Wagner interaction parameter

Wagner interaction parameter between oxygen and solute i... 

Experimental data are well-fitted with a statistical model developed by [1984Fro] in order to ealeulate the hydrogen solubility in the whole concentration range from die solubility in pure metals and the first order Wagner interaction parameters (Fig. 3). 

Efforts to improve the original assumptions by van der Waals and Platteeuw were detailed in a review by Holder et al. (1988). Erbar and coworkers (Wagner et al., 1985) and Anderson and Prausnitz (1986) presented improvements to inhibitor prediction. Robinson and coworkers introduced guest interaction parameters into their prediction scheme, as summarized by Nolte et al. (1985). At Heriot-Watt University, the group of Tohidi and Danesh generated another prediction extension, with emphasis on systems containing oil or condensate (Avlonitis et al., 1989 Avlonitis, 1994 Tohidi et al., 1994a). 

Henry s law (yB nearly constant and equal to yg5) holds for A-B alloys dilute in B. For this range of composition, another quantity can be introduced which takes into account interactions between dissolved O and dissolved B in an A matrix. This is the Wagner s first-order interaction parameter, e , defined by an equation in which high-order terms are neglected ... 

The Wagner first order interaction parameter has first been experimentally determined at 1592°C by [1963Wei] and at 1600°C by [1965Bur], It is defined by = 5 logio/n / d (% Cu) where (% Cu) represents the copper content of the alloy expressed in mass% and n the activity coefficient of H in die alloy defined hyfn = (% H in pure iron) / (% H in die alloy). It is calculated from die solubility measurements at constant temperature and hydrogen pressure and its most probable value is = -0.0004 at 1600°C [1974Boo] for less than 12 tnass% Cu in the alloy. 

The Wagner first order interaction parameter has been experimentally determined between 1570 and 1720°C in Uquid (Fe,C) alloys by [1961Mae], at 1592°C by [1963Wei] and between 1550 and 1700°C by [1972Ngi]. It is defined by... 

The value of the Wagner first order interaction parameter deduced from the accepted solubility of hydrogen in the liquid alloy (ch = -1-0.012 at 1600°C) is confirmed by the following experimental determinations 0.013 [1963Wei], 0.0092 [1970Fuk], 0.011 [1974Banl] and 0.0116 [1974Boo]. 

The experimental data were described by Wagner s formalism wifli a first order interaction parameter e p equal to 1.49 0.16 (e p = 0.015 0.004). According to the fliermodynamic calculations based on Miedema s method, the value of e p parameter is equal to 17.29 [1993Din]. 

The electrostatic image treatment of Wagner (1924) was improved by Onsager and Samaras (1934), taking account of Debye-Huckel screening effects (the K parameter) in the ion distribution resulting from repulsive image interactions. They derived the relation for the relative ion... 

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