Prediction of Silicide First Phase and Phase Sequence from Heats of Formation

1983 ◽  
Vol 25 ◽  
Author(s):  
R. Pretorius
Keyword(s):  
Binary System ◽  
Phase Formation ◽  
Eutectic Temperature ◽  
Heat Of Formation ◽  
Heats Of Formation ◽  
Effective Heat ◽  
Phase Sequence ◽  
Subsequent Phase ◽  
Effective Heat Of Formation

ABSTRACTAn effective heat of formation (δH') is formulated, enabling δH' to be calculated as a function of the concentration of metal and silicon available for interaction to form a silicide. A rule for first phase formation is proposed according to which, “The first silicide compound to form during metal-silicon interaction is the congruent phase with the most negative effective heat of formation at the concentration of the lowest eutectic temperature of the binary system.” The effective heat of formation concept is also extended to predict subsequent phase sequence.

Prediction of First Phase Formation at Au-METAL Interfaces Using the Effective Heat of Formation Model

1991 ◽  
Vol 238 ◽  
Author(s):  
R. Pretorius ◽  
T. K. Marais ◽  
A. E. Muller ◽  
D. Knoesen
Keyword(s):  
Phase Formation ◽  
Binary Systems ◽  
Heat Of Formation ◽  
Liquidus Curve ◽  
Effective Concentration ◽  
Formation Model ◽  
Growth Interface ◽  
Effective Heat ◽  
Metal Interfaces ◽  
Effective Heat Of Formation

ABSTRACTThe effective heat of formation model enables heats of formation to be calculated as a function of concentration. By choosing the effective concentration at the growth interface to be that of the liquidus minimum, the model correctly predicL. first phase formation for 14 binary systems for which experimental data was found, except for the Au-Cu system which does not have a well-defined minimum on the liquidus curve.

scholarly journals Use of the effective heat of formation rule for predicting phase formation sequence in AlNi systems

1990 ◽  
Vol 9 (12) ◽  
pp. 494-499 ◽  
Author(s):  
R. Pretorius ◽  
R. de Reus ◽  
A.M. Vredenberg ◽  
F.W. Saris
Keyword(s):  
Phase Formation ◽  
Heat Of Formation ◽  
Effective Heat ◽  
Effective Heat Of Formation

Only Formation of ZrAl3 Phase Obtained by Self-Propagating Reaction from Zr-Al Elemental Powders

2011 ◽  
Vol 239-242 ◽  
pp. 2805-2808 ◽  
Author(s):  
Mou Sheng Song ◽  
Mao Wu Ran
Keyword(s):  
Heat Of Formation ◽  
Effective Heat ◽  
Structural Lattice ◽  
Effective Heat Of Formation ◽  
Formation Phase

In this paper, the problem of ZrAl3compound obtained by self-propagating reaction as the only and favorable formation phase was considered. It shows that the ZrAl3phase could be synthesized by self-propagating reaction in Zr-Al system and was especially identified as the only phase by XRD, which was further confirmed by DTA. Using the theories of structural lattice of ZrAl3, Modified Effective Heat of Formation (MEHF) model, coupled with the First Nucleation Rule (FNR), the only formation of ZrAl3phase in Zr-Al system could be reasonably interpreted.

Thin-film compound phase formation at Fe–Ge and Cr–Ge interfaces

2003 ◽  
Vol 18 (8) ◽  
pp. 1900-1907 ◽  
Author(s):  
O. M. Ndwandwe ◽  
C. C. Theron ◽  
T. K. Marais ◽  
R. Pretorius
Keyword(s):  
Thin Film ◽  
Phase Formation ◽  
Rutherford Backscattering Spectrometry ◽  
Heat Of Formation ◽  
Miedema Model ◽  
Formation Model ◽  
X Ray Diffraction ◽  
X Ray ◽  
Effective Heat Of Formation ◽  
Transformation Enthalpy

Phase formation was studied in the Fe–Ge and Cr–Ge thin-film systems by means of Rutherford backscattering spectrometry and x-ray diffraction. In the Fe–Ge system, FeGe was the first phase to form while in the Cr–Ge system, Cr11Ge8 was found to form first. The results are compared with the predictions of the effective heat of formation model. Heats of formation were calculated using the Miedema model. The effect of the transformation enthalpy term ΔHtr, used to convert a semiconducting element into a hypothetical metallic one in the Miedema model, is also discussed.

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