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Experimental Phase‐Diagram Study and Thermodynamic Optimization of the Silver‐Strontium‐Copper‐Oxygen (Ag‐Sr‐Cu‐O) and Silver‐Calcium‐Copper‐Oxygen (Ag‐Ca‐Cu‐O) Systems
Author(s) -
Assal Jérôme,
Hallstedt Bengt,
Gauckler Ludwig J.
Publication year - 1999
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.1151-2916.1999.tb02283.x
Subject(s) - strontium , copper , oxygen , copper oxide , calcium oxide , oxide , phase diagram , inorganic chemistry , chemistry , silver oxide , bismuth , strontium oxide , metal , phase (matter) , materials science , analytical chemistry (journal) , metallurgy , organic chemistry , chromatography
The phase relations in the silver‐strontium‐copper‐oxygen (Ag‐Sr‐Cu‐O) and silver‐calcium‐copper‐oxygen (Ag‐Ca‐Cu‐O) systems were studied in oxygen, air, and nitrogen environments, using differential thermal analysis and energy‐dispersive X‐ray spectrometry. The presence of silver reduces the melting temperature of the oxide liquid to a monotectic in the strontium‐ and calcium‐containing systems by 62 and 82 K, respectively (to 1222 and 1244 K, respectively) in oxygen. The oxide liquid dissolves silver (up to a metallic ratio of 0.17) in the Ag‐Sr‐Cu‐O system in oxygen at a temperature slightly higher than that required for monotectic reaction. In the Ag‐Ca‐Cu‐O system, the silver content has been measured to be 0.29 (metallic ratio). The oxide systems have been optimized using the experimental data from monotectics and those from lower‐order systems that have been published previously. This work is part of a project to evaluate the phase relations within the silver‐bismuth‐strontium‐calcium‐copper‐oxygen (Ag‐Bi‐Sr‐Ca‐Cu‐O) system and, in particular, to focus on the influence of silver on the phase equilibria around the superconducting phases during partial‐melt processing.