不同后处理对纯镁微弧氧化涂层组织结构与性能的影响

发布时间：2018-04-25 23:34

本文选题：纯镁 + 超声微弧氧化　；参考：《佳木斯大学》2015年硕士论文

【摘要】：纯镁由于其密度、杨氏模量与人骨接近,又具有可降解性、适当的强度和良好的生物活性,使之成为最具有发展潜力的生物医用材料,也成为了国内外可降解骨内固定修复材料的研究热点。但纯镁在体内存在着降解速度过快的弊端,和骨组织的生长不能很好地达到匹配,因而限制了纯镁在临床领域的应用。对纯镁进行表面改性是解决此问题最行之有效的方法之一。在纯镁表面制备超声微弧氧化(简称UMAO)涂层,可改善其耐蚀性,但是纯镁UMAO涂层存在的微孔仍可使腐蚀介质到达镁基体而将基体腐蚀。因此,针对这一问题,本文采用超声微弧氧化技术在纯镁表面制备出UMAO涂层,再进行植酸、植酸-丝素蛋白(简称SF)、NaOH-硅烷偶联剂(简称SCA)-SF不同的后处理,并对相关后处理工艺参数进行了优化,实现调控了涂层的可降解性及生物活性。本实验对涂层的微观形貌、元素组成、官能团构成、结合强度、耐磨性、润湿性、耐蚀性及体外Hank's浸泡生物活性进行了研究,具体结论如下:采用不同浓度的植酸对纯镁UMAO涂层进行后处理,可发现:随着植酸浓度的升高,UMAO涂层微孔数量减少,无碎裂现象,涂层更加均匀致密,覆盖度提高,表面覆盖羟基和磷酸基,涂层的结合强度、耐磨性、耐蚀性等均有所改善,经过Hank's溶液浸泡后,涂层发生了降解,并与Ca、P等元素结合,生成新的物质-类骨磷灰石。其中植酸的处理浓度为7.5g/L时为最佳。用7.5g/L植酸处理的UMAO涂层经过SF不同时间的处理后,可发现:随着SF溶液处理时间的延长,涂层的孔洞数量逐渐减少,涂层更加致密,涂层的结合强度、耐磨性、润湿性、耐蚀性等均有提高,经过Hank's溶液浸泡3天时即有新的物质-类骨磷灰石生成。其中,SF溶液的处理时间为1.5h时为最佳。对UMAO涂层进行NaOHSCA-SF不同的时间处理后,可发现:随着SF处理时间的延长,涂层的孔隙被填充的越来越均匀致密,平整度也越来越好,且涂层的结合强度、耐磨性、润湿性、耐蚀性等均有所提高。纯镁UMAO涂层经植酸、植酸-SF、SCA-SF处理发生化学反应生成的新物质或发生各物质之间的相互作用,有效地填充了UMAO涂层的孔隙,阻挡了腐蚀介质到达基体,并成膜,达到调控涂层可降解性的目的,同时,由于丝素蛋白具有良好的生物相容性,也提高了复合涂层的生物活性。综合比较,UMAONaOH-SCA-SF/1.5h处理的复合涂层具有最优异的性能。
[Abstract]:Pure magnesium, due to its density, Young's modulus and human bone, has biodegradability, appropriate strength and good biological activity, making it the most promising biomedical material. It has also become the research hotspot of degradable bone internal fixation materials at home and abroad. However, the degradation rate of pure magnesium in vivo is too fast, and the growth of bone tissue can not match well, which limits the application of pure magnesium in clinical field. Surface modification of pure magnesium is one of the most effective methods to solve this problem. Ultrasonic micro-arc oxidation (UMAO) coating on pure magnesium surface can improve its corrosion resistance, but the micropore of pure magnesium UMAO coating can still make the corrosion medium reach magnesium substrate and corrode the substrate. Therefore, in order to solve this problem, the UMAO coating was prepared on the surface of pure magnesium by ultrasonic micro-arc oxidation, and then the phytic acid, phytic acid-silk fibroin (SCA)-SF) coupling agent (SCA)-SF) was used for different post-treatment. The process parameters were optimized to control the biodegradability and bioactivity of the coating. The microstructure, composition of elements, composition of functional groups, binding strength, wear resistance, wettability, corrosion resistance and bioactivity of Hank's immersion in vitro were studied. The specific conclusions are as follows: after treatment of pure magnesium UMAO coating with different concentrations of phytic acid, it can be found that with the increase of phytic acid concentration, the number of micropores in UMAO coating decreases, there is no fragmentation, the coating is more uniform and compact, and the coverage is improved. The bonding strength, wear resistance and corrosion resistance of the coating were improved. After soaking in Hank's solution, the coating was degraded and combined with CaOP-like elements to form a new substance, bone-like apatite. The best treatment concentration of phytic acid was 7.5g/L. After the UMAO coating treated with 7.5g/L phytic acid was treated with SF for different time, it was found that with the prolongation of the treatment time of SF solution, the number of holes in the coating gradually decreased, the coating became denser, the bonding strength, wear resistance and wettability of the coating were increased. The corrosion resistance was improved and a new substance, bone-like apatite, was formed after soaking in Hank's solution for 3 days. The best treatment time is 1.5 h. After NaOHSCA-SF treatment of UMAO coating at different time, it can be found that with the prolongation of SF treatment time, the pores of the coating are more and more uniform and compact, the flatness is better and better, and the bonding strength, wear resistance and wettability of the coating are also improved. Corrosion resistance has been improved. Pure magnesium UMAO coating was treated with phytic acid, phytic acid -SFNSCA-SF to produce new substances or interaction between them, which effectively filled the pores of UMAO coating, prevented corrosion medium from reaching the substrate, and formed film. The biodegradability of the coating was controlled and the bioactivity of the composite coating was improved because of the good biocompatibility of silk fibroin. The composite coating treated with UMAO NaOH-SCA-SF / 1.5 h has the best performance.
【学位授予单位】：佳木斯大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG174.44

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