TY - GEN A1 - Grafe, Hans-Joachim A1 - Löser, Wolfgang A1 - Schmitz, Steffen A1 - Sakaliyska, Miroslava A1 - Wurmehl, Sabine A1 - Eisert, Stefan A1 - Reichenbach, Birk A1 - Acker, Jörg A1 - Rietig, Anja A1 - Ducke, Jana T1 - NMR investigation of boron impurities in refined metallurgical grade silicon T2 - Physica status solidi. A, Applications and Materials Science N2 - The nuclear magnetic resonance (NMR) method was applied for tracking boron impurities in the refining process of metallurgical grade (MG) silicon. From the NMR signal of the 11B isotope at an operating temperature 4.2 K, the boron concentration can be estimated down to the order of 110 wppm B. After melting and resolidification of MG-Si alloyed with Ca and Ti, a major fraction of B impurities remains in the Si solid solution as inferred from the characteristic NMR frequency. The alloying element Ti does not form substantial fractions of TiB2. Acid leaching of crushed powders of MG-Si alloyed with Ca and Ti can diminish the initial impurity content of B suggesting its accumulation in the grain boundary phases. KW - boron KW - impurity KW - intermetallic compounds KW - nuclear magnetic resonance KW - silicon KW - transition-metal diboride KW - Si-Al melt KW - removal KW - solidification Y1 - 2015 UR - http://onlinelibrary.wiley.com/doi/10.1002/pssa.201431908/full U6 - https://doi.org/10.1002/pssa.201431908 SN - 1862-6319 VL - 212 IS - 9 SP - 2031 EP - 2036 ER -