The exposure response of high resolution oxide resist materials has been examined under high intensity irradiation conditions (∼1 ⊠ 105 A/cm2) to determine the relationships among film characteristics, exposure requirements, and ultimate resolution, and to explore further the processes responsible for ablative exposure. Amorphous films of Al2O3, Y2O3, Sc2O3, 3Al2O3·2SiO2, and MgO·Al2O3 were deposited by rf sputtering onto substrates cooled to –196°C and found to require an exposure dose of approximately 5 ⊠ 103 C/cm2 to complete exposure. Amorphous film structure was found to be necessary to achieve rapid removal of material during exposure. Material properties also found to influence irradiation response and help guide the selection of new materials included ionic character, heat of formation, and melting point. Film thickness was found to influence strongly both exposure requirements and resolution, an optimum thickness occurring at approximately 90 nm in amorphous Al2O3. The dose requirement in 90 nm thick amorphous Al2O3 was determined to be 2.5 ⊠ 103 C/cm2, which is two to three orders of magnitude lower than that of oxide films produced by other techniques. Resolution of the rf sputtered oxide films allowed the production of 5.0 nm holes on 8.1 nm centers. A dedicated STEM was used for exposure studies as well as imaging, microdiffraction analysis, and monitoring of the transmitted beam current, and allowed a qualitative model of the exposure process in rf sputtered oxide resists to be developed.

Nanoindenter techniques have been used to determine the hardness. Young's modulus, and strain rate sensitivity of nanophase TiO2, which is currently available only in very small quantities and which cannot be tested by most conventional techniques. Hardness and Young's modulus both increase linearly with sintering temperature over the range 25–900°C but come to within only 50–70% of the single crystal values. Strain rate sensitivity, on the other hand, is measurably greater for this material than for single crystal rutile, and the value of strain rate sensitivity increases as the grain size and the sintering temperature are decreased. In its as-compacted form, the strain rate sensitivity of nanophase TiO2 is approximately a quarter that of lead at room temperature, indicating a potential for significant ductility in these ceramic materials. Finally, a significant scatter in hardness values has been detected within individual nanophase samples. This is interpreted as arising from microstructural inhomogeneity in these materials.

Spherical and rod-like SnO2 particles of narrow size distribution have been obtained by aging at 100°C acidified tin(IV) chloride solutions in the presence of urea or formamide. It was shown that spherical particles, the x-ray diffraction of which was characteristic of cassiterite, consisted of a large number of much smaller subunits. The rod-like particles had the same structure, but of higher degree of crystallinity. Infrared spectra of these powders were evaluated in terms of the theory of the average dielectric constant (TADC), in order to gain additional information on the particle morphology and the state of aggregation.

Amorphous fluoride powder in the ZrF4-BaF2-LaF3-AlF3 (ZBLA) system has been prepared by a direct chemical route from metal alkoxides by reaction with bromine trifluoride. The potential of bromine trifluoride as a solvent for use in sol-gel synthesis of fluoride glass is discussed.

Three series of cordierite powders were prepared by the sol-gel route: a single phase (monophasic) gel prepared from alkoxides, a nominally triphasic nanocomposite gel made with two nanosized powders and one solution phase, and a truly compositionally triphasic nanocomposite gel prepared from three nanosized powders. Crystalline α-cordierite seeds were also incorporated with the gels and their effectiveness as nucleating agents was investigated and found to lower the crystallization temperature of α-cordierite by 125–150°C. The densification behavior of powder compacts was examined and alterations made to the heat treatment until optimum conditions were found. The truly triphasic compact sintered at 1300°C for 2 h resulted in 100% of theoretical density whereas the nominally triphasic and monophasis pellets densified to 96% and 80%, respectively. The enhanced densification achieved with powder compacct prepared for triphasic nanocomposite gels is due to part to the excess free energy of the three components.

Constant pressure molecular dynamics (MD) simulations have been used to simulate amorphous and crystalline forms of BaTiO3 and TiO2. Simulation results for pure RaTiO3 and TiO2 glasses show fourfold titanium coordination with a Ti–O bond distance of 1.8 Å, consistent with experimental evidence for the structure of titania doped glasses for all optical switching and ultra low expansivity (ULE) TiO2–SiO2 glasses. Radial distribution function data for crystalline, liquid, and amorphous forms of BaTiO3 were also obtained. The displacement polarization and its contribution to susceptibilities have been calculated by application of an electric field to the simulation cell. The calculated ionic dielectric constants (Ki) for simulated NaCI (crystal), TiO2 glass, and TiO2 (crystal) were 3.34, 5.96, and 19.4 as compared to the experimental values of ≍3.34, 3–10, and 78, respectively. The calculated cubic nonlinear susceptibility (ξ3) values for NaCI (crystal), TiO2 (glass), and TiO2 (crystal) were, respectively, 0.194, 2.175, and 4.68 (x 10−18m2V−2). The increase in ξ3 values is consistent with experimentally observed trends of the linear refractive indices. Improved agreement between experimental and calculated values of susceptibilities and dielectric constant was obtained for materials with higher ionicity.

The interfacial adhesive shear strengths of four commercial polymer coatings on soda-lime glass were measured by the microindentation and single lap shear tests. The indentation interfacial shear strengths were over an order of magnitude greater and exhibited significantly less variability than those measured by lap shear. It is believed that the indentation test measures the “intrinsic” interfacial shear strength of the bonded coatings, whereas the lap shear strengths are controlled by large processing flaws (pores in this study) in the region of stress concentration near the overlap edge.

It is shown that a phenomenological relation exists between the Debye temperature θ (in degree Kelvin) and the surface energy Γ (in ergs/cm2) of cubic solids: , where M is the atomic weight. This relation is derived theoretically in the Debye isotropic approximation by assuming that the interatomic potential is central. No restrictions are imposed on the range of the potential. The relation is obeyed very well by the observed values of θ and Γ in the case of many solids.

X-ray tomographic microscopy (XTM), utilizing intense, highly collimated synchrotron radiation, has been used to nondestructively image materials structures in three dimensions. The spatial resolution of the technique approaches that of conventional optical microscopy, but XTM does not require polished surfaces or serial sections. We present the results of an XTM investigation of a composite material composed of silicon-carbide fibers in an aluminum matrix. The results reveal the aluminum/silicon-carbide interfaces and show microcracks running along many of the interfaces as well as in the matrix. Excellent contrast is observed between the silicon-carbide sheath of the fiber surrounding the graphite core and the coating at the fiber-matrix interface. The sensitivity to small changes in the linear absorption coefficient allows nondestructive imaging of variations in chemistry between graphite and silicon carbide and between silicon carbide and aluminum. The experimentally determined values of the absorption coefficients of these phases are identical to values published in the literature. For the first time, XTM will allow observation of damage accumulation and crack growth during deformation testing. The availability of such data will greatly improve our understanding of failure in advanced materials.

This review summarizes the results of the joint Japanese (Central Research Institute of Electric Power Industry, CRIEPI, Tokyo), Swiss (National Cooperative for the Storage of Radioactive Waste, NAGRA, Baden), Swedish (Swedish Nuclear Fuel and Waste Management Company, SKB, Stockholm) international ‘JSS’ project on the determination of the chemical durability of the French nuclear waste borosilicate glass, which was completed in 1988. Radioactive and nonradioactive glass specimens were investigated. A data base was created with results from glass corrosion tests performed with different water compositions, pH values, temperatures, sample surface areas (S), solution volumes (V), and flow rates. Glass corrosion tests were performed with and without bentonite and/or steel corrosion products present. Variation of the glass composition was taken into account by including the borosilicate glass ‘MW’ in the investigations, formulated by British Nuclear Fuels, plc. An understanding was achieved of the glass corrosion process in general, and of the performance of the French glass under various potential disposal conditions in particular. A special effort was made to establish a corrosion data base, using high S/V ratios in the experiments in order to understand the glass durability in the long term.