ROLE OF ATMOSPHERE AND IMPURITIES DURING SINTERING OF CEMENTED CARBIDES.

Thermodynamic calculations have been made for the Ca-Al-Si-S-O-C system at 1400 degree C. A computer program was used for calculating phase diagram of multicomponent systems. This allowed the stability regions for the individual sulfides, oxides, and silicates to be plotted as functions of sulfur and oxygen potentials at conditions close to those prevailing during sintering of cemented carbides. Two diagrams are presented, one for a case where the maximum activities of the elements correspond to carbide saturation, and a second for reduced activities of the elements Ca, Si, and Al corresponding to an assumed trace element level in liquid cobalt.