Formation of dysprosium oxide from the thermal decomposition of hydrated dysprosium acetate and oxalate Thermoanalytical and microscopic studies

Formation of dysprosium oxide from the thermal decomposition of hydrated dysprosium acetate and oxalate Thermoanalytical and microscopic studies

Thermogravimetry, differential thermal analysis, X-ray diffractometry, gas chromatography-mass spectrometry and scanning electron microscopy were used to characterize the course of Dy2O3 from hydrated acetate and oxalate of dysprosium in an atmosphere of air. The results show that Dy(CH3COO)3 · 4H2O...

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Bibliographic Details
Published in:Journal of analytical and applied pyrolysis Vol. 39; no. 1; pp. 35 - 51
Main Authors: Hussein, G.A.M., Kroenke, W.J., Goda, B., Miyaji, K.
Format: Journal Article
Language:English
Published: Elsevier B.V 01-01-1997
Subjects:
Decomposition
Differential thermal analysis
Dysprosium acetate
Dysprosium oxalate
Dysprosium oxide
Gas chromatography-mass spectrometry
Pyrolysis
Scanning electon microscopy
Thermogravimetry
X-ray diffractometry
Pyrolysis
Dysprosium oxalate
Dysprosium oxide
Scanning electon microscopy
Dysprosium acetate
X-ray diffractometry
Thermogravimetry
Decomposition
Differential thermal analysis
Gas chromatography-mass spectrometry
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Summary:Thermogravimetry, differential thermal analysis, X-ray diffractometry, gas chromatography-mass spectrometry and scanning electron microscopy were used to characterize the course of Dy2O3 from hydrated acetate and oxalate of dysprosium in an atmosphere of air. The results show that Dy(CH3COO)3 · 4H2O dehydrates completely in two steps at 90 and 150°C and decomposes to Dy2O2 at 580 °C through a noncrystalline intermediate, Dy(OH)(CH3COO)2, at 355 °C, Dy(O)(CH3COO) at 380 °C, and crystalline Dy2O2CO3 at 415 °C. For Dy2(C2O4)3 ° 7H2O, the dehydration occurs in five steps at 100, 196, 227, 300 and 380 °C, forming an anhydrous oxalate, which is amorphous and unstable. The anhydrous oxalate immediately decomposes to Dy2O3 at 610°C through two amorphous intermediates, Dy2(CO3)3 and Dy2O2CO3, that form at 436 and 455°C, respectively. The crystalline oxide obtained from the acetate precursor contains large pores compared to the oxide obtained from the oxalate precursor. The volatile decomposition products from the acetate and oxalate precursors are water vapor, acetic acid, ketene, acetone and methane.
ISSN:0165-2370
1873-250X
DOI:10.1016/S0165-2370(96)00961-8