Yttrium -nitrate.hexahydrate

UH609S uranyl sulfate trihydrate 20910-28-J 5 25.00 3 2800 1 1 4981 YH12N3015 yttrium nitrate hexahydrate 13494-98-J J 25.00 2.680C 1... 

Europium-doped yttria particles were synthesized by Lee et al. [289] from a two-microemulsion system in which aqueous solutions of yttrium nitrate hexahydrate/europium nitrate hexahydrate or ammonium hydroxide constituted the water phase, a 2 1 (wt ratio) mixture of NP-5 and NP-9 was used as the surfactant and cyclohexane was the continuous phase. The two microemulsions were mixed together with 2 hours stirring at 30 C and the microemulsion was broken by addition of acetone. The mixed hydroxide precipitates were washed with acetone... 

Nanocrystalline yttria (Y2O3) powders with most suitable characteristics for the fabrication of yttria crucibles were synthesized by the sol-gel method [85]. The combustion synthesis method was used starting with high-purity (99.9%) yttrium nitrate hexahydrate and citric acid. Different fuel to oxidant (citric acid/nitrate) ratios (0.25, 0.5, 0.75, 1.0, and 1.1) were tested. These mixtures were heated at 373 K until a viscous gel was formed, and its decomposition into powder formation was realized by thermal treatment at 473 K for 3 h. In all mixtures, yttria powders were obtained by thermal treatment at 1073 K. Scanning electron microscopy (SEM) showed that these powders were porous, whereas high-resolution transmission electron microscopy (HRTEM) revealed that they consist of randomly oriented cuboidal nanocrystallites with an average crystallite size of about 17-30 nm. In order to obtain dense ceramics, the powders were compacted as pellets at 120 MPa and were sintered at 1673 K. Pellets with a sintered density as high as 98-99% of the theoretical density could be obtained from powders prepared with fuel to oxidant ratios (/ ) of 0.75 and 1.0. 

Dissolve the sample and 10 mg of beryllium metal in 10 ml 6 M hydrofluoric acid in a plastic bottle. Add 2 ml concentrated hydrofluoric acid. Add the solution to the top of a teflon column (i.d. 1.8 cm height 40 cm) filled with 30 g of Dowex 1X8 resin kept at room temperature. The resin was previously converted to the fluoride form by washing with 250 ml 6 M hydrofluoric acid. Elute with 6 M hydrofluoric acid at a 2.5 ml/min flow rate. After discarding the first 80 ml of eluate, collect the next 200 ml. Add dropwise 50 mg of yttrium nitrate hexahydrate dissolved in 10 ml of water while stirring with a magnetic stirrer. Continue stirring for 15 min. 

Dissolve the sample as for zirconium. Add 2 ml hydrogen peroxide (30 %) and 2 ml hydrogen fluoride (50 %). Add the solution onto the column and elute as for zirconium, collecting the fraction of the eluate between 80 and 280 ml. Precipitate yttrium fluoride at 70-80 C and stir for one hour. Filter off on a membrane filter. Dissolve 50 mg vanadium(III) oxide, 50 mg manganese(II) chloride dihydrate and 50 mg cobalt(II) chloride hexahydrate in the filtrate and add dropwise 6 ml 0.5 M barium nitrate while stirring. Filter off the precipitate, wash with ethanol and dry at 80°C. 

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