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

Abstract: 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 TiC x N y 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 TiN x 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 TiN x at about 1110°C, enabling the dissolution of C and B in the melt to form Ni–Ti–N–C–B liquid. Finally, TiC x N y and TiB2 formed and precipitated out of the liquid. [Copyright &y& Elsevier]