316L不锈钢表面NbC涂层的制备与性能评价

目的探究NbC涂层作为惰性涂层在模拟体液中的耐腐蚀性能及血液相容性能,并为NbC涂层作为生物惰性涂层改善316L不锈钢心血管支架的表面性能提供参考依据。方法采用物理气相沉积法制备NbC涂层,并通过优化工艺参数改善涂层性能。采用扫描电子显微镜(SEM)、原子力显微镜(AFM)、X射线衍射仪(XRD)、纳米压痕仪和原位纳米划痕仪,对涂层的微观结构及性能进行研究。采用循环伏安法对涂层的耐腐蚀性能进行表征。采用血小板粘附实验对涂层的血小板粘附行为进行了评价。结果制备的涂层具有结合性能强和致密度高等优点。随着基体温度的升高,NbC涂层的力学性能、耐腐蚀性能及血小板粘附特性均得到明显改善,硬度及弹性模量分别由(12.5±0.2)GPa和(213±0.8)GPa上升到(24.5±0.4)GPa和(275±1.1) GPa,自腐蚀速率优化明显,由8.76×10~(-6)A/cm~2降到1.98×10~(-8)A/cm~2。结论 NbC涂层在模拟体液中具备与316L不锈钢相当的稳定性,但其腐蚀速率远低于316L不锈钢,血小板粘附数量及变形较基体316L不锈钢得到显著改善,有望成为改善316L不锈钢表面性能的惰性涂层。

Preparation and Property Evaluation of NbC Coating Deposited on 316L Stainless Steel

The work aims to investigate the corrosion resistance and blood compatibility of NbC as biological inert coatings in simulated body fluids, so as to provide a reference for improving the performance of 316L stainless steel as a cardiac stent. NbC coating was prepared by the physical vapor deposition (PVD) widely used in surface modification area and the coating properties were improved by optimized process to obtain high adhesion force and density. Scanning electron microscope (SEM), Atomic force microscope (AFM), X-Ray diffraction (XRD), Nano-indentation and Scratch test were used to investigate the microstructure and mechanical properties. The potentiodynamic polarization curve and platelet adhesion test were used to characterize the corrosion resistance and evaluate hemocompatibility of NbC coatings. With the increasing of substrate temperature, the mechanical properties, corrosion resistance and blood compatibility of NbC coatings were significantly improved, and the hardness and elastic modulus of NbC coatings increased from (12.5±0.2) GPa and (213±0.8) GPa to (24.5±0.4) GPa and (275±1.1) GPa, respectively. The self-corrosion rate was significantly optimized from 8.76?10?6 A/cm2 to 1.98?10?8 A/cm2. In general, the NbC coating has the same stability as 316L stainless steel in simulated body fluids, but the corrosion rate is much lower than that of 316L stainless steel. The platelet adhesion behavior of NbC coating is significantly improved, which is expected to be an inert coating to improve the surface performance of naked 316L stainless steel.