Teruo Takahashi

X–ray Spectroscopic Analysis of Solid State Reaction during Mechanical Alloying ☆

Abstract Niobium or tungsten and graphite powders were mechanically alloyed. Carbon K X–ray spectra of the mechanically alloyed powders were measured using an electron probe microanalyzer (EPMA) in order to investigate the solid state reaction process. In the early stage of the mechanical alloying (10 hours), graphite did not react with metal, but particle size of graphite became smaller. In the next stage of the mechanical alloying (2–4 hours), micro–crystalline graphite powder reacted with metal. Polarization of the X–rays were measured for Nb 2 C and W 2 C, because a single crystal WC emitted polarized X–rays. The measurement of X–ray emission spectra was useful for the structural and chemical analysis of mechanical alloying reaction processes.

New Carbides in the Ni-Ti-Mo-C System

Two new carbide phases, M1-phase and M2-phase, were found in the Ni-Ti-Mo-C quaternary system at 1273 K. M1-phase with the composition (Ti0.46Mo0.54)C is hexagonal with a=0.60313 run, c= 1.02371 nm. M2-phase with the composition (Ti0.28Mo0.72)C is orthorhombic with a=0.51610 nm, b=1.58280 nm, c=0.29810 nm. The Ni content in the both compounds was less than 0.1 at %. Phase relationships among such phases as [γ+C+δ+M1], [γ+C+M1+M2], [γ+C+M2+α-MoC1-x], [γ+δ+ M1+M2], [γ+δ+M2+α-MoC1-x] were also established.