Synthesis of Highly Sinterable Neodymium Ion doped Yttrium Oxide Nanopowders by Microwave Assisted Nitrate-Alanine Gel Combustion

Abstract

Microwave assisted gel combustion synthesis of neodymium doped yttria (Nd:Y₂O₃) nanopowders using L-alanine complexing agent is being reported. Gelation of metal nitrates with L-alanine followed by combustion in microwave and subsequent calcinations at 1000°C for 3 h under oxygen supply gave phase pure nanopowders characterized by FTIR and XRD. Highly sinterable Nd:Y2O3 nanopowders with size range 20–80 nm, close to spherical and uniform morphology were obtained as observed by TEM compared to particles in size range 40–160 nm, with polyhedral morphology, obtained by sol-gel route. Compaction of calcined powders by cold isostatic press at 400 MPa followed by sintering at 1700°C for 7 h gave ceramic with 26% transmission which increased to 32% after 10 h without any sintering aid for microwave gel combustion compact, compared to 6.7% transmission for sol-gel route compacts. XRD of sintered samples showed retention of phase purity in all the cases. SEM of sintered samples showed good grain fusion for close to spherical particles of microwave assisted gel combustion route than polyhedral particles of sol-gel route. Since spherical particles undergo faster densification and sintering, microwave assisted route gave highly sinterable nanopowders compared to sol-gel route.

Keywords:

• Yttria
• Ceramics
• Nanopowder
• Sintering
• Combustion