【作者】 张晓；

【导师】 王庆良；

【作者基本信息】 中国矿业大学 ， 材料加工工程， 2019， 硕士

【摘要】 金属/高分子配副人工关节植入人体后,在循环交变载荷作用下,不仅存在磨损行为,由于金属的存在还会存在腐蚀等综合作用。聚醚醚酮(PEEK)作为新兴骨生物材料,其弹性模量与皮质骨的弹性模量接近,具有“以塑代钢”的特性,其性能可与金属材料媲美,所以在关节领域,PEEK有可能代替金属关节材料,与UHMWPE组成“软对软”的新型关节配副形式。本文选择PEEK/UHMWPE、CoCrMo/UHMWPE和CoCrMo/PEEK三种典型关节配副,研究了其扭动、摆动和滑动生物摩擦学行为,同时探讨了CoCrMo/UHMWPE和CoCrMo/PEEK配副的腐蚀特性。论文所得主要结论如下:PEEK/高交联UHMWPE配副在扭动摩擦条件下,扭动角度越大,摩擦系数越小。法向载荷为1600N时摩擦系数最小,增大和减小法向载荷,摩擦系数都呈增大趋势。摆动条件下,随着摆动角度和法向载荷的增大,摩擦系数都逐渐增大。扭动和摆动条件下,高交联UHMWPE的磨损量都随角位移幅值、法向载荷和循环周次的增大而增大,摆动运动形式下材料损失最严重,同种载荷条件下,其磨损量高于扭动运动形式下的磨损量。T-θ曲线随扭动角度的增大呈现三种形状,由直线形向椭圆形和平行四边形转变,相应的扭动微动运行状态由弹性协调的部分滑移向发生塑性变形的混合滑移和完全滑移转变。不同法向载荷条件下,T-θ曲线始终呈椭圆形,扭动运动状态处于混合区;扭动角度较小时,摩擦耗散能几乎接近为零,随着法向载荷的增大,摩擦耗散能逐渐增大。随扭动角度的增加,材料的磨损情况逐渐加重,高交联UHMWPE磨损机制主要为磨粒磨损和轻微的黏着磨损,PEEK磨损机制主要为磨粒磨损。摆动条件下,高交联UHMWPE表面磨损较轻微,磨损机制为磨粒磨损和疲劳磨损,PEEK的磨损机制为磨粒磨损和粘着磨损。UHMWPE/CoCrMo配副在滑动磨损实验起始阶段的摩擦系数均急剧上升,然后趋于稳定,载荷对摩擦系数的影响较小。PEEK/CoCrMo配副在小载荷时有最大摩擦系数,较大的载荷导致摩擦系数降低。较小的法向载荷对PEEK/UHMWPE配副的摩擦系数影响显著,随载荷的增大,摩擦系数上升,摩擦系数的增幅减小。前两种关节配副的磨损量均随法向载荷和磨损时间的增大而增大。“软对软”配副中,高交联UHMWPE的磨损体积则随法向载荷的增大而逐渐增大。三种摩擦配副中,CoCrMo/PEEK配副的磨损坑最深,但磨痕宽度最短,表面可以观察到由于接触面发生黏着导致的鳞片状剥落层,并伴有犁沟,PEEK的损伤机制以磨粒磨损和黏着磨损为主。CoCrMo/UHMWPE配副的磨损体积最大,材料损失最严重,犁沟边缘存在大量磨屑的堆积,还可以观察到明显的疲劳裂纹和撕裂,高交联UHMWPE的损伤机制主要为磨粒磨损和疲劳磨损。PEEK/高交联UHMWPE磨损面的磨痕较轻微,仅存在少量由黏着磨损导致的裂纹和层片状剥落。CoCrMo/UHMWPE和CoCrMo/PEEK两种配副中,由于CoCrMo表面钝化膜的影响,腐蚀电流在试验起始阶段较小,随着摩擦的进行,腐蚀速度逐渐加快然后达到稳定阶段。实验结果表明随着磨损时间的延长和载荷的增大,极化曲线均出现左移,腐蚀倾向增加,磨损趋于加重。更多还原

【Abstract】 Under the action of cyclic alternating load,there is not only wear behavior,but also corrosion and other comprehensive effects due to the presence of metal after the artificial joint is implanted into the human body.As a new bone biological material,PEEK has a modulus of elasticity close to that of cortical bone.It has the characteristics of "plasticizing steel" and its performance is comparable to that of metal materials.Therefore,PEEK may replace metal joint materials in the joint field,and form a new type of joint with the UHMWPE.In this paper,three typical joints of PEEK/UHMWPE,CoCrMo/UHMWPE and CoCrMo/PEEK were selected to study their twisting,swinging and sliding biological tribological behaviors.Meanwhile,the corrosion characteristics of CoCrMo/UHMWPE and CoCrMo/PEEK were discussed.The main conclusions are as follows:When PEEK/UHMWPE pair is under the twisted friction conditions,the greater the twisting angle is,the smaller the friction coefficient will be.When the normal load is 1600 N,the friction coefficient is the smallest,the normal load is increased and decreased,and the friction coefficient is increasing.Under the swing condition,the friction coefficient increases with the increase of the swing angle and the normal load.Under the condition of twisting and swinging,the wear of high-crosslinking UHMWPE increases with the angular displacement amplitude,normal load and cyclic times.The material loss under the oscillating motion is the most serious.Under the same load condition,the wear amount is higher than that under the twist motion.The T-θ curve has three shapes with the increase of the twisting angle,which changes from linear to elliptical and parallelogram.The corresponding twisting and fretting running state is changing from the elastically coordinated partial slip to the plastic slip.Under different normal load conditions,the T-θ curve is always elliptical,and the twisting motion state is in the mixing zone.When the twisting angle is small,the frictional dissipation energy is almost zero,and when the frictional load increases with the normal load,the energy is gradually increasing.With the increase of the twisting angle,the wear of the material is gradually increased.The wear mechanism of the UHMWPE is mainly abrasive wear and slight adhesive wear.The wear mechanism of PEEK is mainly abrasive wear.Under the oscillating condition,the surface of the UHMWPE is slightly worn,the wear mechanism is abrasive wear and fatigue wear,and the wear mechanism of PEEK is abrasive wear and adhesive wear.The friction coefficient of UHMWPE/CoCrMo with the pair in the initial stage of sliding wear test increased sharply then stabilized,and the load had little effect on the friction coefficient.PEEK/CoCrMo with a pair has a maximum coefficient of friction at small loads,and a larger load results in a lower coefficient of friction.The smaller normal load has a significant influence on the friction coefficient of the PEEK/UHMWPE pair.As the load increases,the friction coefficient increases and the friction coefficient increases.The wear of the first two types of joints increases with the increase of normal load and wear time.The wear volume of “soft-to-soft” with high-crosslinking UHMWPE is gradually increased with the increase of normal load.Among the three friction pairs,the wear pit of CoCrMo/PEEK is the deepest,but the wear scar width is the shortest.The scaly peeling layer caused by the adhesion of the contact surface can be observed on the surface,accompanied by the furrow.The damage mechanism of PEEK is mainly abrasive wear and adhesive wear.The wear volume of CoCrMo/UHMWPE is the largest,the material loss is the most serious,there is a large amount of wear debris on the edge of the furrow,and obvious fatigue cracks and tears can be observed.The damage mechanism of UHMWPE is mainly abrasive wear and fatigue wear.The wear scar of the PEEK/UHMWPE wear surface is slight,and there are only a small amount of cracks and lamellar peeling caused by adhesive wear.Due to the influence of the passivation film on the surface of CoCrMo between the two pairs of CoCrMo/UHMWPE and CoCrMo/PEEK,the corrosion current is small at the beginning of the experiment.With the progress of friction,the corrosion rate gradually increases and then reaches a stable stage.The experimental results show that with the increase of wear time and load,the polarization curve will shift to the left,the corrosion tendency will increase,and the wear will tend to increase.更多还原