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[en] A technique was needed for joining alumina to tantalum to provide a leaktight seal between the ends of an alumina tube and tantalum electrodes for a new generation of lasers. A single-step titanium cored copper-silver procedure eliminates pre-metallization and was better suited to production than conventional methods. 5 refs
[en] We use results from an ab initio investigation by Chang et al. on energetically low-lying stationary points of the Al2O3 molecule to determine interionic potentials for the Al-O, O-O and Al-Al pairs. Our results are discussed in the perspective of previous studies of the condensed phases of alumina, with special regard to the structure of its molten state. (author)
[en] Using the methods of X-ray diffraction, metallographical and weight analysis, changes in the structure of polycrystal aluminium oxide after annealing in the range of temperatures 1888-2000 deg C and irradiation by xenon ions in the doses of up to 2.7 x 1017 cm-2 at the energy of up to 300 keV have been investigated. It is ascertained that radiation effect spreads to the depths, which exceed by a factor of 104 the thickness of amorpherized ion-doped layer. (author)
[en] Full text: Aluminium Oxide films were deposited on glass substrates (18? 18 ? 1 mm,cut from microscope slide) by using resistive evaporation method, from tungsten boats, at room temperature, of two different depositions 20 and 50 degree deposition angles. The evaporated material was pieces of Aluminium Oxide. An ETS 160 (Vacuum Evaporation System) coating plant with a base pressure of 3 ? 10?5 mbar, was used. Prior to deposition, all glass substrates were ultrasonically cleaned in heated acetone first and then in ethanol. The substrate holder was a disk of 36.5 cm in diameter with adjustable height up to 50 cm and also adjustable holders for placing any kind of substrates. Thickness of layers was determined by quartz crystal microbalance technique. The other deposition conditions such as deposition rate, vacuum pressure, and substrate temperature were the same in all tests.The surface physical morphology and roughness were obtained by means of AFM(Dual Scope TM DS 95-200/50) analysis. Scanning electron microscopy methodused for determining nanostructure of layers. The transmittance of films was measured using UV-VIS spectrophotometer (Hitachi U ? 3310) instrument. The spectra of layers were in range of 300?1100 nm wavelength (UV-VIS). The transmission (?T) of electrons through thin films of C, Al2O3, Al, Ni, Ag, and Au, together with their distribution in angle and energy, can measured in a spherical retarding-potential analyzer.Aluminium Oxide thin films of 65 nm thickness at two different deposition angles of 20 and 50 degrees were deposited on glass substrates at room temperature, by using resistive evaporation method under UHV conditions. The structural details were determined by AFM and SEM methods. The optical spectra were measured by spectrophotometer in the spectral range of 300 ?1100 nm wave length (UV-VIS).The relation between nanostructures and optical properties to deposition angle were discussed.
[en] Prominent ceramic raw materials and products manufacturers were surveyed to determine the state of the art for alumina ceramic fabrication. This survey emphasized current capabilities and limitations for fabrication of large, high-density, high-purity, complex shapes. Some directions are suggested for future needs and development
[en] Template-assisted nanofabrication is a simple and effective method to produce various nanostructure morphologies by controlling the polymer, solvent, and template characteristics. In this study, the importance of the surface interactions between the solution and the template in controlling the morphology of the nanostructures has been highlighted. Contact angles between various polymer solutions and anodized aluminum oxide (AAO) templates have been determined. The morphology of the resultant nanostructures has been correlated with the measured contact angles between solution and template. It is generally observed that nanorods (diameter of 100–350 nm) are produced at low contact angles, whereas nanotubes (diameter of 200–400 nm) tend to form at high contact angles. Therefore, desired nanostructure morphology for a given application can be obtained by controlling the initial wetting interaction between solution and template.