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Photoluminescence properties of ZrO2:Gd3+, ZrO2:Gd3+ – Dy3+ and ZrO2:Gd3+ – Yb3+ phosphors by Pechini method

Yildiz E.

Materials Science Poland

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2018

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Vol. 36, No. 1

157--161

EN

Zr0.99Gd0.01O2, Zr0.98Gd0.01Dy0.01O2 and Zr0.99Gd0.01Yb0.1O2 phosphors were synthesized by Pechini method at 1200 °C for 12 h in air. The phosphors were characterized by using X-ray powder diffraction (XRD), differential thermal analysis/thermal gravimetry (DTA/TG), scanning electron microscopy (SEM) and photoluminescence spectrofluorometer (PL). X-ray powder diffraction studies showed that the phosphors were crystallized as monoclinic and tetragonal multiphases. The particle size of the phosphors after heat treatment at 1200 °C was found to be of 200 nm to 250 nm. Luminescence studies on these phosphors have been carried out on the emission and excitation, along with lifetime measurements. The results of emission analysis indicate that the phosphors are expected to find potential applications as new optical materials.

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Synthesis of nanocrystalline Ni/Ce-YSZ powder via a polymerization route

Abolghasemi Z., Tamizifar M., Arzani K., Nemati A., Khanfekr A., Bolandi M.

Materials Science Poland

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2013

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Vol. 31, No. 3

343--349

EN

Pechini process was used for preparation of three kinds of nanocrystalline powders of yttria-stabilized zirconia (YSZ): doped with 1.5 mol% nickel oxide, doped with 15 mol% ceria, and doped with 1.5 mol% nickel oxide plus 15 mol% ceria. Zirconium chloride, yttrium nitrate, cerium nitrate, nickel nitrate, citric acid and ethylene glycol were polymerized at 80 A degrees C to produce a gel. XRD, SEM and TEM analyses were used to investigate the crystalline phases and microstructures of obtained compounds. The results of XRD revealed the formation of nanocrystalline powder at 900 A degrees C. Morphology of the powder calcined at 900 A degrees C, examined with a scanning electron microscope, showed that the presence of nickel and cerium inhibited the grain growth in the system. The average crystallite size of the material doped with nickel oxide (9.33 nm) was bigger than the one doped with cerium oxide (9.29 nm), while the YSZ doping with the two oxides simultaneously promoted the grain growth with crystallite size of 11.37 nm. Yttria-stabilized zirconia powder with a mean crystallite size of 9.997 nm was prepared successfully by this method.

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Nowa metoda syntezy krzemianu trójwapniowego i alitu

Sorrentino F.

Cement Wapno Beton

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2008

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R. 13/75, nr 4

177-183

PL

Spalanie paliw alternatywnych wprowadza domieszkowe składniki do faz klinkierowych, a szczególnie do alitu. Badania wpływu tych domieszek na reaktywność alitu napotykają na trudności wynikające z dostępności większych ilości syntetycznego alitu. Do tej pory synteza tej fazy ograniczała się tylko do badań krystalograficznych i do pomiarów danych termodynamicznych. W artykule porównujemy znane syntezy czystego krzemianu trójwapniowego lub alitu zawierającego roztwory stałe i opisujemy modyfikacje procesu Pechiniego stosowanego w przemyśle ceramicznym. Ten proces pozwala na produkcję większych ilości C3S lub alitu i stwarza nowe możliwości badawcze.

EN

Burning secondary combustibles, using wastes as substituted raw material introduce minor elements into the clinker phases and particularly in the alite. The researches on the influence of these elements on the reactivity of alite have been limited by the availability of large quantity of synthetic material (i.e. C3S, alite,). Up to now, the synthesis of these products have been restricted to crystallography, standard for analysis or for measurement of thermo-dynamic data. In this paper, we compare the existing process to synthesize pure tricalcium silicate or solid solution (alite) and we describe a modification of the Pechini process, originated from the ceramic industry. This process that allows a large scale production of C3S or alite, and thus opens the door to fruitful researches.