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

Abstract

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 = 1.7 μ B (77 K), Curie temperature T c = 590–620 K, coercivity H c = 25 Oe (300 K). Only the ternary chemical compound, Fe 5SiC 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 Fe 5SiC 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. Fe 5SiC is a ferromagnet with T c = 780 K, m ¯ Fe = 1.77 μ B (77 K), H ¯ = 240 kOe (77 K), H c ≈ 450 Oe (300 K).