Precise purity-evaluation of high-purity copper by residual resistivity ratio

Kouji Mimura, Yukio Ishikawa, Minoru Isshiki, Masanori Kato

Research output: Contribution to journalReview articlepeer-review

16 Citations (Scopus)


To evaluate the purity of high-purity copper with high accuracy by the residual resistivity ratio (RRR), the optimum annealing condition before the RRR measurement and the diameter dependence (size effect) of RRR for high-purity copper (5N and 6N grade copper) wires, 0.2-2 mm in diameter, annealed under the optimum condition have been investigated. The most suitable annealing temperature and period were determined to be 923 K and more than 14.4 ks (4 h), respectively. For the size effect on RRR, the relationship between RRRW (RRR measured for a copper wire with diameter d), RRRB (RRR of the bulk copper) and the specimen diameter d (mm) was found as follows: RRRW-1=RRRB-1 + (3.8 × 10-5)·d-1 The product of ρ·λ=6.5 × 10-16 Ωm2 for copper was also obtained from the slope of the above equation. Furthermore, it became clear that the difference in RRRW is dependent on the specimen diameter and increases with purity of the specimen. Therefore, the influence of the size dependence on RRR must be considered carefully whenever to evaluate and to compare the purity of high-purity metals by RRR.

Original languageEnglish
Pages (from-to)714-718
Number of pages5
JournalMaterials Transactions, JIM
Issue number8
Publication statusPublished - 1997 Aug
Externally publishedYes


  • Copper
  • Evaluation of purity
  • High-purity metals
  • Residual resistivity ratio
  • Size effect
  • Vacuum annealing

ASJC Scopus subject areas

  • Engineering(all)


Dive into the research topics of 'Precise purity-evaluation of high-purity copper by residual resistivity ratio'. Together they form a unique fingerprint.

Cite this