Materials Transactions, Vol.53 No.04 (2012) pp.700-706
© 2012 The Japan Institute of Metals
Corrosion of Calcium Phosphate Coated AZ31 Magnesium Alloy under a Salt Spray Test
Smart Biomaterials Group, Biomaterials Unit, Nano-Bio Field, International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), Tsukuba 305-0044, Japan
The corrosion resistance and adhesiveness of a hydroxyapatite (HAp)-coated AZ31 magnesium alloy rolled plate were evaluated by a salt spray test (SST: JIS Z 2371) and a cross-cut test (CCT: JIS K 5600), respectively. The length of the HAp coating solution treatment was 4 or 6 h. A HAp coating consisting of an inner continuous layer and an outer porous layer uniformly covered the surface regardless of the treatment period. After the SST for 7 days, the HAp-coated surfaces showed no significant delamination but several visible pits. The HAp coating in the non-corroded area retained its original morphology after the SST by a SEM observation. The rating number (RN) for the HAp-coated specimens was over 9, which was much higher than RN 4 observed for the chemically polished specimen covered almost entirely with filiform corrosion. The RN of HAp-coated specimen increased slightly with a longer treatment period. The adhesiveness of the HAp coating was not influenced by the SST according to the CCT. After removing the corrosion products and HAp coating from the non-corroded area, small pits with a diameter of a few hundred micrometers appeared; however, general corrosion did not take place underneath the HAp coating. The HAp coating shows high corrosion resistance and good adhesiveness to the AZ31 substrate.
(Received 2011/11/10; Accepted 2012/01/12; Published 2012/03/25)
Keywords: magnesium alloy, rolled plate, calcium phosphate coating, salt spray test, cross-cut test
Table of Contents
- J. Hillis: Magnesium Technology —Metallurgy, Design Data, Applications—, ed. by H. E. Friedrich and B. L. Mordike, (Springer, New York, 2006) pp. 469-497.
- The Japan Magnesium Association (Ed): Magnesium Handbook, (Kallos, Tokyo, 1999) pp. 411-428.
- B. A. Shaw and R. C. Wolfe: ASM Handbook: Vol. 13B Corrosion: Materials, (ASM International, Materials Park OH, 2005) pp. 205-227.
- G. L. Song, A. Atrens, X. L. Wu, X. L. Wu and B. Zhang: Corros. Sci. 40 (1998) 1769-1791.
- J. E. Gray and B. Luan: J. Alloy. Compd. 336 (2002) 88-113.
- D. Hawke and D. L. Albright: Met. Finish. 93 (1995) 34.
- D. Hawke and D. L. Albright: Met. Finish. 93 (1995) 36-38.
- S. Natarajan and V. Ravikiran: Surf. Eng. 22 (2006) 287-293.
- A. Abdel Aal: J. Mater. Sci. 43 (2008) 2947-2954.
- S. Q. Xu, Q. Li, Y. H. Lu, B. Chen and J. M. Fan: Surf. Eng. 26 (2010) 328-333.
- X. M. Song, G. Yu, H. B. Yi, L. Y. Ye and B. N. Hu: Surf. Eng. 26 (2010) 371-377.
- H. Asoh, S. Matsuoka, H. Sayama and S. Ono: J. JILM 60 (2010) 608-614.
- L. Y. Niu, Z. H. Jiang, G. Y. Li, C. D. Gu and J. S. Lian: Surf. Coat. Tech. 200 (2004) 3021-3026.
- M. Zhao, S. S. Wu, J. R. Luo, Y. Fukuda and H. Nakae: Surf. Coat. Tech. 200 (2006) 5407-5412.
- D. MacConnell: Apatite: Its Crystal Chemistry, Mineralogy, Utilization, and Geologic and Biologic Occurrences, (Springer-Verlag, New York, 1973) pp. 22-32.
- T. Nonami, H. Hase and K. Funakoshi: Catal. Today 96 (2004) 113-118.
- S. Hiromoto and A. Yamamoto: Electrochim. Acta 54 (2009) 7085-7093.
- M. Tomozawa, S. Hiromoto and Y. Harada: Surf. Coat. Tech. 204 (2010) 3243-3247.
- M. Tomozawa and S. Hiromoto: Acta Mater. 59 (2011) 355-363.
- S. Hiromoto and M. Tomozawa: Surf. Coat. Tech. 205 (2011) 4711-4719.
- Y. W. Song, D. Y. Shan and E. H. Han: Mater. Lett. 62 (2008) 3276-3279.
- C. Wen, S. Guan, L. Peng, C. Ren, X. Wang and Z. Hu: Appl. Surf. Sci. 255 (2009) 6433-6438.
- J. X. Yang, Y. P. Jiao, F. Z. Cui, In-Seop Lee, Q. S. Yin and Y. Zhang: Surf. Coat. Tech. 202 (2008) 5733-5736.
- JIS Z 2371, Methods of salt spray testing (2000).
- JIS K 5600, Testing methods for paints —Part 5: Mechanical property of film—, Section 6: Adhesion test (Cross-cut test) (1999).
- K. Miura, Y. Kobayashi, T. Naito, A. Yamada, A. Ikarashi, N. Hayashi and K. Isobe: J. Japan Inst. Metals 74 (2010) 771-778.
- P. B. Srinivasan, N. Scharnagl, C. Blawert and W. Dietzel: Surf. Eng. 26 (2010) 354-360.
- S. Hiromoto, T. Shishido, A. Yamamoto, N. Maruyama, H. Somekawa and T. Mukai: Corros. Sci. 50 (2008) 2906-2913.
- L. Wang, T. Shinohara, B. P. Zhang and H. Iwai: J. Alloy. Compd. 485 (2009) 747-752.
- L. Wang, T. Shinohara and B. P. Zhang: Appl. Surf. Sci. 256 (2010) 5807-5812.
© 2012 The Japan Institute of Metals
Comments to us :