TY  - JOUR
A1  - Wilke, Max
A1  - Partzsch, G. M.
A1  - Farges, Francois
T1  - XAFS of iron in silicate melt at high temperature
Y1  - 2004
SN  - 0024-4937
ER  - 
TY  - JOUR
A1  - Farges, Francois
A1  - Djanarthany, S
A1  - de Wispelaere, S
A1  - Munoz, Manuel
A1  - Magassouba, B
A1  - Haddi, A
A1  - Wilke, Max
A1  - Schmidt, C.
A1  - Borchert, Manuela
A1  - Trocellier, P
A1  - Crichton, W
A1  - Simionovici, Alexandre
A1  - Petit, Pierre-Emanuel
A1  - Mezouar, Mohamed
A1  - Etcheverry, M. P.
A1  - Pallot-Frossard, I
A1  - Bargar, John Reeder
A1  - Brown, G. E.
A1  - Grolimund, D
A1  - Scheidegger, A
T1  - Water in silicate glasses and melts of environmental interest : from volcanoes to cathedrals
N2  - In silicate glasses and melts, water acts according to two main processes. First, it can be dissolved in high temperature/high pressure melts. Second, it constitutes a weathering agent on the glass surface. A number of in-situ x- ray absorption fine structure (XAFS) studies for Fe, Ni, Zr, Th and U show that the more charged cations (Zr, Nb, Mo, Ta, Sn, Th and U) are little affected by the presence of dissolved water in the melt. In contrast, divalent iron and nickel are highly sensitive to the presence of water, which enhance nucleation processes, for example, of phyllosilicates at the angstrom-scale. Such information provides additional constraints on the role of water deep in the Earth, particularly in magmatology. By contrast, the weathering of glass surfaces by water can be studied from a durability perspective. Experimental weathering experiments Of nuclear waste glasses performed in the laboratory show a variety of surface enrichments (carbon, chlorine, alkalis, iron) after exposure to atmospheric fluids and moisture. Mn-, and Fe-surface enrichments of analogous glasses of the XIVth century are related to the formation of Mn and Fe oxy/ hydroxides on the surface. The impact on the glass darkening is considered in terms of urban pollution and mass tourism
Y1  - 2005
ER  - 
TY  - JOUR
A1  - Wilke, Max
A1  - Schmidt, Christian
A1  - Farges, Francois
A1  - Malavergne, Valerie
A1  - Gautron, Laurent
A1  - Simionovici, Alexandre
A1  - Hahn, Matthias
A1  - Petit, Pierre-Emanuel
T1  - Structural environment of iron in hydrous aluminosilicate glass and melt-evidence from X-ray absorption spectroscopy
N2  - The iron speciation in hydrous haplotonalitic and haplogranitic silicate glasses was studied using XAFS spectroscopy and transmission electron microscopy (TEM). Spectral features occurring at the main crest of the XANES at the iron K-edge of hydrous glasses indicate contributions to the spectra by iron-moieties present in a more ordered structural environment than found in the dry glass. These differences are also suggested by analysis of the EXAFS. These effects are not completely suppressed even for those samples that were quenched with a higher cooling rate. Strongest differences to the dry glass are observed for a sample that was quenched slowly through the temperature of glass transformation. Crystals (60 to 1500 nm in size) of magnetite, maghemite and another unidentified phase were observed in this sample by TEM, whereas no crystals were found in samples quenched with regular or high cooling rates. In-situ XANES measurements up to 700 degrees C and 500 MPa were performed to reveal the origin (i.e., during synthesis or quench) of the structural differences for those hydrous glasses that do not display any detectable crystallization. The comparison of XANES spectra collected on Fe2+ in water-saturated haplogranitic melt at 700 degrees C and 500 MPa and on Fe2+ in dry melt at 1150 degrees C shows that the local structural environment of Fe2+ in both systems is similar. This indicates that there is no detectable and direct influence of water on the local structure around iron in this type of melt. Hence, the differences observed between hydrous and dry glasses can only be related to artefacts formed during the quench process. (c) 2006 Elsevier B.V. All rights reserved
Y1  - 2006
U6  - https://doi.org/10.1016/j.chemgeo.2006.01.017
ER  - 
TY  - JOUR
A1  - Wilke, Max
A1  - Farges, Francois
A1  - Partzsch, G. M.
A1  - Schmidt, C.
A1  - Behrens, Harald
T1  - Speciation of Fe in silicate glasses and melts by in-situ XANES spectroscopy
Y1  - 2007
ER  - 
TY  - JOUR
A1  - Wilke, Max
A1  - Partzsch, G. M.
A1  - Welter, E.
A1  - Farges, Francois
T1  - Redox Reaction In Silicate Melts Monitored By Static In-Situ Fe K-edge XANES Up To 1180 C
Y1  - 2007
ER  - 
TY  - JOUR
A1  - Wilke, Max
A1  - Farges, Francois
A1  - Petit, Pierre-Emanuel
A1  - Brown Jr., Gordon E.
A1  - Martin, Francois
T1  - Oxidation state and coordination of Fe in minerals : an Fe K XANES spectroscopic study
Y1  - 2001
ER  - 
TY  - JOUR
A1  - Farges, Francois
A1  - de Wispelaere, S.
A1  - Rossano, Stephanie
A1  - Munoz, Manuel
A1  - Wilke, Max
A1  - Flank, Anne-Marie
A1  - Lagarde, Pierre
T1  - Local structures around Si, Al, and Na in hydrated silicate glasses
Y1  - 2008
ER  - 
TY  - JOUR
A1  - Wilke, Max
A1  - Partzsch, G. M.
A1  - Schmidt, C.
A1  - Farges, Francois
T1  - In-situ study of the iron species in silicate melts
Y1  - 2004
SN  - 0016-7037
ER  - 
TY  - JOUR
A1  - Petit, Pierre-Emanuel
A1  - Farges, Francois
A1  - Wilke, Max
A1  - Solé, V. Armando
T1  - Determination of the iron oxidation state in Earth materials using XANES pre-edge information
Y1  - 2001
ER  -