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| ELECTROCHEMICAL CHARACTERISTICS OF PHOSPHATING ACCELERATED BY RARE EARTH NITRATE ON ALUMINUM ALLOY |
| ZHANG Shenglin1;2;LI Chaoyang1;CHEN Huahui2;JING Shuke1;CHEN Yanyan1 |
1.Chemistry & Environmental Science College; Henan Normal University;Xinxiang 453007
2.School of Mechanical; Electronic and Information Engineering; China University of Mining & Technology; Beijing 100083 |
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Abstract The effect of cerium nitrate on the phosphating process and the phosphate coating morphology of 6061Al alloy was investigated by electrochemical measurements and scanning electron microscopy. The addition of cerium nitrate changed the initial potentials of interface between aluminum alloy substrate and phosphating solution. Cerium nitrate was adsorbed on the surface of aluminum substrates to form gel. These gel particles were good crystal pits to form phosphate crystal grains and acted as nucleation agent, resulting in phosphate crystal grains to be fined, phosphate coating to be compacted and the corrosion resistance of coating to be improved. Cerium nitrate made time shortened at which the highest potential value of aluminum alloy was achieved, the current density of cathodic polarization was increased and phosphating velocity was expedited. Cerium nitrate acted as nucleation agent and accelerator in whole phosphating process of aluminum alloy. Under this experimental condition, the optimal content of REN is 20 mg/L-40 mg/L.
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Received: 16 April 2007
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Corresponding Authors:
ZHANG Shenglin
E-mail: zslhnxx@yahoo.com.cn
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