Alloys protected from corrosion by a chromia scale and LaCrO3-based perovskites are used as materials for the interconnect of solid oxide fuel cells (S0FCs). The chromium vaporization of these materials was studied by thermochemical modeling. Partial pressures of the vaporizing species were determined for different 02 and 1120 concentrations in the oxidizing gas. Cr02(OH)2(g) and Cr03(g) are the most abundant species in air with and without humidity, respectively. The potential of the Cr-containing vapor species for the degradation of the electrical properties of an SOFC was analyzed by thermodynamic computations. The electrochemical reduction of the Cr-containing vapor species at the cathode/electrolyte/gas phase boundary can lead to polarization losses.

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In order to test the hypothesis of ionized polycyclic aromatic hydrocarbons (PAHs) as possible carriers of the UIR bands, we realized a computational exploration on selected PAHs of small dimension in order to identify which changes ionization would induce on their IR spectra. In this study we performed ab initio calculations of the spectra of neutral and positively ionized naphthalene, anthracene, and pyrene. The results are significantly important. The frequencies in the cations are slightly shifted with respect to the neutral species, but no general conclusion can be reached from the three molecules considered. By contrast, the relative intensities of most vibrations are strongly affected by ionization, leading to a much better agreement between the calculated CH/CC vibration intensity ratios and those deduced from observations.

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The A l-N i phase diagram has been investigated in the com position range x Ni = 0.70 to 0.97. Phase boundaries were determined by using differential thermal analysis and Knudsen effusion mass spectrometry. The measurements were carried out in the temperature range between 1409 and 1730K. An A l-N i phase diagram is obtained for x Ni Si 0.70 by com bining the data from this work with selected data from the literature. This diagram deviates from that recommended by phase diagram compilations and used generally in the literature to date; it agrees reasonably well with a diagram which has been rejected in the literature. + On leave from: Fuel Chemistry D ivision,