类金刚石薄膜在水环境中的磨损行为研究
发布时间：2018-08-23 15:37
【摘要】：类金刚石(DLC)薄膜具有优异的力学性能和生物相容性,是潜在的人工关节表面改性材料。在体外实验中,DLC薄膜可以提高人工关节的耐磨性和耐腐蚀性,减少人工关节的磨损和金属离子的释放。但是临床应用过程中,DLC改性后的人工关节存在薄膜结合失效的问题。DLC薄膜的种类繁多,不同种类的DLC薄膜具有不同的物理化学性质。在体内环境中服役时,DLC薄膜的磨损与失效机制要受到体液介质的影响。为了研究不同成分、结构的DLC薄膜在人体内摩擦磨损以及失效机制,探索适用于体液介质中服役的DLC薄膜种类以及薄膜/基体组合。本论文以纯水以及无机盐溶液为实验介质,研究了DLC薄膜成分结构、薄膜/基体界面状态、对磨副等因素对DLC磨损失效行为的影响,探讨了氮离子注入(氮化)和DLC薄膜沉积复合处理工艺应用于CoCrMo合金金属人工关节表面改性的可行性。(1)研究了成分、结构对DLC薄膜在水环境下摩擦磨损行为的影响。研究结果表明DLC薄膜在水环境下与Al_2O_3对磨时,含氢DLC薄膜中的H元素会与碳原子成键,抑制摩擦化学反应,在纯水中摩擦时薄膜表面存在着大量的-CH官能团,-CH官能团与水分子之间存在范德华力作用,所以含氢DLC薄膜在纯水中的摩擦和磨损较低。不含氢DLC薄膜在水环境中摩擦时,由于剧烈的摩擦化学反应,在摩擦表面生成较多含氧(-COH)官能团,这些含氧官能团与水分子之间存在氢键作用,故不含氢DLC薄膜在纯水中摩擦时产生较高的摩擦和磨损。DLC薄膜的结构也对耐磨性有着重要的影响,含氢DLC薄膜中的饱和的-CH结构由于饱和键的稳定性在摩擦中不容易发生转变,而不饱和的-CH结构由于不饱和键的不稳定性在摩擦过程中容易发生石墨化的转变,从而造成结构的软化和磨损的加剧。与空气环境相比,水环境可以抑制含氢DLC薄膜的磨损,而促进不含氢DLC薄膜的磨损。(2)研究了薄膜/基体界面化学状态对DLC薄膜结合失效的影响。研究结果表明,含氢DLC薄膜在水中服役时发生结合失效的原因与膜基界面处的氢元素有关,氢元素能够抑制Cr元素的钝化,降低界面的化学稳定性,使界面容易被腐蚀而产生裂纹源,从而导致薄膜的早期结合失效。进一步研究表明,在不同基体表面制备的DLC薄膜具有类似的结构。当不同基体材料表面粗糙度相差不大时,同种工艺制备的DLC薄膜的结合力主要与膜/基界面处的化学状态有关。Ti6A14V基体中含有Ti、V等强碳化物形成元素,可以在膜/基界面处与DLC薄膜形成良好的化学结合,所以Ti6A14V/DLC具有最好的膜基结合力。316L不锈钢中的Fe元素碳化物形成能力较弱,在界面处与DLC薄膜之间的化学键和能力较弱,所以膜基结合力也较弱。不同基体表面DLC薄膜在盐溶液中的磨损失效形式为结合失效,所以具有最强结合力的Ti6A14V/DLC具有最好的耐磨性,而具有最差结合力的316L/DLC具有最差的耐磨性。基体材料的耐腐蚀性直接决定着DLC膜基体系的长期稳定性。Ti6A14V基体因为具有较高的耐腐蚀性,其表面的DLC薄膜也具有最好的长期稳定性,316L不锈钢因具有较差的耐腐蚀性,其表面的DLC薄膜长期稳定性也较差。(3)研究了对磨副材料对不含氢DLC薄膜在空气和纯水介质中摩擦磨损的影响。研究结果表明,CoCrMo对磨副在空气中与不含氢DLC摩擦时,由于形成脆性的、含金属氧化物的转移膜,降低了自润滑作用,增加了与DLC之间的粘着,导致较高的摩擦和磨损。在水中摩擦磨损时,水环境会抑制CoCrMo表面含金属氧化物转移膜的形成并阻止金属对磨副与DLC薄膜的粘着,利于在对磨副表面形成无序石墨结构的粘附物质,降低DLC的摩擦和磨损。对于A1203对磨副,在空气中由于低的粘着和固体润滑,造成的DLC磨损较少。而在水环境中由于难以实现固体润滑,故硬质的A1203会造成较高的DLC磨损。(4)研究了氮离子注入(氮化)和DLC薄膜沉积复合处理工艺应用于CoCrMo合金金属人工关节表面改性的可行性。研究结果表明氮离子注入(氮化)和DLC薄膜沉积复合处理工艺成功的提高了CoCrMo合金的力学性能和耐磨性,但是氮元素在注入CoCrMo基体后,会促进Co离子的释放,抑制Cr元素的钝化能力,从降低基体的腐蚀稳定性。在长时间的服役过程中,由于注氮层的缓慢腐蚀溶解,DLC薄膜的结合力发生了明显的弱化。所以在对人体内植入金属器械的表面改性中,注氮工艺应该被慎重采用。
[Abstract]:Diamond-like carbon (DLC) film is a potential surface modification material for artificial joints because of its excellent mechanical properties and biocompatibility. In vitro, DLC film can improve the wear resistance and corrosion resistance of artificial joints, reduce the wear and metal ion release of artificial joints. However, in the clinical application, the artificial joints modified by DLC film can be used to improve the wear resistance and corrosion resistance of artificial joints. There are many kinds of DLC films, and different kinds of DLC films have different physical and chemical properties. The wear and failure mechanisms of DLC films in vivo are affected by humoral media. In order to study the friction and wear and failure mechanism of DLC films with different composition and structure in vivo, the wear and failure mechanisms of DLC films are studied. In this paper, the composition and structure of DLC film, the interface state of DLC film and substrate, the effect of grinding pairs and other factors on the wear failure behavior of DLC film were studied in pure water and inorganic salt solution. Feasibility of surface modification of CoCrMo alloy artificial joints by the treatment process was studied. (1) The effects of composition and structure on the friction and wear behavior of DLC films in water environment were studied. There are a lot of - CH functional groups on the surface of DLC films when they are rubbed in water. There is Van der Waals force between - CH functional groups and water molecules, so the friction and wear of DLC films containing hydrogen are low in pure water. These oxygen-containing functional groups have hydrogen bonds with water molecules, so the hydrogen-free DLC films have higher friction and wear resistance when they are rubbed in pure water. The structure of DLC films also has an important impact on the wear resistance. The saturated-CH structure of hydrogen-containing DLC films is not easy to change due to the stability of the saturated bonds, but not saturated. Unsaturated bond instability of H-CH structure is easy to occur graphitization transformation during friction process, resulting in structural softening and wear intensification. Compared with air environment, water environment can inhibit the wear of hydrogen-containing DLC films, and promote the wear of hydrogen-free DLC films. (2) The effect of chemical state of film/substrate interface on DLC thin film was studied. The results show that the reason of bonding failure of DLC thin films containing hydrogen in water is related to the hydrogen element at the interface between the film and substrate. Hydrogen element can inhibit the passivation of Cr element, reduce the chemical stability of the interface, make the interface easy to be corroded and produce crack source, which leads to the early bonding failure of DLC thin films. One step study shows that DLC films prepared on different substrates have similar structures. When the surface roughness of different substrates is not different, the adhesion of DLC films prepared by the same process is mainly related to the chemical state at the film/substrate interface. Ti6A14V / DLC has the best adhesion with DLC film because of the good chemical bonding between the film and the substrate. The Fe carbide formation ability of 316L stainless steel is weak, and the chemical bonding and ability between the interface and DLC film are weak, so the adhesion between the film and the substrate is weak. Ti6A14V/DLC with the strongest bonding strength has the best wear resistance, while 316L/DLC with the lowest bonding strength has the worst wear resistance. Corrosion resistance of matrix materials directly determines the long-term stability of DLC matrix system. Ti6A14V matrix has the highest corrosion resistance, and the DLC film on its surface also has the highest wear resistance. Good long-term stability, 316L stainless steel because of its poor corrosion resistance, the long-term stability of DLC film on its surface is also poor. (3) The effect of pair material on the friction and wear of hydrogen-free DLC film in air and pure water medium was studied. The water environment will inhibit the formation of metal oxide transfer film on the surface of CoCrMo and prevent the adhesion between metal pair and DLC film, which is beneficial to the formation of disordered stone on the surface of the pair. For A1203 pairs, the wear of DLC is less due to low adhesion and solid lubrication in the air. But in the water environment, hard A1203 will cause higher wear of DLC because it is difficult to achieve solid lubrication. The results show that the mechanical properties and wear resistance of CoCrMo alloy can be improved by nitrogen ion implantation (nitriding) and DLC film deposition. However, nitrogen element can promote the release of Co ions and inhibit the passivation of Cr element after implanting into the matrix of CoCrMo alloy. In order to reduce the corrosion stability of the substrate, the bonding strength of DLC film is weakened obviously due to the slow corrosion and dissolution of the nitrogen-injected layer during the long-term service.
【学位授予单位】：西南交通大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TB383.2;R318.08
本文编号：2199505
[Abstract]:Diamond-like carbon (DLC) film is a potential surface modification material for artificial joints because of its excellent mechanical properties and biocompatibility. In vitro, DLC film can improve the wear resistance and corrosion resistance of artificial joints, reduce the wear and metal ion release of artificial joints. However, in the clinical application, the artificial joints modified by DLC film can be used to improve the wear resistance and corrosion resistance of artificial joints. There are many kinds of DLC films, and different kinds of DLC films have different physical and chemical properties. The wear and failure mechanisms of DLC films in vivo are affected by humoral media. In order to study the friction and wear and failure mechanism of DLC films with different composition and structure in vivo, the wear and failure mechanisms of DLC films are studied. In this paper, the composition and structure of DLC film, the interface state of DLC film and substrate, the effect of grinding pairs and other factors on the wear failure behavior of DLC film were studied in pure water and inorganic salt solution. Feasibility of surface modification of CoCrMo alloy artificial joints by the treatment process was studied. (1) The effects of composition and structure on the friction and wear behavior of DLC films in water environment were studied. There are a lot of - CH functional groups on the surface of DLC films when they are rubbed in water. There is Van der Waals force between - CH functional groups and water molecules, so the friction and wear of DLC films containing hydrogen are low in pure water. These oxygen-containing functional groups have hydrogen bonds with water molecules, so the hydrogen-free DLC films have higher friction and wear resistance when they are rubbed in pure water. The structure of DLC films also has an important impact on the wear resistance. The saturated-CH structure of hydrogen-containing DLC films is not easy to change due to the stability of the saturated bonds, but not saturated. Unsaturated bond instability of H-CH structure is easy to occur graphitization transformation during friction process, resulting in structural softening and wear intensification. Compared with air environment, water environment can inhibit the wear of hydrogen-containing DLC films, and promote the wear of hydrogen-free DLC films. (2) The effect of chemical state of film/substrate interface on DLC thin film was studied. The results show that the reason of bonding failure of DLC thin films containing hydrogen in water is related to the hydrogen element at the interface between the film and substrate. Hydrogen element can inhibit the passivation of Cr element, reduce the chemical stability of the interface, make the interface easy to be corroded and produce crack source, which leads to the early bonding failure of DLC thin films. One step study shows that DLC films prepared on different substrates have similar structures. When the surface roughness of different substrates is not different, the adhesion of DLC films prepared by the same process is mainly related to the chemical state at the film/substrate interface. Ti6A14V / DLC has the best adhesion with DLC film because of the good chemical bonding between the film and the substrate. The Fe carbide formation ability of 316L stainless steel is weak, and the chemical bonding and ability between the interface and DLC film are weak, so the adhesion between the film and the substrate is weak. Ti6A14V/DLC with the strongest bonding strength has the best wear resistance, while 316L/DLC with the lowest bonding strength has the worst wear resistance. Corrosion resistance of matrix materials directly determines the long-term stability of DLC matrix system. Ti6A14V matrix has the highest corrosion resistance, and the DLC film on its surface also has the highest wear resistance. Good long-term stability, 316L stainless steel because of its poor corrosion resistance, the long-term stability of DLC film on its surface is also poor. (3) The effect of pair material on the friction and wear of hydrogen-free DLC film in air and pure water medium was studied. The water environment will inhibit the formation of metal oxide transfer film on the surface of CoCrMo and prevent the adhesion between metal pair and DLC film, which is beneficial to the formation of disordered stone on the surface of the pair. For A1203 pairs, the wear of DLC is less due to low adhesion and solid lubrication in the air. But in the water environment, hard A1203 will cause higher wear of DLC because it is difficult to achieve solid lubrication. The results show that the mechanical properties and wear resistance of CoCrMo alloy can be improved by nitrogen ion implantation (nitriding) and DLC film deposition. However, nitrogen element can promote the release of Co ions and inhibit the passivation of Cr element after implanting into the matrix of CoCrMo alloy. In order to reduce the corrosion stability of the substrate, the bonding strength of DLC film is weakened obviously due to the slow corrosion and dissolution of the nitrogen-injected layer during the long-term service.
【学位授予单位】：西南交通大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TB383.2;R318.08
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1 刘亚军;池迎春;;国产人工关节产品新进展[J];中国医疗设备;2015年10期
相关硕士学位论文 前1条
1 裴亚楠;超高分子量聚乙烯表面沉积类金刚石薄膜改善耐磨性研究[D];西南交通大学;2012年
，本文编号：2199505
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