Influence of ceramic phase content and its morphology on mechanical properties of MgO-C refractories under high temperature nitriding

摘要

To evaluate the influences of ceramic phase content and its morphology on the mechanical properties of MgO-C refractories, pre-prepared Si powder-phenolic resin loaded with Fe2O3 was introduced to prepare MgO-C refractories via catalytic nitridation. The effects of nitriding temperature and Fe2O3 content on the phase composition, microstructure evolution and properties of MgO-C refractories were studied and compared. The results show that the increase of the nitriding temperature was conducive to the in-situ formation of the ceramic phases, and a new phase of Mg2SiO4 was formed at temperatures >1450 degrees C. Both the increase in nitriding temperature and the addition of catalyst could inhibit the growth of alpha-Si3N4 to promote the formation of beta-Si3N4 and MgSiN2. In addition, the formation of excessive ceramic phases caused samples after nitriding to expand violently and form more porous, thereby reducing the physical properties of MgO-C refractories.