(Pb1−xCax)TiO3 perovskite thin films with nominal compositions of (Pb0.76Ca.24)TiO3 (ferroelectric) and (Pb0.50Ca0.50)TiO3 (relaxor-ferroelectric) were prepared on silicon substrates at low temperatures compatible with those used in Si-technology. The technique used for the processing of these films was ultraviolet (UV) sol-gel photoannealing, using photo-sensitive precursor solutions and UV-assisted rapid thermal processing. The UV-irradiation and thermal treatment of the solution-derived films (gel films) were carried out in air or in oxygen. In both cases, the formation of the perovskite occurred at the same temperature, and this temperature increased as the Ca2+ content increased. Thus, full-perovskite films of (Pb0.76Ca.24)TiO3 were obtained at 723 K whereas those of (Pb0.50Ca0.50)TiO3 were formed at 773 K. Well-defined ferroelectric hysteresis loops were measured in the (Pb0.76Ca.24)TiO3 films, with values of remanent polarization of Pr ∼ 11 μC cm−2 and coercive fields for the films processed in oxygen lower than those of the films processed in air, Ec ∼ 164 and ∼226 kV.cm−1, respectively. These films showed a ferro-paraelectric transition at close temperatures of Tmax ∼ 605 K, although with higher values of the permittivity for the film processed in oxygen, k ∼ 567 at 10 kHz. The (Pb0.50Ca.50)TiO3 films had a diffuse ferro-paraelectric transition with a relaxor-like character, also with higher k values for the films prepared in oxygen, k ∼ 179 at Tmax ∼ 20 K. The possible use of these materials in silicon integrated multifunctional devices is discussed in this paper.

The enthalpies of formation of rare-earth (RE)-doped Hf1−xRExO2−x/2 solid solutions (RE = Sm, Gd, Dy, Yb; x = 0.25 to 0.62) with respect to the oxide end members, monoclinic HfO2 and C-type REO1.5, were determined using oxide melt solution calorimetry. The enthalpies of formation fit a function quadratic in composition. The strongly negative interaction parameters in all solid solutions confirm a strong tendency for short-range order. Though strongly negative for all systems, the interaction parameters become less negative with increasing ionic potential (decreasing RE radius). Crystallization energetics were investigated for amorphous coprecipitation products with x = 0.4. The energy difference between the crystalline (fluorite and pyrochlore) and amorphous phases decreases with decreasing dopant radius. This suggests that systems doped with small RE ions have more similar local structures in the fluorite and amorphous phases. These observations may result in a smaller kinetic barrier to recrystallization and account for the greater radiation resistance of materials with smaller RE cations.

Selective growth of CuO nanowires on the etched face of Al2O3/Cu/Al2O3 thin-film multilayer patterns was achieved by ambient oxidation at 400 °C. The nanowires were observed to selectively grow only from the pattern edge with diameter limited by the thickness of Cu thin film. Transmission-electron-microscopy (TEM) characterization confirmed CuO nanowires of a monoclinic CuO growing in the [010] crystallographic direction. Nanowire growth kinetics was studied at 400 °C for different cumulative growth durations with initial growth rates of ∼1 nm/min. A base growth mechanism with kinetics limited by oxygen diffusion through defects of a scaling oxide film is consistent with observed kinetics. The oxygen diffusivity is found to be ∼10−11 cm2/s, consistent with the grain-boundary diffusion of oxygen through polycrystalline copper oxide.

For low-temperature firing of Pb0.94Sr0.06(Ni1/2W1/2)0.02(Mn1/3Nb2/3)0.07(Zr0.51Ti0.49)0.91O3 (PNW–PMN–PZT) system, BiFeO3 is selected as the sintering agent. In this study, the effects of BiFeO3 addition and sintering temperature on the microstructures and piezoelectric properties of the ceramics were investigated in detail. The ceramic with 10 mol% BiFeO3 sintered at 950 °C possesses optimal microstructure and piezoelectric properties. However, with the increase of sintering temperature the lower relative density, abnormal grain growth, and secondary phase accumulated at grain boundaries are observed, which deteriorates the piezoelectric properties. For the ceramics with different BiFeO3 addition sintered at 950 °C, the densification process and the grain growth are improved by suitable BiFeO3, while the morphotropic phase boundary (MPB) moving to the Ti-rich direction and the shrinkage of crystal cell occur. However, extra BiFeO3 inhabits the grain growth and introduces more cavities into the materials. Because of the microstructural changes that accompany the addition of BiFeO3 and the resulting decrease in sintering temperature, the maximum values of the piezoelectric properties are attained. By doping with 10 mol% BiFeO3, the sintering temperature of the PNW–PMN–PZT system can be lowered successfully from 1200 to 950 °C, while the excellent electric properties are kept.

In the present study, we show by tailoring the combinations of the bonding energy among the elements in the liquid state, glass forming ability and compressive mechanical properties of the metallic glasses (MGs) can be improved. The mixing enthalpy values for binary atom pairs in the ternary Mg–Ni–Gd alloys (Mg–Ni: −12 kJ/mol, Mg–Gd: −27 kJ/mol, Ni–Gd: −161 kJ/mol) covers a wide range, although they are all negative. Mg-rich Mg–Ni–Gd (Mg > 70 at.%) alloys can be readily solidified into an amorphous state in a wide composition range up to 4 mm in diameter using the injection casting method; they exhibit the highest level of glass transition temperature Tg among those reported in Mg-based MGs so far. In particular, Mg-rich Mg–Ni–Gd bulk metallic glasses with 10–15 at.% Ni and 10–15 at.% Gd exhibit high strength over 900 MPa and large plastic strain up to ∼2% during compressive loading.

The precipitation kinetics of growth and coarsening of γ′(Ni3Al) and θ (Ni3V) in Ni75AlxV25−x alloys were investigated by microscopic phase-field simulation incorporated with elastic interactions. For the elastic interactions, γ′ aligned along the 〈001〉 direction and θ aligned along the [100] direction, which resulted in plate shape. For the lower (x < 4, at.%) and higher (x > 6) content regions, the growth of first precipitates was dominant at the initial stage and then coarsening was dominant, but the growth and coarsening proceeded simultaneously for the second precipitates. The growth and coarsening of γ′ and θ were dominant, respectively, at the initial and late stages for middle content regions. In addition, dynamic scaling was analyzed in the two-phase systems. It was shown that the dynamic scaling regimes were attained simultaneously at late-stage coarsening for γ′ and θ, despite the different precipitation order.

Experimental verifications have been performed on three engineering metals to verify recent methods proposed for extracting stress–strain curves from indentation tests. Their sensitivity to data errors is evaluated. Finally, the factors that might cause the inaccuracy and instability of the proposed methods are discussed, providing information that can be useful for further improving these methods.

Nitrogen was doped into titanium dioxide film to alter its surface electrostatic properties, and subsequently modulate the interaction force between MS2 virus and semiconductor films for control of the adsorption behavior of MS2 on semiconductor surfaces. By combining atomic force microscopy (AFM) height profile and phase profile, adsorptions of MS2 virus on TiO2-based semiconductor surfaces were observed in solutions over a range of pH values. The adsorption behavior was shown to agree with the theoretical analysis of colloidal interactions.

Deformation-induced γ → DI-α2 phase transformation was verified to occur in the twin-intersection region of a Ti–45Al–8Nb (at.%) alloy compressed at room temperature. High-resolution image observations of the deformation-induced DI-α2 phase suggested that the orientation relationship between the DI-α2 and γ phases remained the typical one: (0001)DI−α2//{111}γ, [11¯20]DI−α2//〈101]γ. The conversion of stacking sequence from ordered face-centered tetragonal to ordered nonequilibrium hexagonal close-packed structure was accomplished by the movement of a/6〈11¯2] Shockley partial dislocations on every other {111}γ plane. Compositional analysis based on energy dispersive spectra revealed that the DI-α2 phase had the same composition as the matrix γ phase. No compositional diffusion occurred because the plastic deformation was carried out at room temperature. The strong stress concentration in the intersection region was the major force to induce the γ → DI-α2 phase transformation in the process of room-temperature compression.

The formation of synthesized Si2N2O nanowires using the process of Si nitridation depending on the addition of carbon was investigated. The diameter of the Si2N2O nanowires having a high aspect ratio of about 50–80 nm was found in the porous Si2N2O–Si3N4 substrate to which 6 wt% C was added. The synthesized Si2N2O nanowires had orthorhombic single-crystal structure covered with a thin (∼2 nm thick) amorphous layer and a large number of stacking faults along the (2 0 0) plane. The photoluminescence spectrum of Si2N2O nanowires showed a strong, stable green emission at 540 nm.

Properties and phase structures of lead-free piezoelectric ceramics 0.92Na0.5Bi0.5TiO3-0.08BaTiO3 (NBT-BT) modified with La2O3 have been studied. Because of the different valence and ionic radius between La3+ and the exchangeable A-site ions, the lattice distortion and arrangement in the modified compounds can be expected, which will directly influence the phase composition and electrical characteristics of NBT-BT. Differing from familiar frame of gradual variability going with adulteration, NBT-BT doping 0.2–1.0 at.% La2O3 presents an abnormal increase of dielectric constant and a dramatic vanish of piezoelectricity. Further study on the relaxor property and domain structure implies that it originates from a typical relaxor-to-antiferroelectric crossover phase transition. However, a larger addition of La2O3 could rejuvenate the ferroelectricity and piezoelectricity of NBT-BT, correlating well with the model of competing ferro- and antiferroelectric interactions and metastable intermediate phase behavior in the morphotropic phase boundary region of complex perovskites.

To enhance Pt utilization in the fuel-cell electrode by microscopically controlling the distribution of liquid electrolytes around Pt catalysts, the amphiphilic surfactant tergitol phosphate was synthesized and introduced into the fuel-cell electrode. The chemical structure of the surfactant was determined by 1H-nuclear magnetic resonance, and its adsorption property on Pt–C catalyst was ascertained by Fourier transform infrared analysis. The electrode into which the amphiphilic surfactants were incorporated showed improved performance, and especially the amphiphilic surfactant with polyethylene oxide, NPE10-OPO(OH)2, produced higher cell performance.

The high temperature structural stability of nanograined NiCr alloys reinforced with nanoscale yttria and alumina dispersoids, fabricated by electron beam physical vapor deposition (EBPVD), was examined. The yttria particles coarsened very little and also inhibited grain growth in the matrix successfully, whereas the alumina dispersoids coarsened rapidly and were not as effective in restricting matrix grain growth. A hierarchy of phase transformations took place in the Al2O3 particles present as nano dispersoids in a nanograined NiCr matrix , on annealing. Coarsening of the alumina particles was accompanied by these phase transitions. The phase evolution is attributed to differences in free energies between the metastable and stable phases and a kinetic hierarchy in nucleation, brought about by structural and hence interfacial energy considerations.

Size-controlled nanocrystallites of Ni varying in size from 2 to 26 nm distributed in a nonmagnetic matrix of Ni(OH)2–ZrO2have been prepared by changing the reduction reaction time and by adding different concentrations of ZrOCl2solution to the initial reaction mixture. X-ray photoelectron spectroscopy indicates the presence of B2O3, Ni(OH)2, and ZrO2with Ni nanocrystals in the as-prepared composites. The room-temperature saturation magnetization and coercivity of the composites increases from ∼1.5 to 10 emu g−1and 100 to 200 Oe, respectively, when the ZrOCl2concentration in the reaction mixture increases to 0.10 M. The nanocrystals prepared without the addition of ZrOCl2exhibit a typical ferromagnetic response at 300 K, while that prepared with the addition of 0.10 M ZrOCl2shows a ferromagnetic response up to 400 K with higher saturation magnetization and coercivity.

A series of wormhole-like mesoporous borosilicate glasses (MBSGs) with different compositions has been prepared by a combination of surfactant templating, sol-gel methods, and evaporation-induced self-assembly processes. Small-angle x-ray diffraction, high-resolution transmission electron microscopy, and N2 sorption isotherms analysis showed that all the MBSGs prepared possess the mesoporous structure. However, the stability of the mesoporous structure is strongly affected by the boron contents. When boron content was increased, boric acid was found in the final product, and the mesoporous structure was partially degraded. The formation and loss of boric acid through the whole process may account for the partial collapse of the mesostructure.

We present a method that allows changing the anisotropy and the magnetic characteristics of piezoelectric–ferromagnetic hybrid structures by electric fields, thereby suppressing the need for external or local magnetic fields. We have investigated the magnetic properties of single Co50Fe50 and CoFe80B20 magnetostrictive thin films as well as of high-quality bottom-pinned spin valves (SV) sputtered on piezoelectric substrates [lead zirconate titanate (PZT)] and patterned in an interdigitated transducer (IDT). Induction of a uniaxial anisotropy axis and the changes on coercivity and switching fields as a function of the applied bias voltage on the IDT are analyzed and interpreted. The down-scalability of this hybrid method supports the possibility of achieving low-power/low-voltage control of the switching fields and shows the feasibility of a hybrid ferroelectric magnetic memory cell.

In this article, we report a simple and inexpensive approach to micromolding of complex, three-dimensional, high aspect ratio structures (with non-line-of-sight features) out of a high-strength amorphous metal. Inexpensive sacrificial silicon molds were created using lithography and etching techniques originally developed for integrated circuit production by the microelectronics industry and later adopted for microelectromechanical (MEMS) manufacturing. Multiple silicon layers were stacked, and the metallic glass was forced into the cavities under heat and pressure in an open air environment. Following cooling, the metallic structures were released by etching the silicon away in a potassium hydroxide (KOH) bath. Process studies showed that temperature is the most significant variable governing mold-filling. Transmission electron microscopy (TEM) sections of the mold/glass interface showed successful replication of features with characteristic dimensions on the order of 10 nanometers and no discernible gap between the silicon and the metallic glass. This scalable micromolding process leverages the inexpensive and readily available aspects of silicon lithography to economically support the mass customization (low volume production) of metal microcomponents without elaborate infrastructure needs.

An ionic ferrofluid is prepared using coprecipitation and acid treatment techniques. In the ferrofluid, Co3+ and Fe2+ dissolved from CoFe2O4 nanoparticles via suitable acid attack, are absorbed on the surface of the magnetic particles and thus prevent them from aggregating. We call this self-formed ferrofluid. The colloidal particles in the ferrofluid are constructed with a magnetic core and a nonmagnetic surface layer about 2 nm. The size and the volume fraction of particles in the ferrofluid are described with geometric diameter d and volume fraction ϕv, as well as magnetic diameter dm and magnetic volume fraction ϕm. The viscous and magnetic properties of this ferrofluid depend on these parameters. The viscosity can be tunable for any volume fraction of particles by adding poly(ethylene glycol) into the carrier liquid.

Mechanisms of microstructure evolution during annealing after cold working were studied in an Fe-15%Cr ferritic stainless steel, which was processed by bar rolling/swaging to various total strains ranging from 1.0 to 7.3 at ambient temperature. Two types of recrystallization behavior were observed depending on the cold strain. An ordinary primary (discontinuous) recrystallization developed in the samples processed to conventional strains of 1.0–2.0. On the other hand, rapid recovery at early annealing resulted in ultrafine-grained microstructures in the larger strained samples that continuously coarsened on further annealing. Such annealing behavior was considered as continuous recrystallization.

TiCx–Al2O3 composites have been synthesized by pressure-assisted combustion synthesis of (Ti + C + Al2O3) reactant powder. Different alumina contents (10–40 vol%) have been investigated to study the dilution effect on TiC microstructure. A mechanical method and a mixed chemical/mechanical method have been used to obtain (Ti + C + Al2O3) powder mixtures with different alumina distributions. Scanning electron microscopy (SEM) observations of these mixtures show that alumina is distributed inside micrometric (Ti + C) aggregates for the first method whereas alumina is located around (Ti + C) aggregates for the second one. X-ray diffraction (XRD) and SEM analyses of the composites indicate that TiCx is substoichiometric in carbon and mainly consists of submicrometric grains. A distribution of Al2O3 inside (Ti + C) aggregates is more efficient to reduce TiC grain size. For the 40 vol% Al2O3 diluted (Ti + C) mixture prepared from the mechanical route, TiCx nanocrystallites have been successfully stabilized, which demonstrates that the addition of Al2O3 diluent in a (Ti + C) mixture can be efficiently used to inhibit grain growth.