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High-Temperature Dielectric Properties of Goethite From 400 to 3000 MHz

Published online by Cambridge University Press:  03 March 2011

C.A. Pickles ,
J. Mouris  and
R.M. Hutcheon
C.A. Pickles*
Affiliation:
Department of Mining Engineering, Queen’s University, Kingston, Ontario K7L 3N6, Canada
J. Mouris
Affiliation:
Microwave Properties North (MPN), Deep River, Ontario K0J 1P0, Canada
R.M. Hutcheon
Affiliation:
Microwave Properties North (MPN), Deep River, Ontario K0J 1P0, Canada
*
a)Address all correspondence to this author.e-mail: [email protected]
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Abstract

The dielectric properties of goethite and, in particular, the changes during the topotactic conversion of goethite to hematite were studied from room temperature to about 800 °C in the frequency range of 400 to 3000 MHz using the cavity perturbation technique. The complex permittivity, that is, both the real and the imaginary or absorptive parts (έ and ἕ), were measured under various heating regimens. In addition, thermogravimetric analysis (TGA) was performed to characterize the transformation of goethite to hematite. The Debye relaxation formalism was applied to the processes occurring both during and after the main dehydroxylation reaction to calculate the relaxation times. The Arrhenius equation for thermally activated relaxation times was used to determine the activation energies. Both the real and the absorptive parts of the permittivity exhibited a significant peak during the main part of the goethite to hematite decomposition reaction. Above the transformation, there was another, less dramatic, thermally activated increase in the permittivity values. The increase in the permittivities during the goethite to hematite transformation was attributed to the formation of quasi-free migrating radicals, for example, hydroxyl ions, oxygen ions, or hydrogen atoms, during the dehydroxylation of goethite. The derivative thermogravimetric analysis (DTGA) curve was found to be directly related to the transient values of the real and the imaginary permittivities. Higher heating rates resulted in an accelerated rate of dehydroxylation and therefore higher values of the transient permittivities. In the temperature range of 400 °C to 500 °C (i.e., just above the dehydroxylation peak), the real permittivity exhibited a varying frequency dependence, which suggested that changes were occurring in the newly formed, highly defected hematite structure, which is referred to as hydrohematite. During the reaction there were multiple relaxation processes and thus the Debye relationship could not be applied. However, at temperatures above about 500 °C, the structure stabilized, the Debye relationship was more closely followed, and the relaxation times could be determined as a function of temperature. The activation energy for the relaxation process above 500 °C was determined to be 0.47 kJ/mol.

Keywords

Chemical reactionDielectric propertiesThermogravimetric analysis (TGA)
Type
Articles
Information
Journal of Materials Research , Volume 20 , Issue 1 , January 2005 , pp. 18 - 29
Copyright
Copyright © Materials Research Society 2004

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References

REFERENCES

1Sleppy, W.C. Alumina and aluminum. Ullmann’s Encyclopedia of Chemical Technology , edited by Kroschwitz, J.I. and Howe-Craft, M., Fourth Edition (John Wiley and Sons, New York, 1992), pp. 252–256.Google Scholar
2Wefers, K. Bauxite, the principal raw material. Handbook of Extractive Metallurgy , edited by Habashi, F. (Wiley-VCH, 1997), pp. 1068–1072.Google Scholar
3Novotny, M., Solc, Z. and Trojan, M. Pigments. Ullmann’s Encyclopedia of Chemical Technology , edited by Kroschwitz, J.I. and Howe-Craft, M., Fourth Edition, (John Wiley and Sons, New York, 1992), pp. 1–40.Google Scholar
4Bate, G. In Magnetic Oxides, Part 2 , edited by Craik, D.J. (Wiley and Sons, New York, 1975), p. 689.Google Scholar
5Kathrein, H. and Leitner, L. Iron magnetic pigments. Handbook of Extractive Metallurgy , edited by Habashi, F. (Wiley-VCH, 1997), pp. 1068–1072.Google Scholar
6Wolska, E. and Schwertmann, U.: Nonstoichiometric stuctures during dehydroxylation of goethite. Zeitschrift fuer Kristallographie 189, 223 (1989).Google Scholar
7Wolska, E. and Szajda, W.: Structural and spectroscopic characteristics of synthetic hydrohematite. J. Mater. Sci. 20, 4407 (1985).CrossRefGoogle Scholar
8Wolska, E.: The structure of hydrohematite. Zeitschrift fuer Kristallographie 154, 69 (1981).Google Scholar
9Wolska, E.: Relations between the existence of hydroxyl ions in the anionic sublattice of hematite and its infrared and x-ray characteristics. Solid State Ionics 28–30, 1349 (1988).CrossRefGoogle Scholar
10Yariv, S. and Mendelovici, E.: The effect of degree of crystallinity on the infrared spectrum of hematite. Appl. Spectrosc. 33, 410 (1979).CrossRefGoogle Scholar
11Huttig, G.F. and Strotzer, E.: Die Aktiven Zustande, Welche im Verlaufe des Zersetzung des Nadeleisenerzes in α-Eisenoxyd und Wasserdampf Durchschritten Werden. Z. Anorg. Allg. Chem. 226, 97 (1936).CrossRefGoogle Scholar
12Watari, F., Delavignette, P., von Landuyt, J. and Amelinckx, S.: Electron microscopy study of dehydration transformation. Part III: High resolution observation of the reaction process FeOOH→Fe2O3. J. Solid State Chem. 48, 49 (1983).CrossRefGoogle Scholar
13Walter, D., Buxbaum, G. and Laqua, W.: The mechanism of the thermal transformation from goethite to hematite. J. Therm. Anal. Calorim. 63, 733 (2001).CrossRefGoogle Scholar
14Mackenzie, R.C. and Berggren, G. In Differential Thermal Analysis (Academic Press, 1970), pp. 271–302.Google Scholar
15Fey, M.B. and Dixon, J.B.: Synthesis and properties of poorly crystalline hydrated aluminous goethites. Clays Clay Miner. 29, 91 (1981).CrossRefGoogle Scholar
16Schulze, D.G. and Schwertmann, U.: The influence of aluminum on iron oxides: X. properties of aluminum-substituted goethites. Clay Miner. 19, 521 (1984).CrossRefGoogle Scholar
17Goss, C.J.: The kinetics and reaction mechanism of the goethite to hematite transformation. Minerals Magazine 51, 437 (1987).CrossRefGoogle Scholar
18Ruan, H.D. and Gilkes, R.J.: Dehydroxylation of aluminous goethite: Unit cell dimensions, crystal size and surface area. Clays Clay Miner. 43, 196 (1995).CrossRefGoogle Scholar
19Ruan, H.D., Frost, R.L., Kloprogge, J.T. and Duong, L.: Infrared spectroscopy of goethite dehydroxylation: III FT-IR microscopy of in situ study of the thermal transformation of goethite to hematite. Spectrochim. Acta 58A, 967 (2002).CrossRefGoogle Scholar
20Ruan, H.D. and Gilkes, R.J.: Dehydroxylation of aluminous goethite: Unit cell dimensions, crystal size and surface area. Clays Clay Miner. 43, 196 (1995).CrossRefGoogle Scholar
21Stanjek, H. and Schwertmann, U.: The influence of aluminum on iron oxides. Part XVI: Hydroxyl and aluminum substitution in synthetic hematites. Clays Clay Miner. 40, 347 (1992).CrossRefGoogle Scholar
22Kustova, G.N., Burgina, E.B., Sadykov, V.A. and Poryvaev, S.G.: Vibrational spectroscopic investigation of the goethite thermal decomposition products. Phys. Chem. Miner. 18, 379 (1992).CrossRefGoogle Scholar
23Hutcheon, R.M., De Jong, M.S., Adams, F.P., Lucuta, P.G., McGregor, J.E., and Bahen, L.: RF and microwave dielectric measurements to 1400 °C and dielectric loss mechanisms, in Microwave Processing of Materials III, edited by Beatty, R.L., Sutton, W.H., and Iskander, M.F. (Mater. Res. Soc. Symp. Proc. 269, Pittsburgh, PA, 1992), pp. 541–551.CrossRefGoogle Scholar
24Hutcheon, R.M., de Jong, M.S. and Adams, F.P.: A system for rapid measurement of RF and microwave properties up to 1400 °C. J. Micro. Power Electro. Ener. 27, 87 (1992).Google Scholar
25Kryukova, G.N., Tsybulya, S.V., Solovyeva, L.P., Sadykov, V.A., Litvak, G.S. and Andrianova, M.P.: Effect of heat treatment on the microstructure evolution of haematite derived from synthetic goethite. Mater. Sci. Eng. A 149, 121 (1991).CrossRefGoogle Scholar
26Karmazsin, E.: Use of low- and high-power microwave energy for thermal analysis. Thermochim. Acta 110, 289 (1987).CrossRefGoogle Scholar
27Karmazsin, E., Barhoumi, R., Satre, P. and Gaillard, F.: Use of microwaves in thermal analysis. J. Therm. Anal. 30, 43 (1985).CrossRefGoogle Scholar
28Karmazsin, E., Barhoumi, R. and Satre, P.: Thermal analysis with microwaves. Temperature and power control. J. Therm. Anal. 29, 269 (1984).Google Scholar
29Parkes, G.M.B., Barnes, P.A., Charsley, E.L. and Bond, G.: Microwave differential thermal analysis in the investigation of thermal transitions in materials. Anal. Chem. 71, 5026 (1999).CrossRefGoogle Scholar
30Parkes, G.M.B., Bond, G., Barnes, P.A. and Charsley, E.L.: Development of a new instrument for performing microwave thermal analysis. Rev. Sci. Instrum. 71, 168 (2000).CrossRefGoogle Scholar
31Parkes, G.M.B., Barnes, P.A., Bond, G. and Charsley, E.L.: Qualitative and quantitative aspects of microwave thermal analysis. Thermochim. Acta 356, 85 (2000).CrossRefGoogle Scholar
32Parkes, G.M.B., Barnes, P.A., Charsley, E.L. and Bond, G.: Microwave thermal analysis—A new approach to the study of the thermal and dielectric properties of materials. J. Therm. Anal. Calorim. 56, 723 (2000).CrossRefGoogle Scholar
33Hutcheon, R.M., Hayward, P., Smith, B.H. and Alexander, S.B.: High temperature dielectric constant measurement—Another analytical tool for ceramic studies, microwaves: Theory and application in materials processing III, ceramic transactions. American Ceramic Society 59, 235 (1995).Google Scholar
34Wynne-Jones, W.F.K. and Eyring, H.: The absolute rate of reactions in condensed phases. J. Chem. Phys. 3, 492 (1935).CrossRefGoogle Scholar
35Eyring, H.: Viscosity, Plasticity and diffusion as examples of absolute reaction rates. J. Chem. Phys. 4, 283 (1936).CrossRefGoogle Scholar