Ceramics-Silikáty 23, (4) 307 - 314 (1979)

The study deals with the effect of chromium oxides (0.01 - 1.3 wt %. Cr₂O₃) on the sintering of CaO in air atmosphere at 900-1200 °C. The samples were prepared from precursors obtained by thermal decomposition of evaporation residues of homogeneous aqueous solutions of calcium nitrate, chromic nitrate and citric acid of A. R. purity. The sintering of CaO is substantially accelerated by the addition of chromium oxides. The intensification of the process is due above all to the presence of the liquid phase at the boundaries of CaO grains. The sintering rate is also positively affected by the dissolution of Cr³⁺ in CaO. The rapid course of the process in the subsolidus region of the CaO-Cr₂O₃ pseudobinary system is probably related to intermediate formation of a nonequilibrium melt.