The effectiveness of sintering additives for beta-SiC was examined based on thermodynamic calculations and experimental observations under hot pressing conditions of 1700-1800 degrees C. Various types of oxides, such as Al2O3, Fe2O3, MgO, TiO2, WO3 and Y2O3, were examined theoretically by considering the Gibbs formation free energy and vapor pressure. According to experimental observations expanded to their binary and ternary systems after hot pressing at 1750 degrees C and 20 MPa, Al2O3, MgO, Y2O3 and their mixed systems were found to be the only effective sintering additives that do not react with beta-SiC at high temperatures. On the other hand, Fe2O3, TiO2, WO3 and their combinations with other oxides were not effective because of the reaction with beta-SiC by forming the corresponding metal carbides and/or silicides, as predicted by thermodynamic simulations. Moreover, the experimental results for the additional possible components were also included. (C) 2012 Elsevier B.V. All rights reserved.