A semi-empirical interatomic potential of the Ni–W system was developed using a modified embedded-atom method (MEAM) formalism including second-nearest-neighbor interactions. The cross potential was determined by fitting physical properties of tetragonal Ni4W available in the literature. The MEAM potential was used to predict phase stabilities, lattice constants, and bulk moduli of nonequilibrium and equilibrium phases in the Ni–W system. The results were in good agreement with experimental information or first-principles calculation.

A low-temperature metalorganic chemical vapor deposition process was developed and optimized, using a design of experiments approach, for the growth of ultrathin aluminum oxide (Al2O3) as a potential gate dielectric in emerging semiconductor device applications. The process used the aluminum β-diketonate metalorganic precursor [aluminum(III) 2,4-pentanedionate] and water as, respectively, the metal and oxygen source reactants to grow Al2O3 films over a temperature range from 250 to 450 °C. The resulting films were analyzed by x-ray photoelectron spectroscopy, x-ray diffraction measurements, Rutherford backscattering spectrometry, nuclear-reaction analysis for hydrogen profiling, scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. The as-deposited Al2O3 phase was amorphous and dense and exhibited carbon and hydrogen incorporation of, respectively, 1 and 10 at.%. Postannealing at 600 °C led to a reduction in hydrogen concentration to 1 at.%, while maintaining an amorphous Al2O3 matrix.

In a previous computer-simulation experiment, the accumulation of damage in silicon carbide (SiC) from the overlap of 10 keV Si displacement cascades at 200 K was investigated, and the damage states produced following each cascade were archived for further analysis. In the current study, interstitial clustering, system energy, and volume changes are investigated as the damage states evolve due to cascade overlap. An amorphous state is achieved at a damage energy density of 27.5 eV/atom (0.28 displacements per atom). At low-dose levels, most defects are produced as isolated Frenkel pairs, with a small number of defect clusters involving only four to six atoms; however, after the overlap of five cascades (0.0125 displacements per atom), the size and number of interstitial clusters increases with increasing dose. The average energy per atom increases linearly with increasing short-range (or chemical) disorder. The volume change exhibits two regimes of linear dependence on system energy and increases more rapidly with dose than either the energy or the disorder, which indicates a significant contribution to swelling of isolated interstitials and antisite defects. The saturation volume change for the cascade-amorphized state in these simulations is 8.2%, which is in reasonable agreement with the experimental value of 10.8% in neutron-irradiated SiC.

Nb-doped Bi4Ti3O12 (Nb-BIT) ferroelectric thin films were prepared in the presence of a nonionic surfactant (pluronic P123) added as an additive to the sol solution and by rapid thermal annealing (RTA). The film annealed at the relatively low temperature of 600 °C was well crystallized and showed good ferroelectricity. The switching charge of capacitors with polarization reversal rapidly increased with a large amplitude and low frequency of the applied pulse, and gradually decreased with a small amplitude and high frequency. The remanent polarization (2Pr) after subjecting the Nb-BIT capacitors to 108 read/write cycles was 46 μC/cm2, which is remarkably higher than 20 μC/cm2 observed in the initial state. These phenomena seem to appear by the presence of space charges trapped after heat treatment by the RTA process.

The thermo-optic coefficient (dn/dT) of inorganic–organic hybrid material films prepared by the sol-gel process of organoalkylsilanes is measured using a prism coupler equipped with a hot stage. The effect of the organic modifier on the variation of dn/dT in inorganic–organic hybrid material films has been investigated. The value of dn/dT becomes more negative with increasing molecular weight of the organic modifier or with an increase in the proportion of modifier in the sample. On the other hand, dn/dT increases with an increase in the degree of organic photopolymerization. From these results, it can be seen that the value of dn/dT in these films can be varied between −0.83 × 10−4/°C to −2.43 × 10−4/°C by changing the organic modifier concentration and type.

Eu(DBM)3Phen-doped poly(methyl methacrylate) (PMMA) with different doping concentrations was prepared. Judd–Ofelt parameters Ω2 and Ω4 and the fluorescence intensity ratio R were computed from the fluorescence emission spectra and were analyzed. The radiative properties, such as transition probabilities, emission cross section (46.47 × 10−22 cm2), fluorescence branching ratios (90.34%), and radiative lifetime (1.704 ms), reveal that Eu(DBM)3 Phen-doped PMMA has potential use as a laser material.

Phase formation was studied in the Fe–Ge and Cr–Ge thin-film systems by means of Rutherford backscattering spectrometry and x-ray diffraction. In the Fe–Ge system, FeGe was the first phase to form while in the Cr–Ge system, Cr11Ge8 was found to form first. The results are compared with the predictions of the effective heat of formation model. Heats of formation were calculated using the Miedema model. The effect of the transformation enthalpy term ΔHtr, used to convert a semiconducting element into a hypothetical metallic one in the Miedema model, is also discussed.

Metals and alloys processed by severe plastic deformation (SPD) can demonstrate superior mechanical properties, which are rendered by their unique defect structures. In this investigation, transmission electron microscopy and x-ray analysis were used to systematically study the defect structures, including grain and subgrain structures, dislocation cells, dislocation distributions, grain boundaries, and the hierarchy of these structural features, in nanostructured Ti produced by a two-step SPD procedure—warm equal channel angular pressing followed by cold rolling. The effects of these defect structures on the mechanical behaviors of nanostructured Ti are discussed.

The effect of hydrogen dilution during plasma deposition on hydrogen incorporation and the optical and electrical properties of a-SiHx films were studied. The films were grown in capacitive low-frequency (f = 10 and 110 kHz) discharge in SiH4 diluted with H2, varying the ratio RH of the gases H2/SiH4 from RH = 0 to 40. The optical absorption coefficient and optical bandgap were changed with RH. Si–H bonding, studied by infrared spectroscopy, depended on RH. Hydrogen concentration in the films estimated from infrared spectra was in the range 20–30%. We observed the significant effect of RH on the temperature dependence of conductivity σ(T) and on the subgap absorption spectra measured by the constant photocurrent method. The reduction of subgap absorption up to 1.5 order of magnitude was observed with increasing RH.

The high-temperature combustion mechanism of the BaO2–TiO2–organic compound system [urea, CO(NH2)2; hexamethylenetetramine, C6H12N4] was investigated by the microthermocouple technique. The adiabatic combustion temperatures (Tad) and equilibrium compositions of the final products were calculated by the computer program THERMO. The distribution of the temperature T(x), rate of heat generation Φ(x), and degree of conversion η(x) in the combustion wave were determined. The relative sizes of the combustion zones, the leading stage of the reaction, the kinetic law of components interaction, and parameters (activation energy, pre-exponential factor, braking parameter) were then calculated. Through this method, the optimal conditions for tetragonal BaTiO3 powder synthesis with spherical form and particles size of 2–5 μm were found.

We report the fabrication and characterization of a Mg-based metal matrix composite reinforced by MgO ceramic and Mg–Mg2Cu eutectic. The composite was fabricated by sintering and quenching of a Mg–20 wt.% CuO sample. We performed differential scanning calorimetry (DSC) on the sample and found that the reaction between Mg and CuO took place at about 420 °C. When the sample was sintered to 550 °C and cooled down, the two-phase Mg–Mg2 Cu eutectic formed. The final composite product contained MgO particles and Mg–Mg2Cu eutectic, which were embedded in the Mg matrix. Based on the results from DSC and scanning and transmission electron microscopies, a model is proposed to describe the competitive growth of Mg and the eutectic during solidification. We also found that the microstructure of the Mg–Mg2 Cu eutectic strongly depended on the rate of cooling. The lamellar thickness of the eutectic could be reduced to 120 nm by oil-quenching the sintered sample.

AlOx thin films were grown on ZnO-deposited glass substrates under different conditions using magnetron sputtering. The influence of processing parameters (mainly direct-current power and oxidizing atmosphere) on the structure and optical properties were investigated. The AlOx films for all samples in this study showed the coexistence of amorphous and polycrystalline structures. The kinetics of crystal growth could influence the dominant crystal orientation. Fast-growing planes were not the most thermodynamically stable, but were kinetically controlled under the film growth condition. Oxidizing the sample in O2 atmosphere made the AlOx film grow in random directions. The excess oxygen was chemisorbed at the interface between AlOx and ZnO. Therefore, the neighboring oxygen–oxygen distance of AlOx and that of ZnO on their closest-packed planes seriously mismatched. At high power, the particles arrived at the substrate with high kinetic energy and high rate, which led to low density due to porous structure. The transmission decreased with an increase of the pores and surface roughness of AlOxfilm on ZnO-deposited glass. However, the diffusion of oxygen into the grains improved transmission when the sample was oxidized in O2 atmosphere.

MgO–C–Al refractories were used in this study to evaluate high-temperature refractory–metal reactions with molten Fe–Mn–Al alloys. Dynamic reaction tests at 1570 °C and static reaction tests at 1500 °C and 1600 °C, respectively, were used. MgAl2O4 and Al4C3 phases were observed in the refractory bulk, and a large amount of protective MgAl2O4 phase formed due to the decomposition of Al4C3 phases on the refractory–metal reaction interface of the MgO–C–Al brick to retard the high-temperature attack of Fe–Mn–Al alloy melts. The oxygen partial pressure was substantially reduced by the oxidation of graphite in the MgO–C–Al brick during high-temperature test. This resulted in the nitridation of aluminum in molten Fe–Mn–Al alloy. White aluminum nitride (AlN) with the shape of whisker-like powder was formed and adhered to the surface of the MgO–C–Al brick. Aluminum was depleted from the Fe–Mn–Al alloy by nitridation or the oxidation reaction by CO gas. The alloy would also be carburized due to the absorption of CO gas or the reaction between aluminum and CO gas, which was produced by the oxidation of graphite in the MgO–C–Al refractory after static reaction test. It is argued that the MgO–C–Al refractory is not suitable to be used in the melting of Fe–Mn–Al alloys with high aluminum contents.

To develop an effective process for the recovery of precious metals from scrap, we investigated a new platinum extraction process using alloy formation by magnesium vapor and successive leaching with an aqueous solution. Pure platinum plates were reacted with magnesium vapor at constant temperatures ranging between 873 and 1173 K for 3 h, and Mg–Pt alloy samples were synthesized. The obtained Mg–Pt alloy was then dissolved in aqua regia or in an aqueous HCl solution at room temperature. Platinum was recovered from the leaching solution by conventional precipitation technique, and the platinum obtained by each process was analyzed chemically. It was found that 94% of the platinum was recovered by this process. After Mg vapor treatment, 100% of the platinum was dissolved when kept in aqua regia for 1 h, whereas only 25% of untreated pure platinum was dissolved when kept in aqua regia for 4 h.

Using proton nuclear magnetic resonance (1H-NMR), we have studied the thermally activated hydrolysis of aluminum nitride admixed into Al2O3 aqueous suspensions. We paid special attention to the formation of aluminum hydroxide and its role in binding the host ceramic particles into a stiff solid matrix. The water–proton NMR spin-spin relaxation time (T2) was continuously measured as a function of the time of the AlN hydrolysis in the host Al2O3 ceramic suspension. T2 was found to correlate with an increasing fraction of bound water at the surface of the formed hydrogel and so provided us with information about the gel-surface growth during the hydrolysis process. These results are in good agreement with the observed time- and composition-related increases in high-frequency impedance for the analyzed suspensions.

The elastic response of atmospheric plasma-sprayed coatings was investigated using Vickers and spherical indenter geometries. In both cases a strong dependency of the stiffness on the applied load (indentation depth) was observed. The stiffness of the coatings decreased with increasing load for a Vickers indenter, whereas it increased for a spherical indenter. This contrary behavior was related to the relative crack density in the deformed volume and to the stress dependence of the stiffness due to crack closure. The effect of annealing on the stiffness was quantified for both tip geometries. The heat treatment yielded additional information on the relationship between the indentation data and the microstructural defects. From the results it was concluded that the stiffness measured using a sharp indenter and small load reflected the elastic behavior of single spraying splats. With the relatively large spherical indenter, the average global stiffness of the thermal barrier coating was measured even at small loads. From the data obtained using the spherical indenter, a compressive stress–strain curve was suggested. Furthermore, values of the apparent crack density and yield strength were determined from the indentation tests.

Nanocrystal-(Ti, Al)Nx/amorphous-SiNy composite films were prepared in a codeposition process under different substrate bias voltages. The effects of substrate bias voltage on the deposition rate, composition, microstructure, and mechanical properties of nanocomposite films were investigated. Results indicated that the films with bias voltages caused resputtering due to the bombardment of high-energy ions on film surface. The resputtering effect had substantial influence on deposition rate, surface morphology, and composition of films. The films with (220) preferred orientation were also observed as the applied substrate bias voltages exceeded 50 V. As the substrate bias voltage increased, the nanocrystallite size increased, lattice strain raised, and the hardness decreased.

High-current-density electropulsing was applied to a coarse-grained Cu–Zn alloy with two phases of α-phase and β′-phase. It was found that with an electropulsing treatment, ultrafine-grained (UFG) microstructure could be formed in the α-phase, but could not be formed in the β-phase. The results indicated that the formation of UFG microstructure was dependent on solid-state phase transformation. The main reason for the formation of UFG microstructure by electropulsing treatment resulted from the effect of a decrease in thermodynamic barrier and enhancement of nucleation rate in a current-carrying system, but not from the high heating and cooling rate during electropulsing treatment. The bulk UFG samples prepared by electropulsing treatment were free of porosity and contamination and had no large microstrain. It was reasonable to anticipate that a new method might be developed to produce ideal bulk UFG samples directly from the conventional coarse-grained materials by application of electropulsing.

The stress relaxation results below the glass-transition temperature Tg are a continuation of the viscoelastic relaxation above Tg. This means that the dynamic glass transition and not a secondary relaxation is the reason for the observed effects.