Structural properties of chemically synthesized nanostructured Ni and Ni:Ni3C nanocomposites

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 Ni3C 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 Ni3C crystallites are first observed and the maximum temperature to which Ni3C can be retained.