 297-301 ◽  
pp. 467-471
Author(s):  
A.K. Kumar ◽  
T. Laurila ◽  
V. Vuorinen ◽  
Aloke Paul
Keyword(s):  
Activation Energy ◽  
Growth Rate ◽  
Diffusion Couple ◽  
Product Phase ◽  
Growth Constant ◽  
Bronze Alloy ◽  
Phase Layer ◽  
Parabolic Growth ◽  
Different Temperatures ◽  
Parabolic Growth Constant

Nb3Sn growth following the bronze technique, (i.e. by interdiffusion between Cu(Sn) alloy (bronze) and Nb) is one of the important methodologies to produce this superconductor. In this study, we have addressed the confusion over the growth rate of the Nb3Sn phase. Furthermore, a possible explanation for the corrugated layer in the multifilamentary structure is discussed. Kirkendall marker experiments were conducted to study the relative mobilities of the species, which also explained the reason for finding pores in the product phase layer. Based on the parabolic growth constant at different temperatures, the activation energy for the growth is determined. We have further explained the dramatic increase in the growth rate of the product phase by changing just one atomic percentage of Sn in the Cu-Sn bronze alloy.

Diffusion of Ti, V and Nb in Ni3Al at Elevated Temperatures

2010 ◽  
Vol 297-301 ◽  
pp. 384-389 ◽  
Author(s):  
Haruhiko Fukaya ◽  
Md. Moniruzzaman ◽  
Yoshinori Murata ◽  
Masahiko Morinaga ◽  
Toshiyuki Koyama ◽  
...  
Keyword(s):  
Experimental Data ◽  
Diffusion Coefficients ◽  
Binary Systems ◽  
Elevated Temperatures ◽  
Diffusion Mechanism ◽  
Impurity Diffusion ◽  
Diffusion Couples ◽  
Different Temperatures ◽  
Series Of Experiments ◽  
Interdiffusion Coefficients

Interdiffusion coefficients of Al replacing elements in Ni-Al-X (X=Ti, V and Nb) were estimated by a series of experiments using diffusion couples of Al rich pseudo-binary systems at three different temperatures of 1423, 1473 and 1523K. In order to obtain interdiffusion coefficients of the pseudo-binary systems, the experimental data was analyzed by the Sauer and Freise method, and also impurity diffusion coefficients of Ti, V and Nb in Ni3Al were estimated by applying the Darken-Manning equation. The magnitude of interdiffusion coefficient decreased in order of V, Ti and Nb at all three temperatures. Impurity diffusion coefficients were described by the expressions: , , . The activation enthalpies obtained from the experimental data confirmed the retardation of Ti, V and Nb diffusion in Ni3Al by the anti-site diffusion mechanism. These results are consistent with our previous work on diffusion of Re and Ru in Ni3Al .

Tracer Impurity Diffusion in Liquid Metals: Au in Ga

1974 ◽  
Vol 29 (6) ◽  
pp. 959-960 ◽  
Author(s):  
P.-E. Eriksson ◽  
S. J. Larsson
Keyword(s):  
Activation Energy ◽  
Diffusion Coefficient ◽  
Low Temperatures ◽  
Arrhenius Plot ◽  
Liquid Metals ◽  
Impurity Diffusion ◽  
Straight Line ◽  
Linear Plot

The diffusion coefficient of 198Au in liquid Ga has been measured between 35 and 460 °C. The results can be represented by a linear plot of D vs T or by an Arrhenius plot. The latter yields the parameters D0 = 4.9·10-4 cm2/s and Q = 2.65 kcal/mol. However, some distinct departures from the straight line characteristics, showing a considerably higher “activation energy” at the low temperatures, suggest the possibility that clusters composed of two or several atoms may partake in diffusion.

On the Analysis of Composition Profiles in Binary Single-Phase Diffusion Couples: Systems with a Strong Compositional Dependence of the Interdiffusion Coefficient

2018 ◽  
Vol 383 ◽  
pp. 23-30 ◽  
Author(s):  
Bengü Tas Kavakbasi ◽  
Igor S. Golovin ◽  
Aloke Paul ◽  
Sergiy V. Divinski
Keyword(s):  
Diffusion Couple ◽  
Interdiffusion Coefficient ◽  
Chemical Diffusion ◽  
Compositional Dependence ◽  
New Approach ◽  
Correct Determination ◽  
Composition Profiles ◽  
Diffusion Couple Technique ◽  
Interdiffusion Coefficients

Diffusion couple technique is an efficient tool for the estimating the chemical diffusion coefficients. Typical experimental uncertainties of the composition profile measurements complicate a correct determination of the interdiffusion coefficients via the standard Boltzmann-Matano, Sauer-Freise or the den Broeder methods, especially for systems with a strong compositional dependence of the interdiffusion coefficient. A new approach for reliable fitting of the experimental profiles with an improved behavior at both ends of the diffusion couple is proposed and tested against the experimental data on chemical diffusion in the system Fe-Ga. An extension of the approach for reliable description of the up-hill diffusion phenomenon in multicomponent systems is presented.

Diffusion in Cu(Al) Solid Solution

2008 ◽  
Vol 279 ◽  
pp. 63-69 ◽  
Author(s):  
A. Laik ◽  
K. Bhanumurthy ◽  
G.B. Kale
Keyword(s):  
Activation Energy ◽  
Solid Solution ◽  
Temperature Dependence ◽  
Bulk Diffusion ◽  
Impurity Diffusion ◽  
Solid Solution Phase ◽  
Temperature Range ◽  
State Diffusion ◽  
Pure Cu ◽  
Interdiffusion Coefficients

The solid state diffusion characteristics in the Cu(Al) solid solution phase, was investigated in the temperature range of 1023–1223 K using single phase bulk diffusion couples between pure Cu/Cu- 10 at.% Al. The interdiffusion coefficients, D, were calculated using Boltzmann–Matano method and Hall’s method from the concentration profiles of the couples that were determined using EPMA. The interdiffusion coefficients (D) calculated ranges between 1.39 X 10−14 and 3.97 X 10−13 m2/s in the temperature range of 1023 to 1223 K. The composition and temperature dependence of D were established. The activation energy for interdiffusion varies from 123.1 to 134.2 kJ/mol in the concentration range 1 at. % ≤ CAl ≤ 9 at. %. The impurity diffusion coefficient of Al in Cu is determined by extrapolating the interdiffusion coeffficient values to infinite dilution of the alloy i.e CAl →0 and its temperature dependence was also established. The activation energy for impurity diffusion of Al in Cu was found to be 137.1 kJ/mol.

Interdiffusion Studies in the Co- Mo System

2010 ◽  
Vol 297-301 ◽  
pp. 462-466 ◽  
Author(s):  
V.D. Divya ◽  
U. Ramamurty ◽  
Aloke Paul
Keyword(s):  
Activation Energy ◽  
Solid Solution ◽  
Diffusion Coefficient ◽  
Turbine Blades ◽  
Jet Engine ◽  
Solid Solution Strengthening ◽  
Atomic Mechanism ◽  
Impurity Diffusion Coefficient ◽  
Exponential Factors ◽  
Solution Strengthening

Study of interdiffusion in the Co-Mo system is important to understand the performance of turbine blades in jet engine applications. Mo is added to superalloys to increase the solid solution strengthening and the creep resistance. In this study, the interdiffusion coefficient in the Co(Mo) solid solution and impurity diffusion coefficient of Mo in Co are determined. Further, the activation energy and pre-exponential factors are calculated, which provide an idea about the atomic mechanism of diffusion.

Influence of the Temperature on the Diffusion Coefficient Value during the Cobalt Electrodeposition on Different Substrates

2014 ◽  
Vol 976 ◽  
pp. 144-147
Author(s):  
Nancy Ramos Lora ◽  
Luis Humberto Mendoza Huizar ◽  
Clara Hilda-Rios-Reyes ◽  
Carlos Andrés Galán-Vidal
Keyword(s):  
Activation Energy ◽  
Diffusion Coefficient ◽  
Temperature Effect ◽  
Glassy Carbon ◽  
Arrhenius Equation ◽  
Voltammetric Techniques ◽  
Different Temperatures ◽  
Cobalt Electrodeposition

Cobalt electrodeposition on palladium and glassy carbon was studied at different temperatures by using voltammetric techniques. Temperature effect on the diffusion coefficient value was analyzed. The results clearly showed that cobalt electrodeposition is a diffusioncontrolled process. The temperature effect on the values of the diffusion coefficient was analyzed through the Arrhenius equation. The value of the activation energy was calculated as 21.56 kJ mol-1and 25.73 kJ mol1for palladium and glassy carbon respectively.

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