Fe–40 at. % Al–0.1 at. % B specimens were polished flat, strained at room temperature, and examined in an atomic force microscope. The angles of height contours perpendicular to the slip lines were interpreted as shear strains and were statistically evaluated. The frequency distributions of these shear strains correlated well with the macroscopic strains. The maximum shear strains found were not much larger than the macroscopic strains. In particular, no steep slip steps corresponding to large local shears were found.

Aluminum ammonium sulfate (AA) solution (0.1 mol/l) and ammonium hydrogen carbonate (AHC) solution (1.2 mol/l) were allowed to react at room temperature. The precipitates formed were kept with the mother liquor in a closed vessel and aged at 100 °C. Acicular-shaped crystalline particles of Al(NH4)CO3(OH)2, (AACH), were obtained after the elongated aging period. Acicular α-alumina particles were obtained through the thermal decomposition at 1300 °C out of the AACH particles which were previously treated with a small amount of tetraethoxysilane (about 1.6 wt. % of SiO2).

Nanophase Ni particles (<10 nm in diameter) were produced by a blown arc method. A helium gas stream directed at the arc reduces the Ni vapor concentration and increases the quench rate. The helium gas velocity is the predominant factor influencing the size of the Ni particles. Gas velocities of 20 m/s and 56 m/s (at 26.6 kPa total helium pressure) resulted in Ni particle sizes of 13 nm and 7 nm, respectively.

We have used conventional and high-resolution transmission electron microscopy to investigate the microstruture of epitaxial, ferroelectric PbTiO3 films grown by pulsed laser ablation on (001) MgO single crystals, and on MgO covered with epitaxial Pt or SrTiO3. Pronounced variations are found in the widths and lengths of a-axis-oriented domains in these films, although the volume fraction of a-axis-oriented material varies only weakly for the different types of samples. In addition, the films deposited onto Pt-coated MgO have a larger grain size than those deposited onto bare MgO or SrTiO3/MgO. Possible reasons for the variations in the distribution of a-axis-oriented material in these samples include differences in the elastic properties and electrical conductivities of the different substrate combinations.

We report on extended x-ray absorption fine structure (EXAFS) measurements for partially heat-treated gels in the lead zirconate titanate system (PZT). Self-consistent results obtained from the titanium and zirconium K-edges and the lead LIll-edge were used to determine bonding pathways between cations. For lead titantate (PT) and PZT gels, separate networks of predominantly Ti-O-Ti, Zr-O-Zr, and Pb-O-Pb linkages were observed. For lead zirconate (PZ) gels, both Zr-O-Pb and Zr-O-Zr linkages were observed. The results indicate heterogeneity at the molecular level. These findings are discussed in terms of the evolution of structure for PZT materials prepared by our sol-gel method.

Highly conductive metal-oxide RuO2 thin films have been successfully grown on yttria-stabilized zirconia (YSZ) substrates by pulsed laser deposition. Epitaxial growth of RuO2 thin films on YSZ and the atomically sharp interface between the RuO2 and the YSZ substrate are clearly evident from cross-sectional transmission electron microscopy. A diagonal-type epitaxy of RuO2 on YSZ is confirmed from x-ray diffraction measurements. The crystalline RuO2 thin films, deposited at temperatures in the range of 500 °C to 700 °C, have a room-temperature resistivity of 35 ± 2 μω-cm, and the residual resistance ratio (R300 k/R4.2 k) is around 5 for the crystalline RuO2 thin films.

Titanium films were mixed, using excimer laser radiation, into the surface of bulk Si3N4 materials. The tribological and mechanical properties of these surfaces were then evaluated using pin-on-disk and nanoindenter techniques, respectively. Reduced friction and a change in the wear mechanism that resulted in a more benign failure mode were observed. These results are interpreted as resulting from the establishment of a transfer film, changes in the compliance of the surface which reduces instantaneous stresses in the surface, and toughening of the surface, all results of the laser process.

Diamond film was synthesized on thin Ti wafers (as thin as 40 μm) via hot filament chemical vapor deposition (HFCVD). The hydrogen embrittlement of the titanium substrate and the formation of a thick TiC interlayer were suppressed. A very low pressure (133 Pa) was employed to achieve high-density rapid nucleation and thus to suppress the formation of TiC. Oxygen was added to source gases to lower the growth temperature and therefore to slow down the hydrogenation of the thin Ti substrate. The role of the very low pressure during nucleation is discussed, providing insight into the nucleation mechanism of diamond on a titanium substrate. The as-grown diamond films were characterized by scanning electron microscopy (SEM), Raman spectroscopy, and x-ray analysis.

Polycrystalline samples of HgBa2(Ca0.86Sr0.14)2Cu3O8+δ (denoted as Hg-1223) were prepared by a precursor route, which involves the reaction between HgO and two precursors: Ba2CuO3+x and Ca0.14CuO2. X-ray powder diffraction analysis revealed that the Hg-1223 is isostructural with pristine HgBa2Ca2Cu3O8−δ and TlBa2Ca2Cu3O9−δ. The Hg-1223 has tetragonal symmetry with space group P4/mmm, and lattice parameters a = 3.8648(2) Å and c = 16.0319(2) Å. The as-synthesized Hg-1223 sample has a Tc of about 126 K. After annealing in an oxygen atmosphere at 280 °C for 10 h, the Tc increased to 132 K. Using this precursor pathway, Hg-1223 samples can be reproducibly synthesized.

Icosahedral samples of nominal composition Al63.5Cu24Fe12.5, which normally grow a rhombohedral approximant crystal, were submitted to heat treatments of various durations. The atmosphere in contact with the surface of the specimens was either dry air or secondary vacuum in order to test whether the formation of the icosahedral phase is sensitive or not to the nature of the atmosphere. Materials annealed in air showed a very thin surface layer of oxide which contained hydrogen. Beneath this oxide layer, small quantities of oxygen and hydrogen were also detected within the underlying lattice. This contamination was sufficient to shift the composition of the samples out of the stability domain of the icosahedral phase and has induced formation of a significant amount of the cubic phase. In contrast, the rhombohedral compound no longer appeared. This behavior goes along with the great sensitivity of the icosahedral phase stability to a sharply denfined electron to atom ratio.

High-quality bulk REBa2Cu3O7−x (RE = Y,Eu,Gd,Nd,La) was synthesized by a solution method. Stoichiometric amounts of yttrium, barium, and copper acetates were dissolved in glacial acetic acid. The acid was boiled away leaving a glassy acetate precursor. This precursor has shown amorphous scattering in XRD, a phenomenon consistent with atomic level mixing of reactants. The glassy precursor was subsequently heat-treated with a 5 °C/min ramp to 900 °C and a 2 h soak at 900 °C in air. The final product was obtained after heat treatment under oxygen at 550 °C with slow cooling to room temperature. Final products were analyzed by XRD, SEM, and four probe de-resistivity measurements. The mechanism of both precursor and product formation was examined through substitution studies and XRD. It was found that a combination of a rare earth acetate, barium acetate, and acetic acid was necessary for the formation of an amorphous precursor.

A trilayer epitaxial structure of 3C-SiC/Si/3C-SiC was grown on Si(111) substrate by reactive magnetron sputtering. The layered structure consisted of a 300 nm thick Si layer sandwiched between two 250 nm thick 3C-SiC layers. Cross-sectional transmission electron microscopy (XTEM) showed that all layers were epitaxial to each other. The 3C-SiC layers contained stacking faults and double positioning domains with a high density in the second SiC layer. The Si layer showed the lowest density of planar faults, but developed growth facets. Observation was made of stacking faults propagating from 3C-SiC to Si layer as well as stacking faults originating at the termination of 3C-SiC double positioning boundaries into Si. The termination of Si stacking faults during growth of SiC is also reported.

Molten salt electrolysis is a proven technology for the extraction of metals—all the world's primary aluminum is produced in this manner. The unique properties of molten salts also make them excellent media in which to treat a variety of forms of waste. Of special note in this regard is electrolysis in molten oxides, a concept put forward by the author, initially as a “clean technology” for producing primary metal. However, in the context of waste treatment, elcctrolysis in molten oxides is a process offering the prospect of changing the valence of dissolved heavy metals while making pure oxygen gas as the main by-product. Laboratory tests conducted at a temperature of 1550 °C on chromate sludge dissolved in melt composed of Al2O3, SiO2, CaO, and MgO have confirmed electrochemical production of oxygen on a carbon-free anode.

The authors completed a 3 MeV proton irradiation test on a terbium gallium garnet crystal sample. The main goal was to determine the proton dose required to reduce the fluorescence intensity to half its original value (half-brightness dose) at ambient temperature. The 3 MeV proton half-brightness dose was found to be 1.25 × 1015 p/cm2 using the Birks and Black relation. This decay is comparable to other fluors irradiated by the authors. The sample exhibited a yellow glow when irradiated in a 3 MeV beam. The fluorescence spectrum was composed of four peaks at wavelengths of 487.2 nm, 542.4 nm, 589.92 nm, and 624.1 nm.

Stoichiometric Sr1−xBaxNb2O6 (SBN) powder and thin films were prepared by a chemical method. The starting materials were niobium ethoxide and the hydroxides of strontium and barium. Powders were obtained by evaporation of the precursor solution, and thin films were deposited by spin coating. Annealing temperature required to obtain complete conversion to the crystalline material was about 700 °C. Stoichiometric polycrystalline films of Sr1−xBaxNb2O6 were deposited on quartz and silicon substrates. Leakage current-voltage and the capacitance-voltage measurements on a metal/SBN/n-silicon structure show a diode-type characteristic.

Ultrafine BaFe12O19 with uniform particle size was synthesized from an alcohol-in-oil (nonaqueous) microemulsion system where the metal ions were supplied by the surfactant (metal di-2-ethylhexylsulfosuccinate) molecules themselves. A monodisperse, fine-grained precipitate (Ba-Fe oxalate) was ensured by the steric barrier provided by the surfactant monolayer, while the nonaqueous environment promoted stoichiometric coprecipitation. Pure BaFe12O19 was obtained by calcining the oxalate precursor at or above 950 °C. Structural and magnetic properties of the resulting ultrafine magnetic material are reported.

We analyze theoretically the effect of microcracks and voids on the apparent elastic constants of polycrystalline YBa2Cu3O7. Using measurements by Holcomb and Mayo, we calculate crack density and crack aspect ratio. We obtain reasonable intrinsic elastic constants. For the bulk modulus, for example, we predict values close to these obtained by neutron-diffraction studies: 123 GPa for a polycrystal and 122 GPa for a monocrystal.

High-purity tungsten was prepared by the self-propagating high-temperature synthesis (SHS) process from a mixture of WO3 and Mg. The MgO in the product was leached with an HCl solution. The complete reduction of WO3 required a 33% excess of magnesium over the stoichiometric molar ratio Mg/WO3 of 3. The product tungsten had a purity of 99.980% which was higher than that of the reactant WO3. This is because the impurities were either volatilized at the high temperatures generated during the rapid exothermic reaction or dissolved into the HCl solution during leaching.

Aluminum oxide powders doped with MgO (300 to 500 nm) were sintered to almost theoretical density within just 10–15 min at 1150 °C using a plasma-activated sintering process based on charging the loosely filled powders with an electric discharge prior to densification by resistance heating. The microstructure of the consolidated disks was examined by high resolution transmission electron microscopy (HREM) and electron energy loss spectroscopy (EELS) and revealed excellent grain to grain contact with virtually no grain growth and structurally clean grain boundaries.