Interaction of refractory MgO-based ceramics with iron-carbon melt

The authors used the sessile drop method to study the interaction of rail-steel melt with MgO-based ceramics in He + 10 % H 2 at different temperatures (isothermal holding at 1743 and 1973 K). It was shown that, after experiments, carbon and manganese concentrations decreased and silicon and chromium contents increased. At the high-temperature holding (1973 K), carbon concentration in the metal increased at an order of magnitude, which indicated its intense interaction with oxides of ceramics, reduction of the elements from oxides and their transition to the melt. The contact angles decreased from 135 to about 123° in the first 15 min of the experiment with the subsequent increase to 136° or the decrease to 114° depending on the temperature conditions. The structure and the elemental mapping of the boundaries of transverse sections of the metal and ceramics were analyzed. In the metal-ceramics contact zone, in the bonding phase, a new phase was formed which corresponded to merwinite (Ca 3 MgSi 2 O 8 ). This can be related to a change in silicon concentration due to its interaction with carbon dissolved in the metal. An increase in the total oxygen concentration in the metal after experiments was observed, which can be related to the transition of oxide particles from the ceramics into the melt. Analysis of non-metallic inclusions showed that, after the low-temperature holding (1743 K), complex magnesium-containing inclusions prevail and, after the high-temperature holding (1973 K), aluminum- and silicon-containing inclusions are mainly observed.