We propose a new theory with the potential for measuring the elastoplastic properties of compliant and soft materials using one sharp indentation test. The method makes use of the substrate effect, which is usually intended to be avoided during indentation tests. For indentation on a compliant and soft specimen of finite thickness bonded to a stiff and hard testing platform (or a compliant/soft thin film deposited on a stiff/hard substrate), the presence of the substrate significantly enhances the loading curvature which, theoretically, enables the determination of the material power-law elastic-plastic properties by using just one conical indentation test. Extensive finite element simulations are carried out to correlate the indentation characteristics with material properties. Based on these relationships, an effective reverse analysis algorithm is established to extract the material elastoplastic properties. By utilizing the substrate effect, the new technique has the potential to identify plastic materials with indistinguishable indentation behaviors in bulk forms. The error sensitivity and uniqueness of the solution are carefully investigated. Validity and application range of the proposed theory are discussed. In the limit where the substrate is taken to be rigid, the fundamental research is one of the first steps toward understanding the substrate effect during indentation on thin films deposited on deformable substrates.

Multilayered manganese oxide films were prepared on a platinum electrode by potentiostatic oxidation of aqueous Mn2+ ions in the presence of n-tetra-alkylammonium compounds. Alkylammonium cations were intercalated between manganese oxide layers to balance the negative layer charge. Effects of several preparative parameters such as the size of alkylammonium molecules, counteranions, and bath composition on the structure of products were investigated. The interlayer distance of the products increased with increasing alkyl chain length up to C4, and the change became obviously small among C4–C6 compounds. The multilayer formation was achieved only when the manganese concentration was lower than 10 mM, and the highest crystallinity was obtained from a bath composed of 2 mM manganese sulfate and 50 mM alkylammonium chloride. At low concentrations of alkylammonium (<10 mM), a product intercalated with hydrated protons was formed, in which the protons were generated by anodic oxidation of Mn2+ with H2O.

It is known that porous organosilicate glass (OSG) dielectrics tend to lose functional groups and become denser upon the chemical and physical action of the plasmas, but an accurate analysis and estimation of the depth and degree of film densification is not straightforward. In this study, we show that the combination of techniques like x-ray reflectivity, surface acoustic waves, and nanoindentation in depth-sensing and modulus mapping mode allow a complete and self-consistent physical analysis of the damage induced by the direct exposure of porous OSG films to different plasma ambients in reactive ion etching mode. We demonstrate for the chosen dielectric that the characteristics of the damage regions such as density and elastic modulus are very similar regardless of the reducing or oxidizing nature of the plasma. Nevertheless, the physical depth of the damage region shows large variation. Capabilities and limitations of each of the chosen analysis techniques are also discussed.

Sputter-deposited, Al/Pt multilayer thin films of various designs exhibited rapid, self-propagating, high-temperature reactions. With reactant layers maintained at ∼21 °C prior to ignition and films adhered to oxide-passivated silicon substrates, the propagation speeds varied from approximately 20 to 90 m/s depending on bilayer dimension and total film thickness. Contrary to current Al–Pt equilibrium phase diagrams, all multilayers reacted in air and in vacuum transformed into rhombohedral AlPt having a space group R-3(148). Rietveld refinement of AlPt powder (generated from thin film samples) yielded trigonal/hexagonal unit cell lattice parameters of a = 15.634(3) Å and c = 5.308(1) Å; the number of formula units = 39. Rhombohedral AlPt was stable to 550 °C with transformation to a cubic FeSi-type structure occurring above this temperature.

Minor additions of Sn in the bulk glass-forming Fe61−xSnxY2Zr8Co5Cr2Mo7B15 (x = 0% to 2%) system were studied in detail. It was found that combinations of Y and Sn can scavenge oxygen out of the undercooled liquids to form innocuous oxides, thus stabilizing the liquids. Besides this beneficial scavenging effect, Sn additions in the present Fe-based alloys also showed complex alloying effects on glass formation, which can be divided into three stages. At stage I (x ≤ 0.5%), the microalloyed compositions associate with the same eutectic as that of the base alloy. The glass-forming ability (GFA) of the resulting alloys is determined primarily by their liquidus temperature and similar to that of the base alloy. At stage II (0.85% ≤ x ≤ 1.15%), glass-matrix composite structures start to form because the alloy compositions are adjusted into a new “deeper” eutectic system. At stage III (x > 1.15%), however, alloy compositions shift to another new eutectic system, and the GFA is dramatically decreased due to the strong formation of primary phase α–Fe. Homogeneous glass-matrix composites with a diameter of 7 mm in the alloy containing 1.0–1.15% Sn were successfully produced.

A new nonhydrolytic route for the preparation of well-crystallized size-tunable barium titanate (BaTiO3) nanocrystals capped with surface ligands is reported. Our approach involves: (i) synthesizing a “pseudo” bimetallic precursor, and (ii) combining the as-synthesized bimetallic precursor with a mixture of oleylamine with different surface coordinating ligands at 320 °C for crystallization and crystal growth. Different alcohols in the precursor synthesis and different carboxylic acids were used to study the effect of size and morphological control over the nanocrystals. Nanocrystals of barium titanate with diameters of 6–10 nm (capped with decanoic acid), 3–5 nm (capped with oleic acid), 10–20 nm (a nanoparticle and nanorod mixture capped with oleyl alcohol), and 2–3 nm (capped with oleyl alcohol) were synthesized, and can be easily dispersed into nonpolar solvents such as hexane or toluene. Techniques including x-ray diffraction, transmission electron microscopy, selected area electron diffraction, and high-resolution electron microscopy confirm the crystallinity and morphology of these as-synthesized nanocrystals.

Joint reliability of immersion Ag with two different solders, Sn–37Pb and Sn–3.5Ag, were evaluated. We first compared the interfacial reactions of the two solder joints and also successfully revealed a connection between the interfacial reaction behavior and mechanical reliability. The Sn–Pb solder produced a Pb-rich phase along the interface between the solder and the Cu substrate during aging. In contrast, the Sn–Ag solder exhibits an off-eutectic reaction to produce the eutectic phase and Ag3Sn precipitate. The shear test results show that the Sn–Pb solder joint fractured along the interface showing brittle failure indications possibly due to the brittle Pb-rich layer. In contrast, the failure of Sn–Ag solder joint was only through the bulk solder, providing evidence that the interface is mechanically reliable. The results from this study confirm that the immersion Ag/Sn–Ag solder joint is mechanically robust, and thus the combination is a viable option for a Pb-free package system.

Titanium dioxide thin films were deposited on crystalline silicon (100) substrates by delivering a liquid aerosol of titanium-diisopropoxide. The evidence of a metalorganic chemical vapor deposition process observed in the crystalline and morphological features of the films is strongly supported by the behavior of the growth rate rg as a function of the deposition temperature. The rg line shape indicates that in a wide range of temperatures (∼180–400 °C), the film formation is limited by both gas-phase diffusion of some molecular species toward the substrate surface and the thermal reaction of those species on that surface. The activation energy EA that characterizes the surface reaction depends somewhat on the precursor concentration; a fitting procedure to an equation that takes into account both limiting mechanisms (gas-phase diffusion + surface reaction) yields EA ≃ 27.6 kJ/mol.

Subsolidus equilibria in the PbO-poor part of the TiO2–PbO–SiO2 diagram were studied with the aim of investigating possible applications for low-temperature thick-film dielectrics. The tie lines are between PbTiO2 and PbSiO3, and between PbTiO3 and SiO2. The results show that the TiO2, when added to low-temperature softening point glasses, reacts with the PbO from the glass, so forming PbTiO3. These results were applied to a low-temperature firing dielectric, consisting of a lead-rich PbO–SiO2–B2O3 glass filled with a TiO2 powder. The conversion of TiO2 to the PbTiO3 crystalline phase was observed above firing temperatures of approximately 600 °C. The kinetics of the reaction depend on the particle size of the TiO2.

We fabricated three-dimensional photonic crystals by self-assembling gold nanoshells via forced sedimentation method. Gold nanoshells with a diameter of 458 nm (418-nm silica core and 20-nm gold shell) were synthesized and self-assembled into a 5-μm-thick opal structure. We observed reflection peaks at 710 and 1240 nm, which are believed to be from the complete three-dimensional photonic band gap and the (111) directional gap, respectively. Theses results were in good agreement with the photonic band-structure calculations done by the finite-difference time-domain method. Angle-resolved reflectivity measurements were also performed to investigate the existence of the complete three-dimensional photonic band gap.

The wetting of Sn3Ag-based alloys on Al2O3 has been studied using the sessile-drop configuration. Small additions of Ti decrease the contact angle of Sn3Ag alloys on alumina from 115° to 23°. Adsorption of Ti-species at the solid–liquid interface prior to reaction is the driving force for the observed decrease in contact angle, and the spreading kinetics is controlled by the kinetics of Ti dissolution into the molten alloy. The addition of Ti increases the transport rates at the solid–liquid interface, resulting in the formation of triple-line ridges that pin the liquid front and promote a wide variability in the final contact angles.

Cadmium-doped ZnO was prepared for the first time by combustion synthesis using CdCl2 as a dopant precursor, with zinc nitrate and urea as the combustion mixture. Unlike previous studies of combustion synthesis of ZnO in the presence of an indium nitrate precursor, which resulted in (ZnO)mIn2O3 (m = 3 or 4) compound formation, In-doped ZnO was prepared by combustion synthesis in this study using an InCl3 precursor. The doped samples were compared and contrasted with undoped ZnO using scanning electron microscopy, x-ray powder diffraction, energy-dispersive x-ray analyses, and x-ray photoelectron spectroscopy. Diffuse reflectance spectroscopy showed the optical band gap of ZnO to shrink from 3.14 to 3.07 eV and 3.02 eV on Cd and In doping, respectively. Finally, the doped samples showed an improved photoelectrochemical response relative to undoped ZnO over the wavelength range from ∼300 to ∼450 nm.

The formation enthalpies from the oxide end-members (ΔHf,ox) of the CeO2–MO1.5 (M = La, Gd, and Y) systems were determined by high temperature oxide melt drop solution calorimetry. In each system, ΔHf,ox is slightly positive over the investigated composition range with a maximum at a certain doping level. Above that concentration, ΔHf,ox decreases rapidly and stays almost constant. Such behavior is strikingly different from the strongly negative ΔHf,ox of the ZrO2–YO1.5 and HfO2–YO1.5 systems. The absence of substantial energetic stabilization in the CeO2–MO1.5 systems may be attributed to the large size of Ce4+, which has no preference for 7-coordination like the smaller Zr4+ or Hf4+ ions. The primary defect associates in CeO2–MO1.5 are proposed to be neutral trimers with oxygen vacancies nearest neighbor to the dopant cations. It is also suggested that the maximum ΔHf,ox (destabilization) of CeO2–MO1.5 is determined by the local site distortion rather than the global lattice deformation. The relatively stable region after the maximum ΔHf,ox may be attributed to the somewhat stabilizing long-range defect–defect interactions, which become effective above a certain doping level.