Effect of nickel addition on the exothermic reaction of the Ti–C–BN system

The effect of Ni addition on the exothermic reaction in the Ti–C–BN system was investigated using differential thermal analysis (DTA). Based on DTA and X-ray diffraction (XRD) analyses, a reaction path for the formation of TiCxNy and TiB2 in the Ni–Ti–C–BN system was proposed in which the reaction initiated with the solid-state diffusion between Ti and BN. The resultant TiNx then reacted with Ni to form Ni–Ti compounds (e.g., Ti2Ni). With increasing temperature, a Ni–Ti–N eutectic liquid phase formed between the Ni–Ti compounds and TiNx at about 1110 °C, enabling the dissolution of C and B in the melt to form Ni–Ti–N–C–B liquid. Finally, TiCxNy and TiB2 formed and precipitated out of the liquid.