镀液组成对电沉积Fe-Zn合金镀层组织与性能的影响

Influence of Bath Composition on Microstructure and Properties of Electrodeposited Fe-Zn Alloy Coating

利用电沉积技术制备血管支架用可降解Fe-Zn合金镀层。研究了镀液组成对Fe-Zn合金镀层组织与性能的影响。结果表明:向镀液中加入0.50 mol/L的H3BO3和0.05 mol/L的C3H4O4,能够控制Fe-Zn合金镀层中杂质元素O的质量分数。当C6H5Na3O7·2H2O的浓度低于0.035 0 mol/L时,Fe-Zn合金镀层为柱状晶组织,硬度较低,并且具有(211)择优取向。当C6H5Na3O7·2H2O的浓度高于0.035 0 mol/L时,Fe-Zn合金镀层为细晶组织,硬度增大,同时内应力较大。循环伏安曲线表明,随着C6H5Na3O7·2H2O的加入,Fe2+的析出电位负移,更接近Zn2+的析出电位,有利于Fe-Zn共沉积的进行。极化曲线和21 d SBF静态浸泡试验结果表明,随着晶粒的细化及Zn、O元素的增加,Fe-Zn合金镀层的自腐蚀电位由-0.45 V降低到-0.52 V,腐蚀降解速率由0.122 mg/(cm2·d)增加到0.153 mg/(cm2·d)。

Degradable Fe-Zn alloy used for vascular stents was prepared by electrodeposition.The influence of bath composition on the microstructure and properties of Fe-Zn alloy coating was investigated.The results showed that the mass fraction of oxygen impurity in Fe-Zn alloy coating can be controlled by adding 0.50 mol/L H3 BO3 and 0.05 mol/L C3 H4 O4 into the bath.When the concentration of C6 H5 Na3 O7·2 H2 O was less than 0.035 0 mol/L,the Fe-Zn alloy coating had a columnar crystal structure with a low hardness and(211) preferred orientation.When the concentration of C6 H6 Na3 O7·2 H2 O was higher than 0.035 0 mol/L,the Fe-Zn alloy coating was fine-grained with a higher hardness and it was easy to break due to the large internal stress.The cyclic voltammetry tests showed that with the increase of the concentration of C6 H5 Na3 O7·2 H2 O,the deposition potential of Fe2+was negatively shifted to be closer to that of Zn2+,which was favorable for Fe-Zn co-deposition.The polarization curve and 21 day SBF static immersion tests showed that with the refinement of grains and increase of the Zn and O elements,the selfcorrosion potential of Fe-Zn alloy coating decreased from-0.45 V to-0.52 V,and the degradation rate increased from 0.122 mg/(cm2·d) to 0.153 mg/(cm2·d)