不同环境介质下TC4钛合金与工程塑料摩擦磨损行为研究

为优选透平式能量回收一体机关键零部件耐磨材料,以TC4钛合金与共聚甲醛、均聚甲醛、PEEK及改性PEEK组成的配对摩擦副作为研究对象,利用立式万能摩擦磨损试验机开展干摩擦、纯水及海水环境介质下配对材料的摩擦磨损试验,定量获得各摩擦副的摩擦因数和磨损量,并对摩擦试样的表面形貌进行分析。结果表明:在干摩擦环境下共聚甲醛摩擦因数和磨损量最小,在纯水和海水环境下改性PEEK摩擦因数和磨损量最小;TC4钛合金与均聚甲醛、共聚甲醛、PEEK配副时磨损机制为黏着磨损,主要表现形式为涂抹和擦伤,TC4与改性PEEK配副时磨损较轻微,主要表现形式为轻微磨粒磨损。     

WC/TiC层状陶瓷刀具与316L不锈钢间的干摩擦磨损性能研究

研究了在1 750℃下真空热压烧结而成的WC/TiC层状陶瓷刀具材料在干摩擦条件下与316L奥氏体不锈钢之间的摩擦磨损性能,并对磨损面进行了分析。结果表明:载荷和滑动速度对摩擦因数和磨损量的影响较大,随着载荷的不断增大,WC/TiC层状陶瓷刀具材料的摩擦因数和磨损量呈增大趋势;而随着滑动速度的增大,WC/TiC层状陶瓷刀具材料的摩擦因数先降后增,磨损量先增后降;在WC/TiC层状陶瓷刀具材料与316L奥氏体不锈钢的对磨过程中,材料的表面发生了犁削、颗粒及片层剥落现象,在磨损表面留有犁沟、凹坑、微裂纹和片层结构,其磨损机理为磨粒磨损和粘着磨损。     

不同基体CrN/CrCN多层涂层海水环境摩擦学性能研究*

为研究不同基体材料对CrN/CrCN多层涂层在海水环境下摩擦学性能的影响,采用多弧离子镀技术在H65铜合金、TC4钛合金和316L不锈钢基体上沉积CrN和CrN/CrCN多层复合涂层,通过XRD、SEM等技术对涂层的结构进行表征,通过结合力、硬度测试和摩擦磨损试验分析涂层在大气环境和海水环境下的力学性能和摩擦学性能。结果表明:CrN/CrCN多层涂层的内应力相对于CrN明显减小,且硬度相对CrN涂层较高;TC4钛合金为基体的涂层结合力较好且涂层硬度较高;在海水环境下涂层的摩擦因数相对于大气环境都有较大幅度下降,其中,以TC4钛合金和316L不锈钢为基体的涂层摩擦因数较小;以H65铜合金为基体的2种涂层在海水中的磨损率高于大气中,而以TC4合金、316L不锈钢为基体的CrN/CrCN多层涂层在海水环境下的磨损率低于大气环境;TC4钛合金为基体的CrN/CrCN多层涂层在海水环境下具有最低的磨损率,表明TC4钛合金更适合作为海水环境下CrN/CrCN多层涂层耐磨的基体材料。     

摩擦配副材料对TC4钛合金微动磨损行为的影响

为合理选用接触副材料以减缓钛合金的微动失效,采用SRV-IV微动摩擦磨损试验机,研究不同载荷条件下,摩擦配副材料GCr15和Si_3N_4对TC4钛合金微动磨损行为的影响。结果表明:较低载荷下选择高硬度的Si_3N_4陶瓷作为摩擦配副更理想,而高载荷下选择GCr15钢作为摩擦配副更理想;TC4钛合金与GCr15钢对磨的磨损机制为磨粒磨损和疲劳磨损,磨损率随载荷增大而减小;Si_3N_4/TC4组成的摩擦副对摩过程中,磨屑的形成过程伴随有硅的水化物产生,使形成的磨屑黏性增加,载荷较小时磨屑易粘结形成致密的第三体层覆盖在TC4钛合金表面,起润滑、承载和隔离摩擦副的作用,降低材料的磨损率;载荷较大时,第三体层在磨粒磨损和黏着磨损作用下从TC4钛合金表面脱落,摩擦副直接接触,磨损率升高。     

水润滑下316L不锈钢与聚醚醚酮摩擦磨损性能研究

为了寻找适合于水液压泵/马达的摩擦副材料,以316 L不锈钢与纯聚醚醚酮树脂、30%玻璃纤维增强PEEK(PEEKGF30)、30%碳纤维增强PEEK(PEEKCA30),PTFE和石墨及碳纤维填充PEEK(PEEKHPV)组成的摩擦副为研究对象,利用MMW-1立式万能摩擦磨损试验机测量摩擦副在水润滑下接触表面的摩擦因数和温度以及试样的磨损量,并通过激光共聚焦显微镜对试件表面磨损形貌进行分析。结果表明:316 L-PEEKHPV摩擦副的摩擦因数、摩擦温升、磨损量均小于其余3组摩擦副,适合作为水液压泵/马达的关键摩擦副材料。316 L不锈钢与PEEKGF30配对时,摩擦机制为涂抹和擦伤,磨损较为严重;与PEEKCA30配对时,摩擦机制为擦伤;与PEEKHPV配对时摩擦机制主要为划伤,磨损较为轻微。     

高水基液压阀陶瓷摩擦副摩擦学性能研究

为选择适合的高水基乳化液液压阀摩擦副材料,探讨ZrO2与不同结构陶瓷组成的摩擦副在高水基乳化液润滑状态下的摩擦磨损特性。采用摩擦磨损试验机,在不同载荷和滑动速度下,研究在高水基乳化液介质中4种不同陶瓷材料（ZrO2、Al2O3、Si3N4和SiC）分别与ZrO2配副的摩擦学性能,并探讨不同组合陶瓷摩擦副的磨损机制。结果表明：在高水基乳化液中,各陶瓷的摩擦因数均随着滑动速度的增大而降低,其中Al2O3陶瓷的摩擦因数最小;ZrO2、Al2O3和Si3N4陶瓷的摩擦因数受载荷的影响较小,SiC陶瓷的摩擦因数则随着载荷的增大而骤增;各陶瓷的磨损体积都随着速度和载荷的增大而增大,其中Al2O3/ZrO2陶瓷摩擦副的磨损体积最小,其磨损机制以磨粒磨损和微疲劳磨损为主。研究表明,在不同工况下,Al2O3与ZrO2陶瓷配副的摩擦因数和磨损体积均为最低值,更适合作为高水基乳化液液压阀的摩擦副材料。     

不同材料配对机械密封的端面摩擦特性试验研究

以硬质合金YG8为动环,分别配对20%石墨填充聚四氟乙烯、碳石墨和SiC环组成3组密封副进行摩擦特性试验,获得32#液压油中3组密封副的工况参数与摩擦因数关系的包络线。试验表明:SiC-YG8组对的磨损量最小,摩擦因数最大;碳石墨-YG8组对的磨损量最大,摩擦因数最小;20%石墨填充四氟-YG8组对具有较小的磨损量和摩擦因数。机械密封端面摩擦特性取决于动静环配对材料和摩擦磨损条件,包括端面载荷、滑动速度及润滑介质性质等因素,利用工况参数与摩擦因数关系的包络线可以判断某一润滑介质条件下机械密封的端面摩擦特性。     

GCr15轴承钢滑动摩擦性能试验北大核心

利用往复式摩擦磨损试验机对GCr15钢盘/GCr15钢球和GCr15钢盘/Si3N4陶瓷球进行了不同工况下的滑动摩擦试验,并对其摩擦因数、磨损量和磨痕形貌进行了分析。结果表明:2种摩擦副的摩擦因数均随载荷的增大而减小,磨损率均随时间的增加而降低;干摩擦状态下,前者磨损量较小,而钢盘/陶瓷球摩擦副呈现出摩擦因数小,磨损量较大的特点;脂润滑状态下,接触应力较小时2种摩擦副的摩擦因数相差不大,接触应力较大时钢盘/陶瓷球摩擦副磨损较严重,其钢盘表面出现较明显的疲劳剥落现象。     

GCr15轴承钢滑动摩擦性能试验

利用往复式摩擦磨损试验机对GCr15钢盘/GCr15钢球和GCr15钢盘/Si3N4陶瓷球进行了不同工况下的滑动摩擦试验,并对其摩擦因数、磨损量和磨痕形貌进行了分析。结果表明:2种摩擦副的摩擦因数均随载荷的增大而减小,磨损率均随时间的增加而降低;干摩擦状态下,前者磨损量较小,而钢盘/陶瓷球摩擦副呈现出摩擦因数小,磨损量较大的特点;脂润滑状态下,接触应力较小时2种摩擦副的摩擦因数相差不大,接触应力较大时钢盘/陶瓷球摩擦副磨损较严重,其钢盘表面出现较明显的疲劳剥落现象。     

偶件表面粗糙度对PTFE材料摩擦磨损性能的影响

为了研究干摩擦条件下偶件表面粗糙度对聚四氟乙烯(PTFE)密封材料摩擦磨损性能的影响,利用MMW-1立式万能摩擦磨损试验机,在不同载荷和转速下研究由PTFE材料制作的试验环分别与316L不锈钢和45#钢配副时的摩擦磨损性能,并利用粒形分析仪对PTFE试验环试验前后端面的形貌进行观测;利用触针式轮廓仪对摩擦配副钢环的端面粗糙度进行精确测量,分析表面粗糙度对PTFE试验环摩擦磨损性能的影响。试验结果表明:在干摩擦条件下,摩擦配副钢环的表面粗糙度过高或者过低都会引起PTFE试验环磨损量的增加;定载荷时,PTFE试验环磨损量随摩擦配副钢环表面粗糙度的增大先减小后增大,随转速的增大而增大;定转速时,PTFE试验环摩擦因数随摩擦配副钢环表面粗糙度的增大稍减小后而后增大,随载荷的增大先减小后增大;在相同工况下,316L不锈钢对PTFE试验环的切削和犁沟作用比45#钢更加明显。     

表面粗糙度对Al2O3增强Y-TZP陶瓷材料生物摩擦学特性的影响

采用销-盘式摩擦磨损试验机研究了氧化铝增强氧化锆陶瓷(ADZ)的表面粗糙度对ADZ/316L不锈钢摩擦副的摩擦磨损性能的影响。结果表明:在小牛血清润滑下,随着陶瓷表面粗糙度的降低,ADZ陶瓷和316L不锈钢的摩擦因数和磨损率均呈降低趋势。但是对于表面粗糙度最高的陶瓷,由于Fe转移膜的物理吸附,出现了“负磨损”现象。     

Tribological Behavior of Tin-Based Babbitt Alloy Lubricated by Seawater

In this article, the tribological behaviors of tin-based Babbitt alloy ZChSnSb 8–8 sliding against AISI 302 stainless steel lubricated by seawater were investigated. The results indicated that the friction coefficient decreases with increasing load and sliding speed, and the wear rate increases slightly with load but decreases with sliding speed. The low friction coefficient and wear rate are attributed to the unique “concrete structure” and seawater. As a lubrication medium, seawater has lubricating, cooling, and corrosive effects on the sliding couple.     

SLM成形表面织构对TC4钛合金干摩擦磨损性能的影响

基于一步法思路,采用金属3D打印机基于激光选区熔化（SLM）技术制备表面带有凹坑织构的TC4钛合金试样,采用光学相机、超景深显微镜和扫描电镜观察织构成形情况,利用激光共聚焦位移测试仪和显微维氏硬度计分别测试表面粗糙度和表面硬度,在干摩擦条件下采用摩擦磨损试验仪考察不同载荷下织构密度对TC4钛合金试样摩擦学性能的影响,并使用扫描电镜对摩擦实验前后的表面形貌进行分析。研究结果表明：一步法SLM成形能够在TC4钛合金表面获得成形良好的直径500 μm的织构;随着织构密度的提高,钛合金试样表面粗糙度增大,表面硬度有所降低;干摩擦条件下,提高TC4钛合金试样织构密度有利于磨屑的收集从而减少试样的三体磨损,提高载荷有利于改善摩擦副接触状态;5 N载荷下40%织构密度试样的平均摩擦因数和磨痕宽度均最小,与无织构试样相比,平均摩擦因数和磨痕宽度分别降低12%和16%;40%织构密度下,载荷提高会引起摩擦因数的降低和磨损量增大,磨损表面犁沟和片状剥落增多。在干摩擦条件下,3D打印一步法制备的表面织构可以显著改善TC4钛合金的磨粒磨损和黏着磨损。     

不同润滑液下的Al2O3增强Y-TZP陶瓷/316L不锈钢生物摩擦学特性

采用销-盘式摩擦磨损试验机研究了氧化铝增强氧化锆(ADZ)陶瓷材料/316L不锈钢摩擦副在去离子水和小牛血清2种不同介质润滑下的生物摩擦磨损行为,并利用SEM观察了磨损表面形貌。结果表明:与去离子水相比,在小牛血清润滑条件下ADZ陶瓷的摩擦因数和磨损率降低。在去离子水润滑条件下ADZ陶瓷材料的磨损为轻微磨损,相应的磨损机制为塑性变形和微犁削;而在小牛血清润滑条件下,ADZ陶瓷材料的磨损为微量磨损,磨损过程类似抛光作用。     

Corrosion wear behaviors of micro-arc oxidation coating of Al2O3 on 2024Al in different aqueous environments at fretting contact

The fretting wear behavior of micro-arc oxidation (MAO) coating of Al₂O₃ on an aluminum alloy 2024Al flat against a 440C stainless steel ball was investigated in artificial rainwater, artificial seawater and distilled water by using a ball-on-flat configuration with 300 μm amplitude at room temperature for 1 h. The morphology of the wear scars were observed and analyzed using scanning electron microscopy; the 3D-morphology and wear volume-loss were determined using a non-contact optical profilometer. Potentiodynamic anodic polarization was used to measure the corrosion behavior of the MAO coating before and after the corrosion wear test. The influences of the load, frequency and aqueous medium on the friction coefficient and wear volume-loss of the coatings were also analyzed. Results show that the friction coefficient decreases generally with an increase of the frequency in the three aqueous solutions; whereas it presents different variation trends as the load increased. In addition, aqueous environment does significantly influence the friction coefficient, the friction coefficient was the largest when fretting occurred in distilled water, smaller when fretting occurred in rainwater, and the smallest when fretting occurred in seawater. Particularly the remarkable antifriction effect of the seawater is of note. The wear-loss of the MAO coating in the distilled water is the largest at low frequency; however, it increases rapidly in rainwater and seawater at high frequency due to the corrosion effect of Cl^? ion as well as its accelerating effect to the wear process, and results in larger wear-loss than that in distilled water, which implies a positive synergism between corrosion and wear.     

Tribological behaviour of AISI 316L stainless steel for biomedical applications

Abstract

The aim of this research is to study the tribological behaviour of AISI 316L stainless steel for surgical implants (total hip prosthesis). The tribological behaviour is evaluated by wear tests, using tribometers ball on disc and sphere on plane. These tests consisted of measuring the weight loss and the friction coefficient of stainless steel (SS) AISI 316L. The oscillating friction and wear tests have been carried out in ambient air with an oscillating tribotester in accord with standards ISO 7148, ASTM G99-95a and ASTM G133-95 under different conditions of normal applied load (3, 6 and 10 N) and sliding speed (1, 15 and 25 mm s^?1). A ball of 100Cr 6, 10 mm in diameter, is used as counter pairs. These tribological results are compared with those carried out with a tribometer type pin on disc under different conditions of normal load applied P (19·43, 28 and 44 N) and sliding speed (600 and 1020 rev min^?1). The behaviour observed for both samples suggests that the wear and friction mechanism during the tests is the same, and to increase the resistance to wear and friction of biomedical SS AISI 316L alloy used in total hip prosthesis (femoral stems), surface coating and treatment are necessary.     

试验参数对人工滑液边界润滑条件下超高分子量聚乙烯/Ti6Al4V往复摩擦磨损行为的影响

采用自行研制的往复摩擦磨损试验机,在法向载荷50 N、往复频率1 Hz、摩擦副接触形式为圆环外圆周/平面、初始线接触长度为6 mm、相对湿度为80%的试验条件下,研究了钛合金表面粗糙度、试验环境温度、试验延续时间、滑液成分等试验参数对UHMWPE/Ti6A14V摩擦副的往复摩擦磨损行为的影响.结果表明,这些试验参数均显著影响UHMWPE/Ti6A14V摩擦副的往复摩擦磨损行为;在环境温度20℃、25%小牛血清去离子水溶液边界润滑、180 min往复摩擦磨损试验条件下,当钛合金表面粗糙度由Ra0.04 μm增加至Ra0.06μm时,摩擦副的平均摩擦因数由0.033增加至0.096,UHMWPE试样磨损量由0.131 mm3,增加至0.149 mm3;在钛合金表面粗糙度为Ra0.06μm、25%小牛血清去离子水溶液边界润滑、180 min往复摩擦磨损试验条件下,当试验环境温度由10℃上升至37℃时,摩擦副的平均摩擦因数由0.135减少至0.077,UHMWPE试样磨损量由0.188 mm3减少至0.134 mm3.     

Friction and wear of titanium alloys sliding against metal, polymer, and ceramic counterfaces

Recent advances in lower-cost processing of titanium, coupled with its potential use as a light weight material in engines and brakes has renewed interest in the tribological behavior of titanium alloys. To help establish a baseline for further studies on the tribology of titanium against various classes of counterface materials, pin-on-disk sliding friction and wear experiments were conducted on two different titanium alloys (Ti-6Al-4V and Ti-6Al-2Sn-4Zr-2Mo). Disks of these alloys were slid against fixed bearing balls composed of 440C stainless steel, silicon nitride, alumina, and polytetrafluoroethylene (PTFE) at two speeds: 0.3 and 1.0 m/s. The friction coefficient and wear rate were lower at the higher sliding speed. Ceramic sliders suffered unexpectedly higher wear than the steel slider. The wear rates, ranked from the highest to the lowest, were alumina, silicon nitride, and steel, respectively. This trend is inversely related to their hardness, but corresponds to their relative fracture toughness. Comparative tests on a Type 304 stainless steel disk supported the fracture toughness dependency. Energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) analyses confirmed the tendency of Ti alloys to transfer material to their counterfaces and suggested possible tribochemical reactions between the ceramic sliders and Ti alloy disks. These reaction products, which adhere to the ceramic sliders, may degrade the mechanical properties of the contact areas and result in high wear. The tribochemical reactions along with the fracture toughness dependency helped explain the high wear on the ceramic sliders.