Nanocrystalline KTiOPO4 powders were prepared through a chemical process. This process involved the hydrolysis of KOOCCH3 · 2H2O, Ti(OC4H9)4, and PO(OR)3 to produce a homogeneous solution. A gel was formed by the partial evaporation of this solution. After the gel was decomposed at 450 °C, white amorphous powder remained. On calcinating up to 550 °C, the amorphous powder began to transform into nanocrystalline KTiOPO4 powders with an average particle size of 30–50 nm. The KTiOPO4 powders were investigated through x-ray diffraction, infrared spectroscopy, and transmission electron microscopy studies.

Poly(lactic acid) composites containing a mixture of calcium carbonates (vaterite, aragonite, and calcite) were prepared by a carbonation process in methanol. Soaking of the composites for 3 h in simulated body fluid (SBF) at 37 °C resulted in the deposition of bonelike apatite particles on the composite surface. After soaking the composites, vaterite phase in the composites was forward to dissolve rapidly, resulting in increase the supersaturation of the apatite in SBF. 13C cross-polarization magic angle spinning nuclear magnetic resonance (13C CP/MAS-NMR) spectra of the composites suggested the formation of a bond between Ca2+ ion and the COO- group, which induces the apatite nucleation. These results may elucidate the mechanism of means to reduce the induction period for apatite formation.

We report that polycrystalline cubic-Si3N4 with a spinel structure and low oxygen concentration (<0.5 wt%) shows Vickers hardness of 43 GPa when measured with the indentation load of 10 mN. The hardness decreases with the increase of the indentation load, which can be ascribed to the presence of weak grain boundaries. The high hardness can be well explained by its large shear modulus as predicted by first-principles calculations.

The stability of single-wall carbon nanotubes under hydrothermal conditions (100 MPa pressure, from 30 min to 48 h in the temperature range from 200 to 800 °C) has been investigated. The resultant products were characterized by Raman spectroscopy, x-ray diffraction, and transmission electron microscopy. The stability range of single-wall carbon nanotubes (SWCNTs) under hydrothermal conditions suggests that they, similar to fullerenes, can only survive mild and short-term treatment in high-temperature, high-pressure water. SWCNTs gradually transform into multiwall carbon nanotubes (MWCNTs) and polyhedral graphitic nanoparticules. After 48 h at 750 °C only the Raman spectra characteristic of graphitic carbon were observed. Transmission electron microscopy revealed that after 800 °C and 48 h of treatment SWCNTs fully transformed into MWCNTs and polyhedral carbon nanoparticles.

Nanocrystalline nickel particles were embedded in amorphous alumina and crystalline TiN matrices using a pulsed laser deposition process to investigate the effect of texturing on magnetic properties of nickel nanocrystallites. The crystalline quality of both the matrix and magnetic particles was investigated by cross-sectional high-resolution transmission electron microscopy. The embedded Ni nanocrystals were found to be epitaxial in the case of the TiN matrix and polycrystalline in Al2O3 amorphous matrix. The Ni nanocrystals on TiN/Si grow epitaxially because the TiN acting as a template grows epitaxially on Si substrate via domain epitaxy. On the other hand, Ni nanocrystals in the Al2O3 matrix are polycrystalline because of the amorphous nature of the alumina matrix. Magnetization versus temperature measurements have shown that the blocking temperature, above which the samples lose magnetization–field (M–H) hysteretic behavior, of the Ni–TiN sample (approximately 190 K) is significantly higher than that of Ni–Al2O3 sample (approximately 30 K) with a similar size distribution of embedded magnetic particles. A comparison of the values of coercivity (Hc) of the two samples, measured from M–H data, indicates that epitaxial Ni nanocrystals also exhibit significantly higher coercivity than polycrystalline Ni particles in amorphous alumina matrix. The high values of TB and Hc of Ni–TiN samples with respect to TB of N–A12O3 samples are believed to be associated with preferred alignment of nanocrystallites.

The microstructure and adhesion strength of the Sn–0.7Cu/Cu solder joints were examined. The acicular η(Cu6Sn5)-phase was formed inside the solder and at the solder/Cu interface, mostly in the direction normal to the interface. Compared to the Sn–3.5Ag alloy, the Sn–0.7Cu solder showed comparable wettability, but lower microhardness and joint strength. After aging, the acicular η-phase grew into a round and scallop-shaped morphology, thin є(Cu3Sn)-phase evolved just above the Cu substrate, and the joint strength decreased linearly with aging time.

NdBa2Cu3O7-x (NdBCO) superconducting films were successfully grown on MgO substrates by liquid-phase epitaxy (LPE) using YBa2Cu3O7-x (YBCO) seed films which have lower peritectic temperatures. Microstructural characterizations using optical and electron microscopes revealed that most of the seed grains decomposed at the high processing temperature and dissolved when they touched the solution. The NdBCO grains were formed first by the quasi-homoepitaxial growth of NdBCO units on the few surviving YBCO seed grains and then grew pendently to cover the large bare surface areas of the MgO substrates quickly by lateral overgrowth. A micrometer-thick melt layer was entrapped between the film and the substrate. Through the few links provided by the surviving seed grains, a stable film/substrate orientation relationship could still be maintained. A semiquantitative analysis was done for the lateral overgrowth process, and two different lateral overgrowth stages were observed with about 50 times difference in the lateral overgrowth rate. Then, a semiquantitative understanding for the entire YBCO-seeded NdBCO LPE growth process was finally reached.

Multilayered ceramic capacitors (MLCCs) with BaTiO3–BaZrO3 (BTZ) dielectric layers were fabricated, and the dielectric permittivity of the BTZ layers with different thicknesses in MLCCs was measured. The dielectric permittivity of the BTZ ceramic disk was also measured under various ac electric fields. The variation in the dielectric behaviors with the thickness of BTZ layers in MLCCs was explained by the ac-field dependence of dielectric permittivity observed in the BTZ ceramic disk. The ac-field dependence of dielectric permittivity of BTZ was markedly observed below the temperature of a broad maximum in the dielectric permittivity versus temperature (є versus T) curve. It was found that the temperature of the broad maximum shifted to the low-temperature side and the peak shape became asymmetric with increasing ac field. These changes in the dielectric properties under high ac fields were explained by a model of relaxors with the concept of the formation of polar microregions (PMRs) and the freezing of fluctuating ipoles in PMRs.

In this work, the solid solution series directionally solidified eutectic, Co1−xNixO/ZrO2(CaO), 0 ≤ x ≤ 1, was examined as a possible model system for interfacial fracture studies. These materials were grown by the optical floating zone method in an image furnace under controlled atmospheres to prevent the formation of Co3O4. For all compositions, lamellar microstructures were produced. The interface plane orientation relationship {111} Co1−xNixO║{100} ZrO2(CaO) was maintained throughout the solid solution series. The phase compositions were close to nominal values with some solubility of CoO in ZrO2(CaO). Preliminary indentation measurements demonstrate the onset of interfacial delamination for compositions of x <0.2.

The growth and structure of the Co1−xNixO series of single crystals with 0 ≤ x ≤ 1 were investigated with the goal of achieving a single-phase crystal over several centimeters of bulk growth. The single crystals were grown via the floating zone method controlling the partial pressure of oxygen to prevent secondary phase precipitation. The resulting crystals were single phase for all compositions. CoO was a single-domain crystal but contained microvoids. The lattice parameters followed a rule-of-mixtures trend, but the coefficient of thermal expansion exhibited a maximum in the middle of the solid solution, which was attributed to enhanced vacancy formation.

Single-phase Al4SiC4 was successfully synthesized by heating the powder mixture of aluminum, silicon, and carbon black in the molar ratio corresponding to the chemical composition of Al4SiC4 with a small amount of triethanolamine (TEA) above 1200 °C in argon gas. Without TEA, two phases of Al4C3 and SiC were formed, irrespective of the heating temperature. The marked mass gain by oxidation of Al4SiC4 was observed with forming Al2O3 and SiO2 in the range of 850 to 1150 °C, which slightly increased above 1150 °C. At 1600 °C, mullite was formed by the reaction between Al2O3 and SiO2.

Resistance measurement, P–E hysteresis measurement, and transmission electron microscope and energy dispersive analysis of x-rays (TEM-EDAX) analysis were used to study the resistance failure of lead magnesium niobate-based multilayer ceramic capacitors (MLCC) under dc voltage. It was found that the failure rate of MLCC with 1/9 Pd/Ag internal electrodes was 10 times that of MLCC with 3/7 Pd/Ag electrodes after the temperature–humidity–bias test (THB). Voltage shifts of hysteresis loops showed that an internal bias field between electrodes of MLCC was formed after THB test. Ag diffusion from electrodes into the ceramics during cofiring was examined through TEM-EDAX analysis. It was also found that the degraded specimens could be partially restored after storing under natural condition. On the basis of these results, the failure mechanism was established that oxygen vacancies induced by Ag diffusion accumulated under the external bias field, which increased the concentration of electronic defects, thereby resulting in the resistance failure of MLCC.

Direct evidence revealing fundamental differences in sequence of phase formation during the growth of TiSi2 in the presence of an ultrathin surface or interface Mo layer is presented. Results of cross-sectional transmission electron microscopy showed that when the Mo layer was present at the interface between Ti films and Si substrates, C40 (Mo,Ti)Si2 formed at the interface, and Ti5Si3 grew on top after annealing at 550 °C. Additionally, both C54 and C40 TiSi2 were found in the close vicinity of the C40 (Mo,Ti)Si2 grains. No C49 grains were detected. Raising the annealing temperature to 600 °C led to the formation of C54 TiSi2 at the expense of Ti5Si3, and the interfacial C40 (Mo,Ti)Si2 also began to transform into C54 (Mo,Ti)Si2 at 600 °C. When the Mo was deposited on top of Ti, the silicide film was almost solely composed of C49 TiSi2 at 600 °C. However, a small amount of (Mo,Ti)5Si3 was still present in the vicinity of the sample surface. Upon annealing at 650 °C, only the C54 phase was found throughout the entire TiSi2 layer with a surface (Mo,Ti)Si2 on top of TiSi2. Hence, it was unambiguously shown that in the presence of surface versus interface Mo, different routes were taken to the formation of C54 TiSi2.

We report a method for preparing Pr-doped ceria by pyrolysis at 600 °C of aerosols consisting of aqueous solutions of Ce(III) nitrate and Pr(III) chloride. This procedure involves an important decrease of the temperature of solid solution formation (several hundred degrees) when compared with the ceramic and other previously reported methods, and does not require the addition of fluxes. The prepared samples and their products after thermal treatment were characterized in terms of particle shape and size distribution, composition, and crystalline structure. The color properties of these solid solutions were also evaluated as a function of the heating temperature and composition; the optimum red pigment was obtained for samples with a Pr/Ce mole ratio = 0.063 heated for 3 h at 600 °C. The oxidation state of the Pr cations and their distribution in the CeO2 matrix were investigated by x-ray absorption near-edge spectroscopy and x-ray photoelectron spectroscopy. A mixture of trivalent and tetravalent Pr was detected in all studies samples. The Pr(IV)/Pr(III) ratio increased as the Pr content or the heating temperature increased. These Pr(III) cations were found to be mainly located in the particles' outer layers, in which an enrichment of Pr was detected for all samples heated at 600 °C. The further calcination of the pigments at 1200 °C gave rise to a certain diffusion of the Pr cations toward the particle core, which was more significant for the sample with the highest Pr content (Pr/Ce mole ratio 4 0.091).

Titanium diboride has been claimed as a very promising candidate material for protective applications in the magnetic recording. Its oxidation resistance at room temperature is a critical criterion in assessing this application potential. In this paper, the oxidation characteristics of ultrathin TiB2 thin films, such as overcoat erosion and oxide thickness, are investigated via a combination of x-ray reflectivity, x-ray photoelectron spectroscopy (XPS), and atomic force microscopy. It was found that a <2-h exposure to air at room temperature led to the formation of approximately 15-Å-thick, well-defined oxides at the expense of an approximately 9-Å erosion of the TiB2 overcoats, coupled with the existence of a sharp oxide/TiB2 interface. XPS studies confirmed the existence of the oxides. Considering the decreasing allowable thickness for such protective overcoats, oxidation and the resultant thickness gain negate such a potential of ultrathin TiB2 films. The results in our current report provide a new perspective on its potential as protective overcoats in magnetic recording.

The microstructures and their thermal behaviors of quenched Al94V4Fe2, Al90V8Fe2, Al86V8Fe6, and Al85V9Fe2Ni4 alloys were investigated by x-ray diffraction, transmission electron microscopy, and differential scanning calorimetry. The as-quenched microstructures of the four alloys consist of quasicrystal particles and a fcc-α–Al matrix. The as-quenched Al86V8Fe6 and Al85V9Fe2Ni4 alloys also contain a small volume fraction of amorphous phase. All phases observed have fine morphologies with grain sizes of less than 100 nm. With the increase in V from 4 to 8 at.% at 2 at.% Fe, the average grain size decreases from 100 to 70 nm and the melting temperature of α–Al solid solution increases from 640 to 653 °C. The alloy with 8 at.% V has a finer and more stable microstructure than that of the alloy with 4 at.% V. The Fe addition has minor effect on grain size but improves the glass-forming ability. The Ni addition significantly improves the glass-forming ability and refines the microstructure. The metastable amorphous and quasicrystalline phases transform into a stable crystalline phase during continuous heating and cooling. The stable phases in these Al–V–Fe alloys include α–Al(V, Fe), Al10V, and Al80V12.5Fe7.5.

Cupric tungstate (CuWO4) can be synthesized at high rates of conversion from a variety of solid reactants. However, the fixed copper content in the metal phase of CuWO4 limits its use as an oxide precursor for making W–Cu composite powders. This paper presents test results on synthesis of CuWO4-based composite oxides with a variable content of copper in the metal phase (5–25.7%). Hydrogen reduction converts the oxides to W–Cu composite powders with a unique phase distribution: each individual particle consists of a tungsten phase and a copper phase in which the tungsten phase substantially encapsulates the copper phase. These powders, when pressed and sintered without activators, yield high-density parts with a very fine microstructure and high electrical and thermal conductivity.

The morphological and phase composition changes during sintering of ultralight pure Al2O3 and Al2O3/TiO2 foams were investigated in the temperature range of 900–1600 °C in air. The titania (10 wt%) was incorporated during a nonhydrolytic foaming procedure to facilitate its uniform dispersion in the alumina matrix. The changes of linear shrinkage and related changes in effective density and porosity demonstrate a higher reactivity in the Al2O3/TiO2 foam. The formation of tialite phase in the Al2O3/TiO2 foams occurred below 1300 °C and remained stable during cooling under 1200 °C without stabilizers.

In accordance with magnetization studies, the fast-cooled TbBaCo2O5.4 is characterized by spontaneous magnetization around 0.18 μB per cobalt ion, which develops below TN = 245 K. The neutron diffraction study of this compound revealed that magnetic moments of Co3+; ions adopting intermediate spine state are ordered antiferromagnetically. Both magnetization and neutron diffraction study showed that there is a spin reorientation process in the wide temperature range. The crystal and magnetic structures are discussed.

β–BaB2O4 (β-BBO) films with the (00l) preferred orientation were successfully fabricated on Si(100) and fused quartz substrates by the chemical solution deposition technique. The films were characterized by x-ray diffractometry in out-of-plane and in-plane geometry, reciprocal space mapping, transmission electron microscopy, and scanning electron microscopy. The degree of orientation of the films is as high as 95% and the full width at half-maximum (FWHM) of the rocking curve for the films is as low as 2.9°. The films have a mosaic structure. The (00l) planes of some of the crystallites tilt to the substrate and the in-plane orientation of each crystallite is random. The size of each crystallite is 0.5–1.5 μm, and crystallite thickness is equal to the film thickness. The degree of orientation of the films increases and the FWHM of rocking curve for the films decreases with increasing film thickness. The thicker the films are, the larger the crystallite size and the more definite the crystallite boundaries are. These phenomena are thought to be closely related with the increase in internal stress with film thickness. The films irradiated by Nd3+: YAG laser light generated second harmonic wave.