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Journal of Thermal Analysis and Calorimetry
Authors: Soraia de Souza, Mary Alves, A. de Oliveira, E. Longo, F. Ticiano Gomes Vieira, Rodinei Gomes, L. Soledade, A. de Souza, and Iêda Garcia dos Santos

Abstract  

In this work, the synthesis of Nd-doped SrSnO3 by the polymeric precursor method, with calcination between 250 and 700 °C is reported. The powder precursors were characterized by TG/DTA and high temperature X-ray diffraction (HTXRD). After heat treatment, the material was characterized by XRD and infrared spectroscopy. Ester and carbonate amounts were strictly related to Nd-doping. According to XRD patterns, the orthorhombic perovskite was obtained at 700 °C for SrSnO3 and SrSn0.99Nd0.01O3. For Sr0.99Nd0.01SnO3, the kinetics displayed an important hole in the crystallization process, as no peak was observed in HTXRD up to 700 °C, while a XRD patterns showed a crystalline material after calcination at 250 °C.

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Journal of Thermal Analysis and Calorimetry
Authors: Mary Alves, Soraia Souza, Márcia Silva, Elaine Paris, S. Lima, R. Gomes, E. Longo, A. de Souza, and Iêda Garcia dos Santos

Abstract  

SrSnO3 was synthesized by the polymeric precursor method with elimination of carbon in oxygen atmosphere at 250 °C for 24 h. The powder precursors were characterized by TG/DTA and high temperature X-ray diffraction (HTXRD). After calcination at 500, 600 and 700 °C for 2 h, samples were evaluated by X-ray diffraction (XRD), infrared spectroscopy (IR) and Rietveld refinement of the XRD patterns for samples calcined at 900, 1,000 and 1,100 °C. During thermal treatment of the powder precursor ester combustion was followed by carbonate decomposition and perovskite crystallization. No phase transition was observed as usually presented in literature for SrSnO3 that had only a rearrangement of SnO6 polyhedra.

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Journal of Thermal Analysis and Calorimetry
Authors: F. T. G. Vieira, A. L. M. Oliveira, D. S. Melo, S. J. G. Lima, E. Longo, A. S. Maia, A. G. Souza, and I. M. G. Santos

composition, perovskite materials have attracted interest in many applied and fundamental areas of solid state chemistry, physics, advanced materials, and catalysis [ 2 ]. Alkaline earth stannates have recently become important materials in ceramic technology

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Journal of Thermal Analysis and Calorimetry
Authors: D. Melo, R. M. M. Marinho, F. T. G. Vieira, S. J. G. Lima, E. Longo, A. G. Souza, A. S. Maia, and I. M. G. Santos

cations of different sizes and oxidation states, besides cationic and anionic vacancies [ 4 ]. Among perovskite, alkaline earth stannates (ASnO 3 ) stand out, due to applications as thermally stable capacitors, gas sensors, including CO, NO x and

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Abstract  

Inorganic pigments containing lanthanides based on orthorhombic perovskite structure of CaSnO3 have been prepared by solid state reaction of CaCO3, SnO2 and lanthanide oxides (Tb4O7, Pr6O11, CeO2). The TG-DTA analysis indicates the formation of Ca-stannates around of temperature 1200°C, but from the pigmentary — application point of view, it is better to synthesize the product at higher temperature (1400 or 1500°C). The resultant materials were characterised by XRD, particle size distribution and measurement of colour properties. The doping of Ca-stannates by ions of rare earth elements (Tb, Pr, Ce) brings the production of two-and three-phase systems. The most interesting colour properties provided the stannate doped by ions of terbium and cerium and synthesized by heating at temperature 1400°C. The pigment has reddish brown colour hue.

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Abstract  

This article presents, 122Sb (T 1/2 = 2.723 days, I β- = 97.59%) was produced via the natSn(p,xn) nuclear process at the AMIRS (Cyclone-30, IBA, Belgium). The electrodeposition experiments were carried out by potassium stannate trihydrate (K2Sn(OH)6) and potassium hydroxide. The optimum conditions of the electrodeposition of tin were as follows: 40 g/L natSn, 20 g/L KOH, 115 g/L K2Sn(OH)6, DC current density of 5 A/dm2 with a bath temperature of 75 °C. The electroplated Tin-target was irradiated with 26.5 MeV protons at current of 180 μA for 20 min. Solvent extraction of no-carrier-added 122Sb from irradiated Tin-natural target hydrochloric solution was investigated using di-n-butyl ether (C8H18O). Yields of about 3.61 MBq/μAh were experimentally obtained.

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Journal of Thermal Analysis and Calorimetry
Authors: Vittorio Berbenni, Chiara Milanese, Giovanna Bruni, Alessandro Girella, and Amedeo Marini

. References 1. Raghavan , S . 1987 . Gibbs free energy of formation of magnesium stannate from EMF measurement . Thermochim Acta . 122 : 389 – 393 10

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.1016/0079-6786(83)90001-8 . 5. Lian , J , Helean , KB , Kennedy , BJ , Wang , LM , Navrotsky , A , Ewing , RC 2006 Effect of structure and thermodynamic stability on the response of lanthanide stannate pyrochlores to ion beam irradiation

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)00360-3 . 9. Coles , GSV , Bond , SE , Williams , G . 1994 . Metal stannates and their role as potential gas-sensing elements . J Mater Chem . 4 : 23 – 27 10.1039/jm9940400023 . 10

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Reaction Kinetics, Mechanisms and Catalysis
Authors: Viorel Chihaia, Karl Sohlberg, M. Scurtu, S. Mihaiu, M. Caldararu, and M. Zaharescu

8 . The pure-phase cerium stannate pyrochlore (Ce 2 Sn 2 O 7 ) has been prepared for the first time by solid state reaction of CeO 2 , SnO 2 and metallic tin. The redox properties of Ce x Sn 1− x O 2 mixed oxides allowed their use as high

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