Effect of temperature on the preparation of yttrium oxide in microwave field

High-purity yttrium oxide (Y₂O₃) powder is successfully prepared by microwave-assisted calcination of yttrium oxalate. The decomposition process of yttrium oxalate was analyzed by TG-DSC indicate formation of Y₂O₃ undergoes three stages. The X-ray diffraction (XRD) analysis indicates that there is no peak of yttrium oxalate hydrate (Y₂(C₂O₄)₃‧10H₂O) after microwave-assisted calcination at 600 °C for 2 h, with the formation of cubic crystalline Y₂O₃ structure. Fourier transformed infrared spectroscopy (FT-IR) analysis show similar results with emergence of Y₂O₃ after calcination at 600 °C for 2 h. The precursor had a median particle size diameter 30.719 μm, while that of all the calcined powders at different temperatures significantly decreased to about 4 μm. Scanning electron microscopy (SEM) observations demonstrate the morphologies of the precursor and product, and the calcined Y₂O₃ preserved the amorphous character of the precursor, with rod-like shape. All the TG-DSC, XRD, FT-IR and SEM were utilized to understand the molecular changes in the process of microwave-assisted calcination of Y₂(C₂O₄)₃ to Y₂O₃.