Bi-Axially Textured Ni Tapes Fabricated by a Cold Rolling Process of Nickel Powder Compacts

1. Bi-Axially Textured Ni Tapes Fabricated by a Cold Rolling Process of Nickel Powder Compacts Authors: Dong-Wook Lee, Bong KiJi, Jun Hyung Lim, Choong-Hwan Jung, Jinho Joo, Soon-Dong Park, Byung-Hyuk Jun, Gye-Won Hong, and Chan-Joong Kim Scott Bartz 17 September 2007

2. Rolling Rolling: metal forming process (Compression) • Hot Rolling • Cold Rolling

3. Introduction Process: Ni and Ni-W powder compacts were cold rolled into tapes. Purpose: Discuss the effect of the processing variables on the texture development of the Ni and Ni-W tapes for YBCO coated conductors.

4. Ingots • When Ni ingots are formed by melting and casting, impurities can enter from the crucible and mold used. • Powder Metallurgy was used to help reduce impurities in the ingots.

5. Experimental Procedure • 1) Powdered Ni is weighed and Packed (10 mm) • 2) Compacted by cold iso-static pressing (8.3 mm) • 3) Sintered for densification (7.2 mm) • 4) Cold rolled (5% reduction) to final thickness (100 μm) • 5)Texture annealed

6. Results and Discussion “Bi-axially Textured Ni Tapes Fabricated by a Cold Rolling Process of Nickel Powder Compacts”, IEEE Transactions on Applied Superconductivity, Vol. 13, NO. 2, Jun 2003, pp. 2583.

7. Results and Discussion Tensile Test of sintered rods “Bi-axially Textured Ni Tapes Fabricated by a Cold Rolling Process of Nickel Powder Compacts”, IEEE Transactions on Applied Superconductivity, Vol. 13, NO. 2, Jun 2003, pp. 2584.

8. Results and Discussion Microstructures of Ni tapes • Many pores at the grain boundary. • No pores when annealed for 12 minutes.

9. Conclusions • The higher the sintering temperature, the more ductile the Ni rods. • The surface roughness of the Ni and Ni alloy tapes were 3 nm • Important for those working with high temperature superconductors

10. Weaknesses • Lack of explanation in the concluding section • No tables used • More variables could have been incorporated into the experiment

11. References [1] A. Goyal et al., “High critical current density superconducting tapes by epitaxial deposition of YBa2Cu3Ox thick films on biaxially textured metals,” Appl. Phys. Lett., vol. 69, pp. 1795-1797, September 1996. [2] ------, “Texture formation and grain boundary networks in rolling assisted biaxially textured substrates and in epitaxial YBCO films on such substrates and in epitaxial YBCO films on such substrates,” Micron, vol. 30, pp. 463-478, March 1999. [3] D.P. Norton et al., “Epitaxial YBa2Cu3O7 films on rolled-textured metals for High-temperature superconducting applications,” Mater. Sci. and Eng. B, vol. 56, pp. 86-94, 1998. [4] B. De Boer et al., “Cube textured nickel alloy tapes as substrates for YBa2cu3O7- coated conductors ,” Acta mater., vol 49, pp. 1421-1428, January 2001. [5] T. Petrisor et al., “Development of biaxially aligned buffer layers on Ni and Ni-based alloy substrates for YBCO tapes fabrication,” IEEE Trans. Appl. Supercon., vol. 9, pp.2256-2259, June 1999. [6] J. Eickemeyer et. Al., “Nickel-refractory metal substrate tapes with high cube texture stability,” Supercon. Sci. and Tech., vol. 14, pp. 152-159, March 2001.

12. Please give me an “A”!!!