三种新型亚稳β钛合金在人工模拟体液中的腐蚀行为

Corrosion behavior of three new types of metastable beta-titanium alloys in Hank's solution

目的:评估所设计的3种合金在人造生理环境中的耐腐蚀性能。方法:实验于2006-06在河北工业大学生物实验室完成。观察3种基于d-电子合金设计方法设计的具有较低弹性模量的新型亚稳β钛合金Ti35Nb10Zr、Ti35Nb8Zr2Mo、Ti20Nb15Zr10Mo和对比合金Ti6Al4V在Hank’s人工模拟体液中的电化学行为,分析合金铸锭的自腐蚀电位Ecorr随时间变化的关系曲线及阳极极化曲线。结果:①在浸入Hank’s人工模拟体液40min后,所设计的Ti35Nb10Zr合金具有最低的自腐蚀电位值,为-252mV,Ti35Nb8Zr2Mo、Ti20Nb15Zr10Mo的自腐蚀电位值则较高,分别为-217mV和-165mV。而对比合金Ti6Al4V则具有最高的自腐蚀电位值,为-98mV。②从阳极极化曲线得到的自腐蚀电流密度(腐蚀速率)Icorr值来看,Ti35Nb8Zr2Mo具有最大的Icorr值,为14.84mA/m2,其次分别为Ti20Nb15Zr10Mo(6.03mA/m2)和Ti35Nb10Zr(1.38mA/m2)。而Ti6Al4V则具有最小的Icorr值,为0.70mA/m2。③从腐蚀前的合金铸锭及Ti6Al4V(锻态)的扫描电镜照片看,所设计的3种合金铸锭表面均较锻态Ti6Al4V粗糙。结论:Mo含量的多少对于合金的耐腐蚀倾向大小具有一定作用。动电位极化曲线以及用于耐腐蚀实验的合金试样腐蚀前的扫描电镜照片表明影响合金耐蚀性的因素除化学成分外,合金的表面状况(粗糙度不同)可能也起到了重要作用。

AIM： To evaluate corrosion resistance of three designed alloy castings in an artificial physiological solution. METHODS： The experiment was conducted in the Biological Laboratory of Hebei University of Technology in June 2006. The electrochemical behavior of three new types of metastable β-titanium alloys based on the d-electron alloy design method with low elastic modulus, Ti35Nb10Zr, Ti35Nb8Zr2Mo and Ti20Nb15Zr10Mo were investigated together with that of Ti6A14V in Hank＇s solution. The relational curves of the corrosion potential Ecorr variation with time and the anodic polarization curves of designed Ti-alloy castings were also analyzed. RESULTS： （1）The alloy Ti35Nb10Zr had the least Ecorr（-252 mV） in Hank＇s solution after 40 minutes, and Ti35Nb8Zr2Mo, Ti20Nb15Zr10Mo had higher values （-217 mV and -165 mV）. Ti6A14V had the maximum value （-98 mV）（2）The Icorr was obtained from the anodic curves. Ti35Nb8Zr2Mo had the highest Icorr （14.84 mA/m^2）, then Ti20Nb15Zr10Mo and Ti35Nb10Zr were lower （6.03 mA/m^2 and 1.38 mA/m^2）, and Ti6A14V had the least value （0.70 mA/m^2）.（3）The surface of designed Ti-2lloy castings before corrosion were more coarse than that of Ti6A14V （forged） in scanning electdc microscope （SEM）. CONCLUSION： Mo content may have some effect on the designed alloys＇ corrosion resistance trend. The analysis of anodic potentiodynamic polarization curves and the SEM micrographs of alloys before corrosion suggest that surface condition （different surface roughness） is a prominent factor on corrosion resistance besides chemical components.