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Formation of ZrO₂ by the Thermal Decomposition of Zirconium Salts

Goran Štefanić ; Ruđer Bošković Institute, P. O. Box 1016, 10001 Zagreb, Croatia
Svetozar Musić ; Ruđer Bošković Institute, P. O. Box 1016, 10001 Zagreb, Croatia
Stanko Popović ; Ruđer Bošković Institute, P. O. Box 1016, 10001 Zagreb, Croatia
Krešimir Furić ; Ruđer Bošković Institute, P. O. Box 1016, 10001 Zagreb, Croatia

Sažetak

Hydrated zirconium salts containing Cl- , NO3- or SO42- anions were thermally treated up to 1300 °C. The thermal decomposition products were investigated using the X-ray diffraction (XRD), Fourier transform IR spectroscopy (FT-IR) and laser Raman spectroscopy. The thermal decomposition products of all three zirconium salts, characterized as amorphous material, showed a maximum of X-ray scattering at -16° and also in the corresponding FT-IR spectra a broad band at 450 cm-1. With an increase of the heating temperature of all three salts (400 °C for ZrOCl2 ∙ 8H2O, 400 °C for ZrO(NO3)2 ∙ 2H2O and 700 °C for Zr(SO4)2 ∙ 4H2O), the metastable f-ZrC>2 was formed, which disappeared on further heating to higher temperatures. The yield of f-ZrC>2, measured by XRD, depended on the nature of the starting salt, and the highest value was obtained for ZrOCl2 ∙ 8H2O salt. The t-ZrO2 phase formed from ZrOCl2 ∙ 8H2O was thermally most unstable, while the presence of a small amount of t-ZrO2 was observed in the thermal decomposition product obtained by heating Zr(SO4)2 ∙ 4H2O even at 1300 °C. Metastable t-ZrO2, generated by the thermal decomposition of ZrOCl2 ∙ 8H2O or ZrO(NO3)2 ∙ 2H2O salt, was highly sensitive to mechanical treatment, while metastable t-ZrO2 formed from Zr(SO4)2 ∙ 4H2O was stable during the same process. The nature of the starting salt influenced the formation of metastable t-ZrO2, however, when t-ZrO2 was once formed, its stability depended on the anionic impurities that remained in the oxide material.

Ključne riječi

Hrčak ID:

135956

URI

https://hrcak.srce.hr/135956

Datum izdavanja:

4.3.1996.

Posjeta: 1.803 *