Synthesis and characterization of the novel nanostructured NiC carbide obtained by mechanical alloying

In the present work, a comprehensive study of mechanical alloying of Ni-carbon nanotubes (CNT) and Ni-Graphite equiatomic powder mixtures under the same technological modes has provided to reveal the features of using different types of carbon (CNT or graphite) as a charge component. The as-milled powders were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and magnetometric study. A novel nanoscale fcc NiC monocarbide was synthesized regardless the type of the charge used. According to the XRD study the formation of this phase takes place in two stages. A two-step carbide formation mechanism has been proposed. The associated changes in the nickel lattice, such as changes in the lattice parameter, lattice strain and residual stresses, which led to the formation of NiC monocarbide were also evaluated and discussed. Parameters of the electronic structure of NiC were calculated using the MStudio MindLab 7.0 software package with the experimental data on the crystal structure of the NiC phase obtained as input. Temperature dependencies of magnetic susceptibility of NiC synthesized have been studied up to 950 K. Carbides synthesized were found to be weak ferromagnets at the room temperature and their Curie temperature T-C ranges within 670 - 725 K. The calculated value of the magnetic moment per nickel atom (2.83 mu(B)) is higher than that of a bulk Ni (1.3 mu(B)). Likely, the observed increase of mu is caused by the presence of a certain amount of residual single-domain ferromagnetic Ni nanoparticles in the samples synthesized. (C) 2021 The Society of Powder Technology Japan. Published by Elsevier BV and The Society of Powder Technology Japan. All rights reserved.

Automated summary

In this study, the mechanical alloying of Ni-carbon nanotubes (CNT) and Ni-Graphite equiatomic powder mixtures was comprehensively investigated. Regardless of the type of carbon used, a novel nanoscale fcc NiC monocarbide was synthesized. XRD analysis revealed that the formation of this phase occurred in two stages, suggesting a two-step carbide formation mechanism. The synthesized carbides exhibited weak ferromagnetic properties at room temperature, with a Curie temperature range of 670-725 K.