Extended studies on surface‐treated graphite vis‐à‐vis its application in high alumina refractory castable

Abstract This investigation entails our continued research on calcium aluminate coated graphite for application in alumina‐carbon monolithic refractories. Surface treatment of graphite flakes by a scalable sol‐gel route has been utilized to develop stable bonds between ceramic phases with the functionalized graphite sheets. This study has been primarily conducted to differentiate between the coating evolution pattern at green and calcined conditions. In this regard, C‐H‐N analysis, differential scanning calorimetry ( DSC ), transmission electron microscopy ( TEM ), x‐ray diffraction ( XRD ) with Rietveld analysis, Fourier transformed infrared spectroscopy ( FTIR ) and zeta potential studies of three kinds of graphites had been compared and critically estimated. These results were supplemented with thermogravimetry ( TG ), pore size distribution, oxidation resistance and scanning electron microscopy ( SEM ) of selected samples. A schematic outline of the work has also been proposed. An appreciable improvement of bulk density, apparent porosity and crushing strength of the respective castable has been correlated with the compatibility of the coating to the reactive matrix constituents of the refractory in wide temperature region (110‐1500°C).