Comparison of calcium phosphate coatings on Mg-Al and Mg-Ca alloys and their corrosion behavior in Hank's solution
Comparison of calcium phosphate coatings on Mg-Al and Mg-Ca alloys and their corrosion behavior in Hank's solution
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DOI：
10.1016/j.surfcoat.2010.04.038
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发表时间：
2010-08
影响因子：
5.4
通讯作者：
Chungang Zhang;Zeng Rong-chang;Cheng-long Liu;Jiacheng Gao
中科院分区：
文献类型：
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作者：
Chungang Zhang;Zeng Rong-chang;Cheng-long Liu;Jiacheng Gao
采用电化学沉积法在AZ 31镁合金和Mg-1.0Ca镁合金表面制备钙磷涂层。采用析氢试验和动电位电化学技术研究了涂层合金在Hank溶液中的腐蚀行为。结果表明，沉积涂层主要由透钙磷石（DCPD，CaHPO 4·2 H2O）微晶组成。涂层试样的自腐蚀电位（开路电位）明显升高，腐蚀电流密度明显降低，表明涂层显著提高了基体的耐蚀性。在Hank溶液中初始浸泡期间，涂覆样品的析氢速率远低于基底的析氢速率。但是，一旦试样发生点蚀，涂层试样的腐蚀速率迅速增加。此外，涂层样品的腐蚀性能与其基体的腐蚀性能有很大关系。
Calcium phosphate coatings were prepared on AZ31 and Mg–1.0Ca magnesium alloys by electrochemical deposition. Hydrogen evolution testing and potentiodynamic electrochemical technique were employed to investigate the corrosion behavior of the coated alloys in Hank's solution. The results show that the deposited coatings mainly consist of flaky brushite (DCPD, CaHPO4·2H2O) crystallites. The obvious increase in free corrosion potential (open circuit potential) and decrease in corrosion current density of the coated samples indicate that the coating significantly enhanced the corrosion resistance of the substrates. The hydrogen evolution rates of the coated samples were much lower than that of the substrates during initial immersion in Hank's solution. However, the corrosion rate of the coated samples increased rapidly once the samples suffered pit corrosion. Furthermore, the corrosion properties of the coated samples have much to do with the corrosion properties of their substrates.