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Preparation and sintering of nanometric oxides and YAG powders derived from nitrates by precipitation and co-precipitatin method
|Zdzislaw M. Librant 1, Helena Węglarz 1, Tadeusz Łukasiewicz 1, Krzysztof Haberko 2|
1. Institute of Electronic Materials Technology (ITME), Wólczyńska 133, Warszawa 01-919, Poland
Ammonium hydrogen carbonate was applied as precipitant for production of yttrium and neodymium oxides and YAG nanopowders from solution of nitrates. Loose agglomerates of oxide powders derived from proper precursors have crystallite sizes well below 50 nm. Powders were calcined up to 1100oC, milled, mixed in proper proportions for solid state reaction synthesis, and densified by isostatic pressing at the pressure of 200 MPa. For the solid state reaction synthesis of YAG and 1at.%Nd:YAG, commercial Taimei alumina was applied. X-ray diffraction analysis have shown at the low calcination temperatures, presence of YAP phase, which disapear at 1000oC and only YAG phase remains. Powder compacts were sintered in vacuum (10-6Tr) within the temperature range of 1700-1780oC and holding time up to 60 hours. Several samples were prepared with 0,5% of tetraethyl orthosilicate (TEOS) as sintering aid. After grinding and polishing of sample surfaces good translucency and even transparency was found. As a quality indicator of microstructure of produced samples, optical transmission spectra in the infrared wavelength region was measured in relation to YAG and Nd:YAG single crystals. Only 70% of transmittance of YAG single crystal at the upper wave region was achieved. Positive effects of added sintering aids (TEOS) on final microstructure was not found.
Presentation: poster at E-MRS Fall Meeting 2005, Laser Ceramic Symposium, by Zdzislaw M. Librant
See On-line Journal of E-MRS Fall Meeting 2005
Submitted: 2005-06-17 14:14 Revised: 2009-06-07 00:44