Ceramics-Silikáty 25, (4) 309 - 317 (1981)

A series of specimens of the system CaO-MgO with Cr₂O₃ additions were prepared chemically; in these specimens, the volume ratios of the main oxides and the amount of liquid phase at the maximum heating temperature were defined. The course of their shrinkage up to 1600 °C was determined dilatometrically, and the final porosity of the material obtained was established. The final porosity of specimens containing Cr₂O₃ additions was found to be always lower than that of specimens without this addition, while its optimum value depended on the volume ratios of the main oxides. By adding Cr₂O₃ uniformly dispersed in the mixture in amounts up to 1% by wt. it is possible to obtain materials containing 50-80 wt. % MgO with a porosity lower than 5%, by firing up to 1600 °C in an oxidation atmosphere.