Densification of Mn-doped tin oxide films by conventional heating and microwave heating treatment

Mn(II) doped SnO2 thin films used for shielding fluoride glasses against corrosion were investigated by x-ray absorption spectroscopy (EXAFS and XANE)S at the Sn and Mn K-edges. The effect of firing treatment on the densification of the films was studied. It has been evidenced a partial change of Mn valence from 2.3 to 2.6 upon heating which is attributed to a change of ratios of two Mn sites: grafted divalent Mn ions at the surface of SnO 2 nanocrystallites and trivalent Mn ions embedded into a substitutional solid solution with Sn. © Physica Scripta 2005.

Corrosion protection of fluorzirconate glasses coated by a layer of surface modified tin oxide nanoparticles

The protection efficiency against water corrosion of fluorozirconate glass, ZBLAN, dip-coated by nanocrystalline tin oxide film containing the organic molecule Tiron® was investigated by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The chemical bonding structure of the surface region and morphology were studied before and after two water exposure periods of 5 and 30 min. The results of the analysis for the as-grown sample revealed a SnO1.6 phase containing carbon and sulfur, related to Tiron®, and traces of elements related to ZBLAN (Zr, F, Ba). This fact and the clear evidence of the presence of tin oxifluoride specie (SnOxF y) indicates a diffusion of the glass components into the porous coating. After water exposure, the increase of the oxygen concentration accompanied by a strong increase of Zr, F, Ba and Na content is interpreted as filling of the nanopores of the film by glass compounds. The formation of a compact protective layer is supported by the morphological changes observed by AFM. © 2005 Elsevier B.V. All rights reserved.

Turning of compacted graphite iron using commercial tiN coated Si 3N4 under dry machining conditions

Due to their high hardness and wear resistance Si3N4 based ceramics are one of the most suitable cutting tool materials for machining hardened materials. Therefore, their high degree of brittleness usually leads to inconsistent results and sudden catastrophic failures. Improvement of the functional properties these tools and reduction of the ecological threats may be accomplished by employing the technology of putting down hard coatings on tools in the state-of-the-art PVD processes, mostly by improvement of the tribological contact conditions in the cutting zone and by eliminating the cutting fluids. However in this paper was used a Si3N4 based cutting tool commercial with a layer TiN coating. In this investigation, the performance of TiN coating was assessed on turning used to machine an automotive grade compacted graphite iron. As part of the study were used to characterise the performance of cutting tool, flank wear, temperature and roughness. The results showed that the layer TiN coating failed to dry compacted graphite iron under aggressive machining conditions. However, using the measurement of flank wear technique, the average tool life of was increased by VC=160 m/min.The latter was also observed using a toolmakers microscope and scanning electron microscopy (SEM).

Influence of cerium (IV) ions on the inorganic and organic phase for preparation of a siloxane-PMMA based film on tin plate substrate

Tinplate is one of the most widely used food canning materials, however, there are significant problems related to the use of tinplate cans, such as alterations in sensory features affecting food quality and corrosion phenomena of the canning material. To avoid corrosion problems different methods have been used for the passivation of tinplate such protective lacquers or different kinds of corrosion inhibitors (chromate and dichromate). However, chromates and dichromates are extremely harmful to the environment and can cause carcinogenic tumors to humans. An option, protective coatings obtained by the sol-gel process, act as a physical barrier, which isolates the surface of metal protecting from the corrosive agents. The aim of this work is to study the influence of addition of cerium (IV) ions in the inorganic and organic part of sol-gel processing in the formation of hybrid coatings based on siloxane-PMMA on tin plate. The coatings were obtained by dip-coating technique and evaluated by open circuit and impedance measurements, linear polarization and polarization curves obtained in 3.5% NaCl solution. The results have clearly shown the improvement on the protective properties of the Ce 4+ modified film when added into the organic phase, which can be due to the formation of a more uniform and densely reticulated siloxane-PMMA film. © 2009 by NACE International.

Influence of benzoyl peroxide (BPO) on polysiloxane thin films doped with Ce(III) onto tin coated steel and their anticorrosion properties

The influence of benzoyl peroxide (BPO) on the synthesis of polysiloxane thin films doped with Ce(III) deposited onto Sn coated steel as well as their anticorrosion properties are reported. The addition of BPO, whose role is polymerize the film, showed an increase in |Z| values due to the fact that augments the crossed link bonds and therefore improves the protective feature of the film. Ce(III) does not act in the polymerization process and thus is essential the addition of BPO to obtain more resistant polysiloxane films. ©The Electrochemical Society.

Hydrogen oxidation on ordered intermetallic phases of platinum and tin - A combined experimental and theoretical study

Hydrogen oxidation on the surfaces of the intermetallic compounds Pt 3Sn, PtSn and PtSn2 has been studied by the rotating disc electrode technique. Pt3Sn and PtSn were found to be good catalysts, about as good as Pt, while PtSn2 was inactive over the investigated range of potentials. Underpotential deposition of hydrogen is observed only on Pt3Sn. These results are explained by theoretical calculations based on a theory developed within our own group, and by density functional theory. © 2012 Elsevier B.V.

Role of acidic and basic electrolytes on the structure and morphology of cathodically reduced indium tin oxide (ITO) substrates

In this report we track the structural changes suffered by ITO along galvanostatic polarization at different current densities by X-ray diffraction and SEM micrographs. The XRD shown that cathodic treatment induces structural change in ITO, characterized by appearing peaks set distinct from ITO original structure associated to metallic phase of the solid solution of In-Sn. It is interesting to note that although the different ions present in the solution are not, at least to a noticeable degree, incorporated in the metallic phase, the SEM images show that they do influence its formation, pointing to some type of adsorptive mechanism of the inert ions during the lateral diffusion of the metallic ions. © 2013 Elsevier Ltd. All rights reserved.

Opciones tecnológicas y oportunidades para el desarrollo: un estudio comparativo entre el aluminio y el estaño = Technological options and opportunities for development: a comparative study between aluminium and tin

Incluye Bibliografía

Report of the Meeting on Technological Options and Opportunities for Development: the Aluminium and Tin Industries in Latin America and the Caribbean = Informe de la Reunión sobre Opciones Tecnológicas y Oportunidades para el Desarrollo: las Industrias del Aluminio y el Estaño en América Latina y el Caribe

Contiene discurso de inauguración, presentación y comentario de los documentos presentados y recomendaciones de la reunión en que se trataron las opciones tecnológicas para el desarrollo de las industrias del aluminio en América Latina y el Caribe.

Latin American supply and major world market demand for the principal metals, 1970-1990: aluminium, copper, iron, nickel, lead, zinc, tin

Includes bibliography

The tin industry of Latin America: technological options and opportunities for growth

Includes bibliography

Desenvolvimento de uma Plataforma de Software para a Modelagem Digital de Terrenos baseada em TIN

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Links of the transnational corporations with the tin industry in Bolivia = Vinculaciones de las empresas transnacionales con la industria del estaño en Bolivia

Includes bibliography