B₄CとTiの反応性放電プラズマ焼結によるTi-B-C系複合体の合成

抄録

B₄C-TiB₂-C and TiB₂-TiC-C composites were synthesized by reactive spark plasma sintering of powder mixtures of Ti and B₄C, accompanied by their solid-state displacement reactions. When varying the mixing ratio of the starting materials Ti and B₄C, x, the following reactions were completed: when 0<x≤2, B₄C+xTi→xTiB₂+(1-x/2)B₄C+(x/2)C and when 2<x≤3, B₄C+xTi→2TiB₂+(x-2)TiC+(3-x)C. Carbon, which was precipitated in the product TiB₂ phases, increased pores and cracks in the TiB₂ phases and resulted in a decrease of the relative density and Young's modulus. For x=3, the composite contained no carbon and had the highest values for both the Young's modulus and fracture toughness. The Young's modulus of the composites prepared was represented by E/GPa=460V_B4C+600V_TiB2+488VTiC-1414V_C, where V_i is the molar volume of component i.