Indexed on: 01 Apr '98Published on: 01 Apr '98Published in: Metallurgical and Materials Transactions B
The new chemical synthesis process developed in this laboratory for the preparation of the fine powders of intermetallic compounds by the vapor-phase reduction of mixtures of constituent metal chlorides by magnesium vapor, described in Part I for titanium aluminides, was applied to the synthesis of nickel aluminide particles. NiAl, NiAl3, and Ni2Al3 were formed by reducing mixtures of NiCl2 and AlCl3 vapors. The effect of the partial pressure ratios AlCl3/NiCl2 and Mg/NiCl2 on the formation of nickel aluminides was studied. The maximum content of NiAl obtained was 98 mol pct. At the AlCl3/NiCl2 ratio of 19, a two-phase mixture of 17 mol pct of NiAl+83 mol pct of NiAl3 was produced. The product particles were very fine in the size range of 0.1 to 0.2 µm.