Synthesis and Characterization of Nanocrystalline Thoria Obtained from Thermally Decomposed Thorium Carbonate

Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, India
Journal of Nuclear Materials (Impact Factor: 1.87). 06/2002; 303(2-3):156-168. DOI: 10.1016/S0022-3115(02)00816-4


Nanocrystalline thoria was synthesized by temperature programmed decomposition of Th(CO3)2 in an evolved gas analysis mass spectrometer set-up. The structural and stoichiometric changes encountered in the decomposition pathway were studied by off-line thermogravimetry (TGA), X-ray diffraction and X-ray photoelectron spectroscopy (XPS). Accurate conversion temperature for transformation of Th(CO3)2→ThO2 was arrived from the XPS measurements. Fourier transform infrared (FT-IR) measurements were used to compare vibrational activities of nano and bulk polycrystalline thoria. Raman spectroscopic studies indicated optical phonon confinement effects in nanocrystalline thoria. High resolution transmission electron microscopic examination on starting material, intermediates and nanocrystalline final product were carried out for studying the microstructure in the nanometer scale.

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    • "aqueous systems, different hydroxilated species of thorium(IV) can be formed (Mompean et al. 2008), which together with the thorium(IV) ion are usually bound to different types of particle surfaces (Geibert and Usbeck 2004), such as colloids and/or solid hydroxides and oxides (Altmaier et al. 2004; Neck et al. 2003; Bitea et al. 2003; Rothe et al. 2002; Ansoborlo et al. 2006). Notwithstanding, important applications of thoria nanoparticles in the nuclear industry are still in use (IAEA 2005), although synthesis of thoria nanomaterial has received little attention (Dash et al. 2002). Therefore, there is a great interest in the study of nanocrystalline thoria with minimum carry over of impurity phases during synthesis. "
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