Dissolution and precipitation behaviour in steels microalloyed with niobium during thermomechanical processing

Relationship between microstructure, properties and reaction conditions for Cu-TiB2 alloys prepared by in situ reaction

Calcium substituted RBa 2 Cu 4 O 8 with R = Y and Er has been prepared between 805°C and 830°C under oxygen at one atmosphere. The zero-resistance T c is displaced up from 79 K (unsubstituted) to 87 K at 10% substitution. This compound has the benefit of a high- T c while circumventing the problems of oxygen-loading and associated microcracking. The substitution level of 10% lies at the solubility limit under the preparation conditions used and neither prereaction at higher temperatures, nor the use of co-substitution with La assisted in obtaining higher substitution levels.

Calcium-substituted superconducting RBa2Cu4O8 with Tc ∼ 90 K prepared at one atmosphere

Structural, electrical and optical studies of SILAR deposited cadmium oxide thin films: Annealing effect

Optical, structural and surface characterization of ultrasonically sprayed CdO:F films

Ceramic processing of YBa 2 Cu 3 O x -based superconductors and process-related problems are described Conditions for calcination, sintering and for microstructural development are important considerations for obtaining the superconducting properties We examine different forming techniques for preparing superconducting components with different sizes, shapes and configurations We also identify and discuss six problem areas related to (i) the incomplete decomposition of BaCO 3 precursor, (ii) the slow oxidation kinetics of YBa 2 Cu 3 O x ceramics, (iii) the sensitivity to water of the YBa 2 Cu 3 O x phase, (iv) the reactivity of the YBa 2 Cu 3 O x phase with substrates and co-firing materials, (v) the low critical-current density in YBa 2 Cu 3 O x bulk ceramics, and (vi) the low mechanical strength of YBa 2 Cu 3 O x ceramics

Process-related problems of YBa2Cu3Ox superconductors

Ceramic processing of YBa/sub 2/Cu/sub 3/O/sub x/ based superconductors and process-related problems are described. Conditions for calcination, sintering, and microstructural development are important considerations for the superconducting properties. The authors examine different forming techniques to prepare superconducting components with different sizes, shapes, and configurations. They also identify and discuss five problem areas related to: (1) incomplete decomposition of BaCO/sub 3/ precursor; (2) oxidation of YBa/sub 2/Cu/sub 3/O/sub x/ ceramics; (3) sensitivity of the YBa/sub 2/Cu/sub 3/O/sub x/ phase to water; (4) reactivity of the YBa/sub 2/Cu/sub 3/O/sub x/ phase with substrates and co-firing materials; and (5) low critical current density in bulk ceramics of YBa/sub 2/Cu/sub 3/O/sub x/. >

Ceramic processing of YBa/sub 2/Cu/sub 3/O/sub x/ based high-T/sub c/ superconductors

Conventional and chemical processing of the superconducting YBa2Cu3Ox ceramic powders are reviewed. Conditions for calcination, sintering and microstructural development are shown to be important considerations for the superconducting properties of YBa2Cu3Ox ceramics. We examine different forming techniques, e.g. dry pressing, hot pressing, tape casting and screen printing, to prepare superconducting components with different sizes, shapes and configurations. We also identify and discuss problem areas related to incomplete decomposition of BaCo3 precursor; oxidation of YBa2Cu3Ox ceramics; sensitivity of the YBa2Cu3Ox phase to water; reactivity of the YBa2Cu3Ox phase with substrates and co-firing materials; low critical current density in bulk ceramics of YBa2Cu3Ox and low mechanical strength of YBa2Cu3Ox ceramics.

Conventional and Chemical Processing of High Tc Superconductors

Control of alloy composition and processing to achieve grain coarsening resistance in rapidly solidified alloys is examined via the theory of grain boundary pinning and particle coarsening. The principles are illustrated for the case of manganese sulfides in steels. A thermodynamic survey of potential stable dispersed phases identifies TiN and rare-earth sulfides as particularly promising for alloy development via rapid solidification.

Grain-Coarsening Resistance and the Stability of Second-Phase Dispersions in Rapidly Solidified Steels

Processing of YBa/sub 2/Cu/sub 3/O/sub x/-based superconductors and process-related problems are described. Conditions for calcination, sintering and microstructural development are considered for the superconducting properties. Different forming techniques to prepare superconducting components with different sizes, shapes and configurations are examined. Five problem areas related to processing are identified and discussed: (1) incomplete decomposition of BaCO/sub 3/ precursor, (2) oxidation of YBa/sub 2/Cu/sub 3/O/sub x/ ceramics; (3) sensitivity of the YBa/sub 2/Cu/sub 3/O/sub x/ phase to water, (4) reactivity of the YBa/sub 2/Cu/sub 3/O/sub x/ phase with substrates and co-firing materials and (5) low critical current density in bulk ceramics of YBa/sub 2/Cu/sub 3/O/sub x/. >

H. C. Ling

Papers

Process-related problems of YBa2Cu3Ox superconductors

Ceramic processing of YBa/sub 2/Cu/sub 3/O/sub x/ based high-T/sub c/ superconductors

Conventional and Chemical Processing of High Tc Superconductors

Grain-Coarsening Resistance and the Stability of Second-Phase Dispersions in Rapidly Solidified Steels

Processing of ceramic superconductors