Significant improvement of refractoriness of Al2O3–C castables containing calcium aluminate nano-coatings on graphite

The performance of alumina-carbon castables containing graphite flakes coated by nanosized Ca-doped γ-Al2O3 phases has been investigated in terms of refractoriness under load (RUL) and oxidation resistance tests. The coating characteristics and its beneficial effects in castable matrix have been conceived by water-wettability test, differential scanning calorimetry and some physical characteristics. In this regard, a schematic representation of coated graphite has been proposed to elucidate its sustainability in the refractory mass. The comparative gain in performance of the refractory has also been ascertained by scanning electron microscope (SEM) and X-ray diffraction (XRD) studies of the castable matrix. The sol–gel coating overcomes the pitfalls of including uncoated graphites in castables and should be explored for commercial utilization.