Control of carbonate formation in superconductor powders

Control of carbon formation in superconductor powders is critical in determining the superconducting properties of the material. Control of the chemistry at all stages of powder synthesis is important for preventing carbon contamination. A method for eliminating carbonate formation in superconductor powder synthesis will be described. Freeze-dried precursor materials prepared from a mixture of nitrates and acetates are calcined in a two stage process. In the low temperature step the acetate is removed and replaced by nitrate. In the high temperature step the nitrates are decomposed and the superconductor material forms. Powder characteristics and critical current density results will be presented