Graphite grains

The formation of the solid electrolyte interphase (SEI) on the surface of the graphite grains occurs at electrode potentials above 250mV vs. Li+/Li. 

The heavy elements carry clear excesses in a s-process component as can be seen from Figure 7. This has been demonstrated for Kr, Sr, Xe, Ba, Nd, Sm (Ott and Begemann 1990 Prombo et al. 1993 Lewis et al. 1994 Richter 1995 Hoppe and Ott 1997). The models can be made to fit very precisely the measured data (Lattanzio and Boothroyd 1997 Busso et al. 1999). Mo and Zr can occur as microcrystals of Mo-Zr-C within graphite grains. Typical s-process patterns are observed, with isotopic variations of about a factor of more than 5 (Nicolussi et al. 1997 Nicolussi et al. 1998a). 

Figure 7. A few examples of isotopic patterns of Ne, Ti and heavy elements in SiC and graphite grains are displayed. Absolute ratios are plotted for Ne (a) whereas abundance ratios relative to solar wind composition are plotted for Kr (c) and Xe (f). The remaining elements are plotted as %o deviations from laboratory standards. The data have been obtained on bulk SiC separates by traditional mass spectrometry for Ne (Jungck and Eberhardt 1979), Kr (Ott et al. 1988 Lewis et al. 1994), Sr, Ba (Ott and Begemann 1990 Prombo et al. 1993) and Nd (Richter 1995). SIMS techniques (caption continued on facing page)...

Nicolussi GK, Pellin MJ, Lewis RS, Davis AM, Clayton RN, Amari S (1998b) Strontium isotopic composition in individual silicon carbide grains a record of s-process nucleosynthesis. Phys Rev Lett 81 3583-3586 Nicolussi GK, Pellin MJ, Lewis RS, Davis AM, Clayton RN, Amari S (1998c) Zirconium and molybdenum in individual circumstellar graphite grains new data on the nucleosynthesis of the heavy elements. Astrophys J 504 492-499... 

Infallible Propellant. A double-base proplnt consisting of NC (13.25%N) 59.25, NG 40.00 DPhA 0.75%, coated with graphite. Grains 0.055 inch in diam Sl 0.007 inch thick when subjected to 65.5° Surveillance Test and 120°... 

A few silicon carbide and graphite grains appear to have come from novae (Chapter 3). 

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