Thermal stability and crystallization kinetics of the melt-quenched amorphous Al85Ce5Ni8Co2 alloy were investigated by x-ray diffraction and differential scanning calorimetry (DSC). The glass transition was followed by a supercooled liquid region (21 °C) and then by a two-step crystallization process. The final microstructure contained Al3Ce, α–Al, Al3Ni, and Al9Co2 phases. Isothermal annealing of the as-quenched samples in the range of 275–285 °C showed that both crystallization reactions occurred through a nucleation and growth process. Continuous heating DSC measurements following pre-anneals for different times were also carried out to study the crystallization kinetics and the stability of the material. The Avrami analysis of the isothermal DSC-curves revealed that the 3-dimensional nucleation and growth process became more dominant with increasing annealing temperature. The average specific grain boundary energy corresponded to high-angle grain boundaries and indicated independent nucleation events.

Bismuth oxide solubility in Bi2O3–ZnO–Nb2O5 and Bi2O3–MgO–Nb2O5 (BMN) pyrochlore systems was investigated and the solubility limits were identified. Differences in the solubility behavior between the two Bi-pyrochlore systems investigated were analyzed and explained through crystal chemistry concepts. For the BMN system, the dielectric constant was enhanced, and a systematic shift occurred in the dielectric relaxation loss peak to higher temperatures with increases in the excess bismuth are reported in the BMN system. The relationship between solubility and the shift in the dielectric loss curve was analyzed under the scope of possible relaxation mechanisms.

The carbonation of two hydrated ordinary portland cements of alkali content 1.03% or 0.43% Na2O equivalent and hydrated calcium aluminate cement (0.1% Na2O equivalent) was studied in a semi-dynamic atmosphere of 100% CO2, and 65% relative humidity at 20 ± 1 °C, for a period of 100 days. The changes of the microstructure before and during the carbonation were characterized by x-ray diffraction, mercury intrusion porosimetry, and scanning electron microscopy. The kinetics of the process was evaluated from the total CaCO3 content by means of thermogravimetric analysis. The changes of the mechanical flexural strength were also studied. The pore solution was collected and analyzed before and after different periods of time. The results were compared with those obtained under natural carbonation conditions. The results showed that the alkali content of cement does not influence the kinetics of the process when the carbonation is accelerated. In the case of natural carbonation, an induction period is produced in the ordinary portland cement of low alkali content and calcium aluminate cement. The carbonation rate of calcium aluminate cement is the slowest for accelerated and natural carbonation.

BaIn2S4, BaIn2S4:Ho3+, BaIn2S4:Er3+, BaIn2S4:Tm3+, BaIn2Se4, BaIn2Se4:Ho3+, BaIn2Se4:Er3+, and BaIn2Se4:Tm3+ single crystals were grown by the chemical transport reaction method. The optical energy gap of the single crystals was found to be 3.057, 2.987, 2.967, 2.907, 2.625, 2.545, 2.515, and 2.415 eV, respectively, at 11 K. The temperature dependence of the optical energy gap was well fitted by the Varshni equation. Broad emission peaks were observed in the photoluminescence spectra of the single crystals. They were assigned to donor–acceptor pair recombination. Sharp emission peaks were observed in the doped single crystals. They were attributed to be due to radiation recombination between the Stark levels of the Ho3+, Er3+, and Tm3+ ions sited in C1 symmetry.

Nanocrystalline TiO2 anatase with particle size in the range of 5–7 nm has been prepared by in situ cracking of the sol at 85 °C, thereby avoiding the intermediate gel formation process. Hydrolysis of Ti(O-isoPr)4 was carried out in excess of 2-propanol to keep the suspension of fine particles from agglomeration. Differential thermal analysis, thermogravimetric analysis, differential scanning calorimetry, powder x-ray diffraction (XRD), and electron microscopy have been used to characterize the samples. Gel to crystalline conversion, which requires a temperature of at least 400 °C, can be achieved by digesting the TiO2 sol at 85 °C. XRD and selected area electron diffraction patterns show the presence of a small amount of brookite phase along with the major anatase phase. High-resolution transmission electron microscopy shows that the average grain size of TiO2 particle remains around 5–9 nm even when heated at 510 °C.

SmCa4O(BO3)3 (SCOB) crystallizes in the noncentrosymmetric monoclinic space group Cm with cell parameters a = 0.8129(5), b = 1.6076(1), c = 0.3584(1) nm, β = 101.36(2)°, and Z = 2. Raman results showed that the characteristic spectra of SCOB are mainly contributed by the B–O triangles and partly by the Ca(1)–O octahedra. The structural rigidity of SCOB is mainly ascribed to the B–O bond stretching and bending modes and partly by the Ca(1)–O bonds. The rigid structure of the B–O triangles and the quasi-rigid structure of the Ca(1)–O octahedra are necessary to the SCOB crystal as a laser host. The large distortions of the Sm–O and Ca(2)–O octahedra intensify the polar forces and anisotropic lattice forces, which generally imply the best nonlinear properties possible for SCOB as a nonlinear optical material and piezocrystal. Thermal measurements show a larger value of the specific heat and three small expansion coefficients, which show that SCOB can allow a large temperature gradient, especially in the Y direction. Displacement parameters indicated that the thermal ellipsoids of the Sm and Ca(2) atoms had significantly large components along the b direction. Synthetical study indicated that the SCOB crystal should be outstanding as an efficient self-frequency doubled material.

A new method of sintering diamond-silicon carbide composites is proposed. This method is an alternate to the liquid silicon infiltration technique and is based on simultaneous ball milling of diamond and silicon powder mixtures. Composites with fine-grain diamonds embedded in a diamond–SiC nanocrystalline matrix were sintered from these mixtures. Scanning electron microscopy, x-ray diffraction, and Raman scattering were used to characterize the ball-milled precursors and the sintered composites. It was found that the presence of diamond micron-size particles in the initial powder mixture promotes milling of silicone particles and their transformation into the amorphous state. Mechanical properties of the composites, sintered from mixtures of different ball-milling history at different pressure–temperature conditions, (6 GPa/1400 °C and 8 GPa/2000 °C) were studied.

It is thought that high-dielectric constant, suitable conductivity, and dielectric loss dominate electrorheological (ER) effects. According to this viewpoint, the polyaniline/montmorillonite nanocomposite (PANI-MMT) particles with high-dielectric constant and suitable conductivity were synthesized by an emulsion intercalation method. The electrorheological properties of the suspensions of PANI-MMT particles in silicone oil have been investigated under direct current electric fields. At room temperature, it was found that the yield stress of PANI-MMT ER fluid was 7.19 kPa in 3 kV/mm, which is much higher than that of pure polyaniline (PANI), that of pure montmorillonite (MMT) as well as that of the mixture of polyaniline with clay (PANI+MMT). In the range of 10–100 °C, the yield stress changed only 6.5% with the variation of temperature. The sedimentation ratio of PANI-MMT ERF was about 98% after 60 days. The structure of PANI-MMT particles was characterized by infrared, x-ray diffraction (XRD), and transmission electron microscopy (TEM) spectrometry, respectively. The XRD spectra show that the inner layer distance of PANI-MMT can be enhanced to 1.52 nm when the PANI was inserted into the interlayer of MMT, whereas it is only 0.96 nm for free MMT. TEM shows that the diameter of PANI-MMT particles is about 100 nm. The dielectric constant of PANI-MMT nanocomposite was increased 5.5 times that of PANI and 2.7 times that of MMT, besides, the conductivity of PANI-MMT particle was increased about 8.5 times that of PANI at 1000 Hz. Meanwhile, the dielectric loss tangent can also be increased about 1.7 times that of PANI. It is apparent that the notable ER effect of PANI-MMT ER fluid was attributed to the prominent dielectric property of the polyaniline-montmorillonite nanocomposite particles.

Aluminum coordination distribution for alumina catalysts supported on mesoporous silica was examined. It was shown that aluminum coordination correlates to activity of the catalysts for plasma-enhanced, selective catalytic reduction of NOx with propene. Catalysts were prepared by incorporating aluminum onto the surface of a mesoporous silica support via three different post-synthesis routes to produce varying aluminum coordination. Aluminum trichloride, sodium aluminate, and aluminum isopropoxide precursors were examined. High-resolution, solid state 27Al nuclear magnetic resonance was used to determine aluminum coordination distributions for the resulting catalysts. Unsaturated aluminum sites (i.e., structural defects) correlated with increased activity at high temperatures while tetrahedrally-coordinated aluminum or BrØnsted acid sites correlated with activity at low temperatures.

Na0.5K0.5NbO3 thin films have been deposited onto textured polycrystalline Pt80Ir20 substrates using radio frequency magnetron sputtering. Films were grown in off- and on-axis positions relative to the target at growth temperatures of 500–700 °C and sputtering pressures of 1–7 Pa. The deposited films were found to be textured, displaying a mixture of two orientations (001) and (101). Films grown on-axis showed a prefered (001) orientation, while the off-axis films had a (101) orientation. Scanning electron microscopy showed that the morphology of the films was dependent on the substrate position and sputtering pressure. The low-frequency (10 kHz) dielectric constants of the films were found to be in the range of approximately 490–590. Hydrostatic piezoelectric measurements showed that the films were piezoelectric in the as-deposited form with a constant up to 14.5 pC/N.

The dielectric behavior of manganese-doped morphotropic phase boundary (MPB) composition in the Pb(Zn1/3Nb2/3)O3–BaTiO3–PbTiO3 (PZN–BT–PT) system is described in this paper. Materials with perovskite structure were fabricated using the precursor approach. Addition of Mn stabilized the rhombohedral phase against the tetragonal one, moving the MPB territory toward the PbTiO3-rich side. Both the dielectric permittivity maximum (∈′m) and phase transition temperature (Tmax) were reduced by increasing Mn2+ content. Frequency-dispersion characteristics of Tmax were weakened while the frequency spectrum of the dielectric permittivity (∈′) was broadened, reflecting different underlying mechanisms. The broadness of paraelectric to ferroelectric phase transition was significantly enhanced by Mn-doping. This was associated with progressive increase in the degree of chemical heterogeneity on B-site cations. The observed proximity of the non-Curie–Weiss region to Tmax as well as shrinkage of this region for doped compositions suggest increased stability of the ferroelectric phase.

Extensive indentation tests were conducted for nineteen different engineering materials ranging from brittle to ductile materials, and including hard ceramics, ductile metals, and a soft organic polymer. Three tetrahedral pyramid indenters with specific face angles β [shallow pyramid (β = 10°), Vickers (β = 22°), and sharp pyramid (β = 40°) indenters] were used. All the materials tested were subjected to the quadratic load P and penetration depth h relationship P = k1h2 on loading, and most of the tested materials to the quadratic unloading relationship of P = k2(h − hr)2 with the residual depth hr after a complete unload. To determine the contact area at peak indentation load, a specially designed depth-sensing instrument was constructed, on which the contact behavior during loading/unloading was examined by through thickness observation of transparent specimens. All the characteristic indentation parameters were investigated on the basis of simple elastoplastic model, and correlated well with the nondimensional strain E′ tan β/H, in which the elastic modulus E′ was a measure for elasticity, true hardness H was a measure for plasticity, and the inclined face angle β characterized the indenter. The ratio of the conventional Meyer hardness HM to the true hardness H of the materials tested ranged from 0.2 to 0.9 as a function of E′ tan β/H. The cavity model suggested that true hardness H is expressed by the yield stress Y through a constraint factor C as H = C · Y with C ≈ 5.

The acidic dispersion behavior of fused SiO2 particles was investigated and compared to two fumed SiO2 particles. In contrast, the fused SiO2 particles have a larger particle size, broader size distribution, and lower surface area. Fluoride adsorption was used to study surface activity, and acid–base titration was used to study surface charge in 10−1 to 10−3 M NaCl solutions over the pH range of 2–7.5. Each of the three SiO2 particles exhibited similar titration behavior, with the fused SiO2 particles displaying a higher intrinsic pKa2 value of 7.0 as compared to 6.8 and 6.1 for the two fumed SiO2 particles. Rheological experiments designed to test for dispersion and agglomeration/ gellation at 3 and 6 wt% solids loading in 10−3 M NaCl solutions adjusted to pH 2, 4, and 6 showed the fused SiO2 particles to be more stable in suspension, exhibiting lower viscosity results for all test conditions. Results show that the fused SiO2 particles tested in this report display superior dispersion properties as compared to conventional fumed SiO2 particles for slurry applications under acidic conditions.

Thin films of TiO2 were fabricated by spin-coating silicon wafers and cover glass with a titanium citrate complex precursor. The grain growth and phase development of both freestanding and supported films were studied using a combination of atomic force microscopy, x-ray diffraction, and transmission electron microscopy. Freestanding films prepared at 400 °C possess only the anatase phase, while supported films treated under the same conditions formed a small amount of the rutile phase. After heat treatment at various temperatures, results indicated that porosity was introduced into the films when the grain size grew close to the film thickness. Grain growth studies show that the grain size of the freestanding film underwent a drastic increase during the transformation from anatase to rutile. The grain size of the supported films did not show an abrupt change upon heat treatment. The grain size of the freestanding films treated at 900 °C was approximately three times larger than that of the supported films.

Deep donor levels in ZnO single crystals doped with transition metal (TM; Co or Mn) were characterized by isothermal capacitance transient spectroscopy (ICTS) applied to ZnO-based Schottky junctions, Au/ZnO (0001) or Ag/ZnO (0001). The barrier height at the junction and donor concentration was not influenced by TM. A deep donor level at 0.28 eV was detected by ICTS; however, its energy dispersion and concentration was composition independent. The effect of doping with TM was found in the magnitude of leakage current; in other words, the leakage current at the Au/ZnO:Mn junction was lower than the other junctions on undoped or Co-doped crystals.

Polysilicon films were deposited using low-pressure chemical vapor deposition (LPCVD) onto oxidized silicon substrates, after which substrate curvature as a function of temperature was measured. The curvatures changed with temperature, implying that the thermal expansion of LPCVD polysilicon differs from that of the single crystal silicon substrate. Further, polysilicon films with tensile residual stresses displayed an increased thermal expansion, while polysilicon films with compressive residual stresses displayed a decreased thermal expansion. Following high temperature annealing, the residual stresses of the polysilicon films were reduced to near zero, and the thermal expansion of the polysilicon films matched that of the single crystal substrate. The apparent change in thermal expansion coefficient due to residual stress was much larger than predicted theoretically.

The effect of buffer and γ irradiation on the optical properties of hydroxyethyl methacrylate (HEMA) copolymer was investigated. The transmission of HEMA copolymer decreased with the increase of irradiation dose and/or pH value of the buffer. The cutoff wavelength of HEMA copolymer exhibits a bathochromic shift as the γ-ray dose and/or pH value of buffer increases. The influence of atmosphere during γ-ray irradiation on the optical properties of HEMA copolymer was investigated. The change of optical properties of HEMA copolymer irradiated in air was more pronounced than that irradiated in vacuum. Light was scattered by holes in the polymer. The relationship between scattering intensity (Is) and incident wavelength (λ) can be described by the formula Is ∝ λ−n. The span of holes increases with the irradiation dose regardless of radiation atmosphere and pH value in the range of 4.1–6.5. A boundary between the inner and outer layers of HEMA copolymer irradiated in air was observed, separating two differential morphologies of holes.

Wafer curvature was used to study the thermal–mechanical behavior of 1-μm Cu thin films capped with a 100-nm-thick Si3N4 layer. These films were grown with either a Ta or a Si3N4 underlayer. Films on Si3N4 that were exposed to oxygen at the film/capping layer interface or at the center of the copper layer exhibited Bauschinger-like yielding at low stress. Stacks deposited under continuous vacuum, with a Ta underlayer, with carbon exposure at the upper surface of the copper film, or with oxygen exposure of only the underlayer did not demonstrate the anomalous yielding. Preferential diffusion of oxygen into copper grain boundaries or interfaces is the likely cause of the early yield behavior. Possible mechanisms include an increase in interface adhesion due to the presence of oxygen in solution and diffusion-induced dislocation glide as an additional driving force for dislocation motion at low applied stress.

Ferroelectric PZT thin films were deposited on Pt and SrRuO3 substrates in a cold-wall reactor, using the Pb(C2H5)4/Zr(OBu)4/Ti(OPri)4/O2 reaction system. In comparison with Pt substrate, the growth rate of lead zirconate titanate (PZT) thin film was higher on SrRuO3. Lead content of the thin film deposited on either substrate at low temperatures (723–863 K) was much more temperature dependent than the other two metal contents. The strong temperature dependence originated from the high activation energy in the initial decomposition of Pb(C2H5)4 vapor, which was 54 kcal/mol. The surface reaction constant of lead precursor had much lower temperature dependence. The activation energy of surface reaction for PbO, estimated from deposition in a mini-chamber, was 6 kcal/mol on Pt and 9 kcal/mol on the SrRuO3 substrate. Therefore, the incorporation path of component oxide PbO, whose apparent activation energy was 31 kcal/mol on Pt and 29 kcal/mol on SrRuO3, essentially involved considerable gas-phase reaction. The PZT (50/50) thin film on SrRuO3 bottom electrode possessed a lower coercive field and a smaller remnant polarization than that on Pt. The PZT capacitor on SrRuO3 was also less vulnerable to polarization fatigue.

We report a new SBN-tellurite ceram-glass system, where the [(SrO)(y)(BaO)(1−y) (Nb2O5)](1−x) (SBN) ferroelectric crystallites precipitate on a tellurite (TeO2)x glass surface with nominal compositions x < 0.8 and y = 0.6 to 0.75. X-ray diffraction, calorimetry, and electro-optic measurements confirmed the ferroelectric nature of the SBN crystallites. In principle, this system has the potential for high transparency and the property tunability to match the application needs of optical devices.