In the past decade, the research in designing fast oxygen conducting materials for electrochemical applications has largely shifted to microstructural features, in contrast to material-bulk. In particular, understanding oxygen energetics in heterointerface materials is currently at the forefront, where interfacial tensile strain is being considered as the key parameter in lowering oxygen migration barriers. Nanocrystalline materials with high densities of grain boundaries have also gathered interest that could possibly allow leverage over excess volume at grain boundaries, providing fast oxygen diffusion channels similar to those previously observed in metals. In addition, near-interface phase transformations and misfit dislocations are other microstructural phenomenon/features that are being explored to provide faster diffusion. In this review, the current understanding on oxygen energetics, i.e., thermodynamics and kinetics, originating from these microstructural features is discussed. Experimental observations, theoretical predictions and novel atomistic mechanisms relevant to oxygen transport are highlighted. In addition, the interaction of dopants with oxygen vacancies in the presence of these new microstructural features, and their future role in the design of future fast-ion conductors, is outlined.

A hot wire chemical vapor deposition technique is described for synthesis of 1D nanostructures of a controlled morphology, stoichiometry, and composition. The synthesis involves the evaporation and condensation of metal oxide vapor through the reaction of oxygen with the hot filaments of respective transition metals. The stoichiometry and morphology of MoO3 and WO3 were modulated by varying the filament temperature and partial pressure of oxygen in the growth chamber. Based on the results under different conditions, a morphological phase diagram, and a growth model based on the extent of gas phase supersaturation were developed to understand the growth mechanism. Further, ternary transition metal oxide, NiMoO4, was synthesized as a proof-of-concept for tuning the composition of deposition through simultaneous evaporation of two metal oxides.

(1 − x) (Bi1/2Na1/2)TiO3–xBiFeO3 (x = 0–0.9) ceramics were prepared and the ferroelectric and piezoelectric properties along with the crystal structure were investigated. The crystal system of the ceramics was rhombohedral with the R3c symmetry throughout the compositions. The rhombohedral distortion (90° − α), where α was the rhombohedral angle based on a pseudocubic perovskite cell, was minimized at x = 0.1, while the lattice constant increased linearly with x. Saturated ferroelectric polarization-electric field hysteresis loops were observed at x = 0–0.6. The coercive field was reduced at x = 0.05–0.2 and the high remanent polarization of 30–35 µC/cm2 was obtained at x = 0–0.4. The piezoelectric constants d33 and d33* (which was calculated from a unipolar strain–electric field curve) were maximized to 93 pC/N at x = 0.1 and 183 pm/V at x = 0.05, respectively. These results suggested that the increase in the piezoelectric properties was associated with the reduction in the rhombohedral distortion, which could be useful in development of high performance lead-free piezoelectric materials.

Selective area growth of thin films reduces the number of steps in microfabrication processing and enables novel device structures. Here, we report, for the first time, selective area epitaxy of an oxide material on a GaN surface. Chlorination of the GaN surface via wet chemical processing is found effective to disrupt Mg adsorption and selectively prevent molecular beam epitaxy growth of MgO. MgO films grown on neighboring, nonchlorinated surfaces are epitaxial with a (111) MgO||(0001) GaN crystallographic relationship. Better than 3 μm lateral resolution for the selective area growth of MgO on GaN is demonstrated.

Few layer graphene is attractive due to its extraordinary electronic and optical properties, which are strongly influenced by the orientation between the layers called as stacking sequence. It is challenging to synthesize high quality large size single or multi layer graphene crystals on the metal catalyst using chemical vapor deposition technique. The present work is about synthesis of few layer graphene grains on platinum foil using ambient pressure chemical together vapor deposition technique. The main focus is how the different grains coalesced and maintain the stacking sequence. Different characterization techniques are used to analyze the grains when they are in the process of merging to make a bigger grain. Scanning electron microscopy clearly shows different stacking sequences and merging of different nucleation sites of different grains. Interestingly, different stacking sequences are observed during the process of coalescence of grains. Raman spectroscopy gives accurate information about the number of layers and their stacking sequence. We observed Bernal AB and twisted layer stacking in the grains when they were combining together to grow into a bigger size. The full width at half maximum (FWHM) value of 2D Raman peaks appeared in the range of 52–69 cm−1 which shows an increase from the value of single layer graphene (30.18 cm−1) and identifies Bernal stacking in grains. For twisted stacking FWHM values lie in the range of 19–32 cm−1.

Al–12Si (80 vol%)–Ti52.4Al42.2Nb4.4Mo0.9B0.06 (at.%) (TNM) composites were successfully produced by the selective laser melting (SLM). Detailed structural and microstructural analysis shows the formation of the Al6MoTi intermetallic phase due to the reaction of the TNM reinforcement with the Al–12Si matrix during SLM. Compression tests reveal that the composites exhibit significantly improved properties (∼140 and ∼160 MPa higher yield and ultimate compressive strengths, respectively) compared with the Al–12Si matrix. However, the samples break at ∼6% total strain under compression, thus showing a reduced plasticity of the composites. Sliding wear tests were carried out for both the Al–12Si matrix and the Al–12Si–TNM composites. The composites perform better under sliding wear conditions and the wear rate increases with increasing loads. At high loads, the wear takes place at three different rates and the wear rate decreases with increasing experiment duration.

Intermetallic composite has been expected to be one kind of high-performance wear material at elevated temperature due to its inherent high hardness and strong atomic bonds. This paper presents the wear behaviors under elevated temperature conditions of NiMo/Mo2Ni3Si intermetallic “in situ” composite. Metallographic observations were carried out with optical microscope and scanning electron microscope. Elevated-temperature wear tests were performed under pin-on-disc mode dry sliding conditions. Results shown that the relative wear resistant property of NiMo/Mo2Ni3Si alloys at 500 °C is over 7 times, and become higher at 550 °C compared with austenitic 1Cr18Ni9Ti stainless steel. The effect of temperature and applied load on elevated-temperature wear resistance of alloy was evaluated. The corresponding wear mechanism is also reported through examining the worn surface, subsurface, and wear debris of the NiMo/Mo2Ni3Si intermetallic alloys which is found to be soft abrasive wear.

Microalloying refers to the addition of a small concentration of an alloying element to tune the properties of the parent alloy. Microalloying technology enables to control the glass formation and the mechanical properties of bulk metallic glasses (BMGs). This manuscript presents a comprehensive review on recent developments and breakthroughs in the field of microalloying for tuning the properties of BMGs and composites with focus on the results. The ability of multiple element co-addition to optimize the glass formation and the importance of future alloy developments have been highlighted. Proper microalloying can be used to tailor not only the mechanical properties of the amorphous phase but also those of the crystalline phase, which opens up the possibility for tuning the mechanical performance at different length scales. The effectiveness in controlling the mechanical performance through microalloying was shown to greatly depend on the alloy composition and closeness to the critical amorphous diameter. A tentative outlook commenting the potential and challenges of this exciting field of research is also presented.

Disks of commercial Al-1050 and ZK60A alloys were stacked together and then processed by conventional high-pressure torsion (HPT) through 1 and 5 turns at room temperature to investigate the synthesis of an Al–Mg alloy system. Measurements of microhardness and observations of the microstructures and local compositions after processing through 5 turns revealed the formation of an ultrafine multi-layered structure in the central region of the disk but with an intermetallic β-Al3Mg2 phase in the form of nano-layers in the nanostructured Al matrix near the edge of the disk. The activation energy for diffusion bonding of the Al and Mg phases was estimated and it is shown that this value is low and consistent with surface diffusion due to the very high density of vacancy-type defects introduced by HPT processing. The results demonstrate a significant potential for making use of HPT processing in the preparation of new alloy systems.

Magnesium based nanocomposites containing 0.66 vol% of different types of oxide (i.e., Al2O3, Y2O3, and ZrO2) nano particles. The nano oxide particles were dispersed using melt processing. Microstructural characterization reveled that Y2O3 and ZrO2 nano particles were relatively better magnesium matrix grain refiner compared to nano-size Al2O3 particles. Mechanical characterization revealed that the oxides used in this study as reinforcement have strong strengthening effect on the magnesium matrix, where Y2O3 particles were most effective and Al2O3 particles were least effective. Ductility and resistance to fracture of magnesium was significantly improved by Al2O3 nano particles, unaffected by Y2O3 nano particles, and adversely affected by ZrO2 nano particles.

In this study, silver nanowires (Ag NWs) were synthesized in a one-pot method from silver nitrate and poly(vinyl pyrrolidone) (PVP), and reduced by ethylene glycol without the presence of chloride ion. The addition of silver nitrate and PVP was controlled by syringes. The syringe rate, and the concentrations of silver nitrate, and PVP, were manipulated to obtain Ag NWs with different widths and lengths. We have observed the phenomena of coarsening and combination of silver nanorods during the growth of the Ag NWs. With these phenomena, we have developed a growth model of Ag NWs, and successfully synthesized Ag NWs with high aspect ratios via the developed model.

We have developed a new synthesis method that includes a chemical vapor deposition process in a chamber settled in organic liquid, and applied its nonequilibrium reaction field to the development of novel carbon nanomaterials. In the synthesis at 1110–1120 K, using graphene oxide as a catalyst support, iron acetate and cobalt acetate as catalyst precursors, and 2-propanol as a carbon source as well as the organic liquid, we succeeded to create carbon nanofiber composed of novel pot-shaped units, named carbon nanopot. A carbon nanopot has a complex and regular nanostructure consisting of several parts made of different layer numbers of graphene and a deep hollow space. Dense graphene edges, hydroxylated presumably, are localized around its closed end. The typical size of a carbon nanopot was 20–40 nm in outer diameter, 5–30 nm in inner diameter, and 100–200 nm in length. A growth model of carbon nanopot and its applications are proposed.

The article discusses the structure and properties of noncrystalline carbon films synthesized by ion-plasma sputtering of a graphite target in an argon atmosphere at direct current. Analysis of the molecular structure of carbon films was performed using Raman spectroscopy and dependence of the structure of synthesized films on the synthesis temperature and substrate material was revealed. Besides the main G peak possesses the values in a broad frequency range from 1500 to 1575 cm−1. The evolution of molecular structure peculiarities of synthesized carbon films depending on the synthesis conditions was clearly shown using the numerical methods of the Raman spectra decomposition. Studies of the optical spectra showed that the band gap of synthesized films varies from 0.78 to 1.67 eV and with increasing optical band gap, the value of G peak position decreases under laser excitation of 2.62 and 1.96 eV.

On the powder surface of oxygen-ordered ZrC0.6O0.4 obtained via isothermal heating of vacancy-ordered ZrC0.6 at 300 °C, an amorphous ZrC0.6O y>0.4 layer in nanoscaled thickness is found to form if the heating lasts long enough. With the help of high-resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED) measurements, the amorphous formation is recognized to originate from diffusion of superfluous oxygen atoms into Zr-tetrahedral centers in the surface area, thus leading to severe distortion of the lattice. In situ investigation of HRTEM, SAED, and electron energy loss spectra demonstrates that under electron irradiation of sufficient dose, the amorphous ZrC0.6O y>0.4 layer transforms into a cubic ZrO2−x layer with the same orientation as the underlying ordered ZrC0.6O0.4.

In the present work, we are investigating the electronic transport mechanism for antimony-doped tin oxide (ATO) ultrathin films produced by a colloidal deposition process (CDP) of nanocrystals synthesized via a solvothermal route in organic medium. The ATO ultrathin films were prepared from nanoparticles containing 9 mol% of Sb and the observed electrical resistivity at room temperature was 1.55, 1.10 × 10−1, and 1.83 × 10−3 Ω cm, respectively, for the 40, 45, and 71 nm films. X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and atomic force microscopy were carried out to investigate the films and electrical resistivity measurements taken in the four-probe mode with temperature ranging from −260 to 27 °C (13–300 K ± 0.1 K). Results show a good data fitting on Mott's two-dimensional (2D) noninteracting variable range hopping for the 45 nm thin film, which is not further observed for the ATO ultrathin films obtained from CDP.

Direct coagulation casting of alumina via controlled release of high valence counter ions using ammonium polyphosphate (APP) chelate complex as the coagulating agent was proposed. APP chelate complex suspension was prepared from APP and calcium chloride. Calcium used as high valence counter ions was chelated by APP. The average particle size of the chelate complex is 0.13 μm with a narrow particle size distribution which is close to the size of alumina particles. Glycerol diacetate was used to tailor the pH value of the suspension by hydrolysis which produces acetic acid. The lowering of the pH value helps to decompose the chelate complex, and enhance to release the calcium chelated. It is indicated that the viscosity of the suspensions with the addition of APP chelate complex suspension and glycerol diacetate increases to approximately 20 Pa s after heating at 40–70 °C for 1.5–5 h, which is high enough to coagulate the suspension. 55 vol% alumina suspension with a addition of 3 vol% APP chelate complex suspension and 5 vol% glycerol diacetate treated at 60 °C could coagulate completely within 2 h with a compressive strength of 2.1 MPa. Dense alumina with a relative density of above 97% and a flexural strength of 388 ± 23 MPa can be prepared by this method from 55 vol% alumina suspensions without a burnout process.

Zinc phthalocyanine (ZnPc) thin films were prepared by pulsed laser deposition (PLD) using KrF laser (λ = 248 nm, τ = 5 ns). The effect of laser fluence (in the region from 10 to 100 mJ/cm2) and repetition rate of 50 and 200 Hz to the film growth and its properties was investigated. The growth of ZnPc thin film was in situ monitored using transmission measurement in ultraviolet-visible spectral range. The optical properties in conjunction with density functional theory/time-dependent density functional theory calculations suggested the growth of the film in β-phase. X-ray diffraction also revealed crystalline character of the film. The electrical properties analyzed by van der Pauw method exhibited resistivity ρ ≈ 108–1010 Ω cm. Fourier transform infrared spectroscopy analyses revealed low deterioration of PLD deposited ZnPc films. We demonstrate that, by finely tuning the deposition conditions, PLD is a successful technique for fabrication of ZnPc thin films.