Journal Article

FZJ-2016-02301

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png From Atomic Structure to Excess Entropy: A Neutron Diffraction and Density Functional Theory Study of CaO−Al$_{2}$ O$_{3}$ −SiO$_{2}$ Melts

Liu, M. ; Jacob, A. (Corresponding author) ; Schmetterer, C. ; Masset, P. J. ; Hennet, L. ; Fischer, H. E. ; Kozaily, J. ; Jahn, S. ; Gray-Weale, A.

2016
IOP Publ. Bristol

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Please use a persistent id in citations: doi:10.1088/0953-8984/28/13/135102

Abstract: Calcium aluminosilicate $\text{CaO}-\text{A}{{\text{l}}_{2}}{{\text{O}}_{3}}-\text{Si}{{\text{O}}_{2}}$ (CAS) melts with compositions ${{\left(\text{CaO}-\text{Si}{{\text{O}}_{2}}\right)}_{x}}{{\left(\text{A}{{\text{l}}_{2}}{{\text{O}}_{3}}\right)}_{1-x}}$ for x  <  0.5 and ${{\left(\text{A}{{\text{l}}_{2}}{{\text{O}}_{3}}\right)}_{x}}{{\left(\text{Si}{{\text{O}}_{2}}\right)}_{1-x}}$ for $x\geqslant 0.5$ are studied using neutron diffraction with aerodynamic levitation and density functional theory molecular dynamics modelling. Simulated structure factors are found to be in good agreement with experimental structure factors. Local atomic structures from simulations reveal the role of calcium cations as a network modifier, and aluminium cations as a non-tetrahedral network former. Distributions of tetrahedral order show that an increasing concentration of the network former Al increases entropy, while an increasing concentration of the network modifier Ca decreases entropy. This trend is opposite to the conventional understanding that increasing amounts of network former should increase order in the network liquid, and so decrease entropy. The two-body correlation entropy S 2 is found to not correlate with the excess entropy values obtained from thermochemical databases, while entropies including higher-order correlations such as tetrahedral order, O–M–O or M–O–M bond angles and Q N environments show a clear linear correlation between computed entropy and database excess entropy. The possible relationship between atomic structures and excess entropy is discussed.

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Contributing Institute(s):

1. Werkstoffstruktur und -eigenschaften (IEK-2)

Research Program(s):

1. 111 - Efficient and Flexible Power Plants (POF3-111) (POF3-111)

Appears in the scientific report 2016

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Database coverage:
; Current Contents - Physical, Chemical and Earth Sciences ; IF < 5 ; JCR ; NCBI Molecular Biology Database ; National-Konsortium ; Nationallizenz ; No Authors Fulltext ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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