A novel technique has been suggested for synthesis of highly dispersed oxide powders. The method is based on the treatment of aqueous solution of a multivalent metal nitrate (or chloride) by anion-exchange resin in the OH− form. The presented technique yields a stable colloid solution of the corresponding hydroxide with concentration up to 1 M. The subsequent freeze-drying and thermal dehydration results in very fine powder of metal oxide. The individual and multicomponent oxides obtained by the cryosol method were shown to possess unusual properties due to their high dispersity and chemical homogeneity.

The thermal conductivity of silicon nitride prepared with varying sintering additive compositions was studied. Samples of Si3N4 + 0.5 mol% Y2O3 + 0.5 mol% Nd2O3 and a further additional agent were gas pressure sintered at 2173 K. MgO or Al2O3 was employed as the additional agent. While both agents improved sinterability, the former promoted grain growth and the latter suppressed it. Thermal conductivity increased with increasing MgO content, and a maximum value of 128 Wm-1 K-1 was attained when 2 mol% MgO was added. In contrast, addition of Al2O3 degrades thermal conductivity. This is probably due to the suppression of grain growth and the dissolution of Al2O3 into Si3N4 grains.

β–Sialon has been prepared by SHS (Self-propagating High-temperature Synthesis) with Si, Al, Al2O3, and β–Si3N4 under high nitrogen pressure. Rod-like crystals of b–Sialon with an aspect ratio of 4–15 and whiskers with various aspect ratios were obtained in the process. Considering the morphologies of the products, it is concluded that VLS (vapor-liquid-solid) is the predominant mechanism of the formation of rod-like crystals and whiskers.

The frequency and temperature dependencies of the dielectric permittivity and of the electrical conductivity of excess ferrous ions hydrothermal NiZn ferrites were analyzed before and after sintering. A decreasing tendency with frequency of the dielectric responses was observed, but the high permittivities attained (ε′ ≈ 105) masked any relaxation in these materials. This behavior is characteristic of n-type semiconducting ferrites, where electron hopping between Fe+2 and Fe+3 ions leads to very high conductivity values. The temperature dependence of the dielectric permittivities revealed the existence of broader peaks. The electron hopping mechanism leads to a frequency dispersion of the temperature where the permittivities attain their maxima. The electrical conductivity variations with temperature exhibited Arrhenius-type behaviors, with activation energies ranging from 0.34 eV (hydrothermal powder) to 0.16 eV (for the highest sintering temperature). These results were correlated to the variations in Fe+2 concentration and microstructure.

The alloying effect on microstructure and stability of the NbCr2 Laves phases is investigated using x-ray diffraction (XRD) and transmission electron microscopy (TEM). In as-cast condition, the binary alloy as well as the ternary alloy containing V consisted of the C15 phase while the ternary alloys containing Mo, Ti, and W consisted of both the C14 (or C36) and the C15 phases, accompanied by a number of stacking faults and microtwins in their constituent phases. By a prolonged heat treatment at 1673 K, the retained C14 (or C36) phase is completely transformed to the C15 phase. However, their kinetics is slower in the sequence of the ternary alloys containing Mo > Ti > W. The alloying effect on the stability of the C15 (or the C14) phase and the associated transformation process is discussed on the basis of phase stability and kinetics.

The surface composition of BaTiO3, SrTiO3, and CaTiO3 perovskite (100) surface is determined by shell-model calculations. The TiO2-terminated surface is energetically favorable for BaTiO3 and SrTiO3, which is consistent with experimental observations on SrTiO3. On the other hand, the CaO-terminated surface is preferred for CaTiO3 where Ca2+ is the smallest 2+ cation in these titanates. Ions on (100) surface rumple and induce surface dipoles. The surface ferroelectric polarization stabilizes the surface and changes its sign as the surface composition changes from TiO2 to CaO. This phenomenon is expected to affect the stability and properties of epitaxial films on perovskite substrates.

The preparation of vanadium-zirconia yellow pigments from amorphous spherical V–ZrO2 particles obtained by the hydrolysis of liquid aerosols consisting of a mixture of vanadium (V) oxychloride and zirconium n-propoxide is reported. The composition of the amorphous precursors (V/Zr ratio) and the heating temperature were systematically varied to determine their influence on the optical properties of the pigments. The origin of the yellow color of the pigments was found to be mainly due to the presence of V2O5 in the outer layers of the zirconia grains. A small fraction (∼15%) of the total vanadium content was found as vanadium (IV) forming a solid solution with the monoclinic zirconia lattice.

We present results of a large-scale atomistic study of the annihilation of oppositely signed screw dislocations in an fcc metal using molecular dynamics (MD) and an Embedded-Atom-Method (EAM) potential for Cu. The mechanisms of the annihilation process are studied in detail. From the simulation results, we determined the interaction energy between the dislocations as a function of separation. These results are compared with predictions from linear elasticity to examine the onset of non-linear-elastic interactions. The applicability of heuristic models for annihilation of dislocations in large-scale dislocation dynamics simulations is discussed in the light of these results.

The intercalation in vapor phase of cyclic amines (aniline, benzylamine, cyclohexylamine, piperidine, and pyridine) in α–hafnium bis(hydrogen phosphate) monohydrate (α–HfP) has been investigated. Elemental and thermal analysis lead to the establishment of the intercalate composition. The general formula is x[Hf(HPO4)2 · y amine H2O] (1 - x) α–HfP where y = 2, 1 and x ≤ 1. When y = 1 (piperidine and pyridine) the amines form a monomolecular layer. When y = 2 (aniline, benzylamine, and cyclohexylamine) the arrangement is bimolecular. The results are compared to those described for α–ZrP.

Aerosol-assisted chemical vapor deposition using the β-diketonate precursors Sr(tmhd)2 · 2H2O, Fe(tmhd) 3, and Co(tmhd) 3 was investigated for depositing thin films of the mixed-conducting ceramic SrCoyFe1−yO3−δ onto porous α–Al2O3 substrates. Single-phase SrCoyFe1−yO3−δ perovskite films were obtained at a deposition temperature of 550 °C and pressure of 15 mm Hg, whereas deposition at atmospheric pressure produced mixed-phase films. The Co/Fe elemental ratios in the films reflected those in the precursor solution, but the films were depleted in Sr. Reduced-pressure deposition provided a more uniform film morphology than atmospheric pressure, and led to a supported film which was leak-tight to N2 flow.

For very fine, acicular particles of α–Fe prepared for audio/video magnetic recording media, the relationship between their chemical property and surface flatness of the tape material made from the particles was investigated experimentally. It was found that adsorption capacity of acidic resin on the particle surface can be a very good index to predict the flatness of the magnetic tape. Because this index depends strongly on the acidic and basic properties of the particle surface, the tape performance can be well controlled by chemically designing the particle surface of α–Fe.

Semiconductor-metal co-colloids of CdSey/Au have been prepared by various synthetic pathways. Their microstructure, including that of Au–CdSe(TOPO) co-colloid in a core-shell structure, has been examined by high resolution transmission electron microscopy (HRTEM) and found to be well defined within the 10 nm size range. The optical absorption spectra of the colloids and of various synthesis stages have been obtained.

This paper outlines the formation of alkaline earth metal titanates, of the general formula MTiO3, directly from the metal oxides and rutile by mechanical activation in a laboratory ball mill at room temperature. X-ray diffraction analysis showed that the reaction was essentially complete within 100 h for all metals except magnesium. The titanates formed all had a Scherrer crystallite size of 11–12 nm and a lattice strain of 0.5–0.6%, neither of which were affected by extended milling. Annealing studies confirmed that the titanate was formed during milling and showed that grain growth could be achieved at temperatures below that generally used for their formation. Mixed cation titanates could also be formed by milling, but tended to be barium rich until annealed.

Influences of annealing on the structure of mesoporous silica loaded with silver (Ag) nanoparticles, and on the coarsening of Ag particles within pores of the host were investigated from isothermal sorption. Doping a small amount of Ag nanoparticles into pores of silica and subsequent annealing decreases the measured values of specific surface area and pore volume of porous silica significantly. This is attributed to the presence and coarsening of Ag particles within pores or channels between pores, which result in more and more isolated and unmeasured free spaces. The measured value of a specific surface area for the doped samples cannot represent the real value, which is, in fact, unable to be measured directly. During additional annealing, Ag particles within silica coarsen mainly according to the mechanism of formation of Ag adatoms on pore wall and diffusion of the adatoms along with pore walls. Only the larger particles located in the larger pores can continuously grow. The smaller particles and those located in the channels or pores with smaller dimension will disappear. The activation energy of the ripening process was estimated to be about 0.60 eV, and the migration barrier of Ag adatom on the pore wall of silica is about 0.10 eV.

We have developed a new technique for the analysis of particulate contaminants in liquids (or gases) with an elemental detectability limit as low as 0.1 parts per trillion, and a particle concentration detectability limit as low as 1 particle/ml for particles greater than 0.2 μm in diameter. Samples are prepared using extraction replication and analyzed using analytical transmission electron microscopy. The methodology has been applied to the analysis of H2O2 and HF, important chemicals in integrated circuit fabrication. The new methodology should become an important tool in the identification of submicron-sized particles which adversely affect integrated circuit fabrication.

A new method for evaluating modulus and hardness from nanoindentation load/ displacement curves is presented. As a spherical indenter penetrates an elastoplastic half-space, the elastic displacement above the contact line is presumed to diminish in proportion to the total elastic displacement under the indenter. Applying boundary conditions on the elastic and plastic displacements for elastic and rigid plastic contacts leads to an expression that can be best fit to the entire unloading curve to determine E*, the reduced modulus. Justification of the formulation is presented, followed by the results of a preliminary survey conducted on three predominantly isotropic materials: fused quartz, polycrystalline Al, and single crystal W. Diamond tips with radii ranging from 130 nm to 5 μm were used in combination with three different nanoindentation devices. Results indicate that the method gives property values consistent with accepted values for modulus and hardness. The importance of surface roughness and indentation depth are also considered.

We report on the preparation and characterization of epitaxial ACuO2 (A = Sr, Ca, Ba) thin films and multilayers with the so- called infinite layer (IL) structure, by rf magnetron sputtering. Films and multilayers without Ba have a remarkable crystal quality, whereas those containing this large ion are often multiphased and unstable. In spite of the excellent crystalline quality of these samples, obtaining thin films having both IL structure and displaying superconducting properties has not succeeded; our pure IL samples display semiconducting behavior, and the different procedures tried in order to dope them—annealings, introduction of disorder or cation vacancies, artificial layering—have failed. These results support that the pure IL structure ACuO2 (A = alkaline earth) cannot superconduct.

The preferred orientation of the TiN film grown by sputter-deposition was studied by the cross-sectional TEM. The preferred orientation was changed from the (200) through the (110), and then finally to the (111) with the film thickness. The cross-sectional microstructure also shows that the film consists of three layers which are all columnar structure. The (111) preferred orientation was observed in the top layer, and the (110) in the middle layer, and finally the (200) in the bottom layer. It is very surprising that the (110) preferred orientation could be observed in a medium thickness region and there are two kinds of critical thicknesses. These results surely show the strong dependence of the change in the preferred orientation on the strain energy in TiN thin films.

The preferred orientation, grain morphology, and composition heterogeneity of the polycrystalline Pb(ZrxTi1–x)O3 (PZT) thin films were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), transmission electron microscopy (TEM), and x-ray energy dispersive spectroscopy (EDS). PZT thin films with nominal x = 0.5 were grown by metal-organic chemical vapor deposition (MOCVD) on (110)- and (101)-textured RuO2 bottom electrodes at temperatures ≤525 °C. Columnar grain microstructure with strongly faceted surface morphology was observed in both films. The grain morphology and surface roughness of the PZT films were observed to depend on those of the underlying RuO2 layers. TEM-EDS analysis shows notable cation composition heterogeneity in length scales of 0.2–2 μm. Pronounced Pb composition deficiency and heterogeneity were also observed in PZT/(110)RuO2 in length scales above 40 μm. The grain morphology and cation heterogeneity of the PZT films are discussed on the basis of diffusion-limited columnar growth mechanism.

The emissions of CO2, SOx, and NOx of various steel alloys in the production stage were calculated by using the unit requirement of each subsystem of the steel-making process, in order to compare the superiority from the viewpoint of the environmental issue among various types of steel alloys. As steel production is a typical integrated system with multiproducts, allocation of emissions to each product, effect of the composition, and sharing the load by the by-product gases are considered. Calculated values of emission were arranged for fifteen kinds of finished steel products and for arbitrary contents of alloying elements.