[en] This patent describes a method of making a pre-ceramic resinous material capable of being converted into a ceramic semiconductor material substantially free from stable barium carbonate and having the general composition RR'₂Cu₃O_7-x where R is a rare earth metal, R' is an alkaline earth metal, and x is from 0 to 0.5. It comprises: refluxing stoichiometric amounts of a first solution comprising a rare earth isopropoxide and an alkaline earth isopropoxide in isopropanol; adding to the first solution a stoichiometric amount of a second solution comprising copper ethylhexanoate in isopropanol; refluxing the first and second solutions to obtain a precipitate; hydrolyzing the precipitate in a quantity of a first solvent comprising water and isopropanol sufficient to substantially dissolve the precipitate into a precipitate solution; adding a third solution comprising an iodine compound in an alcohol to the precipitate solution to form a precursor solution having at least about 1 mole of iodine per mole of rare earth metal; concentrating the precursor solution by removing a sufficient amount of solvents to produce the pre-ceramic resinous material; and adding a second solvent comprising a nonpolar solvent to the pre-ceramic resinous material to obtain a desired viscosity

[en] This patent describes a method of making a pre-ceramic material capable of being converted into an electrically superconductive ceramic material having the general formula ABa₂Cu₃O_7-x where A is a rare earth metal and x is from 0 to 0.5. It comprises refluxing stoichiometric amounts of a first solution comprising a rare earth isopropoxide and barium isopropoxide in isopropanol under a dry, inert atmosphere; adding to the first solution a stoichiometric amount of a second solution comprising copper ethylhexanoate in isopropanol; refluxing the first and second solutions to obtain a precipitate; adding to the precipitate a quantity of a first solvent comprising water and isopropanol; concentrating the homogeneous solution by removing a sufficient amount of the first solvent to produce a viscous or dry pre-ceramic resinous material; softening or dissolving the pre-ceramic resinous material in a second solvent comprising a binary mixture of a polar solvent and a nonpolar solvent to obtain a desired viscosity; and forming the viscous pre-ceramic material into the desired product shape

[en] This patent describes a method of making a pre-ceramic material capable of being converted into an electrically superconductive ceramic material having the general formula ABa₂CU₃O_7-x where A is a rare earth metal and x is from 0 to 0.5. It comprises: refluxing stoichiometric amounts of a first solution comprising a rare earth isopropoxide and barium isopropoxide in isopropanol under a dry, inert atmosphere; adding to the first solution a stoichiometric amount of a second solution comprising copper ethylhexanoate in isopropanol; refluxing the first and second solutions to obtain a precipitate; adding to the precipitate a quantity of a first solvent comprising water and isopropanol having from about 2 to 10 equivalents of water per mole of rare earth isopropoxide to hydrolyze the precipitate and to sufficiently dissolve the precipitate to produce a substantially homogeneous solution; concentrating the homogeneous solution by removing a sufficient amount of the first solvent to produce a viscous or dry pre-ceramic resinous material; softening or dissolving the pre-ceramic resinous material in a second solvent comprising a nonpolar solvent or alcohol and a nonpolar solvent to obtain a desired viscosity; and forming the viscous pre-ceramic material into the desired product shape

[en] The morphologies and defect structures of TiCr₂ in several Ti-Cr alloys have been examined by optical metallography, x-ray diffraction, and transmission electron microscopy (TEM), in order to explore the room-temperature deformability of the Laves phase TiCr₂. The morphology of the Laves phase was found to be dependent upon alloy composition and annealing temperature. Samples deformed by compression have also been studied using TEM. Comparisons of microstructures before and after deformation suggest an increase in twin, stacking fault, and dislocation density within the Laves phase, indicating some but not extensive room-temperature deformability

No abstract available

[en] A two-phase, NbCrTi alloy (bcc + C15 Laves phase) has been developed using several alloy design methodologies. In efforts to understand processing-microstructure-property relationships, different processing routes were employed. The resulting microstructures and mechanical properties are discussed and compared. Plasma arc melted (PAM) samples served to establish baseline, as-cast properties. In addition, a novel processing technique, involving decomposition of a supersaturated and metastable precursor phase during hot isostatic pressing (HIP), was used to produce a refined, equilibrium two-phase microstructure. Quasi-static compression tests as a function of temperature were performed on both alloy types. Different deformation mechanisms were encountered based upon temperature and microstructure

[en] A multiply-faulted dipole in the C15 Laves phase of composition Nb₁₅Cr₆₈Ti₁₇ has been characterized. The dislocations all lie along [011] and show no residual contrast when imaged edge-on at B = [0 bar 1 bar 1] indicating that they are edge in character. Given this, the Burgers vectors for the Shockley partials are ± 1/6[2 bar 11] and those of the stair-rods are ± 1/6[0 bar 11]. This is consistent with a g · b analysis which was performed. The stacking fault energy was determined to be 35 mJ/m² which is higher than the experimental value of 25 mJ/m² from NbCr₂. Simulations are currently underway to understand, given the site occupancies and observed trend in stacking fault energy, whether Ti would be expected to raise the stacking fault energy of the C15 Laves phase

[en] Homogeneous solution for Y-Ba-Cu-O superconductor was prepared from yttrium i-propoxide, barium i-propoxide, and copper ethylhexanoate. The solution was converted to a resin-like material and was readily dissolved in organic solvents. The resin possesses a cohesive property in a number of solvents, such as benzene and xylene. Single-phase superconducting YBa₂Cu₃O_7-x fibers have been continuously spun from the viscous solution. Controlled amounts of Y₂BaCuO₅ phase in the fibers were made possible by slight adjustments in the solution compositions. Partial substitution of copper ethylhexanoate with copper trifluoroacetate prevents barium carbonate formation in the fiber during curing and organic pyrolysis

[en] This paper reports on soluble resins prepared by controlled hydrolysis of yttrium isopropoxide, barium isopropoxide and copper ethylhexanoate. The resins were converted to cohesive, viscous, fluid and precipitated states by the addition of different combinations of binary polar and non-polar organic solvents. Viscosity and spinnability of the resins were critically dependent on the solvent constituents. Continuous pre-ceramic fibers were spun from these resins and single phase YBa₂Cu₃O_y superconducting fibers with Tc = 91.5K and Δ T = 1.5K have been obtained

[en] OAK-B135 Thin glow discharge polymer (GDP) shells are currently used as the targets for cryogenic direct drive laser fusion experiments. These shells need to be filled with nearly 1000 atm of D₂ and cooled to cryogenic temperatures without failing due to buckling and bursting pressures they experience in this process. Therefore, the mechanical and permeation properties of these shells are of utmost importance in successful and rapid filling with D₂. In this paper, they present an overview of buckle and burst pressures of several different types of GDP shells. These include those made using traditional GDP deposition parameters (standard GDP) using a high deposition pressure and using modified parameters (strong GDP) of low deposition pressure that leads to more robust shells