Hydrogenated microcrystalline silicon (μc-Si:H) grown by a conventional plasma-enhanced chemical vapor deposition from high hydrogen-diluted silane was annealed by increasing the temperature from 25 to 450 °C at a constant rate of 12 °C/min (one annealing cycle). Dark-conductivity activation energy gradually increases with increasing the number of annealing cycle to a saturation value of about 0.6 eV, observed in truly intrinsic μc-Si:H films. For the saturated state, the dark conductivity of the order of 10−8 S/cm was obtained. Little or no change in the oxygen content was observed after the annealing.

Formation of the icosahedral quasicrystalline phase in conventionally cast Al62Cu25.5Fe12.5 and Al55Cu25.5Fe12.5Be7 alloys were investigated. The icosahedral phase (I-phase) forming ability was greatly improved by partial replacement of Al by 7 at.% Be. The as-cast Al55Cu25.5Fe12.5Be7 alloy consisted of dendritic primary I-phase and interdendritic τ-phase, whereas that of an as-cast Al62Cu25.5Fe12.5 alloy consisted of various phases such as the β-, I-, and τ-phases, together with a small amount of the λ- and η-phases. The kinetic barrier for transformation into single I-phase by heat treatment was greatly reduced in an Al55Cu25.5Fe12.5Be7 alloy. The I-phase in an Al55Cu25.5Fe12.5Be7 alloy has the same face centered icosahedral structure as that in an Al62Cu25.5Fe12.5 alloy and is of high quality without phason strain.

Tungsten oxide (WOx) films were fabricated by (i) reactive thermal evaporation (RTE) at room temperature with oxygen ambient pressure PO2 as a parameter, and (ii) reactive magnetron sputtering (RMS) with substrate temperature Ts as a parameter. The film structure revealed by x-ray photoelectron spectroscopy, x-ray diffraction, density measurements, infrared absorption, and atomic force microscopy was correlated with the nanoindentation hardness H. The RTE WOx films deposited at high Po2 were amorphous and porous, while H depended appreciably on normalized penetration depth hD (indentation depth/film thickness) due to the closing of the pores at the point of indentation. Decrease in Po2 from 10 to 2 × 10−3 mtorr led to smaller porosity, weaker hD dependence of H, and higher average H (measured at hD ≈ 0.2 to 0.3, for example). The RMS WOx film deposited at room temperature was amorphous and denser than all RTE films. The rise in substrate temperature Ts first densified the film structure (up to 110 °C) and then induced crystallization with larger grain size for Ts ≥ 300 °C. Correspondingly, the hD dependence of H became weaker. In particular, H of the RMS sample deposited at 110 °C showed a peak at hD slightly above 1 owing to pileup at the contact point of indentation. For higher Ts, pileup occurred at shallower hD and the average H (measured at hD ≈ 0.2 to 0.3, for example) rose, accompanied by the increase of grain size.

Thin films with thickness 100 nm of Ge10+xSe40Te50−x (x ranging from 0.0 to 16.65 at.%) were formed by vacuum deposition at 1.33 × 10−4 Pa. The change in electrical resistivity of the films has been measured using the coplanar method. The measurements have been carried out in a temperature range between 400 and 142 K. The values of the electrical activation energies lie in the range of 0.18–0.38 eV. The optical absorption behavior of these ternary thin films was studied from the reflection and transmission. The optical band gap was found to be in the range of 0.90–1.11 eV and arose from indirect transitions. On the other hand, the width of the band tail Ee was found in the range 0.19–0.32 eV and exhibits opposite behavior. This behavior is believed to be associated with a defected bond of Te–Te and a cohesive energy (CE).

Copper-doped LiNbO3 layers prepared by an Cu–Li ion-exchange process are characterized by electronic paramagnetic resonance. It is found that the majority of Cu2+ ions are coupled by strong exchange interactions which is characteristic of short distances between paramagnetic ions. Such ions are accumulated in a thin layer near the crystal surface and can enter in new crystalline phases formed as a result of the Cu–Li ion exchange. A small amount of Cu2+ ions is incorporated into weakly distorted LiNbO3 crystal lattice inside the diffusion layer.

We present a simple and reproducible method to obtain TiO2 and Fe2O3 mixed-oxide thin films by reactive radio-frequency sputtering. The influence of iron concentration on the structural properties of the layers has been studied. Structural characterization, carried out by electron microscopy analysis, allowed one to correlate the inhibition of the grain growth of titania to the presence of iron oxide and to its segregation at grain boundaries. This behavior should be ascribed to a superficial-tension phenomenon. As a possible application of these thin films, we have investigated the gas-sensing properties toward CO, with particular focus on the role of Fe. The layers were capable to sense CO down to the level requested for environmental monitoring.

A methodology is developed which extends the combinatorial approaches to structural materials research and development. This high-efficiency methodology employs diffusion couples and “diffusion multiples” to create large variations (libraries) of compositions in bulk samples for fast and systematic surveys of bulk properties. These composition libraries coupled with microanalytical techniques such as electron probe microanalysis, electron backscatter diffraction analysis, and nanoindentation tests can be used for efficient surveys of phases, equilibria, diffusion coefficients, precipitation kinetics, properties, and composition–phase–property relations (such as solution hardening and strengthening effect) for accelerated design of multicomponent alloys.

The underlying theory behind the extraction of elastic modulus and hardness from the unloading load–displacement data obtained with a spherical indenter was explored in detail. A formal treatment of the effect of indenter elasticity was given, and the validity of the use of the reduced or combined modulus in analytical treatments was verified. The “Oliver and Pharr” method and the “Field and Swain” methods of analyses were compared in detail and shown to be equivalent.

The corrosive wearing behavior of the Co–Cr–W alloy in liquid zinc was investigated using a specially designed wearing test machine. Its corrosion rate and wear rate during corrosive wearing process with different conditions were analyzed. The corrosive wearing mechanism of the Co–Cr–W alloy was investigated by analysis on its sliding surface using scanning electron microscopy, energy dispersive spectrometry, and microhardness sclerometer. The experimental results led to the following conclusions: (i) The corrosion of the Co–Cr–W alloy is accelerated by wearing process in the liquid zinc. (ii) The liquid zinc provides obvious lubrication to the sliding surfaces of this alloy and then reduces its wearing rate during the corrosive wearing process. (iii) Its corrosive wearing rate is increasing sharply with increasing temperature of the liquid zinc. (iv) The corrosive wearing of the Co–Cr–W alloy is caused by preferential corrosion of the eutectic phases in this alloy and fatigue cracking of the worn surface. The fatigue wearing of this alloy is directly due to the synthetic effect of strain hardening of the layer on and under sliding surface and serious stress corrosion in the crack tips during the corrosive wearing period.

Formation of ordered structure in flux-grown Ba(Mg1/3Ta2/3)O3(BMT) single crystals was studied using x-ray diffraction, electron diffraction, and high-resolution electron microscopy. The low-temperature-grown crystals exhibited no sign of B-site ordering. Annealing at 1500 °C induced the 1:2 ordered phase, and its content increased with the annealing time. The superlattice diffraction peaks were broad initially; they sharpened rapidly with the annealing time. Diffuse superlattice reflections were found in electron diffraction patterns of 1500 °C annealed BMT; they turned into sharp reflections under long annealing time or higher temperature, 1600 °C. The intensity of diffuse reflections was sparsely distributed, but the maximum intensity location was determined in the digitized recording of image plate. The maximum intensity sites of two diffuse reflections in the 〈111〉 direction deviated from the presumed 1/3 and 2/3 positions and shifted towards the center. The diffuse reflection and the deviation from regular positions were interpreted as the composition modulation during B-site cation diffusion.

The fundamental absorption edge of Cu6P(S0.6Se0.4)5I and Cu6P(S0.4Se0.6)5I crystals was studied in the 77–320 K temperature range where no phase transitions were revealed by optical techniques. The temperature behavior of the exponential Urbach absorption edge in Cu6P(S0.6Se0.4)5I and Cu6P(S0.4Se0.6)5I crystals was analyzed. The effect of compositional disorder upon the Urbach edge parameters, parameters of exciton-phonon interaction, and lattice parameters in Cu6P(S1−xSex)5I, 0 ≤ x ≤ 1, crystals was studied. The effect of various types of disordering upon the optical absorption processes in Cu6P(S1−xSex)5I crystals is discussed.

Carbothermal reduction of kyanite, a natural aluminosilicate with high alumina content (Al2O3 · SiO2), was used as a way to synthesize SiC–Al2O3 powder. Carbon black was mixed with the mineral precursor in a molar ratio of (C/SiO2) = 5.5. The Carbothermal reaction sequence was studied in the temperature range 1260–1550 °C. Completion of the reaction at 1550 °C gave β–SiC-whiskers and α–Al2O3 particles as final products. From observations, the impurities contained in the mineral precursor behave as catalysts for the vapor–liquid–solid whisker growth mechanism. When the specific surface area of the starting carbon was increased from 330 to 996 m2/g, the carbothermal reaction rate increased but the morphology of the SiC-whiskers became very irregular. This study aimed to identify the main reaction conditions for obtaining a favorable morphology of the synthesized powder for elaborating Al2O3–SiC-whisker composite materials by using low cost starting materials and a relatively simple in situ synthesis route in comparison to the conventional way of separately preparing the phases SiC (whiskers) and Al2O3 before elaborating composites.

Combustion synthesis (CS) of NiAl-based materials reinforced by TiB2 particles was investigated under both terrestrial and microgravity conditions. The synthesized metal matrix composites (MMC) are characterized by very fine (<1 μm) reinforced particulates, which have strong bonding along their entire surface with matrix (NiAl) and are distributed uniformly in it. It was found that microgravity leads to a decrease in the average TiB2 particle size, while higher volume fraction of NiAl component in the material leads to the formation of coarser reinforced particulates. The mechanism of structure formation of different MMCs during CS was identified by using the quenching technique. For example, it was shown that TiB2 grains appear due to crystallization from the complex (Ni–Al–Ti–B) liquid solution formed in the combustion front. An overall decrease of microstructural transformation rates was observed under microgravity.

An investigation of phase separation phenomena in gel and glassy thin films of silica–titania, with TiO2 contents of 20 and 40 mol%, has been carried out by atomic force microscopy (AFM) and transmission electron microscopy (TEM). The thin films were prepared by spin coating of a precursor sol on silicon wafers. Both the TEM measurements (carried out on scrapped thin film flakes) and the AFM measurements (carried out on films coated on the silicon substrates) for samples with different heat treatments suggest that spinodal-like structural inhomogeneities occur in these samples, unlike the corresponding observations in pure silica films, which are known to be homogeneous. Changes in the microstructure of the films have been noticed with the thermal treatment, in agreement with earlier x-ray photoemission studies. The finer characteristic dimensions of the phase separated regions reveal that silica–titania samples prepared by sol-gel processing exhibit a more intimate mixing of the phases.

A crack reduction by electron beam (EB) irradiation treatment for carbon fiber, used without the traditional method of accompanying heat, was developed to modify the mechanical properties at lower temperature. The EB treatment improved the resistance to fracture. Namely, the maximum ratio of fractured samples (maxRf) and the minimum bending strain on fracture (minεf) were defined as simple indicators of fracture resistance and became smaller by the EB treatment. Furthermore, a critical density of dangling bonds for a fracture was suggested and determined for carbon fiber treated by EB irradiation. The EB irradiation to reduce cracking and the determination of the critical density of dangling bonds are new concepts that can be broadly applied in the fields of aerospace and rapid-transit production engineering.

Partially reacted mixtures of Pb(ZrxTi1−x)O3 and its corresponding starting oxide components were obtained by a high-energy ball milling process. The partially reacted powders were characterized by x-ray diffraction and scanning electron microscopy techniques. The sintering behavior of the milled mixtures has demonstrated a distinct volumetric expansion before the densification of the samples, which clearly shows the occurrence of a reactive sintering process of the partially reacted powders. Such process requires a lower densification temperature as compared with the PZT powders produced by the conventional solid-state reaction process. PZT ceramics were found to form directly from the partially reacted powders sintered at 900–1200 °C. The dielectric and ferroelectric properties of the PZT ceramics as a function of sintering temperature and milling time were also studied and discussed.

PbS-coated CdS nanocomposite particles were synthesized by an ion displacement method in an inverse microemulsion. Their growth kinetics were studied with UV–vis spectroscopy. Transmission electron microscopic characterization shows that PbS-coated CdS particles are uniform in size with a mean diameter of 6 nm. The electron diffraction patterns demonstrate their crystalline nature. Third-order nonlinear optical properties in the samples were investigated using the Z-scan technique with femtosecond laser pulses at 780-nm wavelength. The nonlinear refractive index of PbS-coated CdS nanocomposite particles in microemulsion varied with the molar ratio of Cd/Pb ions and reached a maximum of 5.3 × 10−12 cm2/GW for the sample with a Cd/Pb ion ratio of 1 to 2. The observed large refractive nonlinearity in these nanocomposite particles may be attributed to the optical Stark effect and strong interfacial and inter-nanoparticle interactions.

Microchemistry and mechanical properties of a copper/tin–bismuth Pb-free solder interconnect were examined in the as-reflowed and aged conditions by in situ Auger fracture and interface fracture mechanics techniques. In the as-reflowed condition, the solder–copper interface was highly resistant to fracture, and the fracture mechanism was ductile with the crack path following the interface between the solder alloy and the copper–tin intermetallic phase. Upon thermal aging, bismuth segregation was found to occur on the copper–intermetallic interface. Auger depth profiling indicated that the segregation was confined to about one monolayer from the interface. The segregation was shown to embrittle the interface, resulting in an approximately 5-fold decrease in the interfacial fracture resistance.

The present work shows how data obtained in a depth-sensing indentation test using a Knoop indenter may be analyzed to provide elastic modulus and hardness of the specimen material. The method takes into account the elastic recovery along the direction of the short axis of the residual impression as the indenter is removed. If elastic recovery is not accounted for, the elastic modulus and hardness are overestimated by an amount that depends on the ratio of E/H of the specimen material. The new method of analysis expresses the elastic recovery of the short diagonal of the residual impression into an equivalent face angle for one side of the Knoop indenter. Conventional methods of analysis using this corrected angle provide results for modulus and hardness that are consistent with those obtained with other types of indenters.

Conducting polymers are required for applications such as radio frequency interference shielding, primerless electrostatic painting, and static discharge. We have used vapor-grown carbon fiber (VGCF) as an additive to investigate conducting thermoplastics for these applications. The electrical properties of VGCF/polypropylene (PP) and VGCF/nylon composites are very attractive compared with those provided by other conventional conducting additives. Because of the low diameter of the VGCF used, the onset of conductivity (percolation threshold) can be below 3 vol%. Because of the highly conductive nature of the fibers, particularly after a graphitization step, the composites can reach resistivities as low as 0.15 Ω cm.