Molten salt synthesis of Cr3C2-coated flake graphite and its effect on the physical properties of low-carbon MgO–C refractories

To improve the performance of low-carbon MgO–C refractories, the Cr3C2-coated flake graphite was synthesized by molten salt method, then the Cr3C2-coated flake graphite was added to low-carbon MgO–C refractories. In this work, the effects of reaction temperature, Cr/C mole ratio, and holding time on the synthesis of Cr3C2-coated flake graphite were studied. Furthermore, the effect of Cr3C2-coated flake graphite on the physical properties of low-carbon MgO–C refractories was evaluated. The results indicated that when the reaction temperature was 950 °C, Cr/C molar ratio was 1/2 and holding time was 3 h, the synthesized Cr3C2-coated flake graphite had fewer surface micropores and the crystallinity of Cr3C2 grains was high. In addition, the Cr3C2-coated flake graphite exhibited excellent oxidation resistance. MgO–C refractories containing 2 wt% Cr3C2-coated flake graphite exhibited more excellent physical properties. The results of nano CT detection system showed that the addition of Cr3C2-coated flake graphite promoted the densification of MgO–C refractories.