Incongruent evaporation ceramic form oxides at high temperatures and underpressure

The issues of thermal dissociation of silicon and iron oxides, which are part of corundum-sillimanite ceramic molds, which are used for casting with heat-resistant alloys at high temperatures, are considered. Theoretical studies have determined that the silica, which is part of the ceramic mold, has a low resistance to thermal dissociation at 1873 K. It has been established that iron oxide will intensively evaporate in the melting zone in the range at a reduced pressure of 0.65 - 1.33 Pa. This phenomenon increases the reactivity of the ceramic mold in the zone of contact with heat-resistant alloys and is one of the sources of contamination of the cast surface. Tab. 1., bibliography: 3 titles.