Thermomechanical Processing of High T c Superconducting Wire Super BSCCO Family C. Bjelkengren B. Cooper Y. King S. Maltas

Super BSCCO Family 2 Summary Goal?To Increase the Superconductivity How? By Improving the Grain Alignment in the Polycrystalline BSCCO ST 0.22 mm 7.14 mm ~ 60 % BSCCO

Super BSCCO Family 3 What We’ve Done So Far: Annealing Cold Rolling “Hot” Rolling Some Compression Annealing Consistent Problem: “Oxidation” Past Weeks: Comparing “Apples to Apples”

Super BSCCO Family 4 Pre-Ic Graph

Super BSCCO Family 5 Bad Apples: When we implemented the change to “pre-Ic” our samples before treatment, we were also increasing scale of experimentation. Older ovens were used, strange coincidence, “dust” Solutions: “Glass” Jars, Quartz Tubes

Super BSCCO Family 6 Problem Solved It was the solder. Gee whiz.

Super BSCCO Family 7 Not a Total Loss: Variability Data

Super BSCCO Family 8 Pure Annealing – Varying Temperature (°C)

Super BSCCO Family 9 Pure Annealing – Varying Time (min)

Super BSCCO Family 10 Pure Annealing – Ic (Amps) As received Ic was roughly 110 Amps

Super BSCCO Family 11 Future Work – Cold Rolling First samples ruined – oxidation Strain: ∆w / w 0  Strain ~.1  Strain ~.2  Strain ~.3 Anneal  Time and Temperature from Pure Annealing  Partial Pressure O 2

Super BSCCO Family 12 Future Work - Compression Annealing Simultaneous heat, strain, and oxidation O 2 Partial Pressure: 10 7 Pa Torque: 10 N·m Temperature and time predetermined

Super BSCCO Family 13 Future Work - Hot Isostatic Pressing (Friday) t ~ 40 hours T ~ o C P ~ 70 MPa Ag-based solder Annealing to restore O x

Super BSCCO Family 14 Future Work Deduce:  Most effective processing method and variables Relate:  Improvements in I c to better texture Investigate:  Lotgering Factor  SEM

Super BSCCO Family 15 Gantt Chart