Titanium oxide nanotubes were fabricated by anodic oxidation of a pure titanium sheet in an aqueous solution containing 0.5 to 3.5 wt% hydrofluoric acid. These tubes are well aligned and organized into high-density uniform arrays. While the tops of the tubes are open, the bottoms of the tubes are closed, forming a barrier layer structure similar to that of porous alumina. The average tube diameter, ranging in size from 25 to 65 nm, was found to increase with increasing anodizing voltage, while the length of the tube was found independent of anodization time. A possible growth mechanism is presented.

Most organosilicate glass (OSG), low dielectric constant (low-κ) films contain Si–R groups, where R is an organic moiety such as −CH3. The organic component is susceptible to the chemically reactive plasmas used to deposit cap layers, etch patterns, and ash photoresist. This study compares a spin-on, mesoporous OSG film with a completely connected pore structure to both its nonmesoporous counterpart and to another low-density OSG film deposited by plasma-enhanced chemical vapor deposition. The results show that the film with connected pores was much more susceptible to integration damage than were the nonmesoporous OSG films.

The inability to rapidly grow thick or multilayer epitaxial films for either electronic or electrical power applications limits the utility of fluoride-based processes for YBa2Cu3O7−δ (YBCO). This problem is due to the use of water vapor in the growth process, necessary for the dissociation of metallofluorides. Flowing wet gas at low temperatures is corrosive to cuprates and responsible for destroying underlying YBCO layers in attempts to grow secondary layers. This is avoided simply by increasing the temperature where vapor is introduced into the growth ambient. Resulting two-layer films of YBCO have properties similar to those of high critical current density single-layer films.

Effects of Ba filling fraction and Ni content on the thermoelectric properties of n-type BayNixCo4−xSb12 (x = 0−0.1, y = 0−0.4) were investigated at temperature range of 300 to 900 K. Thermal conductivity decreased with increasing Ba filling fraction and temperature. When y was fixed at 0.3, thermal conductivity decreased with increasing Ni content and reached a minimum value at about x = 0.05. Lattice thermal conductivity decreased with increasing Ni content, monotonously (y ≤ 0.1). Electron concentration and electrical conductivity increased with increasing Ba filling fraction and Ni content. Seebeck coefficient increased with increasing temperature and decreased with increasing Ba filling fraction and Ni content. The maximum ZT value of 1.25 was obtained at about 900 K for n-type Ba0.3Ni0.05Co3.95Sb12.

Cross sections through nanoindents on Si, Ge, and GaAs {001} were examined through transmission electron microscopy. A focused ion beam workstation was used to machine electron transparent windows through the indents. In both Si and Ge there was a transformed zone immediately under the indent composed of amorphous material and a mixture of face-centered-cubic and body-centered cubic crystals. Cracking and dislocation generation were also observed around the transformed zone. In GaAs the dominant deformation mechanism was twinning on the {11} planes. The hardness of these materials is discussed in light of these observations and their macroscopic material properties such as phase transformation pressure.

Deposition of highly textured diamond films on Si(001) has been achieved by using positively bias-enhanced nucleation in microwave plasma chemical vapor deposition. During the biasing period, an additional glow discharge due to the dc plasma effect appeared between the electrode and the substrate. The discharge is necessary for enhanced nucleation of diamond. X-ray diffraction, scanning electron microscopy, and cross-sectional transmission electron microscopy (XTEM) were used to characterize the microstructure of the diamond films on Si. The results show the morphology of diamond grains in square shape with strong diamond (001) texture. XTEM reveals that an amorphous interlayer formed on the smooth Si surface before diamond nucleation.

A simple method is presented for measuring the characteristic spacing between striation defects that sometimes develop when coatings are deposited by the spin-coating process. Striation defects, because of their substantial regularity of thickness variation, are able to diffract laser light. By measuring the diffraction angle, it is possible to determine a characteristic spacing that corresponds to the most dominant spatial frequency for the striation defects that have formed. This diffraction technique is compared with other methods for determining the average striation spacing. This noncontact characterization technique may also be applicable to other regularly or quasi-regularly spaced defect structures that appear in coatings or other materials. The limits and accuracy of this technique are discussed in detail.

Nanorods Bi3Se4 were synthesized directly through the reaction between BiCl3 and elemental selenium in an autoclave with hydrazine hydrate as solvent at 165 °C for 10 h. X-ray powder diffraction patterns, x-ray photoelectron spectra, and transmission electron microscope images show that the products are well-crystallized hexagonal Bi3Se4 nanorods. The solvent hydrazine hydrate played an important role in formation and growth of Bi3Se4 nanorods. The possible reaction mechanism was proposed.

A series of carbon coatings was deposited on a 1040 SiC monofilament using chemical vapor deposition, and failure of the fiber-matrix interfacial region under transverse tension was studied. Deposition substrate temperatures were approximately 920, 1000, and 1080 °C, and all other deposition parameters were held constant. The microstructures of these carbon-coated fibers were examined using optical microscopy, scanning electron microscopy, and transmission electron microscopy (TEM). TEM observations were made using bright-field imaging, dark-field imaging, selected-area diffraction, and high-resolution lattice imaging. Tensile testing of single-fiber composite samples was performed transverse to the fiber axis to determine the stress required to cause debonding of the fiber from the titanium alloy matrix. Adhesion experiments were used to examine differences in bond strength of the SiC–C interfaces of the three coatings. A systematic increase in the grain size of the SiC substrate fiber within 3 μm of the SiC–C interface with increasing deposition temperature was observed. The crystallographic texturing of the basic structural units of carbon within the coatings was also found to increase with increasing deposition temperature. The SiC–C interface strength increased with increasing deposition temperature and correlates with the microstructural changes in both the SiC and carbon at the interface. The overall composite transverse strength was not affected by the change in deposition temperature, although the fracture location was affected. The carbon coating with the lowest SiC–C interface strength failed at this interface, and the coatings with more highly textured carbon failed within the coating, where the proportion of weak van der Waals bonds parallel to the tensile direction was correspondingly higher.

Nanoindentation combined with atomic force microscopy was applied to measure the fracture toughness of polystyrene/glass interfaces. Film delamination occurs when the inelastic penetration depth approximately equals or exceeds the film thickness. The delamination size was accurately measured using atomic force microscopy. Using multilayer indentation and annular-plate analyses, the interfacial fracture toughness was then assessed. The values obtained from the two analyses are in good agreement with the fracture toughness of the interface being approximately 350 mJ/m2. By appropriate fracture surface characterization, it was shown that fracture occurs along the polystyrene/glass interface. Crack arrest marks were observed, and their possible cause discussed. On the basis of the morphology of the fracture surface, the fracture toughness was also evaluated using a process zone analysis. The result agrees well with those obtained from the other two analyses.

The transformation behavior from glassy state was investigated in Zr- and Hf-based glassy alloys. The primary phases are metastable face-centered-cubic (fcc) Zr2Ni and fcc Hf2Ni phases in the Zr65Al7.5Ni10Cu17.5 and Hf65Al7.5Ni10Cu17.5 glassy alloys, respectively. By substitution of 5 at.% Pd for Cu, the primary phase changes to an icosahedral quasicrystalline phase in both alloys. It is found that the addition of elements, which have a positive or weak chemical affinity with one of the constitutional elements in the Zr–Al–Ni–Cu and Hf–Al–Ni–Cu glassy alloys, is effective for the precipitation of the icosahedral phase. It is suggested that Pd plays a dominant role in an increase in the number of nucleation sites. Since an icosahedron is contained as a structure unit in the icosahedral, fcc Zr2Ni and fcc Hf2Ni phases, it is implied that these phases are correlated with the local icosahedral order. The high-resolution transmission electron microscopy images of the as-spun Zr65Al7.5Ni10Cu7.5Pd10 and Hf65Al7.5Ni10Cu12.5Pd5 alloys reveal a possibility of the existence of the icosahedral ordered regions. It is therefore, concluded that the icosahedral short- or medium-range order exists and it stabilizes the glassy state in the Zr- and Hf-based multicomponent alloys.

Activated milled mesophase carbon fibers (AC-mMPCF, MP-series) show a higher specific capacitance in spite of a smaller specific surface area than those of powder-type activated carbons (AC-series). This phenomenon can be interpreted to mean that it is difficult to predict the capacitance of an electric double-layer capacitor (EDLC) knowing just the surface area and the pore size. More information is needed about other inherent characteristics of the samples, for example, the equivalent series resistance (ESR), shape of the pores, etc. We investigate here other characteristics of the samples. Consequently, it was deduced that the MP-series of EDLCs have a slit pore shape, which affects the accessibility of the electrolyte ion onto the electrode surface. Moreover, the MP-series of materials have suitable ESR values, and these material properties themselves should be considered as factors that affects the deterioration of the specific capacitance of EDLCs.

A hydrothermal route was proposed to prepare and control nanocrystalline silver indium sulfides (orthorhombic AgInS2, tetragonal AgInS2, and cubic AgIn5S8). The reaction was carried out in an autoclave in the temperature range of 100–280 °C with AgCl, InCl3, and thiourea as reactants. X-ray powder diffraction patterns and transmission electron microscopy images showed that the products were AgInS2 and AgIn5S8 phases and well crystallized with grain diameter in the range of 20–70 nm. X-ray photoelectron spectra of the single AgIn5S8 phase revealed the surface stoichiometry (AgIn5.05S8.11), and its room temperature Raman spectrum showed a strong peak at 130 cm−1 and a weak peak at around 290 cm−1. The influence of reaction temperature on the phases in the final products was investigated. A possible reaction mechanism of the formation of silver indium sulfides was also briefly discussed.

The interconnected porosity of the Cr3C2–NiCr coatings obtained by high-velocity oxy fuel spraying is detrimental in corrosion and wear resistance applications. Laser treatments allow sealing of their surfaces through melting and resolidification of a thin superficial layer. A Nd:YAG laser beam was used to irradiate Cr3C2–NiCr coatings either in the continuous wave mode or at different repetition rates in the pulsed one. Results indicated that high peak and low mean laser irradiances are not good, since samples presented deep grooves and an extensive crack network. At low peak and higher mean laser irradiances the surface was molten, and only a few shallow cracks were observed. The interconnected porosity was completely eliminated in a layer up to 80 μm thick, formed by large Cr7C3 grains imbedded in a NiCr matrix.

Zinc oxide preferentially crystallizes into a wurzite structure and has a unique set of properties. There have been numerous studies on doped zinc oxide thin films as an optical coating or as a semiconductor material. However, very little work has been reported on its tribological properties. Recent reports from this laboratory revealed that ZnO has good potential for controlling friction and wear. ZnO has an open structure and favorable coordination number, which permits zinc to freely move to different positions in the crystal lattice and to accommodate external atoms as substitutes. The nature of the substitution and the concentration of Zn interstitials may be used to control tribological performance. In this work, thin films of zinc oxide were deposited by pulsed laser ablation while silicon was added simultaneously by magnetron sputtering. The effects of deposition geometry and oxygen partial pressure on stoichiometry and microstructure were evaluated. It was found that the angle of deposition and oxygen partial pressure control coating texture. Depositions normal to the sample surface, along with 10 mtorr of oxygen, produced strong (002) texture. These conditions were selected for Si-doping studies. The tribological characteristics of Si-doped coatings were evaluated at both room and high temperature. Addition of Si around 7–8% gave a coefficient of friction of about 0.2 at 300 °C, decreasing to 0.13 around 500 °C.

By introduction of the chemical effects of fluorine, thick cubic boron nitride (cBN) films with high phase purity and low residual stress were synthesized on silicon substrates by dc-bias-assisted dc jet chemical vapor deposition in an Ar–N2–BF3–H2 system. In this paper, the characterization of the films by scanning electron microscopy, glancing-angle x-ray diffraction, infrared spectroscopy, and Raman spectroscopy was done. Among these techniques, Raman spectroscopy was intensively studied, and a method was established to evaluate the crystallinity and residual stress of the cBN films from the line width and peak shift of Raman charactersitic peaks. The influences of the experimental parameters, i.e., bias voltage, substrate temperature, and deposition time, on the film quality were systematically studied. An experimental window for the deposition of cBN films was described. The cBN films deposited under optimized conditions showed the similar line width of both Raman TO and LO modes and thus a crystallinity comparable to that of 4–8-μm cBN single crystals synthesized by high-ressure and high-temperature methods.

We studied the microstructure of SrTiO3/SrRuO3 bilayer films on (001) LaAlO3 substrates by high-resolution transmission electron microscopy. At the SrRuO3/LaAlO3 interface a defect configuration of stacking faults and nanotwins bounding either Frank partial dislocations or Shockley partial dislocations and complex interaction between these planar defects were found to be the dominant means of misfit accommodation. The misfit in the SrTiO3/SrRuO3 system, however, is mainly accommodated by elastic strain. Most of the observed defects in the SrTiO3 layer can be related to the [111] planar defects in the SrRuO3 layer propagating and reaching the SrTiO3/SrRuO3 interface. Furthermore, a [110] planar defect can also be introduced in the SrTiO3 layer due to the structure change of the SrTiO3/SrRuO3 interface.

Grain growth in nanocrystalline (nc) Al with a grain size of 26 nm produced by cryogenic mechanical milling was studied through x-ray diffraction, transmission electron microscopy, and differential scanning calorimetry. Grain growth kinetics resembled those of ball-milled nc Fe. For homologous temperatures (T/TM) of 0.51–0.83, the time exponent n from D1/n − D01/n = kt was 0.04–0.28, tending toward 0.5 as T/TM increased. Two grain-growth regimes were distinguished: below T/TM = 0.78 growth ceased at an approximate grain size of 50 nm while at higher temperatures, grain growth proceeded steadily to the submicrometer range. Grain growth over the range of temperatures studied cannot be explained in terms of a single thermally activated rate process. The observed high grain size stability was attributed primarily to impurity pinning drag associated with the grain growth process.

The superfine Fe–B–Si–Mo and Fe–B–Zr–Nb alloys were prepared by liquidus casting in which the levitation melting combining with the rapid solidification was used. The melt was poured into a copper mold at various temperatures, and a superfine granular microstructure was obtained at liquidus temperature. The behavior of Cu and Ag addition to Fe–B–Si–Mo and Fe–B–Zr–Nb alloys was studied. Both adding Cu and Ag to Fe–B–Si–Mo and Fe–B–Zr–Nb alloys had influence on refining the alloys. The refinement effect of adding Cu is stronger than that of adding Ag in Fe–B–Zr–Nb alloy.

Raman and infrared measurements of the LiB3O5 (LBO) crystals were completed. The experimental results shown here are more and stronger Raman lines and infrared absorption peaks, which implies that the external vibrations of the trigonal (BO3)3− and tetrahedral (BO4)5− ions, especially the former, in the six-membered boron–oxygen rings at the low wave number are strong and the internal vibrations of the (BO4)5− ions above 200 cm−1 are stronger than those of the (BO3)3− ions if compared with the Raman spectra of BaB2O4 crystals. These are caused due to the slope and distortions of the B3O7 rings and their BO3 and BO4 units in LBO, which change the structural rigidity of the crystals, intensify the long-range electrostatic force and short-range molecular force, and shorten the ultraviolet absorption edge.