The Debye temperature and glass transition temperature of a variety of bulk metallic glasses (BMGs) were determined by acoustic measurement and differential scanning calorimetry, respectively. The relationship between the Debye temperature and glass transition temperature of these BMGs was analyzed, and their observed correlation was interpreted in terms of the characteristics of the glass transition in BMGs.

Three typical interactions of persistent slip bands (PSBs) with different types of grain boundaries (GBs) were investigated and analyzed in fatigued copper crystals. The results show that PSBs cannot transfer through all types of large-angle GBs, regardless of their orientation with respect to the stress axis. Secondary slip was often observed near the GBs, leading to strain incompatibility. When the slip systems of the two adjacent crystals are coplanar, the transmission of a PSB across a GB strongly depends on the slip directions of the two adjacent crystals. It was found that only the low-angle GBs can be passed through by PSBs, and accordingly they are insensitive to intergranular fatigue cracking. For a special copper bicrystal with coplanar slip systems, the ladderlike dislocation arrangements within the adjacent PSBs become discontinuous and a dislocation-affected-zone appears near the GB due to the difference in the slip direction of the two adjacent crystals. Therefore, the necessary conditions for the transmission of a PSB across a GB are that the neighboring grains have a coplanar slip system and identical slip directions.

Mesostructured lamellar lead sulfide has been synthesized for the first time at room temperature in acidic media, employing sodium dodecyl sulfonate (SDS) as template and soluble lead salts, and hydrated sodium sulfide as the inorganic sources. The material was chiefly characterized by x-ray powder diffraction, high-resolution transmission electron microscopy, Raman spectroscopy, x-ray photoelectron spectroscopy, and thermogravimetric analysis. In the material, the Pb:S molar ratio for the inorganic phase is about 1:1.2, with a distance of about 2.7 nm between the inorganic layers.

The microstructure of the melt-spun Cu60Hf30Ti10 and Cu50Hf40Ti10 alloys was investigated. The high-resolution transmission electron microscopy (HRTEM) image in the Cu60Hf30Ti10 alloy reveals the existence of nanoscale inhomogeneity, which appears to originate from nanocrystalline particles. The compositional segregation with a diameter of approximately 5 nm was detected, and its size agrees with the scale of nanocrystalline particle. Small-angle x-ray scattering measurement of the melt-spun Cu60Hf30Ti10 alloy also indicates the development of nanoscale inhomogeneity with the same size as that of nanocrystalline particles. It is found that the Cu element is enriched in and Hf element is rejected from the nanocrystalline particles. Since the melt-spun Cu50Hf40Ti10 alloy, which has a similar alloy composition to that of the glassy region of melt-spun Cu60Hf30Ti10 alloy, has a homogeneous glassy structure without fringe contrast in the HRTEM image, it is suggested that the excess of Cu causes the nanoscale inhomogeneity with crystalline structure in the rapidly quenched Cu–Hf–Ti alloys.

Sodium ion-conductive silicon nitride ceramic with Na2O–Al2O3–SiO2 glass as the grain boundary phase was fabricated by adding Na2CO3, Al2O3, and SiO2 as sintering additives. The electrical conductivity was two and four orders of magnitude higher than that of Si3N4 ceramic with Y2O3 and Al2O3 additives at 100 and 1000°C, respectively. This result clearly indicates that ionic conductivity can be provided to insulating structural ceramics by modification of the grain boundary phase without dispersion of conductive particles.

We report a new Mg-based bulk metallic glass-forming alloy: Mg65Cu7.5Ni7.5Zn5 Ag5Y10. The alloy exhibits a glass-forming ability significantly stronger than all previously discovered Mg-based glass formers. Fully glassy rods 9 mm in diameter can be obtained by using copper mold casting. The critical cooling rate for glass formation was estimated to be <50 Ks−1. The reduced glass-transition temperature (Trg) of the glass was determined to be 0.59.

Plastic deformation of amorphous Al90Fe5Gd5 was investigated using nanoindentation and atomic force microscopy. While serrated flow was detected only at high loading rates, shear bands were observed for all loading rates, ranging from 1 to 100 nm/s. However, the details of shear-band formation depend on the loading rate.

The interface microstructures of Sn-Ag and Sn-Ag-Cu solders with Au/Ni-6P plating were studied primarily using transmission electron microscopy. During soldering at 230°C, Au dissolved into molten solder, and double reaction layers of Ni3Sn4/η–Ni3SnP formed between Sn-3.5Ag solder and Ni-6P layer. P content increases in the surface region of the Ni-6P layer due to the depletion of Ni diffused into molten solder, resulting in the formation of Ni3P+Ni layer. For Sn-3.5Ag-0.7Cu solder, an η-(Ni,Cu)3Sn2 single layer, containing Cu of about 50 at.%, formed as a reaction layer.

A nanoscale continuous coating of In2O3 on phosphors for low-voltage display applications is proposed in which the electrical conductivity of phosphor screen plays a major role. The effect of In2O3 coating by the sol-gel method on the cathodoluminescence (CL) of ZnGa2O4:Mn phosphors improves the intensity of low-voltage CL noticeably compared with that of In2O3 mixing. It is understood that electrically conductive channels are formed by a much smaller amount of In2O3 addition than that of In2O3 mixing. Especially, based on transmission electron microscopy analysis, the formation of uniform nanoscale continuous In2O3 layers on the phosphor surface was confirmed. Also, the structural and CL characterizations presented in this paper clearly demonstrate that the nanoscale encapsulation of In2O3 layers on phosphors served as protective layers retarding the CL degradation introduced by the low-energy electron irradiation, which is critically important for the development of low-voltage display applications.

The electrophoretic deposition of single-crystalline α-alumina particles dispersed in aqueous media was performed in a strong magnetic field of 10 T. The α-alumina particles in the stable suspension were aligned due to their anisotropic diamagnetic susceptibility and then deposited on a cathodic substrate. The orientation of the α-alumina crystallites was confirmed by x-ray diffraction of the sintered specimen.

Subsolidus equilibria in air in the RuO2–Bi2O3–CeO2 systems were studied with the aim of obtaining information on possible interactions between a Bi2Ru2O7-based cathode and a CeO2-based solid electrolyte in solid-oxide fuel cells. Bi2O3 is soluble in CeO2, and forms a cubic fluorite solid solution Bi1-xCexO2-x/2 up to Bi1/3Ce2/3O1.83, while no solid solubility of the CeO2 in Bi2O3 was detected. No ternary compound was found in the system. The tie line is between Bi2Ru2O7 and the CeO2 solid solution.

In this paper, we report a simple method for preparing p-type ZnO thin films by thermal oxidization of Zn3N2 thin films. The Zn3N2 films were grown on fused silica substrates by using plasma-enhanced chemical vapor deposition from a Zn(C2H5)2 and NH3 gas mixture. The Zn3N2 film with a cubic antibixbyite structure transformed to ZnO:N with a hexagonal structure as the annealing temperature reached 500 °C. When the annealing temperature reached 700 °C, a high-quality p-type ZnO film with a carrier density of 4.16 × 1017 cm−3 was obtained, for which the film showed a strong near-band-edge emission at 3.30 eV without deep-level emission, and the full width at half-maximum of the photoluminescence spectrum was 120 meV at room temperature. The origin of the ultraviolet band was the overlap of free exciton and the bound exciton. The N concentration was as high as 1021 cm−3, which could be controlled by adjusting the parameters of the annealing processes.

Results on microstructure and coercivity of current-annealed Fe73.5Cu1Nb3Si13.5B9 amorphous alloy treated at different current densities (12–56 A/mm2) and duration (0.5–720 min) are presented. Saturation magnetization and coercivity dependencies with the current density of the nanocrystalline samples is explained by considering the presence of two phases: nanocrystals of Fe(Si) body-centered cubic (bcc) grains and the residual amorphous matrix. An increase in the magnetic hardness observed when the sample was heated by current densities, giving rise to an increase in the sample temperature above the Curie point of the residual amorphous matrix, could be ascribed to exchange and dipolar decoupling of the Fe(Si)-bcc grains.

Solid-state hydrogen storage alloys are becoming a practical method to transport and utilize hydrogen as fuel for various technologies. In this paper, the kinetics and capacity of hydrogen desorption from Mg-based alloys have markedly been enhanced by tuning the surface composition of alloy particles. Mg2Ni–Ct, x composites (where t refers to the pregrinding time and x to the Brunauer–Emmet–Teller specific surface area) were prepared by ball-milling the alloy in the presence of preground graphite, and Pd-coated Mg2Ni alloy powders were obtained by controlled chemical deposition of Pd on the alloy surface. We have found that the optimization of the pregrinding step of carbon is a determinant factor in enhancing the hydrogen desorption capacity of the Mg2Ni–10 wt.% C10,320 composites to 2.6 wt.% at 150 °C, the maximum performance so far reported on desorption for Mg-based alloys. Such value can even be raised to 2.8 wt.% by applying Pd deposition on the composite.

Lithium manganese oxide powders (LiMn2O4) with a spinel structure were synthesized via an optimized water-in-oil emulsion process. The influence of the emulsification conditions on the microstructures and physicochemical properties of LiMn2O4 powders was investigated. The phase purity of the synthesized powders significantly depends on the water-to-oil volume ratio in the emulsion. Increasing the water-to-oil ratio tends to decrease the stability of the emulsion that in turn leads to a segregation of water and oil phases. The unstable emulsion system results in the formation of an impure phase—Li2MnO3—that markedly decreases the charge and discharge capacities of the cathode materials. When water/oil volume ratio equals 1/5 or 1/10, monophasic spinel powders are formed at temperatures as low as 400 °C. In addition, decreasing the concentration of the aqueous phase substantially reduces the particle size of LiMn2O4 powders. Nanometered-LiMn2O4 powders with a particle size of 50 nm are obtained when the concentration of the aqueous phase is 1.0 M and the water-to-oil volume ratio is 1/5. Decreasing the particle size of LiMn2O4 powders was demonstrated to effectively increase the specific capacity and improve the cyclability of LiMn2O4 powders.

We present an inexpensive, bulk-processing technique for the mass fabrication of a high-performance, nanocrystalline intermetallic with no internal flaws: the recrystallization of plastically deformed ingots through controlled heat treatments. We demonstrate that FeCo alloys with average grain sizes of 100 nm can be produced using this method. The nanocrystalline materials have tensile yield strengths as high as 2.2 GPa and have plastic tensile ductilities over 1.3%. Such superior properties at room temperature are currently unattainable when nanocrystalline materials are prepared by other methods.

Thermal analysis and x-ray diffraction have confirmed that single-phase, cubic-spinel-structured NiMn2O4 (2:1 Mn2O3:NiO) begins to decompose into a rocksalt and a second spinel-structured phase above 907 °C. The decomposition product in samples air-quenched from 900 and 1200 °C was therefore investigated using transmission electron microscopy. Samples quenched from 900 °C (below decomposition temperature) did not show the expected single-phase microstructure, but instead grains contained nanoregions of a lenticular fringe contrast. Samples quenched from 1050 to 1200 °C were generally composed of Mn-rich spinel grains in addition to grains containing Mn-rich spinel precipitates (30–50 nm) surrounded by a Ni-rich rocksalt matrix. As temperature increased, the spinel grains and precipitates became clearly tetragonal, exhibiting a ferroelastic domain structure arising from a cooperative Jahn–Teller distortion. A decomposition mechanism based on the degree of inversion is proposed to explain these microstructures. Slow cooling samples from 1250 °C resulted in partial recomposition, leading to a microstructure principally composed of cubic spinel and regions of much smaller spinel structured precipitates (50–120 nm) in a rocksalt structured matrix. The slow-cooled samples showed a larger increase in resistance over time than single-phase samples did when held at 400 °C. X-ray diffraction measurements carried out before and after electrical characterization showed a reduction in the amount of rocksalt structured material present in slow-cooled samples.

An electromigration failure mechanism in flip chip solder joints is reported in this communication. The solder joints failed by a very rapid, asymmetrical, and localized dissolution of the Cu metallization on the cathode side. The average dissolution rate was about 1 μm/min. The dissolved Cu included not only the Cu under bump metallurgy but also the on-chip Cu conducting trace. From the location and geometry of the dissolved Cu, it can be concluded that current crowding plays a critical role in the rapid dissolution. The dissolved Cu atoms were driven to the anode side by electromigration, and a large amount of Cu6Sn5 was formed there.

A strong temperature dependence of positron annihilation with low-momentum electrons is reported for a Zr-based bulk metallic glass in the temperature range 50–300 K. The observed behavior was rationalized in terms of shallow versus deep positron traps. An interpretation of the data was presented based on the idea that there were two different types of open-volume regions: Bernal interstitial sites and thermally unstable larger holes. Bernal interstitial sites, intrinsic to the glass structure, were found to be insensitive to annealing. Alternatively, the larger holes were removed by annealing. The strong correlation between these larger holes and diffusion and viscous flow processes suggests that they may act as diffusion and flow defects.

Transparent mesoporous silica films were prepared by sol-gel spin coating on silicon wafers at room temperature. An erbium complex, erbium tris 8-hydroxyquinoline (ErQ), was homogeneously impregnated into the pores of the mesoporous silica films, and its concentration was easily controlled by using a solution immersing technique. The ErQ-impregnated mesoporous silica films show a room-temperature photoluminescence at 1.5 µm.