Bi系銅酸化物超伝導バルク体の電気化学的処理(II) Electrochemical Treatment on Bulk Superconductor in the Bi-Cu Oxide System(II)
The electrochemical reduction was applied to porous Bi-Cu system superconductor in 0.05N:Ca⋅(NO<SUB>3</SUB>)<SUB>2</SUB>⋅4H<SUB>2</SUB>O, 0.03N:Sr(NO<SUB>3</SUB>)<SUB>2</SUB>, 0.05N:Pb(NO<SUB>3</SUB>)<SUB>2</SUB>, 0.05N:Cu(NO<SUB>3</SUB>)<SUB>2</SUB>⋅3H<SUB>2</SUB>O in methanol using platinum as the counter electrode. Changes in crystal phase and morphology by electrochemical treatment were investigated by XRD, T<SUB>c</SUB>, oxygen content by iodometric titration and SEM method. T<SUB>c</SUB>(onset) of the sample of the 30Å phase treated electrochemically in Ca<SUP>2+</SUP> solution was highest, and enhansed by 9K, but that of the 37Å phase being decreased. The oxygen content was decreased by 0.14 maximumly, and the c lattice constants were stretched a little except in Cu<SUP>2+</SUP> Solution. In the SEM observation, the reaction proceeded to the inner part of sample except in Cu<SUP>2+</SUP> solution. Then this reaction is considered to be a reduction in which deposited particles react with oxygen atoms in the samples and followed by stretching of the c lattice constants. It was found that a the sample of the 30Å phase could be reduced in liquid phase as well as in gaseous phase.
粉体および粉末冶金 44(2), 147-151, 1997-02-15
Japan Society of Powder and Powder Metallurgy