Low carbon containing Al2O3-C refractories with nanocarbon as the sole carbon source

Abstract The functional refractories used in the continuous casting process of steel are mostly made up of alumina (Al2O3) - carbon (C) system. Graphite is used as the main carbon source because of the properties it offered. Generally, these refractories contain about 30% residual carbon after coking. But the use of high carbon content leads to several disadvantages like carbon pickup by steel, high heat loss and generation of higher extent of COx gases, etc. Hence, the development of low carbon Al2O3-C refractories without conceding any beneficial properties is the challenge to the refractory technologists. Such a challenge is intended in current study with the use of nanocarbon as a complete alternative for graphite. The variation in physical, mechanical and thermo-mechanical properties with variation in amount of nanocarbon in the composition is studied. Phase analysis and microstructural developments are also evaluated along with the oxidation resistance at different temperatures. Because of its high reactivity, nanocarbon helps to form in-situ ceramic phases at much lower temperatures thereby enhances strength and other properties. But the increase in amount of nanocarbon above 2% found to deteriorate the properties.