Co-precipitation synthesis of Nd:YAG nanopowders: the effect of joint thermal and mechanical treatment

Maria Luisa Saladino 1Eugenio Caponetti 1Filomena Serra 2Stefano Enzo 2

1. Università di Palermo (UNIPA), Viale delle Scienze, Pallermo 90128, Italy
2. Università di Sassari, Sassari, Italy

Abstract

Nanopowders of Yttrium Aluminium Garnet (YAG) doped with neodymium ions were obtained by the co-precipitation method from the reaction of aluminium and yttrium nitrate and neodymium oxide with ammonia giving samples of nominal stoichiometry NdX:Y(3-X)Al5O12 (where X = 0, 0.02, 0.05, 0.10, 0.19, 0.38, 0.72). After washing and drying, the hydroxide precursors were heat treated for different times and temperature. Differential Thermal Analysis curves (DTA) from room temperature up to 1000 C show the presence of exothermal events accompanying phase transformation phenomena. X-ray diffraction (XRD) investigations conducted with a high-resolution powder diffractometer on the specimens calcined at high-temperature show that the samples are single phase garnet except for the highest concentration of Nd, where a minor hexagonal YAlO3 phase may also be present. Precise determination of the cubic garnet lattice parameters as a function of the Neodymium content according to the Rietveld method shows a parabolic increase from the value of 12.022 (±2) Å for XNd = 0 up to 12.128 (±2) Å for XNd= 0.72. The line broadening analysis after correction for instrumental factors indicates that the average crystallite size is in the range 50-70 nm. Results will be presented and discussed concerning the role of a mechanical treatment on the amorphous powder in order to skip kinetically the formation of metastable phases and to favor precipitation of the garnet with consistent neodymium content.

 

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Presentation: poster at E-MRS Fall Meeting 2005, Laser Ceramic Symposium, by Maria Luisa Saladino
See On-line Journal of E-MRS Fall Meeting 2005

Submitted: 2005-06-03 08:48
Revised:   2009-06-07 00:44