1. 1) T. Kobayashi, I. Akashi, T. Maruyama, H. Abe, T. Sugiyama and H. Wakai: J. JFS 81(2009) 650-660.
2. 2) Y. Takatani and T. Yokoyama: Corros. Eng. 29(1980) 122-127.
3. 3) Y. Yasuda, H, Abe, R. Matsubayashi, T. Maruyama and T. Haruna: Journal of Japan Institute of Copper 54(2015) 113-118.
4. 4) T. Okane: J. JFS 82(2010) 740-745.
5. 5) JIS H5120: Japan Industrial Standards. (2016).