Novel Duplex Vapor-Electrochemical Method for Silicon Solar Cells. [reaction of Fluorine and Silicon Compounds with Sodium]

Book excerpt: The dependence of the SiF4 Na reaction initiation time and of the efficiency of the reaction on Na particle size and reaction temperature were studied. Close to 100 percent utilization of Na was obtained, and formation of byproduct fluoro-silicate was decreased to below 10 percent. A SiF4 Na reactor was built to scale up the reaction by a factor of about four and is now being tested. A scaled up melting system was built and successfully used to separate Si from kilogram quantities of SiF4 NaF mixtures. Support studies of the volatilization of NaF performed in a smaller melting system indicated minimal loss of NaF as vapor at 1410 C. The wetting of graphite was also investigated to determine the constituents of the NaF phase which promote good wetting. Nanis, L. and Sanjurjo, A. and Sancier, K. M. and Bartlett, R. and Westphal, S. Unspecified Center NASA-CR-162113, ERDA/JPL-954471-79/10, QPR-13 NAS7-100; JPL-954471; SRI PROJ. PYU-4980