Microstructural Analysis of Interface Between Yba2cu3o7-X and Ag/Pd Alloys
Journal
Japanese Journal of Applied Physics Part 1-Regular Papers Short Notes & Review Papers
Journal Volume
32
Journal Issue
10
Pages
4509-4516
Date Issued
1993
Author(s)
Abstract
Pure silver and palladium/silver alloy in a 10/90 weight ratio were either sandwich-coupled or powder-mixed with YBa2Cu307-x (Y123) to prepare Ag-Y123 and (Pd/Ag)-Y123 composites. The reaction and diffusion of elements near the interface of Ag-Y123 or (Pd/Ag)-Y123 were determined by means of differential thermogravimetry (DTA), optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), and precision X-ray diffraction (XRD) analyses. The results reveal that the Pd, Ag, and Cu react to some extent: Cu will diffuse into pure Ag or Pd/Ag alloy. Conversely, Pd and Ag in pure Ag or Pd/Ag will diffuse toward Y123 at temperatures greater than 945 °C. Diffusion of Cu into pure Ag or Pd/Ag alloy will decrease the melting point of the Ag or Pd/Ag alloy due to formation of a solid solution and/or an eutectic constitution. Since molten Cu/Ag or Cu/Pd/Ag alloys can flow across the interface by means of capillary force between Y123 grains, they fill up the voids (or capillaries) between Y123 grains and Ag or Pd diffuse into Y123 grains, occupying Cu sites in Y123. This is consistent with the results of precision XRD, which show the expansion of the Y123 lattice caused by the occupation. © 1993 The Japan Society of Applied Physics.
Type
journal article