Electron microscopic investigation of yttrium aluminum garnet powders Y3Al5O12, synthesized by sol–gel method

• Published in: Nauchno-tekhnicheskiĭ vestnik informat͡s︡ionnykh tekhnologiĭ, mekhaniki i optiki mekhaniki i optiki, 2015-09, Vol.15 (5), p.789-795
• Main Authors: Baranchikov, A.E., Maslov, V.A., Shcherbakov, V.V., Usachyov, V.A., Kononenko, N.E., Fedorov, P.P., Dukel’skiy, K.V.
• Format: Article
• Language: English
• Subjects: laser ceramics; nanopowders; precursor; yttrium aluminum garnet
• ISSN: 2226-1494; 2500-0373
• DOI: 10.17586/2226-1494-2015-15-5-789-795

Subject of Study. The paper presents results of characterization for neodymium doped yttrium aluminum garnet nanopowders - YAG:Nd3+ by the method of scanning electronic microscopy. Method. Synthesis of YAG:Nd3+ was carried out by sol-gel method from nitrate or acetate - nitrate solutions with addition of some organic compounds and ammonia as well. Such substances were used as the source ones: oxides of neodymium and yttrium with the content of the basic substance equal to 99.999 %; organic compounds: citric acid with the content of the basic substance not less than 99.0 %; ethylene glycol (99.5%); the ammonium lauryl sulfate (99.0 %); urea (99.0 %) of Alfa Aesar, Fluka, Aldrich companies. Oxides of yttrium and neodymium (5 at. %) were dissolved in 50% acetic acid, nitrate aluminum was added with a view to the resulting product Y2,85Nd0,15Al5,0O12, the solution was stirred and heated to 60С before reaching its transparency and uniformity. The weight of the portion corresponding to the stoichiometry YAG was 2.0 g. 50 % aqueous solutions of organic substances or 5% NH4OH in a weight ratio of 1:1 to the weight of the garnet were added in aqueous solutions, placed into glass cups. The solutions were thoroughly mixed first using a conventional stirrer, then on ultrasonic installation with simultaneous 60 С heating for 2 hours. Drying of solutions to the consistency of a powder or a thick gel was carried out at 110 С. Then the samples were placed into platinum cups and annealed in a tube furnace at 950 - 1050 С for the period from 0.5 to 2 hours. Additional annealing of the powders in the air at 950 - 1060С were carried out for the purpose of powders clarifying for residual amorphous carbon removal. Main Results. The synthesized powder precursors and powders after annealing were examined using a polarizing microscope to identify anisotropic crystalline phases. X-ray analysis of the synthesized samples was carried out on a DRON - 4 and UDR - 63 diffractometers, radiation λCu Kα. Carl Zeiss NVision 40 electron microscope was used for the study by scanning electron microscopy (SEM). The results indicate significant effects of additives in the original acetate - nitrate solutions on the size and morphology of the particles during the synthesis of powders of yttrium aluminum garnet by sol-gel method. Relatively large particles not susceptible to the mutual sintering were obtained by using ethylene glycol and ammonium lauryl sulfate as additives. Practical Relevance.