In Situ Microscopic Observation of the Formation Process of Pinning Centers in Nd-Ba-Cu-O Superconductor

Novel method of investigation the development of nanolevel microstructure to introduce effective pinning centers in Nd-123 superconductor was attempted. Compositional deviation in nanometer scale of Ba and Nd developed during post heat treatment of Nd-123 crystal grain was observed by means of in situ high temperature microscopic observation, suggested as the origin of improved pinning force. Crystal growth condition of Y-123 superconductor in polycrystalline bodies under applied stress was studied for the microstructure control to improve transport current properties. Behavior of crystal growth front of superconducting grains through the solid state diffusion or the existence of small amount of liquid phase was examined in various conditions of temperature and applied stress. Interfacial reaction of introduced pinning centers and growing surface of superconducting matrix grains was investigated to promote the uniform dispersion of nanoparticles in matrix for increasing Jc

FuelCell2008-65016 RECENT DEVELOPMENT OF MICRO CERAMIC REACTORS FOR ADVANCED CERAMIC REACTOR SYSTEM

ABSTRACT Ceramic reactors, which convert materials and energy electrochemically, are expected to solve various environmental problems, and use of micro reactor design was shown to realize high performance reactor with high thermal durability operable at lower temperatures. Our research project "Advanced Ceramic Reactor" supported by NEDO targets to develop new fabrication technology for such micro reactors and modules using conventional, commercially available materials. In this study, fabrication technology of micro tubular ceramic reactors have been investigated for aiming solid oxide fuel cells (SOFCs) application, such as small distributed power generators, APU for vehicles, and portable power sources. So far, micro tubular SOFCs under 1 mm diam. using doped ceria electrolyte and Ni -ceria based cermet for tubular support has been successfully developed and evaluated. The single micro tubular SOFC showed cell performance of 0.46 W/cm 2 (@0.7 V) at 550 o C with H 2 fuel. Bundle design for such tubular cell was also proposed and fabricated. Discussion will cover fabrication technology of single tubular SOFC and bundle, and optimization of the cell and bundle design by considering gas pressure loss and current collecting loss