Probing the Phase Transition in Nanocrystalline TiO2 Powders by Positron Lifetime (PAL) Technique


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Positron annihilation techniques (PAT) have recently been successfully employed for the characterization of phase transitions in metals and compounds. In the present study, positron annihilation lifetime (PAL) measurements have been carried out on a nanocrystalline titania (TiO2) in the form of powders that had been heat-treated at temperatures ranging from 300 to 1273K. The PAL spectra were analyzed into two lifetime components. The shorter lifetime τ1 (185-300 ps) is attributed to positron annihilation in vacancies and the longer lifetime τ1 (400-580 ps) to positrons in microviods at interfaces. The rutile phase of TiO2 powders was utilized as a reference in order to compare their behavior with the commercially supplied and widely available anatase phase (Degussa P25). The influence of the heat-treatment upon the nanostructure during the transition of the anatase to rutile phase were also investigated by X-ray diffraction (XRD), TEM and BET surface area methods. Understanding of this effect is expected to enhance our knowledge of the morphology and nanocrystallite size of TiO2 powders and their T-dependence, and hence their physical properties.



Defect and Diffusion Forum (Volumes 319-320)

Edited by:

D.J. Fisher




E.M. Hassan et al., "Probing the Phase Transition in Nanocrystalline TiO2 Powders by Positron Lifetime (PAL) Technique", Defect and Diffusion Forum, Vols. 319-320, pp. 151-159, 2011

Online since:

October 2011




[1] N.I. Al-Salim, S.A. Bagshaw, A. Bittar, T. Kemmitt, A.J. McQuillan, A.M. Mills, M.J. Ryan: J. Mater. Chem. 10 (2000) 2358–2363.

[2] S. Ito, S. Inoue, H. Kawada, M. Hara, M. Iwaski, H. Tada: J. Colloid Interface Sci., 216 (1999) 59–64.

[3] B. Yao, L. Zhang: J Mater Sci., 34 (1999) 5983-5987.

[4] A. S. Attar, S. Ghamsari , F. Hajiesmaeilbaigi, Sh. Mirdamadi, K. Katagiri, K. Koumoto: J. Mater. Sci. 43 (2008) 5924-5929.


[5] C. A. Chen, Y. S. Huang , W. H. Chung,D. S. Tsai, K. K. Tiong: J Mater. Sci.: Mater. Electron., 20 (2009) S303–S306.

[6] G. D. Parfitt, Progress in Surface and Membrane Sci., 11 (1976) 181.

[7] H.P. Boem: Adv. Catal., 16 (1966) 249.

[8] M. Primet, P. Pichat and M. V. Mathie: J. Phys. Chem., 75 (1971) 1216.

[9] J. Muscat, V. Swamy, and N. M. Harrison: Physical Review B, 65 (2002) 224112.

[10] M. J. Puska and R. M. Nieminen, Theory of Positrons in Solids and on Solid Surfaces: Reviews of Modern Physics, 66 (1994) 841.

[11] Z.S. Kajcsos, L. Liszkay, L. Varga, K. Lazar, L. Lohony: J. Radioanalytical and Nuclear Chemistry, 190 (1995) 475-480.

[12] K. Süvegh, A. Domján, R. Tarsoly, A. Viértes: J. Radioanalytical and Nuclear Chemistry, 211 (1996) 255-260475-480.

[13] C.H. Shek1, T.S. Gu, G.M. Lin, J.K.L. Lai: Appl. Phys. A, 66 (1998) 413–418.

[14] M.A. Mongea, R. Parejaa, R. Gonzaleza, Y. Chenb: J. Phys. and Chem. of Solids, 60 (1999) 291–297.

[15] J. Dryzek and E. Dryzek: Phys. Stat. Sol. (a) 199 (2003) 250–254.

[16] G.P. Karwasz et al.: Acta Physica Polonica A, 107 (2005).

[17] S. C. Glade, B. D. W., G. R. Odette, P. Asoka-Kumar: J. Nuclear Materials, 351 (2006) 197–208.

[18] A. A. Valeeva, A. A. Rempel, W. Sprengel, and H. -E. Schaefer: Physical Review B, 75, (2007) 094107.

[19] I. Prochazka et. Al.: Acta Physica Polonica A, 113 (2008) 1945-(1949).

[20] A. A. Valeeva, A. A. Rempel, W. Sprengel , and H. -E. Schaefer: Physics of the Solid State, 51 (2009) 924–929.

[21] A.K. Mishra, D. Das: Materials Science and Engineering B, 171 (2010) 5–10.

[22] J. Kansy, Nucl. Instrum. Meth. Phys. Res. A 374 (1996) 235.

[23] Y. Nagai (personal communication 2004).

[24] S. Tanigawa et al, in Proceedings of 5th ICPA, edited by R. R. Hasiguti and K. Fujiwara (The Japan Institute of Metals, Sendai, 1979) p.475.

[25] D. J. Keeble, S. Singh, R. A. Mackie, M. Morozov, S. McGuire, and D. Damjanovic: Phys. Rev. B, 76 (2007) 144109.

[26] H. Murakami, N. Onizuka, J. Sasaki, N. Thonghai: Journal of Materials Science, 33 (1998) 5811-5814.


[27] ICCD Diffraction Databases, 1994-1998. Newton Square: international Center for Diffraction Data (CDRom).

[28] B.D. Cullity: Elements of X-Ray Diffraction, Addison-Wesley Publication Company, Inc., Menlo Park, CA, p.284.