Straight aligned carbon nanotubes with multiwalled cylindrical structure have been produced by pyrolysis of iron phthalocyanine (FePc) after ball milling treatment. The pre-ball milling treatment prevented the formation of curved nanotubes with bamboo or conelike structures. X-ray diffraction analysis revealed that the milled FePc has an activated and disordered structure, which contributes a lower vaporization temperature determined by thermal gravimetric analysis. The low formation temperature and an increased nanotube growth rate are favorable to the formation of cylindrical structure than bamboo tubes.

In this paper, we present a study on the formation of gold colloids by laser ablation of a gold metal target in alkanes and thiol-alkane solutions. The results show a decrease of the gold particles’ size up to 2 nm when thiol molecules are present in the liquid environment. The observation of a blue-shift of the surface plasmon resonance is discussed together with transmission electron microscopy analyses accounting the cluster size decrease and the stabilization of the obtained suspensions.

Effect of nano ZnO on the hydrogen absorption performance of Ti-30V-15Mn-15Cr alloy was investigated. It was found that a small amount addition of nano ZnO (3 wt%) drastically improves the hydrogen absorption property of this alloy powder. The modification enables the air-exposed powder to absorb hydrogen quickly without activation. It could be attributed to the synergetic action of nano ZnO, which might expedite the dissociation of hydrogen on the oxidized alloy surface and play as entrance for hydrogen into the bulk alloy. The fact that nano ZnO addition improves the hydrogen absorption performance of Ti-30V-15Mn-15Cr alloy pioneers a new way for developing highly active Ti-V-based body-centered-cubic phase alloys.

BaSO4 nanotubes were biomimetically synthesized by the combined assembly of eggshell membrane and C12H25SH. The products were tubular structure with the external diameter of 90–140 nm and the length of 1.5–2.5 μm. The formation mechanism was also investigated. It provided a novel method for the fabrication of inorganic oxysalt nanotubes.

A facile, surfactant-assisted, hydrothermal approach has been developed to synthesize lanthanide phosphate single-crystalline nanowires/nanorods with smooth surface, uniform diameter, and good crystallinity. The surfactant Pluronic P123 was found to play a crucial role on the uniform morphology of lanthanide phosphate single-crystalline nanowires/nanorods. Photoluminescence spectra of the lanthanide phosphate single-crystalline nanowires/nanorods show that these nanowires/nanorods have strong photoluminescent emissions in the ultraviolet-visible and near-infrared regions. The present work is a preliminary and significant step toward the potential luminescent and catalytic applications of lanthanide compound based one-dimensional nanostructures.

Understanding the hardening response of small volumes is necessary to completely explain the mechanical properties of thin films and nanostructures. This experimental study deals with the deformation and hardening response in gold and copper films ranging in thickness from 10 to 400 nm and silicon nanoparticles with particle diameters less than 100 nm. For very thin films of both gold and copper, it was found that hardness initially decreases from about 2.5 to 1.5 GPa with increasing penetration depth. Thereafter, an increase occurs with depths beyond about 5–10% of the film thickness. It is proposed that the observed minima are produced by two competing mechanisms. It is shown that for relatively deep penetrations, a dislocation back stress argument reasonably explains the material hardening behavior unrelated to any substrate composite effect. Then, for shallow contacts, a volume-to-surface length scale argument relating to an indentation size effect is hypothesized. A simple model based on the superposition of these two mechanisms provides a reasonable fit to the experimental nanoindentation data.

Phase transformations in near-equiatomic TiNi shape memory alloy thin films were studied, and the phase fraction evolutions were quantitatively correlated to the stress and resistivity of the films. TiNi thin films with compositions of 50.1, 51.1, and 51.7 at.% Ti all exhibited transformation temperatures between 65 and 100 °C, low residual stresses at room temperature (RT), and high recoverable stresses, thus making them suitable for microactuators in microelectromechanical systems. Low residual stresses at RT, less than 50 MPa, can be obtained even when only a small quantity of martensite, less than 30%, is present. Phase fraction evolution during complete thermal cycles (heating and cooling) was studied using elevated temperature x-ray diffraction, combined with quantitative Rietveld analysis. R-phase always appeared in these near-equiatomic TiNi thin films during cooling but did not have a noticeable effect on the stress–temperature hysteresis curves, which mainly depend on the phase fraction evolution of martensite. On the other hand, the occurrence of R-phase determined the variation of film resistivity. Martensite, austenite, and R-phase coexisting within a single grain were observed using transmission electron microscopy.

In this paper, the results of a temperature dependent x-ray diffraction (XRD) study on BaTi0.95Sn0.05O3 (BTS-5) ceramics are compared with dielectric measurements. The orthorhombic-tetragonal phase transition at T2 = 306 K is found to proceed in a considerably wider temperature range than expected from the dielectric anomaly. Although the macroscopic properties of BTS-5 indicate a rather sharp ferroelectric phase transition at Tc = 358K, we observe anomalous XRD-patterns in a 25 K wide temperature range. This is interpreted in terms of mechanically clamped tetragonal and cubic phase, coexisting in the vicinity of Tc in grains with inhomogeneous Sn-distribution.

Ca-doped lead zirconate titanate (52/48) thin film capacitors were prepared on electroless nickel-coated copper foils for embedded capacitor applications. The impact of Ca doping and process parameter variations was studied. Ca addition significantly reduced the temperature coefficient of capacitance. Specifically, the temperature variation was reduced to less than 10% between 300 and 580 K through calcium addition. Optimized capacitance densities and loss tangents were 400 nF/cm2 and 0.02, respectively. Crystallization temperatures of 600 °C yielded these optimized electrical properties, while higher temperatures resulted in interfacial reactions. The influence of oxygen partial pressure during crystallization was also studied. Dielectric properties were sensitive to pO2, with optimal properties occurring in a narrow pO2 window centered about 10−3 Torr. The trends with oxygen pressure were mirrored by changes in phase assemblage. Electrical transport across the dielectric layers was not strongly dependent upon doping level. This insensitivity was attributed to a thin interfacial layer present in all samples. Interface analysis using equivalent circuit analogues showed the nature of the interface to be highly resistive (insulating), rather than semiconducting or conducting.

The influence of the variation in (V2O5/ P2O5) ratio on the local structure of iron in V2O5–BaO–Fe2O3–P2O5 glass system was investigated. Infrared analysis and Mössbauer spectroscopy were used for this propose. Infrared spectroscopic analysis showed that vanadium cations act mainly as network former (NWF) while iron ions occupy both NWF and network modifier (NWM) positions. On the other hand, Mössbauer spectra indicated that, at the lowest V2O5 content, about 29% of iron ions take their positions in the glass matrix as NWF and about 71% of iron ions enter the matrix as network modifier NWM. At the highest value of V2O5 content the iron ions that enter the glass as NWF decrease to about 15%, and the iron ions which enter the glass as NWM increase to about 85%. The density and molar volume measurements also indicate the changes in the structure of these glasses.

The converse piezoelectric response of a thin film constrained by a substrate is analyzed in different geometries under various boundary conditions. We considerthe effects of elastic deformation of the substrate on the total displacement of thefilm surface induced by the electric field. The change of film thickness and the bending curvature of a film/substrate couple are calculated. For a thin film island clamped on a large thick substrate, the theoretical estimation of the piezoresponse, including a local bending in the vicinity of the island/substrate interface, is in agreement with the finite element calculation.

Thin films of vanadium oxides were grown on fused quartz by metalorganic chemical vapor deposition using vanadyl acetylacetonate as the precursor. Growth at temperatures ⩾560 °C results in composites of strongly (00l)-oriented V2O5 and V6O13. The dominant phase of the film changes from V2O5 to V6O13, and back to V2O5, as the growth temperature is raised from 560 to 570 °C, then to 580 °C, as evidenced by x-ray diffraction and Rutherford backscattering analyses. This reentrant-type growth trend was interpreted on the basis of the small difference in the free energy of formation of V2O5 and V6O13 and the presence of metal–oxygen bonds in the precursor. In contrast with single-crystalline V6O13, the film predominantly composed of highly oriented single-crystalline platelets of V6O13 did not undergo the semiconductor–metal transition at −123° K, despite the connectivity being well above the percolation threshold. Instead, a semiconductor-to-semiconductor transition was observed in this film, which is explained in terms of the observed relaxation of the edges of all the platelets of metallic V6O13 to semiconducting V2O5.

A new nano-ternary Mg–8 mol% LaNi0.5 was prepared by melted and subsequent mechanical alloying technique for hydrogen storage. It was found from our experiments that, this kind of alloy had superior hydriding/dehydriding characteristics in comparison with conventional materials for hydrogen storage. It possessed large hydrogen capacity at a lower temperature, which could absorb 4.55–7.01 mass% H under 3 MPa hydrogen pressure and desorb 4.40–6.90 mass% H under 0.0133 MPa in 600 s above 423 K without any activation requirement drawn from our pressure-composition isotherm and kinetic experiments. Through the x-ray diffraction and transmission electron microscopy experiments, we further found that these superior characteristics could be attributed to the multiphase structure and a catalytic effect of LaH3 and Mg2Ni that were formed in the material preparation of mechanical alloying process. Finally, based on these data the relationships between equilibrium pressure of hydrogen and temperature were obtained, they were lgp(0.1 MPa) = −3985/T + 7.188(553 K ⩽ T ⩽ 573K) for hydriding and lgp(0.1 MPa) = −3804/T + 6.770 (553 K ⩽ T ⩽ 573 K) for dehydriding.

Austenite–ferrite transformation at different isothermal temperatures in low carbon steel was investigated by a two-dimensional cellular automaton approach, which provides a simple solution for the difficult moving boundary problem that governs the ferrite grain growth. In this paper, a classical model for ferrite nucleation at austenite grain boundaries is adopted, and the kinetics of ferrite grain growth is numerically resolved by coupling carbon diffusion process in austenite and austenite–ferrite (γ–α) interface dynamics. The simulated morphology of ferrite grains shows that the γ–α interface is stable. In this cellular automaton model, the γ–α interface mobility and carbon diffusion rate at austenite grain boundaries are assumed to be higher than those in austenite grain interiors. This has influence on the morphology of ferrite grains. Finally, the modeled ferrite transformation kinetics at different isothermal temperatures is compared with the experiments in the literature and the grid size effects of simulated results are investigated by changing the cell length of cellular automaton model in a set of calculations.

Sn–9Zn and Sn–8Zn–3Bi solder balls were bonded to Cu or electroless Au/Ni(P)pads, and the effect of aging on joint reliability, including impact reliability, was investigated. For the purpose of quantitatively evaluating the impact toughness ofthe solder joints, a test similar to the classic Charpy impact test was performed.The interfacial compounds formed in the solder/Cu joint during soldering wereCu–Zn intermetallic compounds (IMCs), not Cu–Sn IMCs. One of the Cu–Zn IMCs, γ–Cu5Zn8, thickened remarkably with aging, and eventually its morphology changed from layer-type into discontinuous. The rapid growth of the γ–Cu5Zn8 and void formation at the bond interface led to the significant degradation of the joint reliability due to a ductile-to-brittle transition of the joint. Meanwhile, the compound formed in the solder/Au/Ni(P) joint during soldering was a Au–Zn IMC, above which Zn redeposited during aging. Both the dissolution and diffusion of Ni into the solders were extremely slow, which contributes to negligible void formation at the bond interface. As a result, the solder bumps on the Au/Ni(P) pads were able to maintain the high joint strength and impact toughness even after prolonged aging.

Lead-free solders with high Sn content cause excessive interfacial reactions at the interface with under-bump metallization during reflow. The interface formed after reflow affects the reliability of the solder joint. For this paper, we investigated the interfacial reactions of Sn0.7Cu and Sn36Pb2Ag solder on electrolytic Ni layer for different reflow times. The traditionally used Sn36Pb2Ag solder was used as a reference. It was found that during as-reflowed, the formation of Cu-rich Sn–Cu–Ni ternary intermetallic compounds (TIMCs) at the interface of Sn0.7Cu solder with electrolytic Ni is much quicker, resulting in the entrapment of some Pb (which is present as impurity in the Sn–Cu solder) rich phase in the TIMCs. During extended time of reflow, high (>30 at.%), medium (30-15 at.%) and low (<15 at.%) Cu TIMCs formed at the interface. The amount of Cu determined the growth rate of TIMCs. Cu-rich TIMCs had higher growth rate and consumed more Ni layer. By contrast, the growth rate of the Ni–Sn binary intermetallic compounds (BIMCs) in the Sn36Pb2Ag solder joint was slower, and the Ni–Sn BIMC was more stable and adherent. The dissolution rate of electrolytic Ni layer for Sn0.7Cu solder joint was higher than the Sn36Pb2Ag solder joints. Less than 3 μm of the electrolytic Ni layer was consumed during molten reaction by the higher Sn containing Sn0.7Cu solder in 180 min at 250 °C. The shear strength of Sn–Pb–Ag solder joints decreased within 30 min of reflow time from 1.938 to 1.579 kgf due to rapid formation of ternary Ni–Sn–Au compounds on the Ni–Sn BIMCs. The shear strength of Sn0.7Cu solder joint is relatively stable from 1.982 to 1.861 kgf during extended time reflow. Cu prevents the resettlement of Au at the interface. The shear strength does not depend on the thickness of intermetallic compounds (IMCs) and reflow time. Ni/Sn–Cu solder system has higher strength and can be used during prolonged reflow.

Nanoparticles of barium orthotitanate (Ba2TiO4) was obtained using microemulsions (avoiding Ba-alkoxide). Powder x-ray diffraction studies of the powder after calcining at 800 °C resulted in a mixture of orthorhombic (70%) and monoclinic (30%) phases. The high-temperature orthorhombic form present at 800 °C was due to the small size of particles obtained by the reverse micellar route. Pure orthorhombic Ba2TiO4 was obtained on further sintering at 1000 °C with lattice parameters a = 6.101(2) Å, b =22.94(1) Å, c = 10.533(2) Å (space group, P21nb). The particle size obtained from x-ray line broadening studies and transmission electron microscopic studies was found to be 40–50 nm for the powder obtained after heating at 800 °C. Sintering at 1000 °C showed increase in grain size up to 150 nm. Our studies corroborate well with the presence of a martensitic transition in Ba2TiO4. The dielectric constant was found to be 40 for Ba2TiO4 (at 100 kHz) for samples sintered at 1000 °C. The dielectric loss obtained was low (0.06) at 100 kHz.

A series of experiments were conducted to investigate chemical interactions between silicon carbide (SiC) and synthetic ash compositions expected to be deposited on the surfaces and within the pore structure of a diesel particulate filter. The chosen ash compositions simulated those arising from lubricants and three fuel types: standard diesel, diesel containing ferrocene as a catalytic additive, and diesel containing a cerium-based catalyst. Results demonstrated that SiC suffered little chemical or oxidative degradation in the presence of the ashes at 900 °C. For the ash not containing Fe or Ce, ash sintering effects were a possible mechanism causing filter blockage at temperatures above 970 °C. For ashes containing Fe or Ce, appreciable sintering effects were not observed below 1100 °C. Based upon the work conducted the suitability of SiC as a construction material for diesel particulate filters is not compromised by chemical degradation in the presence of lubricant/additive derived ash at temperatures less than 1100 °C.

Ca5A2Ti1−xZrxO12 (A = Nb, Ta) ceramics were prepared through conventional solid-state ceramic route for 0 ⩽ x ⩽ 1. The crystal structures of the ceramics were studied by x-ray diffraction techniques, and dielectric properties were measured at microwave frequencies. In the Ca5Nb2Ti1−xZrxO12 system as x increases from 0 to 1, ϵr decreases from 48 to 25, Qu× f from 26,000 to 19,000 GHz, and τf from +40 to −21 ppm/°C. In Ca5Ta2Ti1−xZrxO12 ceramics, ϵr varies from 38 to 22, Quxf from 33,000 to 24,000 GHz, and τf from +10 to −26 ppm/°C as x is changed from 0 to 1. The variation of microwave dielectric properties with bond valence and electronegativity in the two systems were also investigated. Ca5Nb2Ti0.2Zr0.8O12 and Ca5Ta2Ti0.7Zr0.3O12 dielectric ceramics were found to have stable resonant frequency with temperature and are potential candidates for applications in personal and satellite communication systems in the S and C band (2–8 GHz).

Nonisothermal crystallization kinetics of amorphous chalcogenide Ga–Sb–Te films with compositions along the pseudo-binary tie-lines connecting Sb7Te3−GaSb and Sb2Te3–GaSb of the ternary phase diagram were investigated by means of differential scanning calorimetry. Powder samples were prepared firstly by film deposition using a co-sputtering method; the films were then stripped from the substrate. The activation energy (Ea) and rate factor (Ko) were evaluated from the heating rate dependency of the crystallization temperature using the Kissinger method. The kinetic exponent (n) was deduced from the exothermic peak integrals using the Ozawa method. The crystallization temperature (Tx = 181 to 327 °C) and activation energy (Ea= 2.8 to 6.5 eV) increased monotonically with increasing GaSb content and reached a maximum value in compositions located at the vicinity of GaSb. The kinetic exponent is temperature dependent and shows higher values in the SbTe-rich compositions. Promising media compositions worthy of further studies were identified through the determined kinetics parameters.