Investigations of the effect of Si addition on graphite elimination and the oxidation behavior of SiC joint using Inconel 625 powder filler

•A method of avoiding graphite formation in SiC joint brazed by Inconel 625 is proposed in this paper. A graphite-free brazed seam is obtained when 23.1 wt% pure Si powder is blended with Inconel 625 powder.•The experimental results confirm the thermodynamic calculation results that Si content is highly associated with the liquid alloy's chemical potential. Once Si content reaches a critical value, the reactions between the liquid and SiC stops.•The oxidation performance at 800 °C in air of the SiC joint with graphite and the graphite-free SiC joint are compared in this paper. It shows that the brazed seam with graphite is seriously damaged due to the voloxidation of graphite, and the joint's shear strength decreases rapidly, while the graphite-free brazed seam maintains intact and the joint's shear strength decreases slightly.