Novel Al 2 O 3 ‐C Refractories with Less Residual Carbon Due to Nanoscaled Additives for Continuous Steel Casting Applications

A new generation of thermal shock resistant Al 2 O 3 ‐C refractories with approximately 30% less residual carbon and functionalized due to nanoscaled additives based on carbon nanotubes (CNTs) and alumina nanosheets (α‐Al 2 O 3 ) were developed and investigated after coking at 1000 and 1400 °C. With the aid of electron backscatter diffraction analyses (EBSD) on fracture surfaces of the carbon bonded samples, Al 3 CON was identified on the nanosheet shapes already at 1000 °C coking temperature. The Al 3 CON new phase based on the reaction between alumina nanosheets and CNTs offers a chemical interconnecting phase for the carbon as well as for the oxide alumina filler. The new refractory composite structure presents excellent thermo‐mechanical properties in spite the lower carbon content. In addition, due to EDS and EBSD analyses amorphous whiskers and platelets within the system of SiO were observed in samples coked at 1000 °C, that were transformed to crystalline β‐SiC‐whiskers in samples coked at 1400 °C.