Structure, phase composition and magnetic properties of mechanically alloyed and annealed quasibinary Fe(70)Si(x)C(30 − x) alloys

It has been demonstrated that mechanical alloying of the powder mixtures Fe(70)Si(x)C(30 − x) with 5 ≤ x ≤ 20 at.% results in the formation of an amorphous single phase, whose magnetic properties do not depend on x  : an average hyperfine magnetic field H¯=225 kOe (77 K), an average magnetic moment per Fe atom m¯Fe=1.7μB (77 K), Curie temperature Tc = 590–620 K, coercivity Hc = 25 Oe (300 K). Only the ternary chemical compound, Fe5SiC iron silicon carbide, has formed within the Fe–Si–C system after mechanical alloying followed by annealing (500 °C, 1 h), with its greatest quantity (95 wt.%) being in the Fe(70)Si(14)C(16) sample. The Fe5SiC silicon carbide has an orthorhombic lattice (Cmc2.1 space group symmetry) with the parameters of a = 1.0043 nm, b = 0.7944 nm, c = 0.7469 nm. The lattice includes six nonequivalent local configurations of Fe-atoms. Fe5SiC is a ferromagnet with Tc = 780 K, m¯Fe=1.77μB (77 K), H¯=240 kOe (77 K), Hc ≈ 450 Oe (300 K).