Authors: Dong-Wook Lee, Bong Ki Ji, Jun Hyung Lim, Choong-Hwan Jung, Jinho Joo, Soon-Dong Park, Byung-Hyuk Jun, Gye-Won Hong, and Chan-Joong Kim

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Authors Dong-Wook Lee, Bong Ki Ji, Jun Hyung
Lim, Choong-Hwan Jung, Jinho Joo, Soon-Dong Park,
Byung-Hyuk Jun, Gye-Won Hong, and Chan-Joong Kim

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

Scott Bartz 17 September 2007
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Rolling

• Rolling metal forming process (Compression)
• Hot Rolling
• Cold Rolling

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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.

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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.

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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

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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.
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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.
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Results and Discussion
Microstructures of Ni tapes

1. Many pores at the grain boundary.
2. No pores when annealed for 12 minutes.

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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

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Weaknesses

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

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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.
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• Please give
• me an A!!!