Microwave-assisted synthesis of micro/nano NdO powders

Abstract

This paper reports the synthesis of Nd2(C2O4)3.10H2O with plate-like morphology employing the microwave-assisted precipitation as a new strategy. Thermogravimetric analysis (TGA-DTG) results supported the presence of 10 water molecules of hydration of the prepared neodymium oxalate, which decomposes to give neodymium oxide (Nd2O3) as a final product throughout the dioxy-carbonate intermediate formation. Based on its thermal behaviour, portions of the prepared neodymium oxalate were heated non-isothermally, utilizing a similar heating rate to that used in the TGA experiment, at the range 400–800 °C, then quenched to room temperature. Phase characterization indicated the formation of an amorphous carbonate phase at 400 °C, which crystallizes at 500 °C giving the hexagonal Nd2O2CO3 phase. The formed Nd2O3 at the range 700–800 °C was found to have a high ability to absorb atmospheric water vapour forming Nd(OH)3. The electrical conductivity measurements revealed strong dependence on the pre-treatment temperature, where the Nd-600 sample showed the highest values. The fluorescent properties of the pre-heated solids revealed the absence of a notable peak shift and fluorescence behaviour of the various samples was correlated with the structure modifications occurring during the pre-treatment.

Keywords

• Neodymium oxalate
• Nd2O3
• Rare earth oxides
• Microwave synthesis
• Electrical conductivity