Alumina powders were synthesized by the emulsion combustion method, using w/o (water in oil) type emulsions with different aqueous microsphere sizes. The effects of microsphere size on the size and shape of the synthesized powder were evaluated. The powders were spherical and hollow in shape with a very thin shell (from 10 to 20 nm in thickness) when synthesized from large aqueous microspheres (from 200 nm to 1 μm). The sizes and specific surface areas of the powders were consistent with those calculated. Large particles, which did not correspond to the microsphere size, were obtained from small aqueous microspheres (6 nm). The short distance (7 nm) between microspheres causes the adhesion of particles during the firing process.

The CHF3 electron cyclotron resonance (ECR) plasma etched LiNbO3 (LN) surface was analyzed chemically and crystallographically to investigate the dry-etch machining process for LN crystal, which was recently needed to obtain broader-band optical modulators. The etched surface was entirely covered with amorphous-like precipitates having ~70 nm diameter. These precipitates (or a part of them) were thought to be LiF from Auger electron and x-ray photoelectron spectroscopy. The results indicated that the LiF was formed and remained on the etched surface while the Nb was almost completely removed.

Powders with a nanostructured mixture of pure Al and Pb phase were produced by mechanical milling of elemental blends of Al and Pb with a composition of Al90Pb10 (wt. %). Under a pressure of 1.5 GPa at 280 °C, the as-milled powders were successfully consolidated into bulk, full-density samples (>99.5% theoretical density) while the average grain sizes of Al and Pb in the compacted samples remain unchanged with respect to those in the as-milled powders. The achievement of the full density without grain coarsening in the consolidation process could be reasonably attributed to melting of the nanometer-sized Pb particles of which the melting point is considerably depressed.

Thin films of wurtzitic AlN have been deposited by molecular-beam epitaxy onto (001) oriented MgO substrates. The films are epitactic and align with the and the , as evidenced by transmission electron microscopy. This configuration, which matches a close-packed direction of the film and substrate, allows for growth of two symmetrically equivalent orientation variants of the AlN film. These variants are distinguished by a 90° rotation about the direction that is normal to the substrate surface. Each variant also aligns the and the to within 5° of being parallel to the (200)MgO. The microstructure of the AlN films and origins of these novel alignments are discussed.

Silica-free phosphate glasses containing small amounts of Na2O and TiO2 with the composition of Ca/P = 1 in atomic ratio were obtained. When powder compacts of the glasses were heated at 850 °C, they crystallized and subsequently sintered, resulting in glass-ceramics containing β–Ca3(PO4)2 and β–Ca2P2O7 crystalline phases. The glass-ceramics show a relatively high fracture toughness of KIC ≈ 2 MPa m0.5. By soaking in simulated body fluid at 37 °C, a calcium phosphate phase was formed newly on the surface of the glass-ceramics.

Dewetting of eutectic SnPb on blank Au(500 Å)/Cu(1 μm)/Cr(800 Å) layered structure was found to have a solder size dependence. At 250 °C, if the solder weight fell below 4 mg, dewetting occurred from the center of the solder cap; if the solder weight went beyond 6 mg, dewetting happened from the cap edge. In the latter case, a smaller cap with a higher wetting angle was formed at the center and a ring of solder was left around the edge. Large voids were left in the solder cap after dewetting in both cases. In contrast, all solder caps were found to dewet from the edge on a patterned film at 250 °C if the solder ball was large enough to wet the whole film initially, irrespective of the solder size. For comparison, pure Sn, eutectic SnAg, and eutectic SnBi caps also dewetted from the edge of the Au/Cu/Cr thin film, irrespective of the solder size or whether the substrate was patterned. Since eutectic SnPb on blank Au/Cu/Cr is the only case in which a large sideband growth was found and the dewetting occurred from the center, we postulated sideband to be the main factor which controls the unusual dewetting. The link between them is discussed.

Mixtures of CaO–CdO (1 : 1) were hydrothermally treated in a pressure reactor at 200 °C and 200 psi of pressure during a period of 16 h. The evolution of the reaction was followed by x-ray diffraction (XRD), infrared spectroscopy (IR), and thermogravimetric (TG and DTG) analysis. Also, the composition of the filtered solutions was analyzed to determine the mechanism of the reaction as well as the thermodynamic solubility constant of the new compound formed. The results show that CaO and CdO react, giving rise to a new CaCd(OH)4 hydroxide whose thermodynamic solubility constant, 1.5 ± 0.4 × 10−11 M2, is six orders of magnitude lower than those of both Ca(OH) 2 and β–Cd(OH) 2. This low solubility constant justifies the Cd2+ concentration measured in the pore solution of cement matrices used to immobilize cadmium containing wastes. The mechanism of the reaction proposed is via dissolution of both Ca(OH) 2 and β–Cd(OH)2, Ca2+ and being the predominant species in solution.

Epitaxial films of (100) Ag were deposited onto (100) MgO substrates to a thickness of 4 μm with no evidence of (111) nucleation. Deposited films were smooth and had large areas, 50 × 50 microns square, free of morphological defects. Films were deposited using a two-step process. First, pulsed laser deposition was used to grow a 1000 Å Ag (100) seed layer on the MgO substrate. Second, e−beam evaporation was used to grow the film to the desired thickness. The high quality of the resulting films will allow them to be used as templates for further epitaxial deposition of other applied materials.

The electronic structures of different morphologies of carbon nanotubes are investigated within either tight-binding or ab initio frameworks. After a brief description of the electronic properties of the “perfect” rolled-up graphene sheet, nanotubes containing pentagon-heptagon pairs, tips (hemispherical caps), sp3-like lines responsible for polygonization, multishell and solid-state packings (bundles) are studied in order to point out the influence of such defects on the electronic states of the “perfect” cylinders. Most of the time, a structural optimization was performed on the atomic topology, prior to the calculation of the electronic properties. Connections with experimental facts are indicated as frequently as possible.

Diamond films were deposited on the p-type Si substrate with the hot filament chemical vapor deposition (HFCVD). Residual stresses in the films were measured in air by the laser curvature, the x-ray diffraction (XRD) dϕψ − sin2ψ, and the Raman peak shift methods. All of the measuring methods showed similar behaviors of residual stress that changed from a compressive to a tensile stress with increasing the film thickness. However, values of residual stresses obtained through the Raman and XRD methods were 3–4 times higher than those of the curvature method. These discrepancies involved the setting of materials constants of CVD diamond film, and determination of a peak shifting on the XRD and Raman method. In order to elucidate the disparity, we measured a Young's moduli of diamond films by using the sonic resonance method. In doing so, the Raman and XRD peak shift were calibrated by bending diamond/Si beams with diamond films by a known amount, with stress levels known a priori from the beam theory, and by monitoring the peak shifts simultaneously. Results of each measuring method showed well coincidental behaviors of residual stresses which have the stress range from −0.5 GPa to +0.7 GPa, and an intrinsic stress was caused about +0.7 GPa with tensile stress.

Production problems attributed to excessive stresses generated during the cure of epoxies led us to develop a formalism to predict these stresses. In our first studies, we developed a fundamental understanding of the complex evolution of viscoelasticity as the cure progresses. We then incorporated these results into a proper tensorial constitutive equation that was integrated into our finite element codes and validated using more complicated geometries, thermal histories, and strain profiles. The formalism was then applied to the original production problem to determine cure schedules that would minimize stress generation during cure. During the pursuit of these activities, several interesting and puzzling phenomena were discovered that have stimulated further investigation.

The embedded atom method (EAM) was applied to calculate the energy on Mg doping in polycrystalline Ni3Al. The EAM predicted the energy of Mg in Al site in grain boundary is lower than that of Mg in Ni site and much lower than that of Mg in Al or Ni site in bulk and in free surface. It means that Mg would segregate to grain boundary rather than bulk and free surface and Mg will favor to be the substitute of Al rather than of Ni in grain boundary. These results were consistent with the experiments that Mg segregated to grain boundaries with Al depletion and Ni enrichment.

La2CaCu2O6 (n = 2) was obtained at temperatures as low as 800 °C by firing the coprecipitates from a mixed aqueous solution of La, Ca, and Cu acetates which were titrated with tartaric acid. The firing temperature was much lower than that in solid state reactions which are usually conducted above 1000 °C. Both La2Ca2Cu3O8 (n = 3) and La2Ca3Cu4O10 (n = 4) were obtained at 700 °C in a similar preparation method. Low temperature firing was very important for these preparations. A porous sintered body of La2CaCu2O6 with a relative density of about 15% was also obtained using this preparation method. This porous sintered body could be effectively oxygen-doped by electrochemical oxidation showing the presence of a new superconducting phase with Tc around 30 K.

For photovoltaic applications silicon is still the predominant material. Besides monocrystalline Czochralski wafers (Cz-Si), multicrystalline sheets (mc-Si) play an important role in terrestrial power applications (almost 50%). Large mc-Si ingots (up to 250 kg) are now produced in large scale by the industry using various directional solidification methods in appropriate crucibles (or molds). However, if the crystallographic properties are now quite satisfactory (columnar structure with large grains of more than 1 cm2, dislocations and intragrains defects), multicrystalline silicon contains larger quantities of impurities than single crystalline silicon which can have detrimental effects on the bulk minority carrier diffusion length (Ln,p). These impurities, including metals as well as high concentrations of carbon and/or oxygen, can degrade the photovoltaic properties of solar cells. Thermal treatments such as gettering, performed in a classical or rapid thermal furnace, studied separately or in conjunction with the doping steps can limit or avoid the degradation of the bulk diffusion length, but its efficiency is strongly dependent on the presence of these impurities in Si.

AlZrN protective film with high transmissivity was deposited onto the organic photoconductor (OPC) surface, and the surface hardness was greatly increased by a factor of 1.5–3. The OPC surface protected by (Al100−xZrx)N (x ≤ 58.5%) film was significantly harder than that protected by AlN film. The electrophotographic properties of the OPC coated with (Al100−xZrx)N (x ≤ 37.7%) film were also better than those without coating or protected with AlN film, thus demonstrating the suitability of AlZrN film as a protective coating for enhancing the operating life of OPC.

A new X7R type dielectric ceramics for the PMN-BT-PT system with a high dielectric constant (4832) and a low firing temperature (1100–1130 °C) was prepared by the mixed-sintering method. The results of XRD, SEM, EDAX, and dielectric measurements showed that the dielectric ceramics is a two-phase composite with the high dielectric constant originating from the ferroelectric relaxor, and the temperature stability of the dielectric properties from two-phase coexistence.

A set of equations were derived to estimate systematic errors in experimental determinations of volume fractions transformed by microscopy methods. For reactions that occur by continuous nucleation and growth, the experimental values of volume fractions transformed may be subjected to significant errors when the largest grain size of the distribution is close to the microscope resolution limit. For transformations occurring from a fixed number of nuclei, the systematic errors are smaller than those observed in the continuous nucleation case, but can still be significant when reflection methods are used. Transmission methods lead to smaller errors than reflection techniques.

Epitaxial SrTiO3(STO) thin films have been grown successfully on Si(001) buffered with single and double buffer layers by pulsed laser deposition. Depending on the buffer structure and under appropriate substrate temperature and oxygen pressure values, epitaxial films are grown with single orientations. Epitaxial STO films with (0hh), (00h), and (hhh) out-of-plane orientation have been obtained for the first time on yttria-stabilized zirconia (YSZ)ySi(001), CeO2/YSZ/Si(001), and TiN/YSZ/Si(001), respectively. Secondary ion mass spectrometry analyses show sharp interfaces and good uniformity of the elements in each layer. The films are practically free of droplets, and the rms value of roughness is smaller than 0.5 nm.

Microwave dielectric properties and the relationship between the temperature coefficient of the dielectric constant (τ ɛ) and the tolerance factor were investigated in (Sr0.2Ca0.8) (Ti1–xZrx)O3 ceramics. The τɛ increased linearly as the tolerance factor decreased from 0.984 to 0.929 in the whole composition range of the (Sr0.2Ca0.8) (Ti1–xZrx)O3 solid solution. At the composition of (Sr0.2Ca0.8) (Ti0.04Zr0.96)O3, the dielectric constant was 34 and Q · f was 10,938 GHz and the temperature coefficient of the resonance frequency (τɛ) was supposed to be near zero.

SiC particles coated uniformly with Al ions (0.25 mass% Al2O3) in an aluminum nitrate solution were consolidated by filtration through a gypsum mold. Hot-pressing in vacuum gave dense SiC (above 99% relative density) in the temperature range of 1900–1950 °C under a pressure of 39 MPa. The microstructures of dense SiC consisted of 2–5 μm grains of low aspect ratios (below 2). The fracture toughness and flexural strength of SiC increased gradually as the hot-pressing temperature became higher and were 4.3 Mpa m0.5 and 350 MPa, respectively, with hot-pressing at 1950 °C. Crack propagation in SiC shifted from intergrain to intragrain with increasing hot-pressing temperature.