Thermaland X-ray diffraction studies of the solid–solid interactions in CuO–MoO3/MgOsystem

详细信息    查看全文

• 作者：H. G. El-Shobaky
• 关键词：Cu2MgO3 ; CuMoO4 ; CuO ; MgMoO4 ; MgO ; MoO3 ; solid solution
• 刊名：Journal of Thermal Analysis and Calorimetry
• 出版年：2006
• 出版时间：August, 2006
• 年：2006
• 卷：85
• 期：2
• 页码：321-327
• 全文大小：233 KB
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Chemistry
  Sciences
  Polymer Sciences
  Physical Chemistry
  Inorganic Chemistry
  Measurement Science and Instrumentation
  
• 出版者：Akad茅miai Kiad贸, co-published with Springer Science+Business Media B.V., Formerly Kluwer Academic
• ISSN：1572-8943

文摘

The solid–solid interactions in pure and MoO₃-doped CuO/MgO system were investigated using TG, DTA and XRD. The composition of pure mixed solids were 0.1CuO/MgO, 0.2CuO/MgO and 0.3CuO/MgO and the concentrations of MoO₃ were 2.5 and 5 mol%. These solids were prepared by wet impregnation of finely powdered basic magnesium carbonate with solutions containing calculated amounts of copper nitrate and ammonium molybdate followed by heating at 400–1000°C. The results revealed that ammonium molybdate doping of the system investigated enhanced the thermal decomposition of copper nitrate and magnesium hydroxide which decomposed at temperatures lower than those observed in case of the undoped mixed solids by 70 and 100°C, respectively. A portion of CuO present dissolved in the lattice of MgO forming CuO–MgO solid solution with subsequent limited increase in its lattice parameter. The other portion interacted readily with a portion of MoO₃ at temperatures starting from 400°C yielding CuMoO₄ which remained stable up to 1000°C. The other portion of MoO₃ interacted with MgO producing MgMoO₄ at temperatures starting from 400°C and remained also stable at 1000°C. The diffraction peaks of Cu₂MgO₃ phase were detected in the diffractograms of pure and MoO₃-doped 0.3CuO/MgO precalcined at 1000°C. The formation of this phase was accompanied by an endothermic peak at 930°C.