Process for making high temperature superconducting powders

A process for making a precursor useful in the making a superconductor of the general formula LM.sub.2 Cu.sub.3 O.sub.y, where L is Sc, Y or a rare earth metal selected from the group consisting of rare earth metals with an atomic number from 57 to 71, and M is an alkali metal, comprising:

• (a) adding a first aqueous solution to a second aqueous solution to form a combined solution and to induce the formation of a precipitate, the first aqueous solution including soluble salts of the L, M and Cu moieties which are to be contained in the superconductor precursor and the second aqueous solution including a hydroxy base and a carbonate or bicarbonate compound;
• (b) separating the precipitate from the combined solution;
• (c) thereafter, adding carbon dioxide while washing the precipitate, the amount of carbon dioxide being sufficient to maintain a pH of about 7 to 9;
• (d) separating the precipitate;
• and
• (e) drying the precipitate to yield the superconductor precursor.

A process for making a superconductor of the general formula LM.sub.2 Cu.sub.3 O.sub.y, where L is Sc, Y or a rare earth metal selected from the group consisting of rare earth metal with an atomic number from 57 to 71, and M is an alkali metal, comprising:

• (a) adding a first aqueous solution to a second aqueous solution to form a combined solution and to induce the formation of a precipitate, the first aqueous solution including soluble salts of the L, M and Cu moieties which are to be contained in the superconductor precursor and the second aqueous solution including a hydroxy base and a carbonate or bicarbonate compound;
• (b) separating the precipitate from the combined solution;
• (c) thereafter, adding carbon dioxide while washing the precipitate, the amount of carbon dioxide being sufficient to maintain a pH of about 7 to 9;
• (d) separating the precipitate;
• (e) drying the precipitate;
• and
• (f) firing the dried precipitate to form the superconductor.