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Abstract The corrosion resistance and anti-corrosion mechanism of the double-layer electroless Nickel alloy deposit system, Ni-P (7. 5μm, outer)+Ni-Mo-P(2. 5μm, inner), were studied. The results of immersion corrosion test and neutral salt spray test showed that in so far as corrosion resistance is concerned, the double-layer deposit was much better than the single-layer (Ni-P or Ni-Mo-P) deposits of the same thickness and that it was better than the single-layer deposit of twice the total thickness. After heat treatment above 400℃, the corrosion resistance is further improved. AES surface analysis and depth profile technique,x-ray diffraction analysis technique,electrochemical tests and metallographic techniques were employed to investigate the anti-corrosion mechanism of this system. The results showed that the outer layer served as a sacrificial anode to provide electrochemical protection to the inner layer when the double-layer deposit was heat treated below 400℃ (including untreated condition),and that the protective effects were due to the changes of structure of system and had higher anti-corrosion performance when heat treated above 400℃.
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Received: 25 April 1991
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[1] U.S. Patent 3,917,464
[2] Pearlstein. F. A.; Weightman,R. F.,J. Electrochem. Soc., 121(8) , 1023(1974)
[3] Cruss,L.L.; Pearlstein.F. A., Plat. Surf. Finish., 70(2) ,47(1983)
[4] J. P. 61-246374
[5] J. P. 60-258473
[6] 陆柱、张刚,化学镀Ni-P和Ni-Mo-P镀层耐蚀性能,(1988) 待发表
[7] 周光穆,材料保护,No.4,P7,(1983)
[8] Satio, M., The Journal of Metal Finishing Soc. of Japan, 14(5) , 168(1963)
[9] Harublak, E.P., Surf. Finish.,67(2) , 49(1980)
[10] ASTM 537-70
[11] Beer,C. F.,et al., Corrosion Prevention & Control,No. 6,P 5,(1983) |
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