A new low-temperature method to produce (InxGa1−x)2O3 (x = 0.1, 0.2, and 0.3) powders with high purity, high chemical homogeneity and improved crystallinity in the as-synthesized state has been developed. This procedure produced finely divided powders through an exothermic reaction between the precursors. The process starts with aqueous solutions of In(NO3)3 and Ga(NO3)3 as the precursors and hydrazine as the (noncarbonaceous) fuel. The combustion reaction occurred when heating the precursors between 150 and 200 °C in a closed vessel filled with an inert gas (Ar), which yields (InxGa1−x)2O3 directly. These materials were compared with powders prepared by a more typical combustion synthesis reaction between nitrates and a carbonaceous fuel at a higher ignition temperature of 500 °C.

Chemical mechanical polishing of copper and tantalum was performed using fumed amorphous silica abrasive particles dispersed in H2O2, Fe(NO3)3, and glycine solutions. Results showed that in DI water silica did not polish Cu but Ta had a relatively high polish rate. Cu polish rate decreased with increasing particle concentration in Fe(NO3)3-based slurries due to the adsorption of Fe3+ on the silica surface. Addition of H2O2 enhanced Cu polish rate but reduced Ta polish rate. The specific surface area of the particles played an important role in the removal of Ta and Cu, presumably due to some chemical bonding between the materials being polished and the silica particles.

The effect of the mechanical activation of the reactants on the self-propagating high-temperature synthesis (SHS) of titanium silicides was investigated. SHS experiments were performed on reactant powders that were milled for different times. Mechanical activation was shown to have a large influence on the combustion characteristics, particularly on wave speed. A much weaker effect was observed on the products phase composition. Single-phase products were obtained only from Ti:Si = 1:2 and Ti:Si = 5:3 starting compositions. Observation of microstructural evolution in quenched reactions of Ti:Si = 1:2 mixtures milled for relatively long times revealed that the combustion reaction was primarily a solid-state process restricted to a surface layer of the large Ti grains. A secondary process involving a solid–liquid interaction between solid Ti and melted Si was dominant in the post front region. The mechanical activation in this case took the role of increasing the contact surface between the reactants. A single reaction coalescence mechanism involving only liquid phases was proposed for the Ti:Si = 5:3 composition. For this composition the apparent activation energy for the overall combustion process was determined (155 kJ mol−1) and was shown to be independent on the degree of mechanical activation of the reactants.

The magnetic Nd–Fe–B powders were prepared by a mechanochemical method, including the processes of spray drying, debinding, milling, H2 reduction, Ca reduction, and washing. The liquid solution dissolved with various metal salts was first spray-dried to prepare the precursor powders having uniformly dispersed Nd, Fe, and B components. The precursor powders in turn were subjected to the subsequent processes. The particle size of the resultant Nd–Fe–B powders was about 1 μm. Effects of the process parameters on phases, morphologies, microstructures, compositions, and thermal properties of the powders were investigated.

We provide a phenomenological grain growth stagnation force incorporating a near-linear temperature dependence of stagnated grain sizes and irreversible growth. The resulting law captures the observation of the restart of grain growth in the size versus time plateau on temperature increases. This description also reduces to standard laws commonly used for data fitting. The law may be useful for workers who wish to characterize a nanocrystalline film or powder annealing process predictively from a limited number of measurements or may be useful in a designed experiment. Other laws are discussed and compared. Fits to size versus time data from the literature are successfully made.

The high degree of mixing of W and Cu phases in copper tungstates makes them an attractive source for manufacturing W–Cu composite powders. Hydrogen reduction of copper tungstates provides composite W–Cu powder products with a uniform, homogeneous dispersion of the metal phases. This paper presents test results for a variety of solid-phase reactions to synthesize cupric tungstate (CuWO4). Hydrated, dehydrated, and complex oxides of tungsten and copper have been used as solid reactants. With stoichiometric ratios of reactants, synthesis in air at 800 °C produced 96% to 100% conversion to CuWO4. Heterogeneous synthesis of CuWO4 with the participation of three solid phases (S1 + S2 →S3) required the simplest, most inexpensive equipment. The end product properties of synthesized CuWO4 could be controlled by the proper choice of reactants.

The relationships among structure and properties have been established in copolymers of ethylene and 1-octene, synthesized by a particular metallocene catalyst system. The most important factor affecting the structure and properties of these copolymers is, evidently, the comonomer content. However, the cooling treatment from the melt has been found to be also a very significant factor and, although its influence on the thermal properties is rather small, some structural parameters and the viscoelastic behavior are clearly dependent upon thermal history. These parameters include the degree of crystallinity, lattice constants, relaxation processes, stiffness, and microhardness of the samples. Regarding the viscoelastic behavior, the β relaxation is shifted to lower temperatures and its intensity is increased as 1-octene content raises. On the other hand, the α mechanism, associated with motions within the crystalline regions, is also moved to lower temperatures. Such a relaxation is only observed up to a certain 1-octene content in the copolymer.

An elastic-plastic crystalline constitutive model implemented in a finite-element code has been used to predict the microscale thermal residual stresses in Al−1%Si−0.5%Cu interconnects. This fully three-dimensional model accounts for the individual grain orientations in these interconnects, as measured by orientation imaging microscopy. The influence of specific crystal orientations on the residual stress distribution in these interconnects was studied in detail. A sensitivity analysis was performed to identify the parameters that influence strongly the predicted values of the residual stresses and their distributions. For the interconnects studied here, the residual stresses in the metal lines were found to be quite sensitive to the elastic modulus of the passivation material and its geometry. In addition, the volume averages of the predicted stresses were in reasonable agreement with the experimentally determined values from the x-ray technique.

Directional solidification using a Bridgman furnace was performed to produce textured Y2BaCuO5 (211) rods of both stoichiometric and off-stoichiometric compositions and to investigate microstructure formation at various solidification rates. The solidification morphology of the samples changed from planar to cellular and eventually to equiaxed blocky grains with increasing solidification rate. The microstructure of the stoichiometric 211 sample revealed elongated, aligned YBa2Cu3Oy (123) phase residual in the 211 matrix. The 211 samples rich in Y2O3 phase showed no trace of residual 123 but did show trapped Y2O3 particles. The morphology of the Y2O3 particles varied from spherical to a rodlike morphology as well along the length of a specific sample as also with decreasing growth rates in different samples. The Y2O3 particles in samples exposed for longer time to the liquid phase at high temperatures exhibited coarsening and unidirectional coalescence into a rodlike morphology and retained their morphology even in the 211 matrix after solidification.

Planar waveguide was fabricated in Er:Yb:phosphate glass by a single energy implantation of 2.5 MeV He+ at a dose of 1.6 × 1016 ions/cm2. The waveguide was characterized by prism coupling method, and the refractive index profile was reconstructed using the inverse Wentzel-Kramers-Brillouin method. The photoluminescence was also measured. The energy loss was simulated, and the results were compared and discussed with respect to the refractive index profile in the waveguide.

Highly ordered TiO2 nanowire arrays were prepared in anodic alumina membranes by a sol-gel method. The nanowires are single-crystalline anatase phase with uniform diameters around 50 nm. At room temperature, photoluminescence (PL) measurements of these TiO2 nanowire arrays showed a visible broad band with three peaks, which were located at about 425, 460, and 530 nm that are attributed to self-trapped excitons, F, and F+ centers, respectively. A model is also presented to explain the PL intensity drop-down of the TiO2 nanowire arrays embedded in the alumina membrane: the blue PL band of the anodic alumina membranes arises from the F+ centers on the pore walls, and the TiO2 nanowires first form in the center area of the pores and then extend to the pore walls.

Striation defects in spin-coated thin films are a result of unfavorable capillary forces that develop due to the physical processes commonly involved in the spin-coating technique. Solvent evaporation during spinning causes depletion at the surface of the more volatile solution components while simultaneous viscous out-flow occurs providing the main source of solution thickness reduction during any typical spinning run. The composition changes in the surface layer can either stabilize or destabilize the surface with respect to convective motions within the coating solution. Destabilization (and therefore possible striation formation) happens when the surface composition changes so that a larger surface tension will develop. Thus, a careful cross-referencing of solvent volatility with surface tension effects can help establish solution conditions that will prevent this instability from arising. A plot of solvent vapor pressure (Pv) versus solvent surface tension (σ) is introduced and utilized to help discuss the impact of solvent choice when making coatings via spin coating. One important result is that when desiring to deposit a coating having a surface tension of σsolid, then it is favorable to use a fully miscible solvent that has a higher surface tension (i.e., σliquid > σsolid). More complicated solution mixtures were also examined, including dual-solvent systems and water-containing systems.

A precursor solution for processing lithium niobate (LiNbO3) films was prepared from lithium niobium ethoxides through modification with acetic acid in hydrolysis. Homogeneous gel films were spin-coated on various substrates. Highly oriented LiNbO3 films were crystallized on sapphire and Pt-coated substrates by heat treatment at 500 °C. Crystallization behavior of the LiNbO3 films depended on the orientation of platinum under-layer films. LiNbO3 films crystallized with preferred (001) orientation on Pt(111) layers, while LiNbO3 films crystallized with preferred (113) orientation on Pt(100) layers. LiNbO3 films prepared on Si(111), SiO2, and MgO(100) substrates showed polycrystalline characteristics with less orientation by heat treatment at 500 °C.

The growth of large, melt-textured Nd1+xBa2−xCu3O6+δ (Nd-123) crystals has been achieved by hot seeding and isothermal solidification under a 1% oxygen in nitrogen atmosphere. These crystals, which exhibit a sharp, faceted growth interface, were grown epitaxially from a small Nd-123 single crystal seed placed on the sample surface at elevated temperature. The growth length of the melt-processed crystal was directly proportional to the isothermal holding time (approximately 17 h), as is observed for the growth of YBa2Cu3O7−δ (Y-123). The variation of growth rate with undercooling for this material was linear, however, in contrast to the parabolic dependence observed for Y-123 crystals grown in air. The growth rate of Nd-123 under reduced oxygen was consequently lower than that of Nd-123 and Y-123 grown in air at relatively high values of undercooling. Evaluation of the experimental data against a solidification models suggested that the interface kinetics are responsible, at least in part, for the observed growth features in hot-seeded Nd-123 crystals. This was attributed to the difference in oxygen partial pressure under the respective growth atmospheres, rather than to the species of rare-earth element in the compound.

Plastic instabilities were investigated in an Al–Zn–Mg–Cu alloy by depth-sensing microhardness testing in Vickers geometry. The alloy investigated showed strong age hardening as a consequence of Guiner–Preston zone formation at room temperature. The orientation dependence of the Portevin–Le Chátelier (PLC) effect was investigated by microindentation tests in differently oriented grains. If the direction of the indentation was close to the 〈100〉 crystal axis and the diagonal of the Vickers indenter coincides with the 〈110〉 crystal direction, the PLC effect was more pronounced. Under these conditions the instabilities could be observed even after 5 h of natural aging, while the PLC effect disappeared in grains with other orientations after 2 h of aging. The orientation dependence of the indentation curves was observed up to the maximal measured imprint size (d ≈ 80 μm). It is suggested that the initialization of the PLC bands takes place in the close vicinity of indenter/sample contact surface. Considering only a uniaxial compressive stress component in the sample/indenter contact planes, in the vicinity of the indenter single sliplike and multiple sliplike conditions are attained depending on the orientation of the indenter relative to the sample. Changes of the slip conditions correlate with changes in the observation regime of instability which explains the orientation dependence.

An amorphous boron–carbon–nitrogen (a-BCN) phase was synthesized by ball milling of a mixture of hexagonal BN (h-BN) and graphite with a nominal composition of (BN)0.5C0.5 in atomic ratio. Electron energy-loss spectroscopy studies indicated that the bonding of the a-BCN is in an sp2 configuration and the mixing between the BN and the C species was achieved at a nanometer scale, but the a-BCN phase was more likely a mechanical mixture rather than a chemical mixture. High-pressure and high-temperature (HPHT) treatment at 7.7 GPa and 2300 °C of the a-BCN phase resulted in complete segregation of the carbon and BN species, forming a nanocrystalline composite material comprising cubic BN (c-BN), amorphous carbon, and turbostratic graphite. The grain size of the c-BN phase was about 70 nm. No mutual solubilities between c-BN and carbon were found, and the two different species (C and BN) were well separated. An epitaxial relationship, i.e., the (0002) planes of graphite being parallel to the (111) planes of c-BN, was also found. The formation of ternary BCN phases was never found in the present experiment. Our experimental results also suggest the possibility of synthesizing c-BN grains encapsulated with graphite under controlled HPHT conditions.

The degradation behavior of polarization and leakage current characteristics of sol-gel-derived (Pb,La)(Zr,Ti)O3 (PLZT) thin films, with Pt, Ir, and IrO2 top electrodes, by annealing under a 4% H2/96% N2 atmosphere were investigated. The leakage current behaviors of Pt/PLZT/Pt and IrO2/PLZT/Pt capacitors annealed at 300 °C for 20 min in 4% H2 were well consistent with the space-charge-influenced injection model proposed. However, IrO2/PLZT/Pt capacitors recovered at 700 °C for 10 min in Ar ambient after hydrogen anneal were not consistent with the proposed model because a conducting phase of IrPb was formed between the top electrode and PLZT during the recovery anneal at 700 °C in Ar ambient and modified the Schottky barrier height. The true leakage current behavior of IrO2/PLZT/Pt capacitors recovered after hydrogen forming are similar to those of Ir/PLZT/Pt capacitors without the hydrogen-forming gas anneal. The P–E loops of Pt/PLZT/Pt and Ir/PLZT/Pt capacitors showed good recovery through recovery anneal after H2 treatment. However, IrO2/PLZT/Pt capacitors depended on the recovery anneal atmosphere (Ar or O2).

A Hf69.5Al7.5Ni11Cu12 metallic glass was prepared by a single roller melt-spinning method, and the crystallization process was studied by x-ray diffraction, differential scanning calorimetry, and transmission electron microscopy. The metallic glass crystallizes through three exothermic reactions. The low-temperature exothermic reaction corresponded to the precipitation of an icosahedral quasicrystalline phase. Further annealing at higher temperature led to the decomposition of the icosahedral quasicrystalline phase to other stable crystalline phases, indicating that the precipitated icosahedral quasicrystalline phase was in a metastable state. The crystallization process of the present alloy was compared with that of other Hf–Al–Ni–Cu alloys, and the reason for the precipitation of the icosahedral quasicrystalline phase was discussed.

The modified Pechini method using ethylenediaminetetraacetic acid as a chelating agent to prepare Ba2Ti9O20 is reported. The resin precursors were prepared and heated at 700 to 1200 °C in air, and x-ray diffraction was used to determine the phase transformations as a function of temperature. Single-phase Ba2Ti9O20 was obtained at 1200 °C for 2–6 h, without the need of prolonged heat treatment time. The process was simple and easy to control: low-temperature conditions or a protective atmosphere was not needed. Differential thermal analysis, thermogravimetric analysis, and Raman spectroscopy were used to characterize the precursors and derived oxide powders. Details of the synthesis and characterization of the resultant products were given.

Polycrystalline BaxSr(1−x)TiO3 (BST) thin films were processed on Pt-coated glass substrates at temperatures below 100 °C by reacting TiO2 films in alkaline solutions containing Ba2+ and/or Sr2+. The TiO2 was deposited by spin-casting a titanium metalorganic precursor onto Pt-coated glass substrates, followed by pyrolysis in air at 400 °C. Film stoichiometry deviated from the initial solution composition, with a preferred incorporation of Sr2+ into the perovskite lattice. The BST thin films had dielectric constants ranging from 100 to 185 and dielectric loss values below 0.25. Capacitance–voltage and current–voltage relationships were examined to determine the effect of phase stoichiometry and processing route on dielectric properties.