模拟体液中Y对Mg-Zn-Ca非晶合金腐蚀行为的影响

Effect of yttrium on corrosion behavior of Mg-Zn-Ca amorphous alloys in simulated body fluid

利用单辊甩带法制得非晶样品,研究了Y的添加量(0,0.5,1.0,1.5,at.%)对Mg-Zn-Ca非晶合金在模拟体液中腐蚀行为的影响,通过扫描电镜观察样品在模拟体液中浸泡不同时间(3 h,3 d,7 d)后的微观形貌,利用电化学工作站对样品浸泡前后的电化学性能进行了检测.结果表明:加入Y元素后Mg-Zn-Ca非晶合金在模拟体液中的腐蚀电位有了明显提高,随着Y添加量的增加,合金耐蚀性在1%Y时最强,当Y增加到1.5%时,合金耐蚀性有所下降.浸泡后的电化学实验显示浸泡3d后样品与未浸泡的样品相比腐蚀电流密度均有明显的下降,在浸泡7 d后添加1%Y的非晶合金腐蚀电流密度继续下降,而含1.5%Y元素的非晶合金的腐蚀电流密度却反而增大.样品耐蚀性能的恶化是由于Y元素的添加使浸泡后的样品表面形貌发生由网状结构到层片状结构的改变.

The paper focuses on the effect ofyt-trium on corrosion behavior of Mg66Zn30Ca4 amorphous alloys in simulated body fluid （SBF）. The amorphous alloys were prepared by single roller melt spinning method. The microstructure and corrosion behavior of the amorphous alloys were characterized by using X-ray diffraction and scanning electron micro- scope. The electrochemical properties of the samples before and after corrosion are examined by electrochemical measu- rements. The results show that the corrosion resistance of the Mg-based amorphous alloy has obviously improved after alloying the Y element to the Mg-Zn-Ca amorphous alloys. The Mg-based alloys containing 1 at. % Y exhibited the best corrosion resistance in SBF at 37~C. However, the corrosion resistance reduced with the further addition of Y element. The corrosion current densities of samples immersed in SBF for 3 days decreased as compared to those of as-spun samples. Moreover, the corrosion current density of the Mg65Zn30Ca4Y, samples continued to decrease during the immersion process, but increased for the Mg64.sZn3oCa4Y,.5 alloy. The corrosion behavior deterioration was due to the structural change from net to lamellar after the addition of yttrium.