Effect of complexing agents on the powder characteristics and sinterability of neodymium doped yttria nanoparticles

We report the synthesis of neodymium doped cubic yttria (Nd:Y2O3) nanopowders by microwave assisted combustion method using citric acid, urea and l-alanine as complexing agents as well as fuels. FTIR and XRD of powders calcined at 1000°C for 3h in oxygen atmosphere demonstrated formation and phase purity of Nd:Y2O3 respectively. Varied morphologies of as prepared precursor and calcined oxide (from polyhedral to spheroidal) due to different complexing agents were observed by SEM and TEM. Sintering of these nanopowders with different morphologies after compaction by cold isostatic press at 400MPa at 1700°C for 10h under 10−5mbar vacuum gave maximum densification with 32.5% transmission by using l-alanine compared to 20% and 8% transmission obtained for urea and citric acid respectively. Thus l-alanine gave highly sinterable nanopowders with narrow size range of 25–40nm with close to spherical morphology. Highly sinterable Nd doped cubic yttria nanopowders were synthesized by microwave gel combustion method using l-alanine as complexing agents and compared with citric acid and urea. Phase purity was achieved in all cases with varied morphologies by TEM. With l-alanine yttria with spherical shape and size range 25–40nm resulted in maximum transmission of 32.5%. Fig TEM of Nd:Y2O3 nanopowders calcined at 1000°C for 3h using (a) citric acid, (b) urea and (c) alanine. [Display omitted] ► Effect on Nd:Y2O3 particle morphology of l-alanine, urea and citric acid was studied. ► Spherical morphology with narrow size range of 25–40nm was obtained for l-alanine. ► Highly sinterable powders were obtained with l-alanine with 32.5% transmission.