In this paper we report the fabrication of organic/inorganic film for optical secondharmonic generation by a sol-gel method for the purpose of the improvement of thermal stability and chemical resistance. The film contains the azo dye Disperse Orange 3 protected by poly(vinylpyrrolidone) in a reticulation of silica gel, whose structure was developed by the spinodal decomposition and the gel-forming process as temperature increased. Corona-poling at elevated temperature could successively induce the optical second-harmonic nonlinearities. The dependence of temperature and field strength on the second-harmonic intensity was also investigated.

The relationship between hardness and cone angle of conical indenters was studied using finite element analysis for elastic–plastic solids with work-hardening. Comparisons were made between the present simulation results, slip line theory, and experimental results. Tabor's concept of representative strain based on indentation experiments in metals (The Hardness of Metals, Oxford, 1951) was shown to be applicable to a wide range of materials. The relative size of plastic zone with respect to the contact radius was found to influence the variation of hardness with indenter cone angle. The method proposed by Atkins and Tabor [J. Mech. Phys. Solids, 13, 149 (1965)] for constructing stress-strain curves using representative strains was also examined, and the conditions under which the method is valid were obtained.

Effects of plasma power on the properties of polymerlike organic thin films deposited by plasma-enhanced chemical vapor deposition using the toluene precursor were studied. As the plasma power was increased from 5 to 60 W, the relative dielectric constant increased from 2.53 to 2.85. The film deposited at higher plasma power showed higher thermal stability. The film deposited at 60 W was stable up to 400 °C. All the films were insulating under applied field ≤1 MV/cm.

A composition-graded solid electrolyte (LaF3)y · (CaF2)1-y was used for the measurement of the standard Gibbs energy of formation of LaGaO3 from its component oxides. An equimolar mixture of CaO and CaF2 was employed as the reference electrode. The composition of the working electrode depended on temperature. A three-phase mixture of LaGaO3 + Ga2O3 + LaF3 was used in the temperature range from 910 to 1010 K, while a mixture of LaGaO3 + Ga2O3 + LaO1-xF1+2x was employed from 1010 to 1170 K. Both the reference and working electrodes were placed under pure oxygen gas. Because of the high activity of LaF3 at the working electrode, there was significant diffusion of LaF3 into CaF2. The composition-graded electrolyte was designed to minimize the electrode–electrolyte interaction. The concentration of LaF3 varied across the solid electrolyte; from y = 0 near the reference electrode to a maximum value y = 0.32 at the working electrode. For the correct interpretation of the electromotive force at T > 1010 K, it was necessary to use thermodynamic properties of the lanthanum oxyfluoride solid solution. The standard Gibbs energy of formation of LaGaO3 from its component oxides according to the reaction, ½La2O3 (A-rare earth) + ½Ga2O3 (b) → LaGaO3 (rhombohedral) can be represented by the equation: δGo f,(ox) /J mol -1 = –46 230 + 7.75 T/K (±1500).

The synthesis of AlN–SiC solid solutions from Si3N4, Al, and C was investigated using the induction-field-activated/self-propagating high-temperature synthesis/static pseudo-isostatic compaction technique. Careful x-ray diffraction analyses were made on the products of combustion to determine reaction routes. Optical microscopy as well as scanning electron microscopy with an electron probe microanalysis was used for microstructural analysis. It was found that initially molten aluminum reacted with silicon nitride producing an Al–Si alloy. At higher temperatures, aluminum evaporated from the Al–Si liquid and the synthesis of AlN via a vapor phase process took place. Subsequently, dissolution of AlN into molten Si resulted in the formation of an AlN–SiC solid solution from the Al–N–Si–C liquid phase. However, below 1850 °C, the resulting solid solution of 4AlN–3SiC was not fully crystallized. Combustion temperatures above or equal to 1850 °C were required to prepare a highly crystallized solid solution with a morphology exhibiting hexagonal platelets. Based on these observations, a model for the formation of AlN–SiC solid solution is proposed.

Thin films of polythiophene, a kind of polyheterocyclic compound with hydrogen function groups, were deposited by KrF excimer laser ablation of a compressed solid target in a vacuum chamber. The laser pulse fluence was approximately selected at 2 J/cm2 with a pulse duration of 25 ns. The structural, topographic, and electronic properties of the deposited thin films were analyzed by atomic force microscope, x-ray diffraction, and Raman and infrared spectroscopy measurements. Deposited thin films were observed to have good crystal properties and to be composed of crystalline cubes with a uniform size of 0.1 μm. The electronic structure of the deposited thin films should be different from the target materials, resulting from the laser irradiation effects. The influence of the deposition temperature on the structural and electronic properties of the deposited thin films was studied.

A silklike protein with fibronectin functionality (SLPF) (ProNectin F®, Protein Polymer Technologies, Inc.) is a genetically engineered protein polymer containing structural and biofunctional segments. The mechanical properties and deformation mechanisms of electrostatically deposited SLPF thin films were examined by scratch testing, tensile testing, and nanoindentation. Scanning electron microscopy and scanned probe microscopy revealed that the macroscopic properties were a sensitive function of microstructure. The SLPF films were relatively brittle in tension, with typical elongation-to-break values of 3%. Nanoindentation data were fit to a power law relationship.

A new route for obtaining calcium-deficient apatites with a Ca/P ratio lower than 1.5 is described, in order to study their proton conduction at temperatures lower than 400 °C. The process is based on the hydrolysis of a mixed solution of Ca(NO3)2 and NH4H2PO4 in the presence of hexamethylenetetramine at a pH of approximately 5 and temperatures of 85–90 °C. The resulting spherical particles of 14 μm in average diameter were aggregates of smaller needles with approximate composition Ca8.5(HPO4)2(PO4)4OH · H2O. The effects of the reagent concentrations, pH, aging time, and temperature were studied, and the solids were characterized by x-ray diffraction, infrared absorption spectroscopy, and electron microscopy. The ionic conduction measured by alternating-current impedance spectroscopy yielded a value of 3 μSm−1 at 200 °C.

The oxidative stability of poly(butylene terephthalate) was investigated over the range 175 to 220 °C by isothermal differential calorimetry. It is shown that this property is affected by a fast recrystallization process, which takes place between 200 and 220 °C, with a maximum around 208 °C. In fact, recrystallization produces an increase of the crystallinity degree of the polymer, which enhances its resistance to oxidation, as proven by the longer oxidation times detected.

Cement pastes containing short steel fibers, which contribute to electron conduction, exhibit positive values (up to 68 μV/°C) of the absolute thermoelectric power. Cement pastes containing short carbon fibers, which contribute to hole conduction while the cement matrix contributes to electron conduction, exhibit negative or slightly positive values of the absolute thermoelectric power. The hole and electron contributions in carbon fiber reinforced cement paste are equal at the percolation threshold. Addition of either steel or carbon fibers to cement paste yields more reversibility and linearity in the variation of the Seebeck voltage with temperature difference (up to 65 °C).

Ni(OH)2 nanoparticles modified with di-n-hexadecyldithiophosphate (DDP) were prepared by a chemical surface modification method. The structure of the nanocluster was investigated using infrared spectroscopy, x-ray photoelectron spectroscopy, x-ray diffraction, transmission electron microscopy, and 31P nuclear magnetic resonance spectroscopy. The thermal stability of DDP coating on the Ni(OH)2 nanoparticles was compared to that of pyridinium di-n-hexadecyldithiophosphate (PyDDP) using thermogravimetric analysis. It was found that coated Ni(OH)2 nanoparticles had an average diameter of about 5 nm. Surface modification with DDP prevented water adsorption and effectively improved the dispersive capacity and antioxidative stability of Ni(OH)2 nanoparticles. The thermal stability of DDP coatings on the surface of nano-Ni(OH)2 particles was higher than that of PyDDP coatings because of the chemical interaction between PyDDP and Ni(OH)2 during the coating process.

Am3+ and Eu3+ /alkali cation exchange selectivity was studied on mordenite and zeolite L at 25 to 60 °C to examine the effect of their openings of ion-exchange sites. The corrected selectivity coefficient at the infinitesimal exchange increased in the order of Eu3+ < Am3+ on mordenite and Am3+ < Eu3+ on zeolite L. The selectivity reversal did not reflect the effect of the ionic form, but reflected the dimension of the opening of the ion-exchange site and charge of trivalent cations, since the crystal ionic radii of alkali cations were much smaller than the openings of these zeolites (7–8 Å).

Ni3Sn4 intermetallic was formed by the depletion of Ni from electroless Ni–P, and a Ni3P layer was formed simultaneously due to solder reaction-assisted crystallization during solder reflow. Both Ni3Sn4 and Ni3P grew rapidly due to the solder reaction-assisted crystallization and their growth was diffusion controlled during the first 15 min of annealing at 220 °C. After that, the growth rate of Ni3Sn4 was greatly reduced and the crystallization of electroless Ni–P to Ni3P was no longer induced. Based on kinetic data and scanning electron microscope morphology observations, underlying mechanisms causing this specific phenomenon are proposed. This finding is indeed very crucial since we may control the growth of Ni–Sn intermetallics by monitoring the solder reaction-assisted crystallization of electroless Ni–P.

Further experimental observations have allowed us to refine and confirm some aspects of our recently proposed mechanism for reactive diffusion between Si single crystal and NbC powder compact, particularly regarding the prediction of Si as the dominant diffusing species and the nature of the dependence of SiC particle morphology on the presence of voids in the NbC end member. In Si|NbC diffusion couples annealed at either 1300 or 1350 °C, a two-phase NbSi2 + SiC reaction layer formed. Although NbSi2 was the matrix in all of the reaction layers, the SiC phase morphology depended upon NbC porosity: when high-porosity NbC was used, SiC was present as discontinuous particles greater than 1-μm-across, while when low-porosity or void-free NbC was used, SiC grew cooperatively with NbSi2 in the form of lamellae less than 0.5 μm thick. We propose that this difference arises from the effect of voids both as nucleation sites for SiC particles and as channels for unrestricted SiC growth. Marker experiments conclusively show that Si is the dominant diffusing species in the reaction layer.

In this article we report the influence of surface oxides and relative humidity on the nanomechanical response of hydrophobic and hydrophilic Si surfaces. Depth-sensing nanoindentation combined with force modulation enabled measurement of surface forces, surface energy, and interaction stiffness prior to contact. Several regimes of contact were investigated: pre-contact, apparent contact, elastic contact, and elasto-plastic contact. Both humidity and surface preparation influenced the surface mechanical properties in the pre- and apparent-contact regimes. Meniscus formation was observed for both hydrophobic and hydrophilic surfaces at high humidity. Influence of humidity was much less pronounced on hydrophobic surfaces and was fully reversible. In the elastic and elasto-plastic regimes, the mechanical response was dependent on oxide layer thickness. Irreversibility at small loads (300 nN) was due to the deformation of the surface oxide. Above 1 μN, the deformation was elastic until the mean contact pressure reached 11 GPa, whereby Si underwent a pressure-induced phase transformation resulting in oxide layer pop-in and breakthrough. The critical load required for pop-in was dependent on oxide thickness and tip radius. For thicker oxide layers, substrate influence was reduced and plastic deformation occurred within the oxide film itself without pop-in. Elastic modulus and hardness of both the oxide layer and Si substrate were measured quantitatively for depths <5 nm.

Cordierite glass-ceramic coatings do not bond to molybdenum directly because of the absence of a suitable transition layer. Dual metallic interlayers of copper/chromium and nickel/chromium were electroplated on the substrates to enhance adhesion. The adhesion of the glass-ceramic coatings was evaluated by indentation testing and a modified analytical method based on interfacial fracture toughness. Quantitative chemical analyses of the interfaces were used to explain differences in fracture toughness among samples with different interlayers. Of those tested, the best interface for adhering glass-ceramic coatings to molybdenum was found to be a 4 μm chromium over 2 μm copper on molybdenum.

An understanding of the relationship between stress and the corresponding microstructure at various stages of thin film growth might allow prediction and control of both microstructure and film stress during thin film deposition. In the present study, a combination of in situ curvature measurement and ex situ microstructural characterization was used to make correlations between stress and microstructure for the growth of Pt on SiO2. Plan view transmission electron micrographs of Pt films with average thicknesses ranging from 3 to 35 Å show the evolution of microstructure from isolated islands to a coalesced film, in agreement with models for stress behavior during the early stages of film growth. Quantitative measurements of grain size, island size, and areal fraction covered are extracted from these micrographs and, in conjunction with an island coalescence model, used to calculate the magnitude of the tensile stresses generated during coalescence. The predicted curvature is shown to compare favorably with the measured stresses.

The effect of 1000 °C vacuum annealing on the structure and hardness of epitaxial Mo/NbN superlattice thin films was studied. The intensity of superlattice satellite peaks, measured by x-ray diffraction, decreased during annealing while new peaks corresponding to a MoNbN ternary phase appeared. The results are consistent with the Mo–Nb–N phase diagram, which shows no mutual solubility between Mo, NbN, and MoNbN. Even after 3-h anneals and a loss of most of the superlattice peak intensity, the room-temperature hardness was the same as for as-deposited superlattices. The retained hardness suggests that a residual nanocomposite structure is retained even after the formation of the ternary structure.

A study of the structural transformation of catalytically grown carbon nanotubes induced by annealing under high pressure is presented in this paper, in which the atomic details of the microstructural transformations have been monitored mainly with electron microscopy. The microstructural change from the multiwalled carbon nanotubes into a quasi-spherical onion becomes obvious just at 770 °C under 5.5 GPa. The nanotubes deform and almost transform into nanographite ribbons directly when the annealing temperature is above 950 °C under 5.5 GPa. It is suggested that the pressure and temperature play an important role in the structural transformations of multiwalled carbon nanotubes described here.

The structural changes of carbon nanotubes induced by high pressure and high temperature were investigated by means of x-ray diffraction, Raman scattering, scanning electron microscopy, and transmission electron microscopy. It is shown that, with increasing pressure and temperature, the lattice constant d002 of tubes shortens, and then tubes collapse into tapelike ones; at the same time the C–C bonds at high curvature break, which lead the tapelike tubes to break into graphite sheets as diamond crystallization centers. Compared with graphite, the diamond particles from carbon nanotubes have many defects as the trace of tubes.