钴基合金表面纳米Ti-O薄膜的制备及其疲劳性能与耐腐蚀性能的初步研究

发布时间：2018-01-27 05:50

本文关键词： 血管支架 CoCrMo合金 Ti-O薄膜疲劳性耐腐蚀性　出处：《西南交通大学》2014年硕士论文　论文类型：学位论文

【摘要】：钴合金因其高强度、抗疲劳等特性成为制备细金属丝冠脉支架的主选材料。然而无论是其裸支架,还是药物洗脱性支架都存在再狭窄或晚期血栓的风险,究其原因在于金属基体的抗凝血性能不足。前期研究表明,Ti-O薄膜具有良好的血液相溶性,利用Ti-O薄膜对血管支架进行表面改性,有望解决这一难题。本文主要针对血管支架在人体内的服役情况,开展钴合金表面Ti-O薄膜的制备以及Ti-O薄膜/CoCrMo体系的弯曲疲劳行为与耐腐蚀行为的研究工作。 Ti-O薄膜的制备采用高功率磁控溅射法(HPPMS),并采用X射线衍射法(XRD)、 X射线光电子能谱法(XPS)对薄膜相结构和成分进行了表征。Ti-O薄膜/CoCrMo体系弯曲疲劳行为的评价采用本文独自发展的一种实验方法,利用该方法本文主要研究了薄膜厚度、应力幅大小、表面形貌对Ti-O薄膜/CoCrMo体系弯曲疲劳行为的影响。采用电化学极化实验研究了经数百万次至千万次循环加载荷后Ti-O薄膜/CoCrMo体系耐腐蚀性能。全文主要内容和结论如下： (1)利用HPPMS方法在CoCrMo合金表面成功制备出金红石型Ti02薄膜； (2)基于悬臂梁共振和纯弯曲理论本文独自发展出一种评价薄膜弯曲疲劳寿命的实验方法； (3)疲劳实验表明,应力幅200Mpa下,循环加载荷1000万次后,Ti-O薄膜表面未见裂纹和预制裂纹的扩展,本文制备的Ti-O薄膜能够满足支架服役过程中不失效：表面质量是影响薄膜疲劳失效的一个重要因素,表面光滑致密的薄膜抗疲劳失效的能力越强；薄膜厚度对弯曲疲劳行为影响不显著； (4)电化学实验表明,经数百万至千万次循环加载后的薄膜试样,其耐腐蚀行能相对于未加载试样有所降低,但仍然高于裸金属样品；膜厚大的样品耐蚀性能优于膜厚小的试样；表面光滑致密的薄膜耐蚀性优于表面粗糙、疏松的薄膜。本文的研究结果,为Ti-O薄膜表面改性钴基合金血管支架及其应用提供一定的理论依据。
[Abstract]:Cobalt alloy has become the main material for the preparation of thin wire coronary stent due to its high strength and anti-fatigue properties. However, both bare stent and drug-eluting stent are at risk of restenosis or late thrombosis. The reason lies in the lack of anticoagulant properties of metal substrates. Previous studies showed that Ti-O thin films have good blood compatibility. The surface modification of vascular scaffolds was carried out by using Ti-O film. It is expected to solve this problem. This paper focuses on the service of vascular stent in human body. The preparation of Ti-O film on cobalt alloy surface and the bending fatigue behavior and corrosion resistance of Ti-O film / CoCrMo system were studied. The Ti-O thin films were prepared by high power magnetron sputtering (HPPMS) and X-ray diffraction (XRD). The phase structure and composition of Ti-O films were characterized by X-ray photoelectron spectroscopy (XPS). The bending fatigue behavior of Ti-O films / CoCrMo system was evaluated by an experimental method developed in this paper. In this paper, the thickness and stress amplitude of the film are studied by using this method. Effect of surface morphology on bending fatigue behavior of Ti-O films / CoCrMo system. Electrochemical polarization experiment was used to study the bending fatigue behavior of Ti-O / CoCrMo films after millions to tens of millions of cycles and loading. Corrosion resistance of the system. The main contents and conclusions are as follows:. 1) rutile Ti02 thin films were successfully prepared on the surface of CoCrMo alloys by HPPMS method. Based on the theory of cantilever beam resonance and pure bending, an experimental method for evaluating the bending fatigue life of thin films has been developed in this paper. 3) fatigue tests show that there are no cracks and prefabricated cracks on the surface of Ti-O films after 10 million cycles of cyclic loading at 200Mpa stress amplitude. The Ti-O films prepared in this paper can meet the requirements of the scaffold service without losing efficiency: the surface quality is an important factor affecting the fatigue failure of the thin films, and the stronger the anti-fatigue failure ability of the thin films with smooth and compact surface is; The effect of film thickness on bending fatigue behavior is not significant. (4) Electrochemical experiments show that the corrosion resistance of thin film specimens after millions to ten million cycles is lower than that of unloaded samples, but still higher than that of bare metal samples. The corrosion resistance of the sample with large film thickness is better than that of the sample with small film thickness. The corrosion resistance of thin film with smooth and compact surface is better than that with rough surface and loose surface. The results of this paper provide a theoretical basis for the surface modification of cobalt-based alloy stent and its application in Ti-O film.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：O484.1

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