Variation of Some Physical Properties of Brownmillerite Doped with a Transition Metal Oxide
Cement clinker is the main component of Portland cement. It is composed of four main phases. One of them is the brownmillerite or the ferrite phase of cement clinker. It is prepared according to the formula (4CaO)(Al2O3)(Fe2O3)l−x (M) x , where M represents transition metal oxides (TMO): TiO2, Cr2O3, Mn2O3 and WO3, where x = 1, 2, 3, 4 and 5 mol%. Each mixture was fired at 1300°C for 30 minutes in a platinum crucible. The samples were pulverized for Mössbauer spectroscopy, X-ray diffraction and a.c. conductivity measurements. A shift in the position of the characterized peaks of pure brownmillerite appears in the X-ray diffraction patterns of brownmillerite doped with a transition metal oxide. The a.c. conductivity showed a maximum value for the samples containing 3 mol% TiO2, Cr2O3 and Mn2O3, and 2 mol% WO3. The Mössbauer parameters for the sample containing 5 mol% M showed a gradual increase in the isomer shift values. The number of electrons in d-orbital for the doped transition atoms, as the nearest neighbor atoms increased from 2 to 5 electrons. The hyperfine magnetic field at Fe3+ (Oh) iron nucleus decreases with increasing M content. This may be due to the decrease of the particle size of brownmillerite.
Key wordsbrownmillerite physical properties cement Mössbauer
Unable to display preview. Download preview PDF.
- 2.Odler, I. and Wonnemann, R., ibid 13 (1983), 477.Google Scholar
- 4.Hassaan, M. Y., Eissa, N. A. and Salah, S. H., TIZ International Powder Magazine 114 (5) (1990), 346.Google Scholar
- 6.Odler, I. and Schmidt, O., ibid 63 (1-2) (1988), 13.Google Scholar
- 7.Hassaan, M. Y., Panteleev, D. and Salah, S. H., Hyp. Interact. 71 (1992), 1389.Google Scholar
- 8.Tareev, B., Physics of Dielectric Materials, Mir Publishers, Moscow, 1979.Google Scholar
- 9.Sayer, M. and Mansingh, A., Phys. Rev. Rev. B 6 (1972), 4629.Google Scholar
- 10.Bhide, V. J., Mössbauer Effect and Its Applications, McGraw-Hill, New Dellhi, 1973, p. 182.Google Scholar
- 11.Salah, S. H., PhD Thesis, Al-Azhar University, Cairo, Egypt, 1979.Google Scholar