ACCURATE WAVELENGTH MEASUREMENTS AND MODELING OF Fe XV TO Fe XIX SPECTRA RECORDED IN HIGH-DENSITY PLASMAS BETWEEN 13.5 AND 17 A

Iron spectra have been recorded from plasmas created at three different laser plasma facilities: the Tor Vergata University laser in Rome (Italy), the Hercules laser at ENEA in Frascati (Italy), and the Compact Multipulse Terawatt (COMET) laser at LLNL in California (USA). The measurements provide a means of identifying dielectronic satellite lines from Fe XVI and Fe XV in the vicinity of the strong 2p → 3d transitions of Fe XVII. About 80 Δn ≥ 1 lines of Fe XV (Mg-like) to Fe XIX (O-like) were recorded between 13.8 and 17.1 A with a high spectral resolution (λ/Δλ ≈ 4000); about 30 of these lines are from Fe XVI and Fe XV. The laser-produced plasmas had electron temperatures between 100 and 500 eV and electron densities between 1020 and 1022 cm-3. The Hebrew University Lawrence Livermore Atomic Code (HULLAC) was used to calculate the atomic structure and atomic rates for Fe XV-XIX. HULLAC was used to calculate synthetic line intensities at Te = 200 eV and ne = 1021 cm-3 for three different conditions to illustrate the role of opacity: optically thin plasmas with no excitation-autoionization/dielectronic recombination (EA/DR) contributions to the line intensities, optically thin plasmas that included EA/DR contributions to the line intensities, and optically thick plasmas (optical depth ≈200 μm) that included EA/DR contributions to the line intensities. The optically thick simulation best reproduced the recorded spectrum from the Hercules laser. However, some discrepancies between the modeling and the recorded spectra remain

A Ba-free sealing glass with a high CTE and excellent interface stability optimized for SOFC/SOEC stack applications

A new glass-ceramic composition containing Si, Mg, Ca, Na, Al, Zr, and B is presented here as sealant for planar SOFCs/SOECs, with the aim of joining the metallic interconnect (Crofer22APU) to the solid oxide cell (YSZ electrolyte or CGO barrier layer). Characteristic temperature, thermo-mechanical properties, and compositional variations are reviewed and discussed by thermal analyses and in situ XRD, in order to design and optimize the sealing profile and reduce the residual porosity. The glass after heat treatment partially devitrifies into augite and nepheline with residual glass phase of around 64.3%; after crystallization the glass-ceramic sealant has a coefficient of thermal expansion of 12.8 9 106 K1 and it is compliant with the other materials typically used for stack components. This work shows that the developed glass-ceramic can successfully join the ceramic cell with the Crofer22APU (preoxidized and alumina coating), proven by tests on small and large-scale samples. No signs of unwanted reactions at the glass-metal and the glass-cell interface are observed and sufficient gas tightness is achieved