The effect of the doping by compounds with bivalent and trivalent cations (BN, Al2O3, MgO + SiO2) on the diffuse reflectance spectra (ρλ) and the integral solar absorptance (as) and their changes at irradiation (with 30 keV electrons, 3 keV protons, and electromagnetic radiation that imitates solar spectra) of the reflecting thermal control coatings based on ZrO2 powders is examined. The coating based on untreated ZrO2 pigment and the coatings based on the pigments treated with 1 and 3 mass% of Al2O3 nanopowder were subjected to simultaneous action of electrons, protons, and electromagnetic radiation that imitates action of these irradiations on geostationary satellite orbit. After that, the comparative investigations of the changes in spectral reflectance and solar absorptance of these coatings were carried out.

The friction and wear behavior of Si3N4-based composites against AISI-52100 steel were investigated in the ball-on-disk mode in a nonlubrication reciprocation motion. It has been found that under the conditions used, all the ceramic components exhibited rather low friction and wear coefficients. For monolithic silicon nitride materials, high friction coefficients between 0.6 and 0.7 and wear coefficients between 1.63 × 10−8 and 1.389 × 10−6 mm3/N · m were measured. The contact load was varied from 100 to 300 N. By adding titanium nitride, the friction coefficients were reduced to a value between 0.4 and 0.5 and wear coefficients between 1.09 × 10−8 and 0.32 × 10−6 mm3/ N · m at room temperature. All materials and worn surfaces as well as wear debris were investigated by means of scanning electron microscopy, energy dispersive spectroscopy, x-ray diffraction, and transmission electron microscopy (TEM) before or after the tribological tests. The TEM micrographs of wear track revealed plastic deformation through twins and cracking along grain boundary which play an important role in the fracture mechanism.

The electromigration behavior of the composite solder composed of eutectic and high-lead SnPb was investigated with 5.7 × 104 A/cm2 current stressing. Voids and hillocks were found only within the eutectic solder, and the high-lead solder remained intact. Electromigration was accelerated dramatically at 150 °C, and Pb became the major migration species of eutectic SnPb for the microstructure change at the anode. The polarity of the opposite current direction was also studied. When electrons drift from the eutectic side to the high-lead side, voids occurred at the eutectic–Cu interface whereas hillocks accumulated at the eutectic–high-lead interface. When the current was reversed, voids occurred at the eutectic–high-lead interface whereas hillocks accumulated at the eutectic–Cu interface. The anchoring effect, which results from the attaching of the lead-rich grains in the eutectic solder to the high-lead solder, was considered to retard the electromigration damage only in this current direction.

The effect of environmental exposure on the fracture characteristics of two polymer–metal interfaces was measured using a four-point bend delamination test. Films of high-molecular-weight polymethylmethacrylate (PMMA) resin were spin-cast on metal-coated silicon wafer substrates, for which the metal was either titanium or aluminum. Sandwich beam specimens were fabricated and stored in one of the following conditions prior to the bending tests: vacuum desiccator at 25 °C, vacuum desiccator at 65 °C, distilled water at 25 °C, or distilled water at 65 °C. Load–displacement behavior measured during bending revealed significant differences between the delamination characteristics of the two PMMA–metal interfaces after vacuum exposure which were eliminated after the degrading effects of water exposure. Three distinctive load–displacement behaviors were observed: plateau, fracture at a single load; R-curve, fracture at increasing load with crack extension; and stick-slip, cycles of gradual load increase and sudden load drop with crack extension. PMMA–Al samples stored in vacuum desiccator at 25 °C exhibited R-curve fracture and the largest average crack driving force, GC, 12.2 (±0.5) J/m2, of all samples tested. After storage in 25 °C water, these PMMA–Al samples exhibited stick-slip fracture and GC decreased to 7.1 (±2.6) J/m2; storage in 65 °C water further decreased GC to 2.1 (±0.7) J/m2. PMMA–Ti samples exhibited stick-slip fracture after storage in vacuum desiccator at 25 °C, with an average GC of 8.0 (±2.6) J/m2; storage in 65 °C water resulted in a transition to plateau fracture and a decrease in GC to 1.6 (±0.3) J/m2. The initial difference and subsequent similarity are interpreted in terms of surface roughness and hydrolysis, respectively.

The dielectric, ferroelectric, and piezoelectric properties of (001) BiScO3–PbTiO3 epitaxial films near the morphotropic phase boundary were investigated. Epitaxial films, 1-μm thick, were grown on (100) SrRuO3/(100) LaAlO3 substrates by pulsed laser deposition from a BiScO3–PbTiO3 (40/60) ceramic target. The films had room temperature dielectric constant of 850, tanδ = 0.08, and maximum dielectric constant of 5530 at 455 °C. Well-saturated hysteresis loops with a remanent polarization of 42 μC/cm2 and a coercive field of 75 kV/cm were observed. The effective transverse piezoelectric coefficient e31,f was −12 C/m2. This result is quite encouraging for sensor and actuator device development because the observed piezoelectric properties are as good as (001) oriented Pb(Zr,Ti)O3 films (e31,f ∼ –12 C/m2) while the transition temperature is 100 °C higher.

Characterization of thin film solid oxide fuel-cell materials can be difficult due to the range of porosities in electrodes and electrolytes as well as the nano-sized pores and particles. In this study, optical characterization techniques such as ultraviolet–visible transmission and reflection spectrophotometry are illustrated as methods for achieving information about the film density from the film refractive index as well as the film thickness. These techniques were used to investigate the sintering process of colloidal CeO2 on sapphire substrates and polymeric precursor-derived ZrO2:16%Y (YSZ) thin films on silicon over the temperature range 400–1000 °C, and the results were compared with traditional characterization techniques such as electron microscopy, profilometry, ellipsometry, and x-ray diffraction line broadening analyses. Most of the techniques were in good agreement with the CeO2 grain size changing from 5–65 nm and the film thickness changing from 0.8–0.5 μm. Comparisons of transmission and reflection spectrophotometry with ellipsometry illustrated that scattering effects from the porous CeO2 films caused an overestimation of the refractive index from ellipsometry, but allowed for accurate grain size measurements from transmission and reflection data. Both techniques were in good agreement during the sintering of the YSZ thin films, with the density changing from 90–100% theoretical after heating between 400 and 800 °C.

To investigate the directional dependence of the Faraday effect in terbium–scandium–aluminum garnet (TSAG) single crystals, grown by the Czochralski method, the Verdet constant was measured at 〈111〉, 〈110〉, and 〈100〉 orientations. Extinction ratio and magnetic susceptibility were measured. From the linear dependence of the Verdet constant and inverse wavelength square 1/λ2, 〈111〉 direction shows the highest value of Verdet constant (for λ⋅ = 649.1 nm, Vav = 8.256 × 10−3 deg · Oe−1 · cm−1). Significant anisotropy of magnetic susceptibility was not observed. The extinction ratio of TSAG shows the highest value for 〈111〉 orientation 38.7 dB, which implies that it can be used as an optical isolator.

Hafnium oxide films were deposited on silicon substrates at deposition temperatures ranging from 190 to 500 °C by metalorganic chemical vapor deposition using an amide precursor, Hf[N(C2H5)2]4, and O2 as source materials. The effect of deposition temperature on the deposition characteristics and electrical properties of the resultant films were investigated. Reaction-limited deposition of hafnium oxide films occurred at deposition temperatures under 380 °C. Concentration of residues, such as carbon, nitrogen, and hydrogen, monotonously decreased with increasing deposition temperature, with nitrogen being the most thermally susceptible. However, surface roughness reached a minimum value at 400 °C. Amorphous films were obtained for deposition temperatures up to 450 °C, but obviously became crystallized at 500 °C. Accumulation capacitance increased with increasing deposition temperature but saturated above 400 °C. Moreover, postdeposition annealing at 800 °C caused no obvious degradation in the electrical properties of the film deposited at 400 °C.

Several thermophysical properties of liquid and supercooled ruthenium were measured using electrostatic levitation. Over the 2225–2775 K temperature interval, the density can be expressed as ρ(T) = 10.75 × 103 – 0.56(T – Tm)(kg ⋅ m−3) with Tm = 2607 K. In addition, the surface tension can be expressed as σ(T) = 2.26 × 103 – 0.24(T – Tm)(mN ⋅ m−1) and the viscosity as η(T) = 0.60 exp[4.98 × 104/(RT)] (mPa ⋅ s) over the 2450–2725 K range. The isobaric heat capacity was estimated as CP(T) = 35.9 + 1.1 × 10−3(T – Tm)[(J/(mol K)] over the 2200–2750 K span by assuming a constant emissivity. The volume expansion coefficient, the enthalpy, and the entropy of fusion were also calculated as 5.2 × 10−5 K−1, 29.2 kJ ⋅ mol−1, and 11.2 J/(mol K).

An approach to pattern directly thin films of various materials deposited by different physical vapor deposition methods is presented. Co and Ag films deposited by pulsed laser deposition and e-beam evaporation, respectively, were fabricated into 650- and 1000-nm-spaced parallel stripes on Si(100) surfaces by simultaneous two-beam ultraviolet laser interference irradiation of the substrate surface during deposition. The resulting morphology consists of 1- to 2-nm-height stripes, which have the same direction and spacing as the interference fringes. This approach has the potential to allow long-range ordering of well-defined patterns over large areas because the spacing and geometrical patterns are defined by the laser interference. Furthermore, the fact that this method works for different materials and does not require any lithography masks, etching steps, or substrate prepatterning, makes it promising as a simple and economical lateral patterning approach.

A new approach to the contact to coated elastic materials is presented. A relatively simple numerical algorithm based on an exact integral formulation of the elastic contact of an axisymmetric indenter to a coated substrate is detailed. It provides contact force and penetration as a function of the contact radius. Computations were carried out for substrate to layer moduli ratios ranging from 10−2 to 102 and various indenter shapes. Computed equivalent moduli showed good agreement with the Gao model for mismatch ratios ranging from 0.5 to 2. Beyond this range, substantial effects of inhomogeneous strain distribution are evidenced. An empirical function is proposed to fit the equivalent modulus. More importantly, if the indenter is not flat-ended, the simple relation between contact radius and penetration valid for homogeneous substrates breaks down. If neglected, this phenomenon leads to significant errors in the evaluation of the contact radius in depth-sensing indentation on coated substrates with large elastic modulus mismatch.

We have grown lead magnesium niobate–lead titanate (PMN–PT) single crystals, using the high-pressure vertical Bridgman (HPVB) technique, around the stoichiometric composition of 0.7 PMN–0.3PT [0.7Pb(Mg1/3Nb2/3)O3 + 0.3(PbTiO3)]. The final ingot (about 50-mm diameter, 25-mm long) was machinable using an inner diameter saw. The room-temperature x-ray diffraction on the starting powders and the final single crystal revealed a desirable perovskite structure. The natural growth direction in most of the crystals, as determined using orientation image microscopy, was (110). Examination of the final microstructures and phases/inclusions had been done using optical and infrared microscopy, energy dispersive spectroscopy, and x-ray backscatter techniques. Microstructural characterizations of the final ingots have revealed the presence of pores filled with Mg–Si–O-rich impurity phase, usually found along the cell boundary–like structures, in all the growths. We have measured some piezoelectric properties including d33 (1200 pC/N), k33 (0.85), kt (0.5), and the dielectric constant at the Curie temperature.

Ni was surface-alloyed with Si by ion implantation. The material was examined for its redox and electrocatalytic behavior in NaOH by cyclic voltammetry. The surface was characterized by x-ray photoelectron spectroscopy, x-ray and electron diffraction, and electron and atomic force microscopy. The ion implantation enhanced activity toward the redox conversion of Ni(OH)2 ↔ NiOOH and the anodic oxidation of glucose reached about 3.5 times and about 2.8 times, respectively. The material is an amorphous mixed oxide of Ni and Si. The effect is discussed considering the true surface area and the generation of active surface sites in relation to the oxygen evolution.

In the pharmaceutical industries, mixing is a critical process. Pharmaceutical products consist of various components, including active ingredient and excipient. After mixing, we should get a homogeneous mixture to ensure the quality of the final products, such as tablets or capsules. For that reason, segregation is an unwanted phenomena in the mixing process. In this study, discrete-element method (DEM) was applied to investigate the mechanism of segregation in a rotating cylinder; basic equipment for powder mixing. In addition, segregation of particles in a rotating cylinder is a very interesting phenomenon and has captured the curiosity of not only industrial engineers, but also physicists. DEM can simulate segregation in a rotating cylinder three-dimensionally. In particular, radial segregation, which was quickly observed, was quantified by computing the granular temperature of the system. Furthermore, particle migration in axial direction, which may be the source of axial segregation, was also shown by the DEM simulation.

Described is a room-temperature hydrogen sensor comprised of a TiO2-nanotube array able to recover substantially from sensor poisoning through ultraviolet (UV) photocatalytic oxidation of the contaminating agent; in this case, various grades of motor oil. The TiO2 nanotubes comprising the sensor are a mixture of both anatase and rutile phases, having nominal dimensions of 22-nm inner diameter, 13.5-nm wall thickness, and 400-nm length, coated with a 10-nm-thick noncontinuous palladium layer. At 24 °C, in response to 1000 ppm of hydrogen, the sensors show a fully reversible change in electrical resistance of approximately 175,000%. Cyclic voltammograms using a 1 N KOH electrolyte under 170 mW/cm2 UV illumination show, for both a clean and an oil-contaminated sensor, anodic current densities of approximately 28 mA/cm2 at 2.5 V. The open circuit oxidation potential shows a shift from 0.5 V to −0.97 V upon UV illumination.

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.

Zirconia–hafnia (ZrO2–HfO2) nanolaminate structures were grown using the atomic layer deposition (ALD) technique with different stacking sequences and layer thickness layer thicknesses. The microstructural evolution and surface roughness were compared with those of single-layer ZrO2 or HfO2 films using transmission electron microscopy and atomic force microscopy. Thin single-layer ALD-ZrO2 films were polycrystalline and composed of the tetragonal ZrO2 phase as-deposited, whereas thicker (>14 nm) films were composed mainly of the monoclinic phase. HfO2 films were amorphous as-deposited and crystallized into primarily monoclinic during subsequent anneals at temperatures over 500 °C. All the nanolaminate structures having individual layer thicknesses greater than approximately 2 nm were crystalline (mixture of tetragonal and monoclinic phases) independent of layer sequence and also exhibited a layer-to-layer epitaxy relationship within each grain. However, the identity of the starting layer determined the final grain size and surface roughness of the nanolaminates. A qualitative model for the observed microstructure evolution of the laminate films is proposed.

Nanocrystalline ZnO particle–polymer hybrid was synthesized by controlled polymerization and hydrolysis of zinc acrylate (ZA). 13C nuclear magnetic resonance spectra revealed the polymerization of ZA during hydrolysis in the presence of hydrazine at 65 °C for 24 h. Nanocrystalline ZnO particles were dispersed in the organic matrix through the polymerization–hydrolysis reaction of ZA using hydrazine or methylhydrazine. ZnO particles increased in crystallinity with increasing amount of water for hydrolysis in the system using hydrazine. Methylhydrazine was found to yield ZnO with higher crystallinity than that obtained using hydrazine. The nanocrystalline particles were identified to be ZnO by electron diffraction. ZnO particle–polymer hybrid was workable by mild heating into transparent films between silica plates. The absorption edge of the transparent ZnO particle–polymer hybrid film was blue-shifted depending on the size of ZnO particles.

Silicon is a principal material in submicrometer-scale devices. Components in such devices are subject to intense local stress concentrations from nanoscale contacts during function. Questions arise as to the fundamental nature and extent of any strength-degrading damage incurred at such contacts on otherwise pristine surfaces. Here, a simple bilayer test procedure is adapted to probe the strengths of selected areas of silicon surfaces after nanoindentation with a Berkovich diamond. Analogous tests on silicate glass surfaces are used as a control. The strengths increase with diminishing contact penetration in both materials, even below thresholds for visible cracking at the impression corners. However, the strength levels in the subthreshold region are much lower in the silicon, indicating exceptionally high brittleness and vulnerability to small-scale damage in this material. The results have important implications in the design of devices with silicon components.

A thin film composed of an ion-exchangeable layered oxide HxTi(2-x/4)⃞x/4O4 (HTiO) (where the open square, ⃞, is vacancy) is studied as an electrode material. The thin film prepared on an indium tin oxide substrate functions as an electrode for the redox reaction of Ru(bpy)32+/Ru(bpy)33+ without noticeable degradation. Lack of reaction in the presence of Fe(CN)64−/Fe(CN)63− indicates that reaction on this electrode occurs in the interlayers between titanate sheets. A Ru(bpy)32+-intercalated form of the electrode generates photocurrent under visible light irradiation.