Thin films with a nominal composition close to Ti62.5Si37.5 were deposited on NaCl substrate at room temperature by pulsed laser ablation to study the evolution of the intermetallic compound Ti5Si3 using a combination of high-resolution and in situ transmission electron microscopy. The as-deposited amorphous films contain Ti-rich clusters, which influence the phase evolution and the decomposition behavior of the amorphous film. These clusters influence the nucleation of a metastable fcc Ti solid solution (ao = 0.433 nm) with composition richer in Ti than Ti62.5Si37.5 as the first phase to crystallize at 773 K. The Ti5Si3 nanocrystals form later, and even at 1073 K they coexist with fine fcc Ti-rich nanocrystals. Subsequent Ar+ ion-milling of the crystallized film results in a loss of silicon. The composition change leads to the dissolution of the Ti5Si3 nanocrystals and evolution of a new metastable Ti-rich fcc phase (ao= 0.408 nm).

Diamond-like carbon films were synthesized by electro-deposition technique from an organic liquid (a solution of alpha- and beta-pinenes in n-hexane) on silicon substrate at room temperature and at room pressure. The x-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectra, Raman spectra, photoluminescence (PL), and x-ray absorption near edge structure (XANES) spectra analysis were used to study the properties of the diamond-like carbon (as-deposited and annealed) films. The XRD measurement indicated that the film contains some diamond-crystalline phases whereas Raman spectra did not show any prominent diamond-like peak. PL intensity as higher for the as-deposited film and decreased with high-temperature vacuum annealing. FTIR spectra showed the presence of sp3 hybridization C–H bonds and their intensity decreases at higher annealing temperature. C and O K-edge XANES spectra showed that π* (sp2) intensity significantly decreases when the annealing temperature is 600 °C.

The synthesis behavior of mullite in an aqueous system was investigated. Two kinds of aluminosilicate precursor sols were prepared by the dissolution of two kinds of salt (aluminum chloride hexahydrate, AlCl3·6H2O, and aluminum sulfate with 14–18 molecules of water, Al2[SO4]3·14–18H2O) into the mixture of colloidal silica sol. The effects of the solution pH, which was controlled by addition of ammonium hydroxide (NH4OH), and the type of aluminum salt on the mullite crystallization and the grain size and morphology in the sintered materials are discussed in this paper. It has been discovered that in an aqueous system, the mullitization temperature strongly depends on the solubility and decomposition temperature of the aluminum salt used and that the pH of the initial sol impacts the grain size and morphology of mullite, in addition to the homogeneity of mixture. Mullite is synthesized at 850 °C without resorting to the addition of an organic additive or nonaqueous solvent.

We report for the first time on load versus depth-of-indentation response of Ti3SiC2 surfaces loaded with a 13.5 μm spherical tipped diamond indenter up to loads of 500 mN. Using orientation imaging microscopy, two groups of crystals were identified; one in which the basal planes were parallel to, and the other normal to, the surface. When the load-penetration depth curves were converted to stress-strain curves the following was apparent: when the surfaces were loaded normal to the c axis, the response at the lowest loads was linear elastic—well described by a modulus of 320 GPa—followed by a clear yield point at approximately 4.5 GPa. And while the first cycle was slightly open, the next 4 on the same location were significantly harder, almost indistinguishable, and fully reversible. At the highest loads (500 mN) pop-ins due to delaminations between basal planes were observed. When pop-ins were not observed the indentations, for the most part, left no trace. When the load was applied parallel to the c axis, the initial response was again linear elastic (modulus of 320 GPa) followed by a yield point of approximately 4 GPa. Here again significant hardening was observed between the first and subsequent cycles. Each cycle resulted in some strain, but no concomitant increase in yield points. This orientation was even more damage tolerant than the orthogonal direction. This response was attributed to the formation of incipient kink bands that lead to the formation of regular kink bands. Remarkably, these dislocation-based mechanisms allow repeated loading of Ti3SiC2 without damage, while dissipating significant amounts of energy per unit volume, Wd, during each cycle. The values of Wd measured herein were in excellent agreement with corresponding measurements in simple compression tests reported earlier, confirming that the same mechanisms continue to operate even at the high (≈9 GPa) stress levels typical of the indentation experiments.

Oxides and silicates of zirconium and hafnium are actively being considered and tested to replace SiO2 as the gate material. Though these materials have the high-dielectric constant (k ∼ 20–25) needed to provide a larger equivalent oxide thickness, they are very refractory and difficult to etch by wet and dry methods. In this paper, work done on wet etching of ZrO2, HfO2, and HfSixOy in dilute hydrofluoric acid (HF) solutions is presented and discussed. Experiments were done on various high-k films deposited by metalorganic chemical vapor deposition. It was found that the as-deposited high-k films can be dissolved with a good selectivity over SiO2 in dilute HF solutions, but heat-treated high-k films are difficult to etch with good selectivity over SiO2 under the same conditions.

The reactivity of AlN powder in an aqueous environment was studied by measuring the pH and the temperature during the hydrolysis of the powder at room and elevated temperatures. The influences of the powder concentration and the starting pH of the slurry were also investigated. The results of the measurements at room temperature show that there is an incubation time before the start of the AlN hydrolysis reactions. Once this incubation time is over, the pH and the temperature of the slurry start to increase, indicating the onset of the reactions. A higher starting temperature not only speeds up the reaction of the AlN powder with water, but it also shortens the incubation time. In addition, the starting temperature influences the morphology of the reaction product: at temperatures below 60 °C, the final product of the hydrolysis is crystalline Al(OH)3, whereas at higher temperatures (above 60 °C), crystalline AlOOH is formed. At very low pH values (pH = 1), the reaction of AlN powder with water is prevented (i.e., the incubation time is very long), whereas in an alkaline environment, the incubation time is approximately the same as in distilled water, but the reaction is accelerated.

A solid composite of desirable microstructure can be produced by curing a liquid polymeric suspension in an electric field. Redistribution effect of the field-induced forces exceeds that of centrifugation, which is frequently employed to manufacture functionally graded materials. Moreover, unlike centrifugational sedimentation, the current approach can electrically rearrange the inclusions in targeted areas. The electric field can be employed to produce a composite having uniformly oriented structure or only modify the material in selected regions. Field-aided technology enables polymeric composites to be locally micro-tailored for a given application. Moreover, materials of literally any composition can be manipulated. In this article we present testing results for compositions of graphite and ceramic particles as well as glass fibers in epoxy. Electrical and rheological interactions of inclusions in a liquid epoxy are discussed. Measurements of tensile modulus and ultimate strength of epoxy composites having different microstructure of 10 vol% graphite, ceramic particles and glass fiber are presented.

The diffusion behavior of elements constituting Hastelloy C-276 (C, Si, Mn, Co, W, Fe, Cr, Mo, and Ni) in alumina films was investigated using secondary ion mass spectroscopy. The films were deposited by ion-beam-assisted deposition and annealed in vacuum over a temperature range of 500–1000 °C. Characterization of film microstructure was performed using transmission electron microscopy and selected area diffraction analyses. The films were predominantly amorphous with alumina nanocrystallites nonuniformly dispersed throughout the volume both before and after annealing. A relatively wide interface region between the Hastelloy substrate and alumina film was formed in the as-deposited sample due to ion beam mixing. No diffusion of any of the substrate elements was observed after annealing, except for Mn, Cr, and Ni. The impurity depth distributions consisted of two components, which differed by several orders of magnitude with respect to diffusion coefficient and solubility. Activation energies and temperature dependencies of the diffusion coefficients were determined, and a diffusion mechanism was discussed.

For an interface to be considered thermodynamically stable, the phases in contact must be in equilibrium with each other (connected by a stable tie-line) and have negligible mutual solubility on the phase diagram. The stability of Co based magnetic tunnel junctions (MTJs), with Co/MxO1-x/Co structures (M = Al, Gd, Hf, La, Mg, Si, Ti, Ta, Y and Zr), were evaluated with regard to these two conditions. Specifically, low temperature ternary isothermal phase diagrams were calculated and evaluated for the Co–M–O systems. All of these systems have at least one oxide in equilibrium with Co and thus have at least one thermodynamically stable tunnel barrier candidate for use in Co based MTJs. In light of the assumptions made in this analysis, along with the uncertainty in applying bulk enthalpy data to thin films, the current evaluation of interfacial stability serves as a first step in identifying suitable stable tunneling barrier materials in MTJs for detailed study.

We developed an Al2O3 and Al3Ni intermetallic reinforced Al-based metal matrix composite by sintering an Al-20 wt% NiO powder compact at 1000 °C. Differential thermal analysis showed that a two-step reaction took place between Al and NiO in the temperature range 600–650 °C. The initial stage was a solid-state reaction, but it was soon paused by the newly formed Al2O3 and Al3Ni phases that separated the Al and NiO grains. A liquid–solid reaction was later resumed as the temperature was increased above the eutectic temperature of Al–Al3Ni at 640 °C when molten Al–Ni appeared. When the molten sample was quenched to room temperature, a two-phase Al–Al3Ni eutectic was found in the sample. In comparison with the air-quenched and the oil-quenched samples, the sizes of proeutectic Al3Ni grains and Al–Al3Ni eutectic phases in the salt-solution-quenched sample were much finer. The eutectic contained Al3Ni nanofibers with a diameter of approximately 50 nm. A reaction model of Al and NiO was proposed. A thermodynamic model was also proposed to describe the formation of the composite.

Interfacial oxygen diffusion from high-permittivity gate dielectrics (ZrO2 and HfO2) into Si substrates in ultra-large-scale integrated circuits must be suppressed to prevent the formation of interfacial layers between the gate dielectrics and the Si substrates. Oxygen diffusion was analyzed by using a molecular dynamics technique that includes many-body interactions and charge transfer between different elements. The analysis results showed that the addition of Ti is effective in suppressing interfacial oxygen diffusion. The results also showed that the diffusion at the ZrO2/Si(111) and HfO2/Si(111) interfaces is much more suppressed than the diffusion at the ZrO2/Si(001) and HfO2/Si(001) interfaces.

Yb3+-doped single-crystal Ca3Y2(BO3)4 with dimension φ20 × 55 mm was grown by the Czochralski method. The structure of it was determined by x-ray diffraction. It belongs to the orthorhombic system, space group Pnma, with the following parameters: a= 7.1690(4), b = 15.4758(8), c = 8.5587(6) Å, V = 949.55(10)Å3, Mr = 537.51, Z = 2, Dc = 3.8 g/cm3, (MoKa) = 0.71073 Å, F(000) = 508, μ = 6.927 mm-1, final R = 0.0670, and wR = 0.1542 for 2975 independent reflections. The structure of Yb:Ca3Y2(BO3)4 is made up of three set of M-oxygen distorted polyhedrons, and three set of BO3 planar triangles. Ca2+ and Y3+ ions occupy three M sites statistically. Yb3+ ions substitute Y3+ ions to enter these three lattices. The adsorption and emission spectra were measured. It exhibits a broad absorption band ranging from 850 to 1000 nm in the absorption spectrum, which is well matched with the emission wavelength of a laser diode. A broad emission spectrum ranging from 927.95 to 1102.7 nm was observed under the excitation of 895 nm.

Monodisperse and uniform γ-Fe2O3 (maghemite) nanocrystals of variable size were prepared by thermal decomposition of iron pentacarbonyl [Fe(CO)5] in the presence of surfactants, following controlled oxidation with trimethylamine N-oxide as a mild oxidant. The influence of carboxylic acids with variable alkyl carbon chain lengths on the synthesis of γ-Fe2O3 nanocrystals was investigated. The effect of the molar ratios of surfactant to iron precursor was also studied. The nanocrystals were characterized by x-ray diffraction (XRD) and transmission electron microscopy (TEM). XRD showed the particles were highly crystalline at the nanometer scale. The results showed that the size and shape of the nanocrystal is strongly influenced by the decomposition temperature of iron pentacarbonyl and closely related to the length of carbon chain of the capping groups and the molar ratio of surfactant to iron precursor. Following controlled evaporation from nonpolar solvents, self-assembly into two-dimensional arrays could be observed by TEM. It was also found that the distance between the nanocrystals in self-assembled structures matched the length of the capping molecules very well.

The development and relaxation of stress in metal interconnects strained by their surroundings (substrate and passivation layers) is predicted by a discrete dislocation analysis. The model is based on a two-dimensional plane strain formulation, with deformation fully constrained in the line direction. Plastic deformation occurs by glide of edge dislocations on three slip systems in the single-crystal line. The substrate and passivation layers are treated as elastic materials and therefore impenetrable for the dislocations. Results of the simulations show the dependence of the stress evolution and of the effectiveness of plastic relaxation on the geometry of the line. The dependence of stress development on line aspect ratio, line size, slip plane orientation, pitch length, and passivation layer thickness are explored.

Hydrophilic Co–Pt alloy nanoparticles nearing the equiatomic ratio and dispersedin water-soluble sodium carboxymethyl cellulose were synthesized by the aqueous reduction of CoCl2⋅6H2O and [Pt(NH3)4]Cl2⋅H2O with NaBH4 in presence of the cellulosic derivative. The as-received Co–Pt nanoparticles in the cellulosic matrix possess a disordered fcc structure that, upon calcination under an Ar atmosphereand carbonization of the cellulosic mantle of the particles, transformed to an ordered fcc phase. Both as-synthesized and calcined samples are magnetically soft at room temperature and exhibit a strong magnetic response when a magnetic field is applied. On account of the chemical composition of the carboxymethyl cellulose, the coated Co–Pt nanoparticles are easily soluble in water in high concentrations and exhibit interesting ion-exchange properties.

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 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.

Ni-Ti surface alloy was prepared by ion-implanting Ni into Ti. The surface film was amorphous having a Ni surface content of 10–40 at.%. The material was compared with a Ni-Ti bulk alloy (44.08:55.9) regarding their redox and electrocatalytic behavior in NaOH by cyclic voltammetry. The surface was characterized by x-ray photoelectron spectroscopy, x-ray and electron diffraction, transmission electron microscopy, and atomic force microscopy. The ion-implanted material revealed an enhanced activity toward the redox conversion of Ni(OH)2 ↔ NiOOH and the anodic oxidation of glucose. The effect is discussed considering the enhanced generation of active Ni surface sites from amorphous Ni and the stabilization of higher valence Ni by Ti.

The kinetics for the crystallization of amorphous Ni(P) films and the formation of intermetallic compounds in Sn/Ni(P) films during isothermal aging treatment were studied with in situ intrinsic stress measurements. The intrinsic stress changes from crystallization were about 200 and 150 MPa for Ni(14P) and Ni(11.7P) films, respectively, and according to Johnson–Mehl–Avrami analysis, the Avrami exponents were about 3.6 ± 0.46 and 4.2 ± 0.39, and the activation energies were 242 and240 kJ/mol, respectively, for the crystallization of Ni(14P) and Ni(11.7P) films. The stress due to the formation of intermetallic compounds such as Ni3Sn4 and Ni3P in Sn/Ni(11.7P) films was about 320 MPa. Application of in situ stress measurementsto the empirical growth model during isothermal phase transformation of Sn/Ni(P) showed that the intermetallic compounds growth was interface reaction-controlled (n = 0.91 ± 0.08) in the early stage and then became diffusion-controlled (n =0.38 ± 0.01), and the activation energy was about 35.9 kJ/mol.

We investigated the discrepancy between the significant 18O isotope motion observed after bipolar voltage cycling used to induce ferroelectric fatigue in unannealed Pt/Pb(Zr,Ti)O3/Ir (PZT) capacitors and the lack of any observable oxygen tracer motion in annealed capacitors. We found that while unannealed Pt electrodes are permeable to oxygen, annealed Pt electrodes are oxygen impermeable. Further, when the initial oxygen tracer profile does not vary strongly with depth, the ability to detect oxygen motion during fatigue voltage cycling depends critically on the oxygen permeability of the capacitor’s top electrode. Our results indicate that oxygen exchange between the PZT film and external oxygen sources and sinks during voltage cycling is not necessary for ferroelectric fatigue to be manifest. In addition, studies of the dependence of ferroelectric materials properties on ambient gases should be accompanied by analysis of the permeability of exposed surfaces to the gases of interest.