Diffusion coefficients in some ternary systems

1976 ◽  
Vol 21 (4) ◽  
pp. 452-456 ◽  
Author(s):  
Jaroslav Bulicka ◽  
Jaroslav Prochazka
Keyword(s):  
Diffusion Coefficients ◽  
Ternary Systems

A PROCEDURE TO DETERMINE THE SEGREGATION PARAMETERS IN TERNARY SYSTEMS FROM EXPERIMENTAL DATA OF A LINEAR TEMPERATURE RUN

2007 ◽  
Vol 14 (04) ◽  
pp. 681-685
Author(s):  
W. D. ROOS ◽  
J. K. O. ASANTE
Keyword(s):  
High Temperature ◽  
Temperature Region ◽  
Diffusion Coefficients ◽  
High Speed ◽  
Ternary Systems ◽  
Equilibrium Temperature ◽  
Rate Equations ◽  
Interaction Coefficients ◽  
Linear Temperature ◽  
Good Set

Profiles of surface concentrations as a function of temperature, where the temperature is increased at a constant rate, contain the necessary information to extract segregation parameters. A model using rate equations can be used to simulate these profiles. Even on a high-speed computer, solving these equations can take hours. For ternary and higher component alloys the fit parameters are at least nine and finding the best fit manually can extend the search to days. Theoretical segregation and diffusion models show two temperature regions of interest. In the low-temperature region, representing the kinetics of segregation, the diffusion coefficients of the species dominate the flux of atoms to the surface, and in the high-temperature region the surface concentrations are independent of the diffusion coefficients. In the high-temperature equilibrium region the surface concentrations are determined only by the segregation energies and interaction coefficients. A procedure is presented that can find a good set of segregation parameters within seconds. The sensitivity of selecting the kinetics, as well as the equilibrium temperature regions will be demonstrated. The procedure is used to extract the segregation parameters for a Cu (111) 0.13 at% Sn 0.18 at% Sb system.

The Influence of Thermodynamic Properties of Alloys on Effective Interdiffusion Coefficients in Ternary Systems

2007 ◽  
Vol 263 ◽  
pp. 141-146 ◽  
Author(s):  
Ü. Ugaste ◽  
Tony Laas ◽  
T. Škled-Gorbatšova
Keyword(s):  
Thermodynamic Properties ◽  
Diffusion Coefficients ◽  
Reasonable Agreement ◽  
Ternary Systems ◽  
Tracer Diffusion ◽  
Diffusion Couples ◽  
Experimental Values ◽  
Tracer Diffusion Coefficients ◽  
Interdiffusion Coefficients ◽  
The Relationship

To prove the validity of Dayananda’s phenomenological model of interdiffusion in ternary systems the effective interdiffusion coefficients for a few diffusion couples in the system Cu-Ni-Fe, annealed at 1000 oC, are calculated on the basis of this model using available tracer diffusion and thermodynamic data. It is found that the calculated values of effective interdiffusion coefficients are in reasonable agreement with experimental values extracted independently from experimental concentration--penetration curves. Using the relationship between effective interdiffusion coefficients, tracer diffusion coefficients and thermodynamic factors, it is shown that thermodynamic properties of alloys play a significant role in interdiffusion processes in the system Cu-Fe-Ni.

scholarly journals Diffusion Path in Ternary One-Phase Systems: An Overview

2020 ◽  
Vol 44 (1) ◽  
pp. 1-8
Author(s):  
D. Serafin ◽  
W. J. Nowak ◽  
P. Wierzba ◽  
S. Wędrychowicz ◽  
B. Wierzba
Keyword(s):  
Diffusion Coefficients ◽  
Ternary Systems ◽  
Diffusion Path ◽  
System Of Equations ◽  
New Materials ◽  
Intrinsic Diffusion ◽  
Full System ◽  
Initial Concentration ◽  
Phase Systems ◽  
The Difference

AbstractIn this article, the fundamental questions concerning the diffusion path, in particular, what is the shape of diffusion path in ternary systems and how to approximate it from the initial concentration profile, will be answered. The new rules were found which allow for determining the diffusion path from a known initial concentration of the components. This approximation will allow for designing new materials without a time-consuming numerical simulation of the full system of equations. It is shown that the difference in intrinsic diffusion coefficients determines the up-hill diffusion.

Thermodynamic Diffusion Coefficients

2008 ◽  
Vol 279 ◽  
pp. 39-52 ◽  
Author(s):  
G.B. Kale
Keyword(s):  
Diffusion Coefficient ◽  
Diffusion Coefficients ◽  
Driving Force ◽  
Chemical Potential ◽  
Potential Gradient ◽  
Ternary Systems ◽  
Tracer Diffusion ◽  
Chemical Potential Gradient ◽  
Concentration Difference ◽  
Phenomenological Coefficients

A new form of diffusion coefficient termed as thermodynamic diffusion coefficient is introduced in this paper. Conventionally, diffusion coefficients are evaluated using concentration gradient as driving force. But truly, chemical potential gradient is the actual driving force that determines the material flow in any part of the system. Thermodynamic diffusion coefficients are based on chemical potential gradient as driving force. The relation between thermodynamic diffusion coefficients and phenomenological coefficients has been established. The advantages of thermodynamic diffusion coefficients have been underlined, especially, in the cases of line compounds where concentration difference across the phase is zero or in case of intermetallic compounds with narrow homogeneity range. The intrinsic thermodynamic diffusion coefficients are equal to tracer diffusion coefficients. This helps in estimating tracer diffusivities in cases where tracers are not easily available. The advantages of thermodynamic diffusion coefficients are shown in binary and ternary systems by illustrating them in Ni-Al and Fe-Ni-Cr systems.

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