Molten salt synthesis and characterization of SiC coated carbon black particles for refractory castable applications

Abstract

Silicon carbide (SiC) coatings were prepared on carbon black (CB) particles after 6 h at 1100 °C by a molten salt synthesis (MSS) technique. By controlling the Si to CB ratio (Si/C) in the initial batch mixture, the SiC coating thickness could be readily tailored to meet practical requirements in real castable systems. True densities of CB particles after SiC coating increased with Si/C. The zeta potential values indicated that their dispersivity was improved evidently over a wide range of pH. At a given shear rate, the apparent viscosity of a water suspension containing SiC-coated CB was significantly lower than that of a water suspension containing as-received uncoated CB, indicating the improved flowability of SiC-coated CB in water. The improvements in both the water-dispersivity and flowability of SiC coated CB particles would make them a promising candidate carbon material for future castable applications.