The effect of replacement of Ti with Y or Nb in Ti-rich Ti–Zr–Be–Cu–Ni bulk metallic glasses (BMGs) has been investigated. The minor addition (MA) of Y (Y–Ti: +58 kJ/mol) induced phase separation into Y-rich crystalline particles and Ti-rich amorphous matrix, while the MA of Nb (Nb–Ti: +10 kJ/mol) led to nanocrystallization in Ti-rich BMGs with icosahedral nuclei. This result indicates that MA of elements having positive enthalpy of mixing can induce a different degree of instability in the single amorphous matrix depending on the amount of repulsive interaction energy. In particular, MA of Nb (up to 4 at.%) significantly increased the compressive fracture strain (ϵf) up to ∼9.35 ± 0.2%, which indicates that the plasticity of BMGs can be enhanced by the size-modulated icosahedral phase embedded in the amorphous matrix.

The electrical behavior of modified soft lead zirconate titanate (PZT) ceramics has been studied as a function of temperature at different direct current (dc) electric fields and grain sizes. As ferroelectrics, such as PZT, are highly polarizable materials, poling, depolarization, and electric conduction contribute to the total electrical current, which leads to anomalous electrical behavior as a function of temperature. The PZT appeared to have a high pyroelectric coefficient, and it was found that the displacement current hides the conduction current near room temperature. The (long-time) steady-state electrical resistivity of the soft PZT used has a typical, relatively high value of 3.6 × 1012 Ω·cm near room temperature. The resistivity above the Curie temperature was two orders of magnitude lower than the room temperature. The resistivity decreases with increasing grain size probably due to the increased Pb vacancy concentration resulting as a consequence of a higher sintering temperature. The values of activation energies suggest that the charge carriers at high temperature are mainly oxygen vacancies. At intermediate temperature, the electrical behavior is controlled by the counteracting effect of depolarization and conduction. Considering the pyroelectric effect and the conduction, it was thus possible to explain the electrical behavior of this soft PZT ceramic over the temperature range considered.

Tetrakis-diethylamino hafnium (TDEAH), tris-diethylamino aluminum (TDEAA), and ozone were used for the atomic layer deposition (ALD) of HfO2, Al2O3, and HfAlOx films. The ALD rates were measured to be 1.1 Å/cycle for HfO2 and 1.3 Å/cycle for Al2O3. The ALD temperature windows were found to be between 200 and 325 °C for TDEAA, and between 200 and 275 °C for TDEAH. The overlap of these ALD windows between 200 and 275 °C is critical for ALD of the composite film, HfAlOx. In addition to the overlapping ALD temperature windows, the two metal precursors have similar thermal characteristics, as shown by TGA and differential scanning calorimetry. As-deposited films and films postannealed at 600 and 800 °C films were analyzed using Fourier transformed infrared (FTIR) spectroscopy, x-ray photoelectron spectroscopy, and x-ray diffraction (XRD) techniques. FTIR spectra revealed interfacial oxide growth during deposition of both HfO2 and Al2O3 whose thickness increased with annealing temperature. The FTIR data also indicated hydroxyl and nitrate groups in the films; these species were removed after annealing in Ar at a temperature of ⩾600 °C. Both FTIR and XRD results indicated the crystallization of pure HfO2 after annealing at temperatures as low as 600 °C. On the other hand, pure Al2O3 remained amorphous after annealing at temperatures up to 800 °C. XRD data of the composite HfAlOx film show that films deposited by alternating five cycles of HfO2 and one cycle of Al2O3 remained amorphous after annealing at 600 °C. Rutherford backscattering analysis of HfAlOx deposited with a varied number of alternating HfO2 and Al2O3 cycles demonstrated a strong correlation between the cyclic dosage of TDEAA and TDEAH and the film composition.

In the present study, we solidified magnesium-based AZ31 alloys by an electromagnetic vibration technique in a superconducting magnetic field at a vibration frequency of 500 Hz. Two groups of processing variables were used to carry out experiments; one is that the electric current is set as 60 A so as to testify to the influence of magnetic flux density on microstructure development from 1 up to 10 T. The other is that the electric current increases from 10 up to 120 A in the static magnetic field of 10 T, from which the dependence of structure formation on electric current is revealed. It is found that with the increase of both magnetic flux density and the level of electric current, solidified structures experience a transition from coarse dendrites to equiaxed grains. The melt fluid induced by the vibration force during solidification may promote the dendrite to a fragment. Meanwhile, the solids can be driven to move out of the operating region of the solute redistribution boundary. These effects make it difficult to form a complete dendrite but a refined structure. Furthermore, the vibration force can result in the formation of deformation twins in the alloy that has a low critical stress for basal slip. Regarding the effect of the electric current on microstructure, heat (measured in joules) can be produced when a large electric current is imposed, which can ripen the microstructure and induce a nonuniform structure. The slow cooling rate also makes the number fraction of deformation twinning decrease due to a rapid migration rate of atoms at high temperatures.

Although GaN is one of the important electronic materials of this decade, thermodynamic data for this compound are not known with sufficient reliability. The limited information available is not internally consistent. Measured in this study are high-temperature heat capacities using a differential scanning calorimeter and Gibbs energies of formation employing a solid-state electrochemical technique. The solid-state cell was based on single-crystal CaF2 as the electrolyte and Ca3N2 as the auxiliary electrode to convert the nitrogen chemical potential established by the equilibrium between Ga and GaN into an equivalent fluorine potential. The heat capacity of GaN at ambient pressure can be represented by the equation: CoP / J mol−1 K−1 = 74.424 − 0.00106T + (46720/T2) − (685.9/T0.5), in the temperature range from 350 to 1075 K. The standard Gibbs energy of formation of GaN in the range from 875 to 1125 K can be expressed as: ΔfGo/ J mol−1 (±465) = −128,749 + 115.029 T. This corresponds to a decomposition temperature of 1119 ± 4 K for GaN in pure nitrogen at standard pressure. On the basis of these new measurements and a critical assessment of information that is available in the literature, a refined set of data for GaN in the temperature range from 298.15 to 1400 K is presented.

Ultrathin lanthanide (Nd, Pr, Eu, Sm) oxide films with functional dielectric properties down to 3.3 nm thickness were deposited by aqueous chemical solution deposition (CSD) onto hydrophilic SiO2/Si substrates. Precursor solutions were prepared from the oxides via an intermediate, solid Ln(III)citrate. A film heat treatment scheme was derived from thermogravimetric analysis of the precursor gels, showing complete decomposition by 600 °C. Crystalline phase formation in the films depended on the lanthanide, annealing temperature, and citric acid content in the precursor. Through variation of the precursor concentration and number of deposited layers, thickness series of uniform films were obtained down to ∼3 nm. The film uniformity was demonstrated both by atomic force microscopy and cross-section transmission electron microscopy. The lanthanide oxide films possessed good dielectric properties. It was concluded that aqueous CSD allows deposition of uniform ultrathin films and may be useful for the evaluation of new high-k candidate materials.

Control of the low-temperature sintering of nanosilver particles was attained by dispersing and stabilizing nanosilver particles into a paste form using the selected organic binder systems. As demonstrated by scanning electron microscopy (SEM) and thermogravimetric analysis (TGA), with the existing binder systems, undesirable premature coalescence of nanosilver particles was prevented and the metastable structure was retained until the binder burned out at relatively higher temperatures. Enhanced densification was achieved upon the binder burnout because at the relatively higher temperatures the densification mechanisms, e.g., grain-boundary or lattice diffusion, become more dominant. We propose that the onset of sintering, extent of densification, and final grain size can be controlled by either the size of the initial nanosilver particles or the binder systems with different burnout characteristics.

The intercolumnar fracture strength of a columnar TiN film was deconvoluted by nanoindentation load-displacement curves. The columnar boundary strength of such films strongly depends on the amount of residual stress present in the film. The residual stress of the coating was modified by plastically stretching the substrate. Indentation studies on the columnar TiN coating as a function of residual stress reveals that the column sliding stress diminishes with residual stress, suggesting that the presence of a high compressive stress substantially improves the fracture strength of a columnar TiN film. True film hardness on the other hand does not change.

We present an experimental methodology for locating and studying local failure sites in multilayer electroceramic devices at the submicron-length scale. In particular, the inhomogeneous degradation of multilayer ceramic capacitors is studied using a judicious combination of scanning electron microscopy (SEM), local-probe electrical measurements, focused ion beam (FIB) extraction, and transmission electron microscopy (TEM). Voltage-contrast SEM permits the identification of regions of different electrical potential within degraded multilayer devices. The local impedance from specific regions is measured in situ between a tungsten probe and the internal device electrodes, while impedance spectra are extracted for more detailed analysis. Because implementation occurs in dual-beam FIB/SEM, these locally defective sites can be extracted and thinned to electron transparency for further investigation by TEM. In this study, degraded sites in BaTiO3 multilayer capacitors are found to be associated with local oxygen deficiencies in BaTiO3, as measured by electron energy loss spectroscopy.

Organic–inorganic hybrid materials were prepared by sol-gel processes starting from tetraethoxysilane (TEOS) and a triethoxysilane-terminated polyethylene–b-poly(ethylene glycol) copolymer (PE–PEG–Si). Curing of the initial reactant solution was carried out under different reaction conditions, and the materials so obtained were investigated by solid-state nuclear magnetic resonance (NMR). In particular, the molecular structure resulting from a conventional oven heating was compared with that obtained by unconventional microwave heating. The results highlighted that the extent of condensation reactions occurring over several hours under conventional heating is very similar to that resulting in 1 min under microwave heating. Additionally, 29Si–magic angle spinning (MAS) spectra showed that even though the overall extent of cross-linking in the inorganic network is only slightly affected by the thermal history of the sample, significantly different distributions of silicon sites can be present. 13C–CP/MAS selective spectra revealed the presence of PE “crystalline” domains within the organic phase, not detectable by differential scanning calorimetry (DSC). Finally, 1H–MAS spectra showed that different hydrogen-bond interactions are present in samples obtained under different curing conditions.

Vickers indentations of ZnO crystals grown by the hydrothermal method were studied by cathodoluminescence. The defects induced by indentation influenced the luminescence spectrum, indicating the generation of non radiative recombination centers and a band close to the first phonon replica of the free exciton, in the surrounding area near the indentation. The possible nature of the defects responsible for such band is discussed. A comparison with polishing induced damage is also presented.

Chromium oxide coatings were deposited on low-carbon steel by radiofrequency reactive magnetron sputtering at different oxygen flux values. X-ray diffraction, x-ray photoelectron spectroscopy, and high-resolution transmission electron microscopy were used to investigate the microstructure of chromium oxide coatings. Varying oxygen flux changed the coating microstructure; as with increasing oxygen flux the chromium oxide coating undergoes amorphous-to-crystalline transformation. The coating developed strong (300) texture at higher oxygen flux. Hardness, elastic modulus, wear resistance, and adhesion were investigated by nanoindentation and pin-on-disk tests. With changes in the coating microstructure as a function of increased oxygen flux, hardness, elastic modulus, and wear resistance were improved, but its adhesion was weakened.

Through acid-leaching treatment, the degree of hydrophobicity of a zeolite β can be controlled in a broad range. As the treatment time increases, the nanopore surface can change from hydrophilic to hydrophobic, leading to the formation of an infiltration plateau in sorption isotherm curve. The infiltration pressure and hysteresis are dependent on the testing temperature. As temperature rises, the effective degree of hydrophobicity is lowered, while the defiltration is much more pronounced.