锆基大块非晶合金在NaCl溶液中的腐蚀行为

Corrosion Behavior of Zr-based Bulk Amorphous Alloys in NaCl Solution

利用电化学方法研究了3种锆基大块非晶合金Zr60Al15Ni25、Zr65Al10Ni10Cu15和Zr52.5Al10Ni10Cu15Be12.5在1%、3.5%和10%(wt.%)NaCl溶液中的腐蚀行为.极化曲线的测试结果表明,在相同浓度NaCl溶液中Zr60Al15Ni25合金表面形成相对稳定的钝化膜,表现出较好的耐腐蚀能力.元素Cu和Be的添加,降低了合金Zr52.5Al10Ni10Cu15Be12.5和Zr65Al10Ni10Cu15在NaCl溶液中的钝化能力,增加了点蚀的敏感性.失重法研究结果表明3种合金腐蚀速率的大小顺序依次为Zr65Al10Ni10Cu15>Zr52.5Al10Ni10Cu15Be12.5>Zr60Al15Ni25.利用扫描电镜(SEM)和能量散射X射线谱(EDS)分析了极化后的合金表面,结果表明点蚀孔内部Zr、Al、Ni的选择性溶解和Cu在钝化膜下的富集导致了合金的耐腐蚀性能降低.

The corrosion behavior of Zr-based bulk amorphous alloys Zr60Al15Ni25,Zr65Al10Ni10Cu15 and Zr52.5Al10Ni10Cu15Be12.5 was investigated by electrochemical method in 1%,3.5% and 10%（wt.%） NaCl solutions.The results of polarization curves show that in the same concentration of NaCl solution Zr60Al15Ni25 exhibits the best corrosion resistance because it has a wide passive region and low passive current density.The addition of Cu and Be elements decrease the passive ability of Zr65Al10Ni10Cu15 and Zr52.5Al10Ni10Cu15Be12.5,conducing to an increase of the susceptivity to pitting corrosion.The results of weight loss method show that the descending order of corrosion rate is Zr65Al10Ni10Cu15,Zr52.5Al10Ni10Cu15Be12.5,and Zr60Al15Ni25.Corroded surface of alloys after polarization was investigated by scanning electron microscopy（SEM） and energy dispersive X-ray spectroscopy（EDS）.The results indicate that selective dissolution of Zr,Al and Ni and enrichment of Cu under passive film reduce corrosion resistance of alloys.