scholarly journals Viscosity of liquid Na-K alloy

BIBECHANA ◽  
2014 ◽  
Vol 12 ◽  
pp. 135-144 ◽  
Author(s):  
R. P. Koirala ◽  
B. P. Singh ◽  
I. S. Jha ◽  
D. Adhikari
Keyword(s):  
Experimental Data ◽  
Atmospheric Pressure ◽  
Composition Dependence ◽  
Dynamic Behaviour ◽  
Enthalpy Of Mixing ◽  
Mixing Properties ◽  
Energy Of Mixing ◽  
Using Data ◽  
Free Energy Of Mixing ◽  
Theoretical Assessment

The present work reports a theoretical assessment of the composition dependence of mixing properties of liquid Na-K alloy at 384K at fixed pressure, most likely, at the atmospheric pressure. In this work we have estimated the interaction energy in the alloy at the mentioned temperature on the basis of quasi-chemical approximation for regular alloy and employed it to work out basic thermodynamic properties of mixing such as free energy of mixing, entropy of mixing and enthalpy of mixing as function of composition of the alloy. To understand the dynamic behaviour in the liquid Na-K alloy, we have carried out theoretical investigation of viscosity under consideration of Moelwyn-Hughes equation by using data for enthalpy of mixing obtained from quasi-chemical approximation. Due to scanty of experimental data on viscosity of Na-K alloy at 384K, we have performed computation of viscosity also from Kaptay equation for comparison. The calculations have shown that there is a good match between theoretically computed thermodynamic functions and the available corresponding experimental data. The sets of viscosity values obtained against composition from the two equations show deviations from the ideality and themselves are reasonably comparable to each other.DOI: http://dx.doi.org/10.3126/bibechana.v12i0.11797BIBECHANA 12 (2015) 128-137

scholarly journals Thermodynamic and structural properties of Mg-Tl liquid alloy

BIBECHANA ◽  
2012 ◽  
Vol 8 ◽  
pp. 81-89 ◽  
Author(s):  
BP Singh ◽  
D Adhikari ◽  
IS Jha ◽  
BC Kumar ◽  
SK Chaudhary ◽  
...  
Keyword(s):  
Short Range ◽  
Enthalpy Of Mixing ◽  
Mixing Enthalpy ◽  
Mixing Properties ◽  
Long Wavelength ◽  
Energy Of Mixing ◽  
Chemical Complex ◽  
Free Energy Of Mixing ◽  
Associated Solution Model ◽  
Associated Solution

The concentration dependent asymmetry in mixing properties of Mg-Tl liquid alloys at 923 K has been investigated on the basis of regular associated solution model. The concentration of ApB type complex in a regular associated solution of Mg and Tl have been determined. We have then used the concentration of complex to calculate the free energy of mixing, enthalpy of mixing, entropy of mixing, activity, concentration fluctuations in long wavelength limit SCC(0) and the Warren Cowley short-range parameter 1 α .The analysis suggests that heterocoordination leading to the formation of chemical complex Mg2Tl is likely to exist in the melt. The analysis reveals that there is a tendency of unlike atom pairing (Mg-Tl) in Mg-Tl alloy whole range of concentration.Keywords: Mg-Tl alloy; microscopic structure; pairwise interaction energy; chemical short range orderDOI: http://dx.doi.org/10.3126/bibechana.v8i0.5692BIBECHANA 8 (2012) 81-89

scholarly journals Thermodynamic, structural, surface and transport properties of Zn-Cd liquid alloy at 800 K

BIBECHANA ◽  
2016 ◽  
Vol 14 ◽  
pp. 54-65 ◽  
Author(s):  
K K Mishra ◽  
H K Limbu ◽  
B Yadav ◽  
A K Khan ◽  
I S Jha ◽  
...  
Keyword(s):  
Wave Length ◽  
Heat Of Mixing ◽  
Size Factor ◽  
Mixing Properties ◽  
Binary Liquid ◽  
Long Wave ◽  
Energy Of Mixing ◽  
Alloy Increase ◽  
Structural Surface ◽  
Free Energy Of Mixing

The mixing thermodynamic and structural properties of Zn-Cd liquid at 800K has been studied using Flory’s model. To explain the mixing properties of binary liquid alloys, size factor (ф) and ordering energy (ω) are taken into account. Thermodynamic properties like free energy of mixing (GM), activity (a), Heat of mixing (HM) and entropy of mixing (SM) and the microscopic properties like concentration fluctuation in the long wave length limit (Scc(0)) and chemical short range order parameter (α1) have been calculated. Surface property has also been studied with the help of Buttler’s model. The viscosity of the melt has been computed from Kaptay equation and BBK models. Both the viscosity and surface tension of the alloy increase with addition of zinc- component. BIBECHANA 14 (2017) 54-65

scholarly journals Thermodynamic and structural behaviour of Tl-Na liquid alloy

BIBECHANA ◽  
2014 ◽  
Vol 12 ◽  
pp. 20-29 ◽  
Author(s):  
S. K. Yadav ◽  
L. N. Jha ◽  
D. Adhikari
Keyword(s):  
Structural Properties ◽  
Liquid Alloy ◽  
Enthalpy Of Mixing ◽  
Heat Of Formation ◽  
Liquid System ◽  
Heat Of Mixing ◽  
Structural Behaviour ◽  
Energy Of Mixing ◽  
Free Energy Of Mixing ◽  
Experimental Values

In this work we intend to study the thermodynamic and microscopic structural properties of Tl-Na liquid alloy at 673 K on the basis of regular associated solution model. We have estimated the mole fractions of the complex and the free monomers assuming the complex TlNα as energetically favoured in the initial melt. In thermodynamic properties, we have computed free energy of mixing (GM), enthalpy of mixing (GM), entropy of mixing (SM) and activities of the monomers (αTl and αNα). The compositional contributions of the heat of mixing and the heat of formation of the complex to the net enthalpy change have also been studied. The microscopic structural properties of the alloy have been studied by computing concentration fluctuation in the long wavelength limit (SCC(O)), chemical short range order parameter (α1) and the ratio of mutual to intrinsic diffusion coefficients (DM/Did). Both the theoretical and the experimental values of SCC(O) are found to be less than the ideal values at all compositions which indicates the ordering nature of Tl-Na liquid alloy at 673 K. All the interaction energy parameters are found to be negative and temperature dependent. The liquid system is found to be moderately interacting.DOI: http://dx.doi.org/10.3126/bibechana.v12i0.11784BIBECHANA 12 (2015) 20-29

scholarly journals Thermodynamic Mixing Properties of Li–Mg Binary Alloy

2021 ◽  
Vol 66 (5) ◽  
pp. 369
Author(s):  
A. Kumar
Keyword(s):  
Free Energy ◽  
Complex Formation ◽  
Theoretical Calculations ◽  
Heat Of Mixing ◽  
Negative Deviation ◽  
Formation Model ◽  
Mixing Properties ◽  
Energy Of Mixing ◽  
Coeffi Cients ◽  
Free Energy Of Mixing

Theoretical calculations of thermodynamic mixing properties viz., Gibbs’ free energy of mixing GM , heat of mixing HM , entropy of mixing SM , as well as the activity and its coeffi cients, are performed using the Bhatia–Hargrove complex formation model. The mixture is assumed to be pseudobinary. The components exhibit a negative deviation from Raoult’s behavior, and the system is weakly interacting in nature.

scholarly journals Hetero-Coordination in Liquid Pb-K Alloys

2015 ◽  
Vol 5 ◽  
pp. 87-90
Author(s):  
B. P. Singh ◽  
I. S. Jha ◽  
I. Koirala
Keyword(s):  
Enthalpy Of Mixing ◽  
Chemical Activity ◽  
Mixing Enthalpy ◽  
Interaction Energies ◽  
Molten State ◽  
Energy Of Mixing ◽  
Frame Work ◽  
Free Energy Of Mixing ◽  
Constituent Atom ◽  
Good Agreement

The observed asymmetry in properties of mixing of Pb-K alloys in the molten state is successfully explained on the basis of the quasi-lattice model. The thermodynamic functions such as free energy of mixing, enthalpy of mixing, entropy of mixing and chemical activity of the constituent atom of the alloys have been computed within the frame work of presented model. Most of the computed values are in good agreement with the experimental data. The pair-wise interaction energies between the species of the melt are found to depend considerably on temperature. Theoretical analysis suggests that hetero-coordination leading to the formation of complex Pb2K is likely to exist but is of weakly interacting in nature. The Himalayan Physics Vol. 5, No. 5, Nov. 2014 Page: 82-86

scholarly journals Theoretical assessment on hetero-coordination of Alloys Silver-Antimony at Molten State

2020 ◽  
pp. 68-73
Author(s):  
Narayan Panthi ◽  
Indra Bahadur Bhandari ◽  
Ishwar Koirala
Keyword(s):  
Reasonable Agreement ◽  
Chemical Activity ◽  
Heat Of Mixing ◽  
Thermodynamic Quantities ◽  
Molten State ◽  
Energy Of Mixing ◽  
Interchange Energy ◽  
Free Energy Of Mixing ◽  
Experimental Values ◽  
Theoretical Assessment

The thermodynamic and structural properties of binary alloy Ag- Sb at temperature 1250K have been reported theoretically using quasi lattice model. The interchange energy has been considered a function of a temperature and thus various thermodynamic quantities are calculated at elevated temperature. The theoretical values of free energy of mixing, heat of mixing, entropy of mixing and chemical activity are reasonable agreement with experimental values in all concentrations of antimony from 0.1 to 0.9. The theoretical analysis tells that the alloy shows both ordering nature in Ag rich end and segregating nature in Sb rich end .The study reveals that the properties of alloy are asymmetric around equi-atomic composition. The Ag_3 Sn complexes are most likely to exist in the liquid state and are moderately interacting.

scholarly journals Effect of temperature on mixing behavior and stability of liquid Al-Fe alloys

2021 ◽  
Vol 2070 (1) ◽  
pp. 012025
Author(s):  
I B Bhandari ◽  
N Panthi ◽  
S Gaire ◽  
Ishwar Koirala
Keyword(s):  
Free Energy ◽  
Surface Composition ◽  
Dynamic Properties ◽  
Enthalpy Of Mixing ◽  
Effect Of Temperature ◽  
Mixing Enthalpy ◽  
Energy Parameters ◽  
Energy Of Mixing ◽  
Free Energy Of Mixing ◽  
Experimental Values

Abstract A theoretical model based on the assumption of compound formation in binary liquid alloy has been used to investigate the thermodynamic properties (free energy of mixing, enthalpy of mixing and entropy of mixing), microscopic properties (concentration fluctuation in long wavelength limit and chemical short range order parameter), surface properties (surface tension and surface composition) and dynamic properties ( viscosity and diffusion coefficient). All the properties of Al2Fe binary melt have been measured using the same energy parameters configured for experimental values of free energy of mixing. The energy parameters are detected as independent of concentration, but depend on temperature. The findings are well consistent with the experimental standards.

Liquidus Curves of Eutectic NaK and NaCs Systems

1984 ◽  
Vol 39 (9) ◽  
pp. 842-845 ◽  
Author(s):  
L. J. Gallego ◽  
J. M. López ◽  
J. A. Alonso
Keyword(s):  
Free Energy ◽  
Cell Surface ◽  
Enthalpy Of Mixing ◽  
Semiempirical Model ◽  
Binary Liquid ◽  
Energy Of Mixing ◽  
Free Energy Of Mixing ◽  
Modified Forms ◽  
Atomic Cell ◽  
Surface Area Concentration

The Conformal Solution and Flory's expressions for the free energy of mixing ΔGM of a binary liquid alloy have been modified by using a form for the enthalpy of mixing ΔHM which incorporates the concentration dependence given by Miedema's semiempirical model. This model emphasizes the importance of the atomic cell-surface area concentration in evaluating ΔHM. The modified forms of ΔGM have been used to construct the liquidus curves of NaCs and NaK.

scholarly journals Mixing properties of Ni-Pd liquid alloy

BIBECHANA ◽  
2013 ◽  
Vol 10 ◽  
pp. 108-114
Author(s):  
L Gurung ◽  
RP Koirala ◽  
D Adhikari
Keyword(s):  
Liquid Alloy ◽  
Energy Parameter ◽  
Simple Theory ◽  
Heat Of Mixing ◽  
Structural Behaviour ◽  
Mixing Properties ◽  
Long Wavelength ◽  
Energy Of Mixing ◽  
Free Energy Of Mixing ◽  
Alloy Concentration

In this work, thermodynamic and microscopic properties of Ni-Pd liquid alloy at 1873 K have been studied using a simple theory of mixture. In thermodynamic properties, free energy of mixing, heat of mixing and entropy of mixing have been studied. To understand the structural behaviour of the alloy concentration fluctuation in long wavelength limit and chemical short range order parameter have been computed. The Ni-Pd melt at 1873 K is found to be slightly deviated from regular behaviour. The best estimated value of energy parameter is found to be positive. The alloy is found to be weakly segregating system. The symmetric behaviour of all functions has been well explained by the simple theory of mixing. DOI: http://dx.doi.org/10.3126/bibechana.v10i0.9341   BIBECHANA 10 (2014) 108-114

scholarly journals Entropy of Mixing of Liquid NaCd System

1970 ◽  
Vol 10 ◽  
pp. 105-107
Author(s):  
S. K. Chatterjee ◽  
L. C. Prasad ◽  
A. Bhattarai
Keyword(s):  
Solid Phase ◽  
Excess Free Energy ◽  
Liquid Alloys ◽  
Compound Formation ◽  
Mixing Properties ◽  
Entropy Of Mixing ◽  
Energy Of Mixing ◽  
Asymmetric Behaviour ◽  
Statistical Mechanical ◽  
Free Energy Of Mixing

The observed asymmetric behaviour of mixing properties of NaCd liquid alloys, with smaller negative value for excess free energy of mixing (-4.4919KJ) has aroused our interest to undertake a theoretical investigation of this system.The existence of an intermetallic compound in the solid phase, which is manifested in the phase diagram,  may be one of the factors for the anomalous behaviour of property of mixing. A simple statistical mechanical theory based on complex formation model (the complex is formed by the preferential arrangement of A and B constituent atoms of the alloy AB ;( μA + νB = Aμ Bν) has been used to investigate the phenomena of compound formation in NaCd liquid alloys through the study of entropy of mixing through out the whole concentration range.Nepal Journal of Science and Technology Volume 10, 2009 December Page: 105-107 

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