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.

Study of Structural Behavior of Cadmium Based Alloys at Molten State

2021 ◽  
Vol 7 (2) ◽  
Author(s):  
G. Shrestha ◽  
I. Koirala
Keyword(s):  
Thermodynamic Functions ◽  
Structural Behavior ◽  
Heat Of Mixing ◽  
Molten State ◽  
Long Wavelength ◽  
Structural Functions ◽  
Energy Of Mixing ◽  
Interchange Energy ◽  
Free Energy Of Mixing ◽  
Experimental Values

The simple statistical model or simple theory of mixing has been used to study the structural behavior of cadmium based alloys at their molten state at a temperature of 800 K by computing thermodynamic functions and structural functions. The thermodynamic functions include free energy of mixing (GM), activity (a), the heat of mixing (HM), and the entropy of mixing (SM). The structural functions include concentration fluctuation in the long-wavelength limit (SGG(0)) and Warren-Cowley short-range order parameter (α1). Interchange energy or interaction energy or ordering energy (ω) was calculated for the respective alloys system and found to be positive and temperature-dependent. Based on interchange energy (ω) and coordination number (Z), theoretical values of all the functions are calculated by applying the grand partition function. All the computed values for the mentioned functions are in good agreement with experimental values. For the cadmium based alloys, viz., Cd-Zn & Cd-In, both show the segregating in nature at temperature 800 K for the concentration of range 0.1 to 0.9, however, Cd-Zn is more segregating than Cd-In.

scholarly journals Theoretical investigation of mixing properties of Sb-Sn binary liquid alloy at 905K

BIBECHANA ◽  
2017 ◽  
Vol 15 ◽  
pp. 1-10
Author(s):  
H K Limbu ◽  
K K Mishra ◽  
A K Sah ◽  
I S Jha ◽  
D Adhikari
Keyword(s):  
Liquid Alloy ◽  
Nearest Neighbor ◽  
Regular Solution Model ◽  
Concentration Fluctuations ◽  
Heat Of Mixing ◽  
Entropy Of Mixing ◽  
Energy Of Mixing ◽  
Interchange Energy ◽  
Free Energy Of Mixing ◽  
Experimental Values

The thermodynamic, microscopic, surface and transport properties of Sb-Sn liquid alloy at 905K have been studied using regular solution model. In thermodynamic properties, free energy of mixing(GM) , activity(a), entropy of mixing(SM), heat of mixing (HM) have been studied. To understand structural behavior of the liquid alloys concentration fluctuations in the long wavelength limit i.e. (Scc(0)) and short range order parameter (α1) have been computed. Surface property is studied with the help of Butler’s model while transport property is computed from Moelwyn-Hughes equation. The theoretical and experimental values of thermodynamic and microscopic properties of Sb-Sn liquid alloy at 905K have been compared. In present work the value of interchange energy (w) is found to be negative suggesting that there is a tendency of unlike atoms pairing (i.e. Sb-Sn) as the nearest neighbor indicating the ordering behavior in Sb-Sn liquid alloy. The symmetric behavior of concentration fluctuations of the liquid alloy has been well explained by the model. The temperature dependence of interchange energy (w) has been found during the computation of entropy of mixing (SM) and heat of mixing (HM) of the liquid alloy.BIBECHANA 15 (2018) 1-10

scholarly journals Thermodynamic, structural, transport and surface properties of Pb-Tl liquid alloy

BIBECHANA ◽  
2015 ◽  
Vol 13 ◽  
pp. 100-113 ◽  
Author(s):  
SK Yadav ◽  
LN Jha ◽  
D Adhikari
Keyword(s):  
Liquid Alloy ◽  
Surface Concentration ◽  
Heat Of Formation ◽  
Concentration Fluctuation ◽  
Heat Of Mixing ◽  
Long Wavelength ◽  
Wavelength Limit ◽  
Energy Of Mixing ◽  
Free Energy Of Mixing ◽  
Experimental Values

Thermodynamic properties, such as free energy of mixing, heat of mixing, entropy of mixing, activities and the microscopic structural properties, such as concentration fluctuation in long-wavelength limit and chemical short-range order parameter of Pb-Tl liquid alloy at 773 K have been studied on the basis of regular associated solution model. We have estimated the mole fractions of the complex and the unassociated atoms assuming the existence of  complex as energetically favoured in the liquid state. The compositional contributions of the heat of mixing of the species Pb and Tl and the heat of formation of the compound to the net enthalpy change have also been studied. The transport properties such as, viscosity and the ratio of mutual and intrinsic coefficients have been studied using different approaches. The surface concentration of Tl atoms has been computed and it has been employed to calculate the surface tension of Pb-Tl liquid alloy. Both the theoretical and the experimental values of the concentration fluctuation in long-wavelength limit are found to be less than the ideal value, revealing that the concerned system is hetero-coordinating in nature. The interaction energies are found to be temperature dependent and respective alloy is found to be weakly interacting system. BIBECHANA 13 (2016) 100-113

scholarly journals Activity of Mercury in its Amalgams at Molten Stage

1970 ◽  
Vol 8 (8) ◽  
pp. 56-58
Author(s):  
SK Chakrabarti ◽  
BK Jha ◽  
IS Jha
Keyword(s):  
Free Energy ◽  
Successive Approximations ◽  
Method Of Successive Approximations ◽  
Size Factor ◽  
Thermodynamic Relation ◽  
Binary Liquid ◽  
Energy Of Mixing ◽  
Interchange Energy ◽  
Free Energy Of Mixing ◽  
Experimental Values

In the present work we have considered two molten amalgams e.g. sodium amalgam and potassium amalgam. Efforts are made to compute the activity of mercury therein by applying Flory's model. This statistical mechanical model is based on the size factor of the ingredients of a binary liquid alloy. In case of each of the amalgams we have started with the expression for the free energy of mixing (GM) according to this model. After knowing the ratio of the atomic volumes of the constituent species of an amalgam the prime task becomes the determination of the interchange energy (ω) between them. For this purpose the experimental values of GM for different concentrations of the ingredients of the amalgam are collected. From these known values ω has been computed by using the expression for GM. A suitable value of ω is chosen from the set of values so obtained. Putting this value of ω the free energy of mixing is calculated for several concentrations and then compared with its observed values. Accordingly, a modified value of ω has been considered and the calculations are repeated. In this way by the method of successive approximations we have ascertained the value of the interchange energy. Thereafter, with the help of standard thermodynamic relation activity has been computed. The results explain the observed anomaly of the activity of mercury in the present molten amalgams. Keywords: Binary liquid alloys; Flory's model; Amalgams; Activity of mercury. DOI: 10.3126/sw.v8i8.3850 Scientific World Vol.8(8) 2010 pp.56-58

scholarly journals Energy Disorder in Liquid Fe-Si Alloy

2011 ◽  
Vol 1 ◽  
pp. 37-40
Author(s):  
D. Adhikari ◽  
I. S. Jha ◽  
B. P. Singh
Keyword(s):  
Pairwise Interaction ◽  
Heat Of Mixing ◽  
Interaction Energies ◽  
Molten State ◽  
Energy Disorder ◽  
Energy Of Mixing ◽  
Free Energy Of Mixing ◽  
Alloy Clusters ◽  
Associated Solution Model ◽  
Associated Solution

The observed asymmetry in the properties of mixing of Fe-Si alloy in molten state is successfully explained on the basis of regular associated solution model. We have determined the free energy of mixing, heat of mixing and entropy of mixing of Fe-Si alloys in molten state at 1873 K. The analysis suggests that heterocoordination leading to the formation of complex Fe 2Si is likely to exist in the liquid and is of a strongly interacting nature. The theoretical analysis reveals that the pairwise interaction energies between the species depend considerably on temperature.Keywords: Liquid alloy; Clusters; Thermodynamic propertiesThe Himalayan Physics Vol.1, No.1, May, 2010Page: 37-40Uploaded Date: 28 July, 2011

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 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 Free energy of mixing and activity of indium-tin alloy

BIBECHANA ◽  
1970 ◽  
Vol 7 ◽  
pp. 26-29 ◽  
Author(s):  
IS Jha ◽  
Arun K Khan ◽  
BC Kumar
Keyword(s):  
Free Energy ◽  
Thermodynamic Parameters ◽  
Liquid Alloy ◽  
Reasonable Agreement ◽  
Energy Of Mixing ◽  
Free Energy Of Mixing ◽  
Experimental Values

Flory's model has been used to calculate the free energy of mixing and activity of In in InSn liquid alloy at 700 K. The values of these thermodynamic parameters obtained from this model are compared with corresponding experimental values. The computed values are in reasonable agreement with the observed values. Keywords: Flory's model; Activity; Indium-tin alloy DOI: 10.3126/bibechana.v7i0.4040BIBECHANA 7 (2011) 26-29

scholarly journals Thermodynamic Prediction of the Free Energy of Mixing and Activities of some Goldbased Binary Liquid Alloys

2020 ◽  
Vol 9 (1) ◽  
pp. 11-16
Author(s):  
Y.A. Odusote ◽  
A.I Popoola
Keyword(s):  
Experimental Data ◽  
Free Energy ◽  
Reasonable Agreement ◽  
Liquid Alloys ◽  
Approximation Model ◽  
Binary Liquid ◽  
Thermodynamic Prediction ◽  
Energy Of Mixing ◽  
Free Energy Of Mixing ◽  
Experimental Values

The free energy of mixing and activities of gold in selected six Au-based binary liquid Au-Cu, Au-Zn, Au-Pb, Au-Ni, Au-Sn and Al-Au alloys at different working temperatures have been studied using the quasi-chemical approximation model (QCAM). The predicted free enegry of mixing and activities results were compared with available experimental values. The predicted results are in reasonable agreement with reported experimental data and confirms that the model is reliable and, thus should serve as an alternative for the prediction of thermodynamic properties of binary liquid alloys. Keywords: free energy of mixing, activities, Au, Binary liquid alloys, concentration

scholarly journals Free Energy of Mixing of some Binary Liquid Alloys

2016 ◽  
Vol 3 (1) ◽  
pp. 97
Author(s):  
S.K. Chakrabarti ◽  
J.P. Yadav ◽  
S.M. Rafique
Keyword(s):  
Free Energy ◽  
Theoretical Work ◽  
Heat Of Mixing ◽  
Size Factor ◽  
Liquid Alloys ◽  
Binary Liquid ◽  
Energy Of Mixing ◽  
Statistical Mechanical Model ◽  
Interchange Energy ◽  
Free Energy Of Mixing

<p>Binary liquid alloys often show interesting behaviour as regards their thermodynamic properties. The heat of mixing often bears a large negative value and the entropy of mixing an S-shape. The free energy of mixing becomes asymmetric around the equi-atomic composition especially in case of complex forming alloys. In the present theoretical work we have tried to compute the free energy of mixing of some binary alloys e.g. lithium-lead, potassium amalgam and magnesium-tin―all in liquid state near their respective melting points. All these alloys form strongly interacting systems. So, we have applied Flory’s model which is a statistical mechanical model considering the size factor of the constituent species of a binary liquid alloy. We have ignored the interaction between the complex and each ingredient within an alloy and amended the formula accordingly. In the light of observed activity of a metal within an alloy we have ascertained the interchange energy by the method of successive numerical approximations and then calculated the free energy of mixing according to the said model for different concentrations of the ingredients. Our results explain the observed anomaly in the free energy of mixing of the present liquid alloys.</p><p>Journal of Nepal Physical Society Vol.3(1) 2015: 97-101</p>

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