Micromolding in capillaries has been used to generate patterned microstructures of ZrO2 or SnO2 from its polymeric precursor. After patterning, the amorphous precursor was converted into the desired polycrystalline ceramic material by calcination in air at 460 °C. The final phase for each ceramic material was determined by powder x-ray diffraction. The shrinkage of the precursor material during pyrolysis was investigated by scanning electron microscopy and atomic force microscopy. These ceramic microstructures could be either supported on solid substrates or released as freestanding fibers and membranes. Their lateral dimensions could be as small as approximately 500 nm.

Interfacial phenomena and microstructure in Ag–Si multilayers with a modulation period of 7.64 nm during annealing from 323 to 573 K were investigated by in situ x-ray diffraction and high-resolution transmission electron microscopy. Uphill and downhill diffusion were observed on annealing. The temperature dependence of the effective diffusion coefficient from 373 K (as to downhill diffusion regime) to 523 K was De = 2.02 × 10−20 exp(−0.24 eV/kBT) m2/s. Diffusion of silicon atoms along silver grain boundaries was proposed as the main diffusion mechanism. After annealing, continuous silver sublayers changed to nanometer-sized silver particles (about 4.5 nm) coated completely by amorphous silicon.

Ferroelectric Pb(Zr, Ti)O3 (PZT) thin films were grown on Pt/Ti/SiO2/Si, RuO2/Pt/Ti/SiO2/Si, and Pt/MgO substrates at the substrate temperature of 600 °C by the metalorganic chemical vapor deposition (MOCVD) method. Pb(C11H19O2)2(Pb(DPM)2), Ti(OiC3H7)4, and Zr(OtC4H9)4 as source material and Ar and O2 as a carrier gas and oxidizing agent were selected, respectively. In order to investigate the effect of Zr and Ti component changes on the growth aspect of PZT thin films, Zr and Ti source materials were varied by controlling Zr and Ti flow rate. From the Rutherford backscattering spectroscopy (RBS) measurement, it was confirmed that the composition of the films, particularly Pb content, changed with the increasing Zr flow rate. In addition, the x-ray diffraction (XRD) spectra analysis showed the existence of a Pb-deficient pyrochlore phase as well as ZrO2 as a secondary phase. From these results, it is believed that the higher Zr partial pressure in the gas phase reduces the sticking of the Pb precursor to the substrate. The film with Pb:Zr:Ti = 1:0.42:0.58 showed a dielectric constant of 816 at 1 MHz. The spontaneous polarization, remanent polarization, and coercive field measured from the RT66A by applying 3.5 V were 44.1 μC/cm2, 24.4 μC/cm2, and 59.6 kV/cm, respectively. The fatigue analysis of PZT thin films with Pb:Zr:Ti = 1:0.42:0.58 at an applied voltage of Vp-p = 5.4 V showed 40% degradation on the basis of initial polarization value after 109 cycles.

β–Si3N4 seed crystal has been synthesized from α–Si3N4 powder. Reaction-bonded Si3N4/SiC composite has been fabricated with β–Si3N4 seed crystals. The nitridation behavior and the changes in mechanical properties resulting from the addition of seed crystals were studied before and after gas pressure sintering. Addition of seeds showed a considerable improvement in the nitridation, resulting in increase in fracture strength of the composite. Highly nitrided reaction-bonded Si3N4 (RBSN) as a result of the addition of seed crystals gave rise to high strength of composite after postsintering. Fracture toughness of the seeded Si3N4 was also improved up to 35% compared to the baseline Si3N4. Micrographs showed that the seeded Si3N4 developed a bimodal microstructure which resulted in an improvement in fracture toughness.

The electrical properties of hydrothermally grown epitaxial pseudocubic BaTiO3 thin films formed on epitaxial electrode layers of SrRuO3 on SrTiO3 single crystal substrates have been evaluated by variable frequency dielectric testing. The initial as-synthesized BaTiO3 film displayed a dielectric constant of 450 with very high losses (tan δ ˜ ~ 100%) at 10 kHz due to OH− and H2O, incorporated during growth, contributing to migration losses within the film. Improvements were seen with increasing postprocessing heat-treatment time and temperature with improved properties seen after a heat treatment at 300 °C for 24 h (ε ˜ ~ 200, tan δ ˜ ~ 8%). Relationships were established for dielectric constant and loss tangent with structural changes observed by Fourier transform infrared spectroscopy, thermal gravimetric analysis, nuclear magnetic resonance spectroscopy, and x-ray diffraction.

The mechanism for grain growth of β–SiC was investigated by annealing hot-pressed β–SiC–oxynitride glass (Y–Mg–Si–Al–O–N) ceramics at 1800 °C. An observed decrease in grain growth with increasing weight fraction of liquid confirms a diffusion-controlled growth mechanism in the system. The growth of nearly spherical β–SiC grains in the annealed specimen also supports the above conclusion.

The growth of ultrathin gold films on polyimide (PI) surfaces and the stability of the films upon thermal annealing have been studied using a combination of various techniques. With scanning electron microscopy (SEM) we observe that, at room temperature, the Au film initially grows by nucleation of compact Au islands. With increasing metal coverage, the clusters partially agglomerate to produce a wormlike structure. Finally, percolation, hole-filling, and continuous thin-film growth are observed. To evaluate the thermal stability of the Au/PI system, annealing at various temperatures was performed on films that displayed the wormlike structure. SEM results indicate strong temperature-dependent changes in film morphology. Finally, from our SEM data we determine contact angles, allowing us to estimate interfacial and adhesion energies.

ZrO2–Al2O3 powders were synthesized by spray pyrolysis. These powders were sintered at 1 GPa in the temperature range of 700–1100 °C. The microstructural evolution and densification are reported in this paper. The application of 1 Gpa pressure lowers the crystallization temperature from ∼850 to <700 °C. Similarly, the transformation temperature under 1 GPa pressure for γ → α–Al2O3 reduces from ∼1100 to 700–800 °C range, and that for t → m ZrO2 reduces from ∼1050 to 700–800 °C range. It was possible to obtain highly dense nanocrystalline ZrO2–Al2O3 composite at temperatures as low as 700 °C. The effect of high pressure on nucleation and transformation of phases is discussed.

Ca4(PO4)2O (TetCP) reacts with an acidic polyelectrolyte in the absence of a solvent to form a composite composed of Ca10(PO4)6(OH)2 (hydroxyapatite, or HAp) and the Ca salt of the polyelectrolyte. Mixtures of an acrylic copolymer and TetCP powders were hot-pressed, and the effects of temperature, pressure, and time on HAp formation were studied. Reaction starts when the copolymer is heated to above Tg. Initial carboxyl site neutralization liberates water, continued TetCP hydrolysis, liberates Ca2+ ions, which react with the copolymer forming its Ca salt. When 90% conversion to HAp was achieved, the composite had an average tensile strength of 51 MPa, a Vickers hardness of 145 kg/mm2 and a Tg ˜50 °C.

We report on the properties of BaBi2Ta2O9 (BBT) thin films for dynamic random-access memory (DRAM) and integrated capacitor applications. Crystalline BBT thin films were successfully fabricated by the chemical solution deposition technique on Pt-coated Si substrates at a low annealing temperature of 650 °C. The films were characterized in terms of structural, dielectric, and insulating properties. The electrical measurements were conducted on Pt/BBT/Pt capacitors. The typical measured small signal dielectric constant and dissipation factor, at 100 kHz, were 282 and 0.023, respectively, for films annealed at 700 °C for 60 min. The leakage current density of the films was lower than 10−9 A/cm2 at an applied electric field of 300 kV/cm. A large storage density of 38.4 fC/μm2 was obtained at an applied electric field of 200 kV/cm. The high dielectric constant, low dielectric loss and low leakage current density suggest the suitability of BBT thin films as dielectric layer for DRAM and integrated capacitor applications.

CeO2 films with thicknesses ranging from 8.8 to 199 nm were grown on Al2O3 (1102) (R-cut) substrates by off-axis rf magnetron sputtering. X-ray diffraction showed an epitaxial relationship with the CeO2 (001) planes parallel to the Al2O3 (1102) planes for all film thicknesses. Atomic force microscopy (AFM) revealed a rough surface morphology consisting of crystallites with lateral dimensions of 10–90 nm. In the thinnest film, these crystallites were regularly shaped and uniformly distributed on the substrate, while they were rectangularly shaped and oriented mainly in two directions, orthogonal to each other, in the thicker films. The surface roughness of the films increased with increasing layer thickness. Characterization of the microstructure was done by cross-sectional transmission electron microscopy (XTEM) and showed a polycrystalline, highly oriented, columnar structure with a top layer terminated by (111)-facets. High-quality YBa2Cu3O7−δ (YBCO) thin films were deposited directly onto the CeO2 layers. XTEM, rather surprisingly, showed a smooth interface between the YBCO and CeO2 layer. Postdeposition ex situ annealing was carried out on two CeO2 films and evaluated by AFM. Upon annealing samples at 930 °C, a relatively smooth morphology without facets was obtained. Annealing films at 800 °C caused no appreciable change in surface morphology, whereas igniting a YBCO plasma during a similar anneal clearly altered the sample surface, giving facets that were rounded.

The chemical and morphological properties of a sol-derived layered perovskite compound, Kca2Nb3O10 (KCN), are presented. Development of this compound is motivated by its use as an interphase fiber-coating material for ceramic matrix composites (CMC's). In such systems, this material is to be placed between the fiber and matrix to control crack propagation in the vicinity of the fiber, thereby enhancing toughness. Comparative analyses are performed between known bulk specimens of KCN and the sol-derived product using transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS). The suitability of the sol-derived KCN for CMC applications is demonstrated through microstructure and chemical composition similar to that of the known bulk KCN samples.

[Si–Y–Ti–O–C–N] multicomponent powders were synthesized by pyrolysis at 1000 °C, in NH3 flow, of chemically modified perhydropolysilazane using yttrium triisopropoxide and titanium tetrachloride. [Si–Y–Ti–O–C–N] powders yielded uniform and fine-grained Si3N4–TiN–Y2O3 ceramics by heat treatment at 1800 °C in N2. The fully densified Si3N4–TiN–Y2O3 ceramics were also synthesized by heat treatment at 1800 °C, followed by powder-vehicle hot pressing at 1800 °C in N2. The resulting ceramics revealed that TiN was dispersed as particles having a size range of about 60–600 nm and the fine particles less than 80 nm were dispersed within the β–Si3N4 matrix grains.

0.53Ti0.47)O3 have been prepared on platinized GaAs (Pt–GaAs) substrates using a new 1,1,1-tris(hydroxymethyl)ethane (THOME) based sol-gel technique. Rapid thermal processing (RTP) techniques were used to decompose the sol-gel layer to PZT in an effort to avoid problems of GayAs outdiffusion into the PZT. A crystalline PZT film was produced by firing the sol-gel coatings at 600 or 650 ° for a dwell time of 1 s using RTP. A single deposition of the precursor sol resulted in a 0.4 μm thick PZT film. X-ray diffraction measurements revealed that the films possessed a high degree of (111) preferred orientation. Measured average values of remanent polarization (Pr ) and coercive field (Ec) for the film annealed at 650 ° for 1 s were 24 μC/cm2 and 32 kV/cm, respectively, together with a low frequency dielectric constant and loss tangent at 1 kHz of 950 and 0.02. These values are comparable to those obtainable on platinized silicon (Pt–Si) substrates using conventional sol-gel methods, and are an improvement on PZT thin films prepared on platinized GaAs using an earlier sol-gel route based on 1,3-propanediol.

The microstructure and the defects of ZnO coatings deposited at room temperature by sputtering onto fibers and flat substrates were characterized using transmission electron microscopy (TEM), scanning electron microscopy, and x-ray diffraction (XRD). XRD shows that the films have a [0001] preferred orientation and a large angular width of the 0002 reflection. According to TEM observations, the film microstructure consists of columnar grains which contain large concentrations of basal planar defects and dislocations. High-resolution transmission electron microscopy analysis and the associated image simulation are in full agreement with the presence of single (type I) and double (type II) stacking faults. The relation between the observed defects and the 0002 peak broadening is discussed.

The degree of mixing is a critical factor in controlling the magnetic properties and mechanical properties of polymer-bonded magnets. Pretreatment of the NdFeB fillers with a silane coupling agent improved the degree of mixing of the fillers in the polymer matrix. The observed improvement in the degree of mixing of the silanetreated fillers was ascribed to good wetting as evidenced by viscosity reduction of the coupled polymer-bonded magnets. However, traditional materials characterization methods could not be used to quantitatively determine the degree of mixing of the polymer-bonded magnets. This paper describes use of thermogravimetric analysis to quantify the degree of mixing of polymer-bonded magnets. The intensity of segregation of the fillers was calculated from the measured weight change of the magnetic filler in the samples. The results of this work showed that the thermogravimetric analysis method was useful in determining the degree of mixing of NdFeB fillers in polymer-bonded magnets.

Gas-sensing properties of a novel surface functionalized tin oxide material have been studied to demonstrate the possibility of selectivity control by surface state formation. Covalent anchoring of ruthenium oxide on the tin oxide surface (ruthenated tin oxide) is found to give considerable enhancement in sensitivity (320) as well as selectivity to 1000 ppm of liquified petroleum gas (LPG) at 300 °C compared to the sensitivity (4) of pure tin oxide samples. The amount and distribution of grafted ruthenium oxide on the surface of tin oxide seems to be the most important parameter controlling the change in electrical transport with LPG gas adsorption.

The Ni/(ZrO2 + 9.5 mol% Y2O3) interface was used as a model system to investigate decomposition reactions of a yttria-stabilized ZrO2 electrolyte in contact with a metal at elevated temperature. In the present study, the sample was a diffusion-bonded symmetrical galvanic cell Ni‌ZrO2 + 9.5 mol% Y2O3‌Ni. Various electron microscopy techniques were used to study the morphology and structure of the reaction products at the Ni–ZrO2 electrolyte phase boundary after current flow. Below a critical oxygen partial pressure of approximately 10−27 atm, an intermetallic reaction layer formed at the Ni–electrolyte interface. Between the intermetallic layer and electrolyte a thin Y2O3 layer was present, which acted as a diffusion barrier for Zr and Ni, slowing down the overall chemical reaction. At several locations at the interface the Y2O3 layer broke up, leading to a morphological instability of the interface between electrolyte and Ni5Zr, allowing further reaction. The thickness of the total reaction layer varied widely as a consequence of such an instability.

The texture in the melt-processed GdBCO superconductor is studied as a function of Gd2BaCuO5 additions, using a texture goniometer. A systematic variation observed in the background intensity is connected to the microstructural variations and the powder x-ray diffraction spectra.

The structural transformation of anatase TiO2 by high-energy vibrational ball milling was studied in detail by different analytical methods of x-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). This structural transformation involves both phase transition and nanoparticle formation, and no amorphization was observed. The crystallite size was found to decrease with milling time down to nanometer size ∼13 nm and approaching saturation, accompanied by phase transformation to metastable phases, i.e., TiO2(II), which is a high-pressure phase and TiO2(B), which was identified in ball-milled powder reported for the first time in this paper. These phases eventually started transforming to rutile by further milling.