Concentration Fluctuations and Chemical Complexes in the Zn-Au Liquid Alloy

Abstract

The concentration-concentration fluctuations in the long wavelength limit S _cc(0) and the Warren-Cowley short range order parameters (SRO) α₁ have been calculated for the Zn-Au liquid alloy at 1173 K by applying the Quasi Chemical Approximation (QCA). The results of the calculations show that Zn-Au liquid alloy manifest hetero-coordination throughout its whole concentration range. There exist evidence for the presence of two complexes Zn₄AU₃ and Zn₄Au₆. The Zn₄Au₃ complex which manifests dominance in the thermodynamic properties of the liquid alloy yielded a minimum short range order value of about α^min ₁ ≈ ?0.26 while Zn₄Au₆ has its minimum as α^min ₁ ≈ ?0.34. Studies from the S _cc(0) indicate that these complexes are weak and hence cannot encourage glass formation in the liquid alloy.