COVALENCY IN LIQUID SI AND LIQUID TRANSITION-METAL SI ALLOYS - X-RAY-DIFFRACTION STUDIES

We present data, obtained by x-ray diffraction measurements, of the structure factors for pure liquid Si, and for liquid Ni-Si and Cu-Si alloys. We find it possible to analyse these data as well as data for Fe-Si by decomposition of rg(r) where g(r) is the pair distribution function; this analysis provides evidence for Si-Si covalency both in pure liquid Si and in the Si-rich liquid alloys. The degree of covalency in the Si-rich alloys appears to increase with changing species in the order Fe --> Ni --> Cu.