Joining of silicon carbide and graphite by spark plasma sintering

After placing SiC powder on an isotropic graphite substrate, the two materials were successfully joined by spark plasma sintering (SPS). The effect of an Al2O3–Y2O3 sintering aid on SiC during joining was studied. The tensile strength of the joints prepared at 1800 °C under 30 MPa for 5 min reached 18 MPa. The fracture occurred not at the interface, but at the graphite substrate. The joining mechanism of SiC/graphite is attributed to the following: after the SiC powder squeezes into the open pores of graphite during sintering, the sintered SiC produces a strong bond through the interface between SiC and graphite.