Growth of bismuth oxide (most probably Bi2O3) was observed in situ in a transmission electron microscope. Bi liquid particles were dispersed on the substrates of diamond or SiO2. Introduction of oxygen up to ∼5 × 10−4 Pa resulted in formation of bismuth oxide (most probably Bi2O3) whiskers. The growth mechanism of the whisker was discussed in terms of a vapor-liquid-solid (VLS) mechanism. It is suggested that the liquid droplet of Bi acts as a physical catalyst for growth of bismuth oxide (most probably Bi2O3) whiskers.

Calcium phosphate [single-phase hydroxyapatite (HA), single-phase tricalcium phosphate (TCP), and biphasic HA-TCP] nanowhiskers and/or powders were produced by using a novel microwave-assisted “combustion synthesis (auto ignition)/molten salt synthesis” hybrid route. This work is an example of our “synergistic processing” philosophy combining these three technologies while taking advantage of their useful aspects. Aqueous solutions containing NaNO3, Ca(NO3)2·4H2O and KH2PO4 (with or without urea) were irradiated in a household microwave oven for 5 min at 600 watts of power. The as-synthesized precursors were then simply stirred in water at room temperature for 1 h to obtain the nanowhiskers or powders of the desired calcium phosphate bioceramics.

Nanostructure copper whisker growth was observed in an atmospheric pressure chemical vapor deposition (CVD) system, which used copper acetylacetonate vapor and 10-15 torr of water vapor as reactants, with 0.04-0.10 torr of chromium acetylacetonate vapor added as growth promoting catalyst. Water vapor initiated nucleation of these helical, spiral shape Cu(111) and (200) polycrystalline whiskers. While chromium acetylacetonate accelerated the growth rate. Copper whiskers had radii from 0.1 to 0.24 μm, lengths from 1 to 10 μm, and distribution density of 0.20-3.6 whiskers/μm2. Dependence of such whisker characteristics on temperature, partial pressures of H2O and chromium acetylacetonate was used to construct a kinetic model. From the Arrhenius equation, data analysis for whisker growth rate against deposition temperature showed that the activation energy for whisker growth along radial direction is 12.4 kcal/mol, and 19.6 kcal/mol for growth along axial direction. Based on such data and SEM observations, a base vapor-liquid-solid (VLS) model involving BCF theory was proposed to describe the governing mechanism for the axial growth. This model interpreted the competitive growth phenomena in both radial and axial directions, and controlling steps for radial and axial growth being assigned to mass transfer and surface reaction, respectively.