摘要
铁具有较高的力学性能和良好的生物相容性,是极具潜力的可降解血管支架材料,但难以在规定的治疗期内完成降解是其面临的主要问题。在前期工作中利用电沉积技术制备出Fe-5Zn合金。为进一步优化其显微组织,将阴极平均电流密度由3.0 A/dm^2降至1.0 A/dm^2,控制电解液pH值在2.3左右,电沉积制备出成分均匀、组织细小致密,且具有(112)择优取向的Fe-5Zn单相固溶体合金。该合金经800℃氩气保护再结晶退火后,显微硬度由681 HV_(0.1)降至287 HV_(0.1),材料韧性得到改善。同时合金中有耐蚀性较高的铁、锌氧化物相析出,增加了微阴极数量。动电位极化曲线测量和模拟体液静态浸泡试验结果显示,热处理后的Fe-5Zn合金自腐蚀电位为-0.89 V,自腐蚀电流密度为1.77×10^(-6) A·cm^(-2),腐蚀速度则为0.259 mg·cm^(-2)·d^(-1),降解性能优于常规纯铁。
Pure iron with high mechanical properties and good biocompatibility, is one of the potential biodegradable materials for endovascular stent. However, it is difficult to be fully degraded within the limited treatment period. An innovative Fe-5Zn alloy was designed and electrodeposited in previous work. To further optimize its microstructure, the average current density was reduced from 3.0 A/dm^2 to 1.0 A/dm^2 and the solution pH was adjusted around 2.3 in this study, and a solid solution of Fe-5Zn alloy was finally prepared. This alloy has homogenous composition distribution with refined and dense microstructure and also has strong preferred grain orientation of （112）. After annealling at 800℃ in the argon atmosphere, the average microhardness of the alloy is reduced from 681 to 287 HV0.1, resulting in toughness improvement of the material. Through heat treatment, new oxide phases of iron and zinc form in the deposited layer, and their corrosion resistance is higher than that of the ferrite substrate. The results of potentiodynamic polarization curves and static immersion tests in the simulated body fluid show that after heat treatment, the corrosion potential, corrosion current density and corrosion rate of electrodeposited Fe-5Zn alloy are -0.89 V, 1.77×10^-6 A· cm^-2, and 0.259 mg· cm^-2·d^-1, respectively, which means the degradation property of the alloy is better than that of conventional pure iron.
作者
王伟强
江杰
梁婧
于凤云
WANG Wei-qiang;JIANG Jie;LIANG Jing;YU Feng-yun(School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024, Liaoning)
出处
《中国表面工程》
EI
CAS
CSCD
北大核心
2017年第6期95-102,共8页
China Surface Engineering
基金
国家自然科学基金(51371042)~~
