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Surface oxidation of rhodonite: structural and chemical study by surface scattering and glancing incidence XAS techniques

Published online by Cambridge University Press:  05 July 2018

M. L. Farquhar ,
R. A. Wogelius ,
J. M. Charnock ,
P. Wincott ,
C. C. Tang ,
M. Newville ,
P. J. Eng  and
T. P. Trainor
M. L. Farquhar
Affiliation:
Department of Earth Sciences, University of Manchester, Manchester M13 9PL, UK
R. A. Wogelius*
Affiliation:
Department of Earth Sciences, University of Manchester, Manchester M13 9PL, UK
J. M. Charnock
Affiliation:
CLRC Daresbury Laboratory, Warrington, Cheshire WA4 4AD, UK
P. Wincott
Affiliation:
Department of Earth Sciences, University of Manchester, Manchester M13 9PL, UK
C. C. Tang
Affiliation:
CLRC Daresbury Laboratory, Warrington, Cheshire WA4 4AD, UK
M. Newville
Affiliation:
Argonne National Laboratory, APS, GSECARS, Argonne, Illinois 60439, USA
P. J. Eng
Affiliation:
Argonne National Laboratory, APS, GSECARS, Argonne, Illinois 60439, USA
T. P. Trainor
Affiliation:
Argonne National Laboratory, APS, GSECARS, Argonne, Illinois 60439, USA
*
* E-mail: [email protected]
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Abstract

Oxidative dissolution of a primary Mn-silicate phase (rhodonite) was studied via synchrotron X-ray techniques. The study was designed to combine the element-specific chemical technique of Glancing Incidence X-ray Absorption Spectroscopy (GIXAS) with the surface structural technique of X-ray scattering in order to produce the first depth resolved study of Mn-silicate low-temperature reactivity. A chemo-mechanically polished polycrystalline rhodonite sample was characterized and then reacted with pH 3.5 nitric acid. The surface originally had a mosaic structure and 15.5 (±1) Å r.m.s. roughness. Surface composition was not measurably different from bulk rhodonite before reaction, indicating that the surface preparation regimen had not produced an altered surface. After 1 h of reaction, the roughness of the mineral surface decreased and reflectivity oscillations developed, resulting from the formation of a leached layer. This layer was 74.7 (±2) Å thick with an electron density equal to 72% of that of bulk rhodonite (equal to the loss of ~1 in 2 Mn atoms). Both the primary and the buried interfaces had similar roughnesses; 4.9 and 4.5 (±1.0) Å , respectively. Diffuse scatter indicated that the correlation length between surface features also decreased. The GIXAS analysis showed that the Mn remaining in the surface had become oxidized, with the degree of oxidation decreasing as a function of depth. Oxidation penetrated at least 140 Å into the structure. A further 2.5 h of reaction at pH 3.5 caused dissolution of the leached layer and reduced the thickness of this altered region to 16.0 (±2) Å , while surface roughness increased slightly to 6.2 (±1.0) Å . Depletion of Mn in this region increased only slightly relative to the first reaction step; the electron density was 67% that of bulk rhodonite, equivalent to the loss of 2 in 3 Mn atoms. The thickness of the oxidized region however, persisted. Analysis by XPS on the same specimen corroborates the X-ray results.

Keywords

X-ray scatteringX-ray absorption spectroscopyoxidationdissolutionrhodonite
Type
Research Article
Information
Mineralogical Magazine , Volume 67 , Issue 6 , December 2003 , pp. 1205 - 1219
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2003

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References

Borst, C.L., Korthius, V., Shinn, G.B., Luttmer, J.D., Gutmann, RJ. and Gill, W.M. (2001) Chemical-mechanical polishing of SiOC organosilicate glasses: the effect of film carbon content. Thin Solid Films, 385, 281.CrossRefGoogle Scholar
Briggs, D. and Seah, M.P. (1990) Practical Surface Analysis, Vol. 1. Auger and X-ray Photoelectron Spectroscopy. Wiley, New York.Google Scholar
T.A., Crabb, P.N., Gibson and K.J., Roberts (1993) REX - a least-squares fitting program for the simulation and analysis of X-ray reflectivity data. Computer Physics Communications 77, 441—449.Google Scholar
DaiUant, J. and Gibaud, A. (1999) X-ray and Neutron Reflectivity: Principles and Applications. Springer-Verlag, Berlin.Google Scholar
Farquhar, M.L., Charnock, J.M., England, K.E.R. and Vaughan, D.J. (1996) Adsorption of Cu(II) on the (0001) plane of mica: A REFLEXAFS and XPS study. Journal of Colloid and Interface Science, 177, 561—567.CrossRefGoogle Scholar
Farquhar, M.L., Vaughan, D.J., Hughes, C.R., Charnock, J.M. and England, K.E.R. (1997) Experimental studies of the interaction of aqueous metal cations with mineral substrates; lead, cadmium and copper with perthitic feldspar, muscovite and biotite. Geochimica et Cosmochimica Ada, 61, 3051—3064.CrossRefGoogle Scholar
Farquhar, M.L., Wogelius, R.A. and Tang, C.C. (1999) In situ synchrotron X-ray reflectivity study of the oligoclase mineral-fluid interface. Geochimica et Cosmochimica Acta, 63, 1587—1594.CrossRefGoogle Scholar
Farquhar, M.L., Wogelius, R.A. and Vaughan, DJ. (2001) Probing an electrochemically oxidised layer at the pyrite surface via glancing incidence X-ray absorption spectroscopy. Applied Surface Science (in press).Google Scholar
Gammons, C.H. and Seward, T.M. (1996) Stability of manganese (II) chloride complexes from 25 to 300°C. Geochimica et Cosmochimica Acta, 60, 4295—4311.CrossRefGoogle Scholar
Junta, J. and Hochella, M.F. (1994) Manganese(II) oxidation at mineral surfaces — A microscopic and spectroscopic study. Geochimica et Cosmochimica Acta, 58, 4985—4999.CrossRefGoogle Scholar
Manceau, A., Gorshkov, A.I. and Drits, V.A. (1992) Structural chemistry of Mn, Fe, Co and Ni in manganese hydrous oxides: Part 1. Information from XANES spectroscopy. American Mineralogist, 77, 1133—1143.Google Scholar
Mitchel, W.C., Brown, J., Buckanan, D., Bertke, R., Malalingham, K., Orazio, F.D., Pirouz, P., Tseng, H.J.R., Ramabadran, U.B. and Roughani, B. (2000) Comparison of mechanical and chemomechanical polished SiC wafers using photon backscattering. Silicon Carbide and Related Materials - 1999 Pts, 1 & 2, Materials Science Forum, 338, 841—844.Google Scholar
Pertlik, F. and Zahiri, R. (1999) Rhodonite with a low calcium content: crystal structure determination and crystal chemical calculations. Monatshefte fiir Chemie, 130, 257—265.Google Scholar
Saddow, S.E., Schattner, T.E., Brown, J., Grazulis, L., Mahalingan, K., Landis, G., Bertke, R. and Mitchel, W.C. (2001) Effects of substrate surface preparation on chemical vapor deposition growth of 4H-SiC epitaxial layers. Journal of Electronic Materials, 30, 228—234.CrossRefGoogle Scholar
Waychunas, G.A., Apted, M.J. and Brown, G.E., Jr (1983) X-ray K-edge Absorption Spectra of Fe minerals and model compounds: Near-Edge Structure. Physics and Chemistry of Minerals, 10, 1—9.CrossRefGoogle Scholar
Wogelius, R.A. and Fraser, D.G. (1996) Surface oxidation and hydroxylation of olivine produced by reaction with aqueous solutions: an ex situ XAS (REFLEXAFS) and ERDA study. Journal of Conference Abstracts, V.M. Goldschmidt Conference, 1, 684.Google Scholar
R.A., Wogelius and Vaughan, DJ. (2000) Analytical, experimental, and computational methods in envir-onmental mineralogy. Pp. 7—88 in: Environmental Mineralogy (Vaughan, D.J. and Wogelius, R.A., editors). EMU Notes in Mineralogy 2. Eotvos University Press, (European Mineralogical Union), Budapest.Google Scholar
Wogelius, R.A., Farquhar, M.L., Fraser, D.G. and Tang, C.C. (1999) Structural evolution of the mineral surface during dissolution probed with synchrotron X-ray techniques. Pp. 269—289 in: Growth, Dissolution and Pattern Formation in Geosystems (Jamtveit, B. and Meakin, P., editors). Kluwer Academic Publishers, Dordrecht, The Netherlands.CrossRefGoogle Scholar
Zhao, Y. and Chang, L. (2002) A micro-contact and wear model for chemical-mechanical polishing of silicon wafers. Wear, 252, 220—226.CrossRefGoogle Scholar
Zhou, L., Audurier, V., Pirouz, P. and Powell, J.A. (1997) Chemomechanical polishing of silicon carbide. Journal of the Electrochemical Society, 144, L161—L163.CrossRefGoogle Scholar