Cibele Melo Halmenschlager

Elaboration of Yttria-Stabilized Zirconia Films on Porous Substrates

The development of solid oxide fuel cell has shown that the thin film concept for the electrode supported designs, based on the yttria-stabilized zirconia, is more promising than the research of new electrolyte materials. In this work, the spray pyrolysis process was investigated in order to obtain dense thin films of YSZ on porous ceramic substrates. High porosity LSM, a typical material of SOFC cathodes, was used as substrate. The precursor solution was obtained by zirconium and yttrium salts dissolved in a mixture of ethanol and propylene glycol, with volume ratio 1:1. The substrate was heated and maintained at a constant temperature (280°C, 340°C or 560°C). The as-obtained films were heat treated in a temperature of 700°C, aiming to obtain yttria-stabilized-zirconia films from the amorphous film. The morphology and microstructure of the films were characterized by scanning electron microscopy and X-ray diffraction.

Nanostructured YSZ Thin Film for Application as Electrolyte in an Electrode Supported SOFC

The development of solid oxide fuel cell with thin film concepts for an electrode supported design based on the yttria-stabilized zirconia has demonstrated favourable results due to its high chemistry stability in oxidization and environment reduction. The spray pyrolysis process was investigated in order to obtain dense thin films of YSZ on different substrates. The precursor solution was obtained by zirconium and yttrium salt dissolutions in a mixture of water and glycerine in several ratios to study the solvent influence. The substrate was initially heated at 600 °C and during the deposition it ranged from 260-350°C, finishing at a fast increase in temperature of 600°C. The heat treatment was carried out in four different temperatures: 700 °C, 750 °C, 800 °C, and 900 °. The precursors were characterized by thermal analysis. The microstructures of the films were studied using scanning electron microscopy and X-ray diffraction. The results obtained showed that the films obtained were crystalline before the heat treatment process and have shown ionic conductivity above 800°C.

Nanostructured Materials for Energy Applications

There is great interest in research related to alternative forms of electricity production in order to promote increased quantity and quality of the energy system, maintaining and enhancing environmental sustainability, economic, emphasizing efficient use of renewable energy resources. In this context, it is important to develop new technologies for energy generation, especially those from renewable resources. Nanostructured materials have been extensively researched in application like lithium ion batteries, supercapacitors, solar cells and fuel cells. This chapter contains a brief overview of some companies that are already dealing with nanostructured materials for lithium ion batteries, supercapacitors, solar cells and fuel cells, followed by recent developments on research of nanostructured materials for elements of Intermediate Temperature Solid Oxide Fuel Cell.

Chemical resistance of silicate glass-ceramics

ABSTRACT This work is concerned about the chemical characterization of monolithic diopside-based glass ceramics (GCs). Variations from this composition were carried out through the addition of P2O5 to increase crystal density and Al2O3 to optimize the chemical properties of the GCs. The addition of MgO was sufficient for the crystallization of diopside, but additions of P2O5 made the formation of this crystalline phase difficult. The highest volume of diopside crystals was about 76% for the formulation with 5% weight of alumina. As expected, chemical resistance is directly influenced by the composition of the glass ceramic, but not so much by the fraction of crystals volume.