Nanocrystallization significantly influences the electrochemical corrosion behaviors of metals/alloys in liquid system. In active dissolution, nanocrystallization accelerates the corrosion reactions. If the corrosion products are dissoluble, the corrosion rate is increased by nanocrystallization; if the corrosion products are insoluble, the
corrosion rate is decreased on the contrary because the corrosion products act as a block layer to delay the dissolution. In passivation, nanocrystallization changes the composition of the passive film, and results into different morphology and growth process of the passive film, both of which improves the formation of compact film and influences the semiconductor property. It influences the passivation depending on fast element diffusion and special adsorbed ability. The small grain size improves the element diffusion, which leads to the different composition of passive film (passive elements enrichment such as Cr, Ti). The small grain size also changes the surface condition, which influences the ions adsorption. All increase the corrosion resistance of materials. In local corrosion, nanocrystallization increases the unstable points
on the surface of the materials, which increases the possibility of local corrosion. However, the excellent ability of element diffusion helps heal the local corrosion points, which inhibits the growth of the local corrosion.

GaPO₄-GaN coaxial nanowires were synthesized by two-step chemical vapor deposition method using H₂ and NH₃ as reactant gas in turn at 950°C. The morphology and microstructures of the GaPO4-GaN coaxial nanowires were studied by scanning elctron microscopy (SEM), X-ray diffraction (XRD) and transmission lectron microscopy (TEM). The nanowires have an average diameter of ~15 nm and length of hundreds of anometers. The core is GaPO₄ crystal and the outer shell is GaN crystal. The formation  mechanism was iscussed and the key factors controlling the growth are temperature and the concentration of reactant gases. hese coaxial nanowires may have potential application for piezoluminescence nano-devices, and the two-step ynthetic technique could be used to grow rationally other 1D GaN-based nanowire heterostructures.

Double-walled carbon nanotube (DWCNT) macro-films with large areas, excellent flexibility and superhy-drophobicity are reported. The area of the macro-film is larger than 30 cm×15 cm, and this large film can be bended, or folded without any damage, and even can be tailored freely. After a simple modification of perfluoroalkysilane, the surface of the macro-film shows excellent superhydrophobicity with a water contact angle of 165.7±2 deg. and sliding angle lower than 3 deg., the prepared superhydrophobic films showing excellent antifouling, self-cleaning and water-repellent functions. The topographic roughness and per°uoroalkysilane modification are found to contribute to the observed superhydrophobicity. Considering the outstanding electronic, chemical and mechanical properties of DWCNTs, it is expected that this multifunctional DWCNT macro-film has potential applications in many fields.

For the first time, petal-like and spherical Mg-based icosahedral quasicrystal phase (I-phase) were obtained by introducing Ti, Sb, Ce and C nanotubes into Mg-Zn-Y alloy under normal casting conditions. The formation mechanism and stability criterion of spherical I-phase were discussed. The morphology and microhardness of I-phase and their determinants were studied in this paper. The results show that the different value of microhardness of I-phase could be attributed to the different kinds of the fourth component and its content, and its different innate characters. The final morphology of icosahedral quasicrystalline (IQC) is decided by the size of critical stable radius Rr, the content of the fourth component and degree of undercooling.

Barium titanate (BaTiO₃) and strontium titanate (SrTiO₃) nanoparticles were synthesized separately through hydrothermal reaction of crystalline TiO₂ particles and corresponding alkaline earth hydroxides, Ba(OH)₂ and Sr(OH)2 respectively, in 50 mol·dm^-3 KOH solution at 150°C. Each structural evolution of BaTiO₃ and SrTiO₃
during the hydrothermal treatment was investigated by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), field emission transmission electron microscopy (FE-TEM) and thermogravimetry- differential analysis (TG-DTA). In the BaTiO₃ system, round particles with cubic perovskite-type structure were obtained within 1 h. However, these particles were gradually dissolved and then were re-precipitated in the form of cube-shape BaTiO₃ particles with a smaller lattice constant ac than that of the former phase. After the BaTiO₃ particles formed firstly have disappeared completely, or the two phases coexistence stage with different lattice constant ac passed, lattice constant ac of BaTiO₃ phase re-precipitated continuously decreased with annealing time. In contrast, once SrTiO₃ particles are formed, the lattice constant ac decreased continuously throughout the reaction. The result indicates that SrTiO₃ particles were annealed without dissolution and precipitation process under the present condition.

The preparation of polyaniline nanofibers in aqueous solution was studied as functions of the concentrations and ratios of reactants. The morphology and microstructure of polyaniline nanofibers are affected by the concentrations and proportions of the reactants. A special kind of sea cucumber-like polyaniline nanofibers can be prepared under control of reaction conditions. Secondary growth is the formation mechanism. In addition, the bulk electrical conductivity of these sea cucumber-like polyaniline nanofibers was higher than that of other common polyaniline nanofibers.

A solution-solid method is developed to construct cerium phosphate (CePO₄) nanofibers. Tetraphosphoric acid formed the condensed linear polyphosphate (PnO_3n+1)^(n+2)-before reacting with cerium carbonate (Ce₂(CO₃)₃) powder, which was favourable for one dimensional CePO₄ nanofibers forming. The growth mechanism was proposed based on solution-solid process. CePO₄ nanofibers display strong UV luminescence emission and weak blue emission.

The electric contact material of Ag/SnO₂ composite was achieved by reactive synthesis method. The com-positions and microstructure of Ag/SnO₂ composite were analyzed and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and high-resolution electron microscopy (HRTEM). The structural feature was typical of the particle reinforced composites. The HRTEM images revealed that the observed Ag/SnO₂ interface was absence of the precipitated phase and the lattice contrast across the interface was clear and sharp. The average particle size of SnO₂ in composite was near 50 nm and it was well dispersed in spherical shape. The thermodynamic mechanism of reactive synthesis method was also discussed. The electronic density distribution analysis of the interface showed the charges of Ag atoms transmitted to O
atoms and the conductivity of the material was also affected. No extra compounds expected such as Ag_xO_y formed at interface. The distribution of electrons was of inequality near the interface which explained why the mechanical property of the metal/ceramic materials was improved but the machining property declined.

Nanoindentation simulations on single crystals Al and Cu via the quasicontinuum method have been performed. Two kinds of atomic-level local stress calculation methods, i.e. the coarse-grained local stress and the virial local stress, are employed to calculate the stress state of the contact area. Various comparisons between the coarse-grained local stress and the virial local stress have been made. Firstly, the averaged normal stress beneath the contact surface calculated by coarse-grained method agrees well with continuum mechanical pressure measurement, while the virial method gives unphysical results sometimes. Secondly, the coarsegrained results reflect the indenter size effect on the critical shear stress quite accurately, while the virial calculations fail. Thirdly, the distribution of maximum shear stress of the coarse-grained method predicts the
defects nucleation locations reliably, while the distribution of virial local stress gives an incorrect prediction sometimes. Thus it is concluded that the coarse-grained method can offer a more reliable description of the local stress states of atoms in spatially inhomogeneous solids.

The Si-TaSi₂ eutectic in situ composite, which has highly-aligned and uniformly-distributed TaSi₂ fibers in the Si matrix, can be obtained when the solidification rate changes from 0.3 to 9.0 mm/min. It is very interesting that one or two TaSi₂ fibers are curved when the solidification rate reaches 6.0 mm/min, although it is very brittle in general. The formation mechanism of the curved fiber is discussed and mechanical properties of the TaSi₂ fibers are examined by nanoindentation. It is found that the hardness and the elastic modulus of the bended TaSi₂ fiber are much higher than that of the straight TaSi₂ fiber. Moreover, the reasons why the mechanical properties of the straight TaSi₂ fiber are different from that of the curved TaSi₂ fiber are discussed. This can be ascribed to internal stress which results from mismatch of the thermal expansion coefficients of the two phases and di®erent crystallographic orientations.

A nanocrystal model for liquid metals and amorphous metals has been developed. With the nanocrystal model, the broadening peak profiles (BPPs) of Cu, Al, Al₆₅Cu₂₀Fe₁₅ alloy, Cu₇₀Ni₃₀ alloy and Fe₅₀Si₅₀ alloy were gained by broadening the X-ray diffraction (XRD) peaks of a crystal lattice. By comparing the BPPs with the XRD intensity curves measured on the liquid metals, it is found that the BPPs are closely in agreement with the XRD intensity curves, respectively, except the Fe₅₀Si₅₀ alloy. Therefore, the nanocrystal model can be used to determine if the atomic cluster structure of the liquid metal is similar to the structure of its crystal lattice.

The nano-concentrates and fiame retardant nano-coating were prepared in thhis study. The effect of nano-SiO₂ on the corrosion resistance and fire resistance of ammonium polyphosphate-pentaerythritol-melamine (APP-PER-MEL) coating was investigated by differential thermal analysis (DTA), scanning electron microscopy
(SEM), effective thermal conductivity (λ/d), X-ray photoelectron spectroscopy (XPS) and fire protection test. The chemical action and endothermic effect of ammonium polyphosphate, pentaerythritol and melamine in traditional flame retardant coating were damaged by salt spray condition, whereas the flame-retardant additives in the nano-coating demonstrated the good chemical interaction in salt spray condition. The uniformly dispersed nano-SiO₂ particles could improve corrosion resistance of the coating, and hence nano-coating could remain the good fire-resistant properties even after 500 h salt spray test.

In order to achieve the optimum conditions for electroplating nanocrystalline nickel coating from Watts-type bath, the effect of some process parameters namely, bath temperature, current density, and saccharin addition on grain size and texture coefficient (TC= I₍₂₀₀₎ /I₍₁₁₁₎ ) of the deposits were investigated by X-ray diffraction
(XRD). The results showed that in a bath containing 5 g/L saccharin, by increasing the bath temperature from 45°C to 55°C, the grain size decreased, whereas further increase of bath temperature resulted in a contrary effect. By increasing the current density from 10 to 75 mA/cm², both the grain size and TC decreased, while further increase in current density had no significant effect on the grain size. At a given current density, the grain size and TC decreased rapidly by increasing the saccharin content before leveling off at 3 g/L of saccharin. Finally, based on the grain refining the optimum conditions for producing nanocrystalline nickel coating from Watts-type bath have been proposed.

Tungsten (W) thin films were prepared by magnetron sputtering onto Si (100) substrates. Their microstructures were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The hardness and modulus were evaluated by nanoindentation. It is found that a 30 nm Cr sticking layer induces structure changes of deposited W film from β-W to α-W structure. In addition, remarkable hardness enhancement both for the deposited and annealed W films, were compared with that of bulk coarse-grained W, although their nanoindentation modulus is very close to that of corresponding bulk W. The intrinsic reasons that lead to structure changes and super hardness are discussed.

Radio-frequency (RF) magnetron sputtering was employed to prepare gallium phosphide (GaP) thick films on zinc sulfide (ZnS) substrates by sputtering a single crystalline GaP target in an Ar atmosphere. The infrared (IR) transmission properties, structure, morphology, composition and hardness of the film were studied. Results show that both amorphous and zinc-blende crystalline phases existed in the GaP film in almost stoichiometric amounts. The GaP film exhibited good IR transmission properties, though the relatively rough surface and loose microstructure caused a small loss of IR transmission due to scattering. The GaP film also showed a much higher hardness than the ZnS substrate, thereby providing good protection to ZnS.