RF induction thermal plasma was applied to the chemical vapor deposition of carbon nitride from graphite powders and Ar–N2 gas at about 1 atm. Low-density and fragile amorphous powder-like bulk deposits whose color is light yellow were obtained. Elementary analysis by a combustion method and x-ray photoelectron spectroscopy showed that the N/C ratio is higher than that of stoichiometric C3N4. Also, a large amount of hydrogen and oxygen are included, which seems to be due to the absorption of moisture and oxygen after exposure to air. Infrared absorption spectra suggest the presence of sp CN and sp2 CN bonds, and nitrogen-containing polycondensed ring structures. Thermogravimetric analysis with mass spectroscopy shows that the deposits decompose almost completely at 800 °C, suggesting that the polycondensed rings are not large and not well cross-linked.

An in situ high temperature heat treatment was used to investigate the crystallization and growth behavior of AlB2 flakes in aluminum. Aluminum samples containing 1.8% boron were heated above the liquidus and then rapidly cooled through the Al(L) + AlB12 region to avoid the formation of AlB12 crystals. Subsequently, a homogeneous distribution of high aspect ratio AlB2 flakes crystallized upon holding below the peritectic transition temperature. Growth rate in the (a) and (c) dimensions increased during elevated hold temperatures below the peritectic transition temperature. Surprisingly, faster cooling rates from above the liquidus to room temperature resulted in thinner, wider flakes. Similar to graphite this phenomenon is believed to result from a need to accommodate a changing misfit strain energy between the solidifying aluminum and the growing AlB2 flakes.

Microstructural development of SCS-6 SiC fibers induced by creep deformation at 1400 °C is presented. Grain growth occurs in all SiC regions of the fiber during creep. Portions of the SiC4 region transform from βSiC to αSiC growing at the expense of the βSiC. The SiC1 through SiC3 regions of the fiber consist of a distinct (C + βSiC) two-phase region. The grain growth of the βSiC grains in the two-phase region is not as extensive as in the SiC4 region, suggesting that the presence of excess carbon may inhibit the growth of βSiC.

Layered nanostructures of copper metal and cuprous oxide are electrodeposited from alkaline solutions of Cu(II) lactate at room temperature. No subsequent heat treatment is necessary to effect crystallization. The electrode potential spontaneously oscillates during constant-current deposition. At a fixed current density the oscillation period decreases as either the pH or temperature is increased. The oscillations are periodic in stirred solution, but show period doubling and evidence of quasi-periodic or chaotic behavior in unstirred solution. The phase composition and resistivity of the films can be controlled by varying the applied current density. The resistivity of the films can be varied over ten orders of magnitude. Scanning electron microscopy shows that the films are layered.

The authors describe a technique for melt infiltration casting of composites with a metallic-glass matrix. We made rods 5 cm in length and 7 mm in diameter. The samples were reinforced by continuous metal wires, tungsten powder, or silicon carbide particulate preforms. The most easily processed composites were those reinforced with tungsten and carbon steel continuous wire reinforcement. The Zr41.2Ti13.8Cu12.5Ni10.0Be22.5 matrix was quenched to a glass after infiltrating the reinforcement. We analyzed the microstructure of the composites by x-ray diffraction and scanning electron microscopy. The measured porosity was less than 3% and the matrix was about 97% amorphous material.

Single crystals of barium samarium titanium oxide Ba6−3xSm8+2xTi18O54 (x = 0.27) have been synthesized and studied using x-ray diffraction. Superstructure reflections, which cause a doubling of the cell along the short axis, were taken into account and the refinement was conducted in the orthorhombic space group Pnma. Unit cell parameters from single crystal x-ray diffraction were a = 22.289(1), b = 7.642(1), and c = 12.133(1) Å. Refinement on F resulted in R1 = 5.37% for 1410 Fo > 4σ with the thermal parameters of the Sm and Ba atoms refined anisotropically and the thermal parameters of the Ti and O atoms refined isotropically. The structure is made up of a network of corner sharing TiO6−2 octahedra creating rhombic (perovskite-like) and pentagonal channels. The two pentagonal channels are fully occupied by Ba atoms. The refinement suggests that one rhombic channel is fully occupied by Sm atoms (Sm3/Sm4), one rhombic channel is partially occupied by Sm atoms (100% Sm1/86.25% Sm5), and one rhombic channel is shared by BaySm atoms (59.25% Ba3/40.75% Sm2), resulting in a formula of Ba10.38Sm17.08Ti36O108 with Z = 1. The above site occupancies differ from the site occupancies previously reported in the literature for refinements conducted with the short axis approximately equal to 3.8 Å.

Electrochemical thin film deposition in aqueous mixtures containing Cd2+, Zn2+, and thioacetamide has been investigated. It has been found that the atom-by-atom growth of well-crystallized CdS thin film preferentially takes place at the early stage of the reaction, followed by the cluster-by-cluster growth of the poorly crystallized ZnS outer layer, thus resulting in the formation of CdS/ZnS bilayer by a one-step synthesis.

Nitrogen was introduced in an iron layer underneath a top layer of nickel. This was done by ion implantation of N into the Ni layer at a temperature of 200 °C. During implantation and subsequent anneals at 250 and 300 °C, N diffuses from the Ni layer into the Fe layer because of a larger affinity of Fe for N than of Ni for N. The concentration depth profiles of N in the Ni/Fe bilayers, as recorded with the nuclear reaction analysis technique, show at the highest implantation dose a peak below the Ni/Fe interface. From structural analysis techniques (x-ray diffraction and cross-sectional transmission electron microscopy) it was observed that this peak is due to the presence of an ε–Fe3−xN layer below the Ni/Fe interface. It is thus shown that ε –nitride can be formed in Fe at such low temperatures in the absence of radiation damage.

Mechanochemical reactions in the system FeTiO3 –Si have been investigated as functions of the powder composition and milling conditions, using x-ray diffraction and thermal analyses. Reduction reactions of FeTiO3 by Si were observed during room-temperature milling with the formation of α–Fe, amorphous SiOx, nanocrystalline TiO2, or intermetallic compounds, depending on the Si content. The mechanochemical reaction process consists of a mechanical activation stage and a reaction stage. Higher milling intensity leads to a shorter activation step and a higher reaction rate.

Yield stresses, ultimate tensile strengths, and specific strengths of aluminum/titanium multilayer thin films are determined from the results of uniaxial tensile tests. The plasticity in the stress-strain curves, the nature of the fracture surfaces, and the relationship of the yield stress and the bilayer thickness are discussed. Properties are compared with those of other multilayer materials published in the literature.

Photoluminescence for PbMg1/3Nb2/3O3 (PMN)– PbIn1/2Nb1/2O3 (PIN) solid solutions in the temperature ranging from 35 to 295 K have been obtained for the first time. An abrupt photoluminescence enhancement of the system has been observed to occur at ∼210 K, which can be attributed to the growing and merging of dynamic polar microregions or to the phase transformation of the material at this temperature. The PIN content has been found to affect the photoluminescence of the PMN-PIN system significantly. The photoluminescence mechanism for PMN-PIN has been studied.

Dibutoxybis (acetylacetonato) zirconium, a difunctional zirconium alkoxide, was polymerized at 130 °C for 5 h in vacuo to produce oligomers that could be pyrolyzed to form a tetragonal zirconia (t-ZrO2), metastable at room temperature. This metastable phase was retained considerably below the equilibrium transformation temperature (∼1200 °C) without the use of dopants. Comparative pyrolysis of the oligomers between 600 and 900 °C in either flowing O2 or N2 for processing times under 12 h indicated t-ZrO2 nucleated first. Pyrolysis in oxygen facilitated transformation to the monoclinic symmetry, whereas pyrolysis in nitrogen demonstrated retention of the tetragonal phase. The formation of oxygen vacancies during pyrolysis, their role in stabilizing the metastable tetragonal phase, and contributions of O2 and crystallite size in the polymorphic transformation are discussed.

The densification behavior of silica-coated alumina particles was investigated during sintering using a laser scanning micrometer. Traditional dilatometric techniques require contact between a push-rod and the sample under study and thus place the sample under stress during the test. However, the utilization of a noncontact laser micrometer to measure dimensional changes during sintering enabled the densification behavior to be very accurately characterized under a stress-free condition. Thus higher temperature experiments, where densification rates are particularly temperature sensitive and the samples are especially soft, can be reliably investigated without the disturbing influence of an external force. The present paper describes an application of the technique to evaluate the densification behavior from 900–1300 °C of silica-coated alumina microcomposite particles used for the fabrication of mullite.

A method of forming TiN films for Si/Cu metallization by using plasma source ion implantation (PSII) of nitrogen into Ti is described. The PSII process utilizes a dose of 1 × 1017 ions/cm2 and peak voltages of –10, –15, and –20 kV. The properties of such TiN films as diffusion barriers between Cu and Si were investigated by annealing Cu(2000 A)/TiN/Ti/Si films in vacuum from 500 °C to 700 °C, and by analyzing with four-point probe sheet resistance measurements, Rutherford backscattering spectrometry (RBS), and Auger electron spectroscopy (AES). The TiN films made at peak voltages of –15 and –20 kV were stable barriers against Cu diffusion after annealing at temperatures higher than 600 °C.

Nb75M25 (M = Al, Si, Ga, Ge, and Sn) alloy ingots were prepared by the conventional arc-melting method and then were directly reacted with high purity hydrogen of 0.1 MPa in an arc-;melting chamber without exposing the ingots to air. As the clean surface of the arc-;melted ingots is preserved, the ingots rapidly absorb a large amount of hydrogen without any activation treatments and disintegrate violently into fine particles. The disintegration of ingots depends on the M element. The collected particles are investigated by x-ray diffraction, electron microscopy, chemical analysis, and thermal analysis. The particles are hydrides of Nb75M25 after hydrogenation and have a sharp-edged polygonal appearance. After dehydriding, fine Nb3M powders with A15 crystalline structure are obtained except for Nb75Si25. In comparison with the atomized Nb3M powders, the Nb3M powders prepared by the present study have a smaller average particle size and lower impurity contents.

An interesting reverse burning phenomenon was observed during the combustion synthesis of zirconium-based materials. When an external heat was applied to one end of a green pellet, the ignition was initiated at the other end. Also, the ignition position, measured from the heated end, was proportional to the apparent green density of the compact. The possible explanations for this reverse burning phenomenon are discussed.

The microstructure and lattice defects of SrTiO3 and BaTiO3 thin films with columnar grains prepared by a chemical solution deposition technique have been investigated by means of transmission electron microscopy. The columnar grains in the SrTiO3 films exhibit a preferential orientation with a crystallographic 〈111〉 direction parallel to the normal of film, which, in turn, follows the orientation texture of the substrate Pt layer. Cubic-to-cubic relationships have been found for the two materials. For the BaTiO3 films the columnar grains are oriented in a random way without any preferential relationship to the substrate Pt layer. Pores, lattice defects, and grain boundaries occur in either type of film, however in different configurations. This reflects the individual nature of the materials and the different formation and growth mechanisms of the films under the preparation conditions.

“Aging,” defined as the drift of resistance with temperature after 1000 h, was investigated for iron manganite temperature coefficient thermistors. For these devices, aging is relatively large, about 10%. The cationic distributions before and after aging were determined by Mössbauer spectroscopy. These distributions explain all the x-ray diffraction and correlated electrical data. The origin of the aging observed on iron manganites thermistors has been identified. It is due to the migration of Fe3+ ions from tetrahedral to octahedral sites of the spinel structure in order to reach a structural equilibrium.

Calcium phosphate growth on cellulose fibers phosphorylated in 1.5 × SBF (simulated body fluid) solution at various temperatures from 36.5–60 °C was studied. Cellulose fibers phosphorylated by using urea and H3PO4 and then soaked in saturated Ca(OH)2 solution at ambient temperature were found to stimulate the growth of a calcium phosphate coating on their surfaces after soaking in 1.5 × SBF solution for as little as one day. Soaking in 1.5 × SBF solution at higher temperature produced a thicker layer of calcium phosphate on the fibers, which may be due to the decrease of solubility of calcium phosphate. The specific surface area of the coatings decreased with an increase of soaking temperature and soaking time in 1.5 × SBF solution.

A fast and accurate method has been developed for measuring crystalline texture in homogeneous materials. The method uses a conventional powder x-ray diffractometer capable of θ scans. Two scans are recorded from the sample: first, a high resolution θ-2θ scan is obtained of a Bragg peak whose diffracting planes are normal to the preferred orientation direction; second, a θ scan is obtained using this peak. The η scan contains the required texture information, but the intensities must be corrected for defocusing and absorption to obtain the texture profile. The θ-2θ scan of the Bragg peak is used to make the defocusing correction, and first principles calculations are used to correct for absorption. The theory behind these corrections is presented here. The validity of the technique has been verified by making measurements on untextured alumina. Data obtained from Bi2Sr2Ca2Cu3O10 superconducting tape specimens with this technique are compared with texture data obtained with a four-circle diffractometer.