Mechanochemical synthesis in the Ni-Al-C system

Specific features of the phase formation during mechanochemical synthesis of mixtures of elementary components, Ni, Al, and graphite, in an atomic ratio of 2:1:1 and a mixture of the intermetallic compound Ni₃Al and graphite (1:1) have been considered. It is shown that nanocrystalline (D = 4–6 nm) three-component solid solutions Ni(Al, C) with identical lattice constants (a = 0.366 nm) are formed during mechanosynthesis, independent of the initial components. Annealing at a temperature of 800°C for 2 h leads to decomposition of solid solutions into three phases: double carbide Ni₃AlC_0.46 (a = 0.3592 nm), solid solution Ni(Al, C) with the lattice constant 0.3546 nm, and graphite with the lattice constants a = 0.2461 nm and c = 0.660 nm.