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Effect of Lead Loss and Sheath Structure on Phase Formation and Alignment in (Bi,Pb) 2 Sr 2 Ca 2 Cu 3 O 10+δ /Ag Composite Conductors
Author(s) -
Luo Jian Shu,
Merchant Nazarali,
Maroni Victor A.,
Dorris Stephen E.,
Lanagan Michael T.,
Tani Benjamin S.
Publication year - 1995
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1995.tb08055.x
Subject(s) - materials science , scanning electron microscope , energy dispersive x ray spectroscopy , annealing (glass) , lead oxide , composite number , inductively coupled plasma , analytical chemistry (journal) , oxide , evaporation , metal , electrical conductor , silver oxide , composite material , transmission electron microscopy , strontium oxide , ceramic , spectroscopy , activation energy , metallurgy , chemical engineering , plasma , nanotechnology , chemistry , physics , organic chemistry , chromatography , quantum mechanics , engineering , thermodynamics
The effects of metallic constituent evaporation and sheath structure on grain growth and alignment in silver‐sheathed (Bi,Pb) 2 Sr 2 Ca 2 Cu 3 O 10+δ (Bi‐2223)/Ag composites have been investigated by inductively coupled plasma/atomic emission spectroscopy (ICP/AES), X‐ray diffraction, scanning electron microscopy, and energy dispersive X‐ray spectroscopy. Specimens of Bi‐2223/Ag composites fabricated by the oxide‐powder‐in‐tube technique were peeled (opened) lengthwise to expose the ceramic powder core, and then heat‐treated in 0.075 atm of oxygen for selected temperatures and times. The results were compared with those for as‐processed samples with closed silver sheaths treated under identical conditions. ICP/AES analysis indicated that lead was the only metallic element to undergo substantial evaporation during annealing of opened samples. The lead‐release process in parallel with the Bi‐2223 formation reaction had an activation energy of ∼25 kJ/mol. Lead loss from the opened samples resulted in incomplete conversion to Bi‐2223. The combined results show that the silver sheath effectively prevents evaporative lead loss, preserves and promotes densification, and induces texturing of the layered phases.