The structures of oxides formed in water and lithiated water on three Zr-based alloys with varied corrosion behavior were studied with micro-beam synchrotron radiation and optical microscopy. Micro-beam synchrotron radiation (0.2 μm spot) has a unique combination of high elemental sensitivity (ppm level) and fine spatial resolution that allowed the determination of various oxide characteristics such as phase content, texture, grain size, and composition as a function of distance from the oxide-metal interface.
Micro-beam X-ray fluorescence shows that the oxides formed in lithiated water have increased levels of Fe absorbed from the autoclave environment indicating greater oxide porosity in these oxides. The phase content, texture, and grain size of oxides were studied in detail using synchrotron radiation micro-beam diffraction for samples corroded in water and lithiated water. A remarkable periodicity was observed in the oxide structures using various techniques including X-ray peak intensities for both monoclinic and tetragonal zirconia, texture, and optical microscopy. The periods were similar to the transition period and were less visible in the oxides that behaved worse in lithiated water. These results are discussed in terms of models of oxide growth and of the differences between alloys.
ABSTRACT:We have developed a one-step method for preparing nanocomposites based on powdered isotactic polypropylene (i-PP) as a matrix polymer (melt-flow index (MFI) = 7.2 g 10 min −1 ), oligo(i-PP-g-MA) (MFI = 35-70 g 10 min −1 ) as a reactive compatibilizer and docecylamine-surface-modified montmorillonite clay (organo-MMT). This method includes grafting maleic anhydride (MA) onto i-PP chains in the melt state under the controlled thermal degradation conditions and intercalative compounding of the obtained oligo(i-PP-g-MA) with i-PP and organo-MMT by reactive extrusion. The effect of extrusion parameters on MFI, composition and properties of the grafted i-PPs, and mechanism of formation and properties of PP/oligo(PP-g-MA)s/organo-MMT nanocomposites were investigated by FTIR, XRD, and thermal analysis (DSC, TGA, and DTA). The results indicate that the formation of nanostructured morphologies proceeds through the formation of
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