Fine particles of nickel aluminides were synthesized for the first time by reducing mixtures of AlCl3 + NiCl2 vapors by hydrogen. A thermodynamic equilibrium calculation was carried out in the Ni–Al–H–Cl–Ar system to evaluate the effect of the reactant partial pressures and temperature on the formation of intermetallic phases. A single intermetallic phase was found to be feasible only in a very narrow range of the reactant partial pressures. For all other conditions the predicted solid product was a mixture of two phases. Experimentally, Ni3Al was formed along with metallic Ni. Though the coreduction of NiCl2 and AlCl3 by H2 to form Ni3Al is thermodynamically favorable at 1100 °C, it did not happen experimentally under the conditions of this work. However, with a small addition of aluminum vapor, the coreduction reaction proceeded as expected by thermodynamics. The effects of reactant partial pressures and temperature were studied. The content of Ni3Al was maximized to 52 mol% at 1050 °C under the partial pressures of H2, AlCl3, and NiCl2 at 57, 1.5, and 0.5 kPa, respectively. The product particles, as observed by TEM, were very fine, but usually agglomerated. The electron diffraction analysis identified the particles of NiAl and NiAl3 along with Ni3Al and metallic Ni.