The solubility of carbon in liquid silicon equilibrated with silicon c
arbide was determined in the temperature range from 1723 to 1873 K. Si
licon was melted in a silicon carbide crucible with an Ar-CO mixture g
as flowing. Carbon in silicon was analyzed by the combustion-IR absorp
tion method. The temperature dependence of the carbon solubility in li
quid silicon can be represented by the following equation: log (C-(c u
nder bar)/mass%)=3.63-9660/T(+/-0.02) (T:1723-1873 K) The carbon solub
ility at the melting point of silicon was calculated to be 79 ppm (9.1
x 10(18) atoms.cm(-3)). The level of oxygen impurities in the melt wa
s much lower than that of liquid silicon equilibrated with solid silic
a. The standard Gibbs free energy change for carbon dissolution in liq
uid silicon can be represented as: C(s)=(C) under bar C(1 mass%, in li
quid silicon) Delta G degrees=7.20x10(4)-11.4Tlog T+6.20T (J).