STRUCTURAL-PROPERTIES OF CHEMICALLY SYNTHESIZED NANOSTRUCTURED NI ANDNI-NI3C NANOCOMPOSITES

We have used a reductive technique known to produce highly reactive me tals to fabricate nickel and nickel-based nanostructured materials. Th e 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 synthes is parameters on the structure is critical for the refinement of fabri cation techniques. X-ray diffraction and electron microscopy are used to determine the effect of the synthetic conditions and subsequent pro cessing on the material structure. Characteristic lengths of these mat erials range from 3 to 50 nm, depending on synthesis and annealing con ditions. 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(P h)(3) affects the time and temperature dependence of the nickel crysta llite growth, the temperature at which Ni3C crystallites are first obs erved and the maximum temperature to which Ni3C can be retained.