Aqueous Electrochemistry of Cuprate-Based High T sub c Superconductors.
01 January 1987
We have examined spontaneous dissolution processes and the resulting electrode potentials of new high T sub c cuprate- based superconductors Ba sub 2 YCu sub 3 O sub 7 and La sub (1.8) Sr sub (0.2) CuO sub 4, and the copper source compound, CuO, in 1M NaCl solutions containing 1-10 mM HCl. Ba sub 2 YCu sub 3 O sub 7 is attacked by protons at a mass transfer limited rate and exhibits potentials above that of the O sub 2 /H sub 2 O electrode. La sub (1.8) Sr sub (0.2) CuO sub 4 dissolves under mixed mass transport-surface kinetic control and has much less positive potentials which are very sensitive to acid concentration and mass transport, indicative of a changing surface. CuO is quite stable to attack and has steady potentials under comparable conditions. The implications of these results to aqueous exposure or treatment and to systematic study of potentials, T sub c, and composition are noted.