Spin-coating was conducted on single-crystal silicon substrates using a xylene solution of perhydropolysilazane (PHPS) to obtain 0.14-μm-thick PHPS films. The PHPS films obtained were suspended over various acidic and basic solutions at room temperature so that they were exposed to the vapors from the solutions. PHPS-to-silica film conversion was studied by infrared absorption spectroscopy, and the stability of the exposed films in hot water was examined by soaking the films in 80 °C water. The as-deposited PHPS films were found to be dissolved in water. When the PHPS films were suspended over water, the films were partially converted into silica, but the resultant film had low stability in hot water. Higher degrees of PHPS-to-silica conversion and higher stabilities in hot water were found on exposing the PHPS films to basic or acidic vapors. Exposure to highly basic vapors from aqueous solutions of ammonia and ethylamine was significantly effective in PHPS-to-silica film conversion, which provided silica thin films with high stability in hot water.

The shear strength, intermetallic compound formation, and failure mechanism of high-lead solder (5Sn–95Pb) bump on flip chip under bump metallurgy, Al/Ni(V)/Cu, were investigated after thermal cycling, multiple reflow, and high-temperature aging. Two kinds of intermetallic compound, Cu3Sn and AlxNiy, were found at the interface. The Cu3Sn was formed between the solder and Ni(V) layer while AlxNiy was formed between Ni(V) and Al layer. The formation of the Cu3Sn compound will not affect the shear strength, 27–30 g, of the solder bump even after a high temperature long time aging test. However, the shear strength after the 30th reflow drops to less than 25 g, ascribed to the formation of a brittle compound, AlxNiy. The failure modes of the solder bump upon shear test were also discussed.

In this paper, single-phase Yb α-SiAlON powder with rod-like crystals was fabricated by combustion synthesis. The microstructural development of the rod-like α-SiAlON crystals was studied, and anisotropic grain growth was observed. Furthermore, the growth mechanism of the rod-like α-SiAlON crystals was investigated, and the experimental results indicated that during the anisotropic grain growth, the fast growth plane was the basal plane in the hexagonal crystal lattice.

Amorphous metallic alloys possess high strength characteristics, which are superior to crystalline materials. Here we report an influence of Sc addition on glass-forming ability, glass-transition behavior, supercooled liquid region, and mechanical properties of an Al84Y9Ni5Co2 glassy alloy. This paper also aims to present a promising (Al0.84Y0.09Ni0.05Co0.02)95Sc5 amorphous alloy. This alloy has an ultrahigh tensile fracture strength exceeding 1500 MPa, which surpasses those for all the other Al-based fully crystalline and amorphous alloys reported to date, in addition to high Young’s modulus of 78 GPa. The fracture surface of this new alloy exhibited vein pattern typical for amorphous alloys with good ductility, and multiple shear bandswere observed on the lateral surface. The ultrahigh tensile strength of the (Al0.84Y0.09Ni0.05Co0.02)95Sc5 amorphous alloy results from an increase in the interatomic constraint force by the addition of Sc, an element having highly negative enthalpy of mixing with Al, Ni, and Co and the highest chemical affinity with Al among the alloying elements.

Dense lossy AlN–SiC composites doped with Y2O3 were fabricated by spark plasma sintering (SPS). Both the microstructure and the dielectric properties are different from those of hot-pressed samples. Microstructure analysis reveals little solid solution (AlN)x(SiC)1-x is formed. Scanning evanescent microwave microscopy images show that the materials by SPS exhibit large contrast in dielectric permittivity, whereas the hot-pressed materials show very mild fluctuation in dielectric permittivity over the samples. The results indicate that AlN–SiC composites fabricated by SPS can be treated approximately as a mechanical mixture of AlN and SiC when estimating complex permittivity of the composite in the microwave range. The complex permittivity of the composites with different SiC contents can be phenomenologically predicted by effective medium approximation.

Accurate determination of frame compliance is an essential component of instrumented micro- and nanoindentation experiments. In load frames of finite stiffness, the load applied via the indenter induces displacement in both the sample and the load frame. Frame compliance must be identified and subtracted from the total indenter displacement to account properly for sample deformation. Current experimental procedures, in which the frame compliance is inferred from the elastic unloading indentation response of a reference sample, are based on several assumptions and simplifications that can propagate significant uncertainty with respect to subsequent analyses of mechanical behavior of the sample. We outline a new procedure that measures the compliance of the load frame, and identify the effects of load, loading direction, and loading rate on the measured compliance, as well as several possible sources of uncertainty in other available methods of frame compliance determination.

Ions of Li, Na, K, and B were incorporated in Ca-mica, CaMg3Al2Si2O10F2. The crystallization process and the properties of the resulting glass-ceramics were experimentally determined, and the role of the anions and cations is discussed. According to the results, Li, K, and Na ions strongly affected the formation of the crystalline phases. Until 900 °C, pargasite and F-cannilloite amphiboles and KLi-mica were predominately crystallized. The two amphiboles are dissociated, yielding stable forsterite at 900 °C and Ca-mica and spinel at 950 °C. KLi-mica showed remarkable stability and growth within the investigated temperature range, until 1000 °C. The optimum crystallization temperature for the investigated glass-ceramics is between800 °C and 900 °C. The produced glass-ceramics exhibited capability for easy bulk crystallization, high whiteness, translucency, and mechanical and chemical properties suitable for several applications.

The enthalpy of formation of cubic yttria-stabilized hafnia from monoclinic hafnia and C-type yttria was measured by oxide melt solution calorimetry. The enthalpies of formation fit a function independent of temperature and quadratic in composition. The enthalpies of transition from m-HfO2 and C-type YO1.5, to the cubic fluorite phase are 32.5 ± 1.7 kJ/mol and 38.0 ± 13.4 kJ/mol, respectively. The interaction parameter in the fluorite phase is strongly negative, -155.2 ± 10.2 kJ/mol, suggesting even stronger short range order than in ZrO2–YO1.5. Regular solution theory or any other model assuming random mixing on the cation and /or anion sublattice is not physically reasonable. A more complex solution model should be developed to be consistent with the new calorimetric data and observed phase relations.

When exposed to air at room temperature, Zn nanoparticles oxidize gradually to form crystalline ZnO shells with a thickness of a few nanometers. Electron diffraction and high-resolution lattice imaging revealed that the ZnO layer on the Zn {0001} surface is composed of many epitaxial domains with small rotation angles relative to the lattice of the Zn core. The oxidized Zn particle bends when irradiated by the electron beam in a transmission electron microscope. This is due to the increase of internal stress in the ZnO layer as a result of the realignment of adjacent domains under electron beam irradiation. Corrosion of Zn nanoparticles was observed and the scaling and spalling start to occur on the {1010} prismatic faces.

The structural and electrical properties of lanthanum copper oxide were examined as a function of Sr addition. It was observed that the lanthanum oxide and copper oxide formed La2CuO4 with K2NiF4 structure when the powder mixture was heated at 800 °C in ambient pressure. Interestingly, the samples of Sr-doped (15∼25%) lanthanum copper oxides showed single perovskite-based phase after being heated at 800 °C. Without Sr addition, a single-perovskite phase of lanthanum copper oxide was observed only under the oxygen pressure as high as 65 kbar. The stabilization of perovskite structure in lanthanum copper oxide was effectively achieved by the addition of Sr. Based on the titration analysis and pertinent defect reactions, the enhancement of perovskite stability was due to the presence of trivalent copper ions that were created to balance the electrical charge of doping ion (SrLa′). With the increasing concentration of trivalent copper ions (or electron holes equivalently) in Sr-doped samples, lanthanum copper oxide also changed from a semiconductor to metallic conductor. When the Sr dopant exceeded its solubility limit of approximately 25% in the A-site sublattice, the Sr-rich second phases, La2SrCu2O6 and Cu2SrO3, appeared and suppressed the electronic conduction drastically.

Ag–Pd alloy nanoparticles have been generated from silver and palladium nitrate precursors using a high temperature aerosol method, the liquid flame spray (LFS) process. In the LFS process, a spray aerosol of precursor liquid is introduced into a high-temperature H2–O2 flame. The primary micron-sized spray droplets evaporatein the flame, and the final particulate product is a result of the nucleation of the pure metal vapors shortly after the flame. In the study, three Ag–Pd molar ratios—10:90, 50:50, and 90:10—were used in the precursor. As a result of the synthesis, metalalloy nanoparticles with practically the same concentration ratios, correspondingly, were produced with the method. In the experiments, metal mass flow rates of 0.01–0.8 g/min were covered. The size of the particles was determined to be in the rangeof 10–50 nm by aerosol instrumentation. The particles were spherical and slightly agglomerated. It was concluded that the particle size can be controlled via the total precursor mass flow rate, and the composition can be controlled by the molar ratio of Ag and Pd compounds in the precursor liquid.

The near-surface deformation of equal-channel angular extruded (ECAE) pure aluminum was investigated using the micro-indentation technique. Compared with fully annealed Al samples, there is a distinguishable difference in the indentation deformation. The unloading slope of the ECAE deformed Al after a short unloading period was found to be less than that of the annealed samples due to plastic recovery. Work hardening was observed, which depended on the history of local deformation. A new relationship between the plastic energy dissipated in the indentation and the applied load was derived, which is supported by the experimental results.

Aging of precipitation hardened alloys results in particle coarsening, which in turn affects the strength. In this study, the effect of particle size distribution on the strength of precipitation-hardened alloys was considered. To better represent real alloys, the particle radii were distributed using the Wagner and Lifshitz and Slyozov (WLS) particle size distribution theory. The dislocation motion was simulated for a range of mean radii and the critical resolved shear stress (CRSS) was calculated in each case. Results were also obtained by simulating the dislocation motion through the same system but with the glide plane populated by equal strength particles, which represent mean radii for each of the aging times. The CRSS value with the WLS particle distribution tends to decrease for lower radii than it does for the mean radius approach. The general trend of the simulation results compares well with the analytical values obtained using the equation for particle shearing and the Orowan equation.

Using depth-sensing indentation, a pop-in phenomenon induced by grain boundaries, namely, a sudden indenter displacement jump when indented near a grain boundary segment, was observed in polycrystalline niobium. This grain-boundary type of pop-in occurs at a larger force than the initial elasto-plastic pop-in, which is observed with and without a grain boundary nearby. The experimental results show that this pop-in effect has a close relationship with the misorientation across the grain boundary. The occurrence of this pop-in phenomenon is rationalized in terms of slip transmission across the grain boundary.

Preferred orientation in textured ceramics is often assessed by comparing the relative intensities of x-ray diffraction reflections to those of a randomly oriented ceramic using the Lotgering degree of orientation (f). However, this paper provides evidence that indiscriminate assessments of f can be misleading. Using measured intensities of a modestly textured tape cast bismuth titanate (Na0.5Bi4.5Ti4O15) ceramic, calculated f values vary from 7.4 to 73.2% depending on the reflections included in the calculation. The texture is also quantified by calculating the orientation distribution function (ODF) using measured pole figures. A model is then presented that demonstrates f is nonlinear with the multiple of preferred (00l)-orientations, the standard unit of the 00l pole figure.

An analytical solution for shape evolution of a coherent misfit precipitate in triaxially stressed solid has been proposed based on Eshelby inclusion theory. With complete energy consideration, the free energy that controls the shape evolution of the precipitate is a function of the precipitate shape, size, triaxially applied stresses, misfit strains, and Young’s moduli of the precipitate and the matrix. Based on the energy analysis, a comprehensive picture of shape evolution of the precipitate is presented.

Deposition of thin films via hydrothermal method has various advantages: low deposition temperature, high purity, deposition on a three-dimensional structure,and a large thickness. Although an epitaxial lead zirconate titanate (PZT) thin-film deposition has been reported, the ferroelectric measurement has not been conducted due to the peel-off morphology of the film. The current paper investigates the improvement of an epitaxial PZT thin film deposited via a hydrothermal method. By adjusting the position at which the substrate was suspended in the solution, smooth morphology surface was successfully obtained. As a bottom electrode, a 200-nm SrRuO3 thin film was deposited on SrTiO3 single crystals, and the PZT thin film was deposited on SrRuO3. The remanent polarization 2Pr and coercive electric field for PZT on SrRuO3/SrTiO3 (001) were 17.1 μC/cm2 and 36 kV/cm, respectively, and those of PZT on SrRuO3/SrTiO3 (111) were 32.7 μC/cm2 and 59 kV/cm, respectively. The reason for large imprint electrical field, 91 kV/cm and 40 kV/cm for each film, was unclear at this stage, although it is associated with self–alignment poling direction. This self–alignment poling direction was confirmed via scanning nonlinear dielectric microscopy and is thought to have been related to the deposition mechanisms.

The morphology and distribution of high-pressure metastable phases BC8 and R8, formed in monocrystalline silicon under microindentation, were identified and assessed using transmission electron microscopy nanodiffraction analysis. It was discovered that the crystal growth inside the transformation zone was stress-dependent with large crystals in its central region. The crystal size could also be increased using higher maximum indentation loads. The BC8 and R8 phases distributed unevenly across the transformation zone, with BC8 crystals mainly in the center of the zone and smaller R8 fragments in the peripheral regions. Such phase distribution was in agreement with the theoretical residual stress analysis.