TiC_0.7 and Mo₂C powders were prepared by heating Ti-C and Mo-C compacts and Li or Na at temperatures of 800-900°C for 12 h in an Ar atmosphere. These temperatures were 200-350°C lower than those at which Ti and Mo fully reacted with C without the addition of Li or Na. The grain size of the TiC_0.7 and Mo₂C powders was close to that of the source metal powders. In the Tm-C systems (Tm = Zr, V, Nb, Ta, Cr, and Mn), the addition of Li or Na to Tm-C compacts enhanced the formation of ZrC, VC, NbC, TaC, Cr₇C₃, and Mn₂₃C₆ at 800°C. On the other hand, no effect was observed for the formation of carbides in the systems with Tm = Fe, Ru, Hf, W, and Re.