聚四氟乙烯编织复合材料摩擦温度与磨损特性

在高频压摆摩擦磨损试验机上对自制聚四氟乙烯(Polytetrafluoroethene,PTFE)编织复合材料进行摩擦学性能试验,研究摩擦温度与摩擦磨损特性的关系。试验结果表明:摩擦温度对PTFE编织复合材料的摩擦因数影响显著,摩擦温度在30～60℃范围内升高,摩擦因数有明显的降低趋势,在65～210℃范围内摩擦因数处于稳定阶段,210℃是摩擦因数的突变摩擦温度。通过扫描电子显微镜对不同工况下产生的磨屑进行显微分析表明:高温下产生的磨屑与低温下的磨屑明显不同,低温下产生的磨屑为细小的片状,高温下产生的磨屑以大片的断裂纤维为主,材料磨损严重。PTFE编织复合材料的耐磨性受摩擦温度影响较大,200℃是PTFE编织复合材料磨损率的转折点。为保证该PTFE编织复合材料良好的摩擦磨损性能,摩擦温度动态监测值不能超过200℃。     

高速条件下PTFE编织复合材料的摩擦磨损性能

将PTFE编织复合材料与9Cr18Mo钢组成摩擦副,在高速压摆摩擦磨损试验机上进行干摩擦磨损试验,研究了循环次数和摩擦温度对摩擦因数的影响,用扫描电镜观察了不同阶段摩擦表面及磨屑的形貌,并分析了PTFE编织复合材料的磨损机理。结果表明:PTFE复合材料的摩擦因数随着循环次数的增加先迅速降低,后在一定范围内达到动态平衡,随着摩擦的继续进行,摩擦因数急剧上升,PTFE复合材料发生磨损失效;摩擦温度是影响PTFE复合材料摩擦磨损机制一个重要因素,摩擦温度的急剧升高将加剧PTFE复合材料的磨损;随着磨损的加剧,磨屑也表现为相应的恶化趋势;磨损机理以疲劳磨损为主。     

纳米金属粉填充Ekonol/PTFE复合材料的摩擦磨损性能研究

评价了分别用不同体积含量的纳米镍粉和纳米铜粉填充聚苯酯/聚四氟乙烯(Ekonol/PTFE)复合材料体系的力学性能,利用M-200型磨损试验机研究了纳米Ni、纳米Cu含量对Ekonol/PTFE复合材料摩擦学性能的影响,借助扫描电子显微镜和能谱分析手段考察试样磨损表面和磨屑,并探讨其摩擦磨损机制。结果表明,纳米Ni能在一定范围内增加Ekonol/PTFE复合材料的冲击强度;纳米金属粉填入量较小时均能增加复合材料的洛氏硬度。纳米Ni与纳米Cu均能增加Ekonol/PTFE复合材料的摩擦因数并降低磨损率。其原因在于纳米金属粉在复合材料摩擦表面富集,通过金属分子间的吸引作用,增大复合材料的摩擦因数。     

高速摆动下PTFE编织复合材料干摩擦研究

利用高速摩擦试验机对PTFE编织复合材料进行干摩擦试验,研究不同条件(载荷、速度和湿度)下PTFE编织复合材料干摩擦磨损性能;并利用扫描电子显微镜对不同条件下的磨屑形貌进行分析。结果表明:单因素变化条件下,摩擦因数随载荷和相对湿度的增大而减小,随摩擦速度的增大而增大;磨损量随载荷和速度的增大而增大,但相对湿度的增加可降低磨损;载荷及速度的增加显著影响材料磨损状况。     

低含量磷片石墨填充改性PTFE复合材料的摩擦磨损性能

为了改善聚四氟乙烯高磨耗的缺点,通过冷压烧结成型工艺制备4种低含量鳞片石墨填充改性聚四氟乙烯(PTFE)复合材料,探究其在较高载荷(0.8 MPa)及不同转速下的摩擦磨损情况。采用三维视频显微镜观察样品的表面磨痕深度,借助扫描电镜观察摩擦表面形貌并分析磨损机制。结果表明:在较高载荷下石墨填充PTFE复合材料的摩擦因数和体积磨损率都较纯PTFE有一定程度的降低;且当石墨填充质量分数为5%时,复合材料的摩擦因数和体积磨损率降到最低,在载荷为0.8 MPa、转速为80 r/min时较纯PTFE分别降低了19.7%和84.25%;在较高载荷下,随着石墨含量的增大,复合材料的磨损机制逐渐由犁耕磨损向黏着磨损转变,且当石墨质量分数为10%时,出现轻微的疲劳磨损。     

石墨填充聚四氟乙烯基复合材料的摩擦学性能

为了研制PTFE基粘弹-摩擦型阻尼材料,采用机械共混-冷压成型-烧结的工艺制备了石墨、聚苯硫醚、聚醚醚酮混合填充PTFE基复合材料,利用环-块式磨损试验机,在干摩擦条件下考察了复合材料的摩擦学性能,并用扫描电镜观察了磨损表面形貌,研究了复合材料的磨损机制。结果表明:PTFE含量不同的复合材料,随石墨填充量的增大,摩擦因数和磨损率的变化趋势不同,磨损主要由犁削、粘着和疲劳剥落中的一种或几种引起;适当配比的PTFE基复合材料具有较好的摩擦阻尼性能,能够满足粘弹-摩擦阻尼材料的要求。     

聚苯酯填充聚四氟乙烯复合材料的力学及摩擦学性能研究

采用共混-冷压-烧结工艺制备了聚苯酯(POB)填充聚四氟乙烯(PTFE)复合材料,考察了POB含量对PTFE/POB复合材料机械性能和摩擦学性能的影响,探讨了材料的磨损机制和POB的减磨机制.结果表明复合材料的拉伸强度和断裂伸长率随着POB含量的增加而降低,压缩强度随着POB含量的增加而增大;随着POB含量的增加材料摩擦因数呈现增大趋势,POB质量分数在16%～27%范围内材料摩擦因数为0.20～0.24;在与AISI 1045钢的对磨中复合材料发生了黏着磨损,磨损率随着POB质量分数的增加呈现下降趋势,POB质量分数超过25%后继续增加其含量复合材料磨损率降低幅度逐渐变小.     

碳材料填充PTFE复合材料摩擦磨损性能

利用 MM-200 型磨损试验机考察了石墨、碳纤维、硬碳和软碳填充 PTFE 复合材料的摩擦磨损性能,采用扫描电子显微镜观察分析磨损表面形貌及磨损机制.结果表明,碳材料可以不同程度地提高 PTFE 的耐磨性,它们对PT-FE 耐磨性的提高程度各不相同,其中以硬碳填充 PTFE 复合材料的磨损质量损失最小,石墨填充 PTFE 复合材料的磨损质量损失较大;不同填充材料对 PTFE 摩擦因数的影响各不相同,其中石墨填充 PTFE 的摩擦因数较小.石墨、软碳填允复合材料磨损机制以粘着磨损为主,硬碳、碳纤维复合材料,则表现为粘着磨损和磨粒磨损.     

聚四氟乙烯与超细高岭土填充聚甲醛复合材料的摩擦学性能

用聚四氟乙烯(PTFE)和超细高岭土填充聚甲醛(POM),采用热模压成型工艺制备出四种不同成分的试样,在往复式滑动摩擦试验机上进行摩擦磨损试验,并对磨损表面形貌进行了分析.结果表明:只填充PTFE的复合材料的摩擦因数和磨损率较纯POM均有较大幅度的下降,7.5%高岭土与20%PTFE复合填充的复合材料摩擦因数最小,耐磨性最好;纯POM的磨损机制是粘着磨损和磨粒磨损,POM复合材料的磨损机制以粘着磨损为主.     

聚四氟乙烯填充高岭土基矿物聚合物复合材料的摩擦学性能

研究了PTFE填充量对高岭土基矿物聚合物复合材料的力学性能和摩擦磨损性能的影响,利用XRD、SEM分析了材料的微观结构和磨损表面形貌。结果表明:填充PTFE对矿物聚合物材料的力学性能会有一定程度的降低,但可以有效改善复合材料的摩擦磨损性能,当PTFE体积分数为30%时,摩擦因数和磨损率均达到最低,分别为0.429和1.22×10-5mm3/N·m;当PTFE含量较高时,磨损机理除了磨粒磨损外还有对偶件的粘着转移。     

不同载荷下水润滑高分子材料磨损机制的试验研究

为了研究载荷对新型水润滑高分子轴承材料磨损机制的影响,在CFT-1型摩擦磨损试验机上对该材料进行不同载荷下的无/有水润滑摩擦磨损试验,通过考察试样的摩擦因数、磨痕和磨损表面形貌,分析该材料的磨损机制。结果表明:在无水润滑条件下,该材料的摩擦因数随着载荷的增加呈现先降低后逐渐上升的变化趋势,磨损表面均出现塑性变形和撕裂脱落现象,磨损机制主要为黏着磨损,其中随着载荷的增大表面塑性变形趋于严重,而表面撕裂脱落在中等载荷下较为轻微,在低载荷和高载荷下较为严重;在水润滑条件下,该材料的摩擦因数随着载荷的增加也呈现出先下降低后急剧上升的趋势,磨损表面未发生塑性变形和撕裂脱落,但出现脱落的磨粒和犁沟,磨损机制主要为磨粒磨损,其中在中等载荷下,表面脱落的磨粒少、犁沟细小而浅,在低载荷和高载荷下表面脱落的磨粒多、犁沟深。     

干摩擦条件下树脂刹车片磨损机制研究

为了优化拖缆机刹车部件的设计参数,同时进一步提高刹车片的耐磨性能,采用MPV-600型磨粒磨损试验机研究无石棉树脂摩擦片和黄铜试样与45#钢配副在干摩擦条件下的摩擦学性能,利用体式显微镜观察试样的磨损形貌并分析其磨损机制。结果表明:摩擦热引起的温升导致的硬度下降及磨损机制的改变是干摩擦条件下摩擦片磨损的主要原因;树脂刹车片的耐热性能、耐磨性能均好于黄铜试样,树脂刹车片与钢配副的摩擦因数主要是由树脂刹车片中的铜纤维材料决定的;干摩擦条件下树脂摩擦片的磨损机制是以磨粒磨损和氧化磨损为主,而黄铜试样以磨粒磨损和黏着磨损为主。     

Tribo-investigation on PTFE lubricated PEEK in harsh operating conditions

A series of blends with Polytetrafluroethylene (PTFE) powder and Polyetheretherketone (PEEK) was developed by varying the PTFE contents in steps of 5 wt.% from 0 to 20 wt.%. The composites were evaluated for their friction and wear properties at room temperature as well as high temperature in low amplitude oscillating wear (LAOW) mode against steel (100 Cr 6) ball against polymer plate. The same blends were also evaluated in abrasive wear mode to study the influence of harsh operating conditions on wear and friction performance. Incorporation of PTFE benefited PEEK in various ways such as it increased the tribo-utility of the latter by increasing its limiting load value, removing its stick-slip tendency, lowering coefficient of friction and specific wear rate significantly. With increase in PTFE content, benefits to the wear performance increased regularly. This was not the case for friction coefficient. Lowest μ was recorded for 15% PTFE contents. The enhancement in wear and friction performance, however, was at the cost of strength properties which decreased substantially with increase in PTFE content. At 100 °C, friction coefficient and wear rates of all blends increased marginally. In abrasive wear mode, on the other hand, PTFE filled PEEK showed poorer wear resistance than neat PEEK. This was correlated with strength properties and it was observed that these blends closely followed the predictions of Ratner–Lancaster plot. SEM was used to examine the micro-structural features of worn surfaces.     

聚合物填充聚四氟乙烯复合材料的摩擦磨损性能

采用机械共混-冷压成型-烧结的工艺制备了PEEK、PPS填充PTFE基粘弹．摩擦型阻尼材料，用环-块式磨损试验机研究了在干摩擦条件下的摩擦磨损性能；用扫描电子显微镜观察磨损表面形貌和内部组织结构。结果表明：混合填充PEEK和PPS时，2种填充物的比例对材料的摩擦因数影响不大，当二者含量相近时，摩擦因数最大；填充物对磨损性能的影响与对摩擦因数的相同；随着PEEK含量的增加和PPS含量的减少，材料的磨损方式由疲劳剥落磨损为主转变为犁削、粘着磨损；PTFE含量的增加，使得复合材料的摩擦因数减小，而磨损有所增大。综合考虑认为，PTFE与适当比例的PEEK／PPS混合填充，具有合适的摩擦因数和较好的耐磨性，能够满足特殊工况下阻尼材料的需要。     

Effect of Blowing Air and Floating Sand-dust Particles on the Friction and Wear Behavior of PTFE, UHMWPE and PI

The friction and wear behaviors of polytetrafluoroethylene (PTFE), ultra-high molecular weight polyethylene (UHMWPE), and polyimide (PI) have been comparatively evaluated under dry sliding, blowing air, and simulated sand-dust conditions. The tribological tests were conducted on an improved block-on-ring test rig equipped with an attachment for simulating the sand-dust environment. The reason for the difference in the tribological behavior of these polymers under the three test conditions was also comparatively discussed, based on scanning electron microscopic examination of the worn polymer specimens and counterfaces. Under blowing air conditions, the decrease of the contact temperature produced by blowing air led to the increase in the shearing strength of the sliding surface when compared with dry sliding conditions and hence to cause an increase in the friction coefficient and a remarkable decrease in the wear rate of PTFE and UHMWPE. On the contrary, blowing air produced a decrease in the friction coefficient of PI because of the formation of transfer film on the counterfaces, and an increase in the wear rate, because the blowing air considerably promoted the transfer of PI onto the counterfaces when compared with dry sliding conditions. Both PTFE and UHMWPE registered the lowest wear rate under sand-dust conditions, owing to the tribolayer formation on the worn surfaces, while PI exhibited the highest wear rate because no tribolayer was formed during the abrasive wear process.     

表面改性硅灰石纤维填充PTFE复合材料的摩擦学性能

用KH550硅烷偶联剂表面改性的硅灰石纤维(WF)填充PTFE,在MPX-2000型磨损试验机上研究复合材料的摩擦磨损性能,并与经典的炭纤维(CF)填充PTFE复合材料进行比较。采用SEM对磨损面和对偶面进行分析。结果表明:较高载荷(200和300 N)下复合材料摩擦因数随WF含量变化的幅度不大,较稳定地维持在较低值;细小尺寸WF填充PTFE复合材料的耐磨性能较好,在WF质量分数为10%时,复合材料的磨损量只有相同含量CF填充PT-FE复合材料的81%;细小尺寸WF填充PTFE复合材料的磨损面较为平整,存在轻微黏着磨损,其对偶面转移膜平整光滑、结构致密;而CF/PTFE复合材料磨损面存在许多裸露和碎断的CF,犁削和磨粒磨损是主要的磨损形式。     

聚酰亚胺复合材料与不同金属间干滑动时的摩擦学性能

采用MPX-2000型摩擦磨损试验机研究了聚四氟乙烯和二硫化钼填充聚酰亚胺复合材料在干滑动摩擦条件下与45钢、镍铬合金、铜和铝对磨时的摩擦磨损性能,并利用扫描电子显微镜和光学显微镜分析了复合材料及对偶件的磨损表面形貌。结果表明:复合材料与铝对磨时的摩擦因数和磨损率最低,分别约为与钢摩擦时的43%和49%;摩擦后铝表面形成均匀连续的转移膜,45钢、镍铬合金和铜的表面没有形成有效转移膜,因此复合材料的摩擦因数较大;复合材料与不同金属材料摩擦时的磨损机理主要是粘着磨损与疲劳磨损。     

Investigation into sliding wear performance of zinc-based alloy reinforced with SiC particles in dry and lubricated conditions

The objective of the present investigation was to assess the influence of SiC particle dispersion in the alloy matrix, applied load, and the presence of oil and oil plus graphite lubricants on the wear behaviour of a zinc-based alloy. Sliding wear performance of the zinc-based alloy and its composite containing SiC particles has been investigated in dry and lubricated conditions. Base oil or mixtures of the base oil with different percentages of graphite were used for creating the lubricated conditions. Results show a large improvement in wear resistance of the zinc-based alloy after reinforcement with SiC particles. The lubrication improved the wear resistance and friction behaviour of both the reinforced and base alloys. It was also observed that there exists an optimum concentration of graphite particles in the lubricant mixture that leads to the best wear performance. The composite experienced higher frictional heating and friction coefficient than the matrix alloy in all the cases except oil lubricated conditions; a mixed trend was noticed in the latter case. The wear rate and frictional heating increased with load while friction coefficient was affected in an opposite manner. Test duration influenced the frictional heating and friction coefficient of the samples in a mixed manner.Examination of worn surfaces revealed a change of predominating wear mechanisms from severe ploughing and/or abrasive wear for base alloy to delamination wear for the reinforced material under dry sliding conditions. The presence of the lubricant increased the contribution of adhesive wear component while reducing the severity of abrasion. This was attributed to the generation of more stable lubricant films on the contacting surfaces. Cross-sections of worn surfaces indicated substantial wear-induced plastic deformation, thereby suggesting adhesive wear to be a predominant wear mechanism in this study. The debris particles revealed deformed flakes and machining chips signifying the involvement of adhesion and abrasion modes of wear respectively.     

两种受电靴材料与不锈钢带电接触摩擦磨损特性的试验研究

在销-盘式摩擦磨损试验机上分别进行了不锈钢／铜基烧结合金材料和不锈钢／铜石墨烧结材料接触的载流摩擦磨损行为的试验研究。在试验中记录了摩擦因数和磨损量的变化,并对磨痕形貌进行了光学显微镜观察。结果显示,电流对2种摩擦副带电接触的摩擦磨损行为有重要的影响。2种材料的摩擦因数随电流的增大而呈现截然相反的变化趋势,但两者的磨损量却随电流的增加而增大。不锈钢／铜基烧结合金材料的磨损机制主要是粘着磨损及氧化磨损。不锈钢／铜石墨烧结材料磨损机制包括磨粒、粘着磨损和电弧烧蚀,其中电弧烧蚀对磨损量的影响随电流的增大而增加。