Structural Properties of Chemically Synthesized Nanostructured Ni and Ni:Ni₃C Nanocomposites

Abstract

We have used a reductive technique known to produce highly reactive metals to fabricate nickel and nickel-based nanostructured materials. The strong dependence of the magnetic, chemical, electrical, and optical properties of nanostructured materials are intimately correlated with material structure; thus, thorough knowledge of the effect of synthesis parameters on the structure is critical for the refinement of fabrication techniques. X-ray diffraction and electron microscopy are used to determine the effect of the synthetic conditions and subsequent processing on the material structure. Characteristic lengths of these materials range from 3 to 50 nm, depending on synthesis and annealing conditions. Annealing produces a metastable Ni 3 C phase that forms only in the presence of active carbon, suggesting that not only active nickel but also active carbon results from this process. The addition of P(Ph) 3 affects the time and temperature dependence of the nickel crystallite growth, the temperature at which Ni 3 C crystallites are first observed and the maximum temperature to which Ni 3 C can be retained.

Preparation and characterization of γ-Fe2O3 nanoparticles in SBA15 host material

“…This implies that their size must be larger than 16 nm, which leads to the conclusion that particles must be strongly elongated, because their cross-sectional area is limited by the pore size of diameter of 6 nm which gives minimum aspect ratio of the particles equal 3. It has also been verified by the Scherrer equation of the XRD peak [5]. This is actually a desirable shape of the particles, which was successfully utilized in case of larger particles for magnetic recording in the past.…”

Structural and magnetic properties of NiCxand NiNx(x=0toFang1, Sluiter2, Huis3 et al. 2012Phys. Rev. B

“…This difference is useful to identify and distinguish the Ni phases and Ni 3 X phases in different forms, such as in nanocrystals or in thin films. [6][7][8][9][10][11][12]19,23,24 Both hcp-and 3R-Ni 3 X phases have hexagonal closepacked (hcp) Ni sublattices ( Fig. 1 and Table II).…”

“…[1][2][3][4][5][6][7][8][9][10][11][12] In recent years, much attention has been paid to different Ni 3 X materials, such as nanosized crystallites [3][4][5][6][7][8][9][10] and thin films. 11,12 Ni 3 N samples were first prepared by means of nitridation of Ni metal using ammonia.…”

Synthesis of Nanoparticulate Magnetic Materials

“…In order to obtain metals in colloidal or nanocrystalline powder form, it is however advantageous to use a dissolved reducing agent; therefore solutions of sodium in ammonia or amines would be preferred over bulk metal or its amalgam [19]. Bulk metals as reducing agents work well for metal refining, especially for noble metals, which precipitate in a bulk form.…”