Mechanochemical synthesis of Co3C carbide with carbon nanotubes

Abstract

Nanoscaled (about 15 nm of size) metastable carbide Co3C was synthesized in a high-energy planetary ball mill by mechanical alloying of a mixture of powder cobalt (75 at. %) and multiwalled carbon nanotubes (CNT, 25 at. %). Phase transformation takes place at reaction milling according to the reaction hcp-Co + CNT ® Co3C (reaction time is 120 - 220 min). The crystal structure of the Co3C carbide formed in the milling products was studied by X-ray diffraction method. It has revealed that the Co3C phase crystallizes in a Fe3C-type structure with a = 0.4982(3) nm, b = 0.6715(6) nm, c = 0.4457(7) nm, Pnma space group. The reliability factor RB is equal to 0.065 for 48 reflections presented at diffraction pattern. It is found that the crystal structure of the Co3C carbide obtained by reaction milling of the Co-CNT charge is significantly internally deformed (distortion degree of the CCo6 octahedron is 3.67 %) and contains the reduced interatomic Co-C distances (up to 0.188 nm). It was shown that the use of carbon nanotubes instead of graphite substantially reduces the duration of the Co3C carbide synthesis.

Synthesis of large-sized spherical Co–C alloys with soft magnetic properties though a high-pressure solid-state metathesis reaction

“…5,[14][15][16][17][18][19][20][21][22] Experimental and theoretical studies have conrmed its notable magnetization strength and coercivity, suggesting that it could serve as an ideal rare-earth-free permanent magnet material with promising developmental prospects. 5,14 Co 3 C nanoparticles have been synthesized using methods like wet chemical synthesis, 5,23,24 mechanical alloying, 3,6,25 ion irradiation, 26 and the one-pot template-free solvothermal approach. 27 P. V. Marshall et al utilized a DAC (diamond anvil cell) device with a size of 300 mm to synthesize microscale Co 3 C under conditions of 5-15 GPa and 1200 K. 28 However, stable carbides are not present in the Co-C system.…”

Parameters of crystal and electronic structure and magnetic properties of mechanically alloyed Ni3C cubic carbide

“…Mechanical alloying has recently been gaining increasing application due to the possibility of obtaining novel nanoscale materials with an interesting set of functional properties. Previously we have successfully synthesized such well-known d-metal carbides as TiC, ZrC, HfC, VC, NbC, TaC, Mo2C, W2C, WC, Fe3C and Co3C using multi-walled carbon nanotubes (CNTs) as a carbon component of the charge [1][2][3][4][5]. It was also shown that the crystal structures of the carbides obtained have certain features in the atoms arrangement [5].…”