碳纳米管掺杂Fe3Al基复合摩阻材料的摩擦磨损特性研究

采用冷压烧结法制备了CNTs-Fe3Al基复合摩阻材料。经添加0.5%~5%CNTs、1%~5%Al2O3,研究了掺杂物含量及摩擦载荷对摩阻材料摩擦磨损性能的影响,并采用SEM对材料初始表面形貌及磨损形貌进行了观测。结果表明,随着CNTs及Al2O3含量的逐渐增加,磨损方式将由磨粒磨损向疲劳磨损转变。添加CNTs时,摩擦系数先降低后升高再降低;添加Al2O3时,摩擦系数不断升高。加入0.5%CNTs、3%Al2O3可制备平均摩擦系数0.7,硬度295.8HV的摩阻材料。     

摩圣技术在邯钢CSP钢包回转台减速机上的应用

本文针对邯钢CSP钢包回转台减速机小齿轮和中间齿轮的齿面磨损严重的现状,对其损坏原因进行了分析,采取了相应地措施,并采用摩圣技术对小齿轮和中间齿轮的齿面进行在线修复,取得了良好的效果。     

自润滑材料及其摩擦特性的影响因素

自润滑复合材料是材料科学研究领域的一个重要发展方向,由于其在特殊使用条件下具有优良的摩擦学特性而受到人们的广泛关注。综合介绍与评述了国内外自润滑复合材料的开发与进展,讨论了对材料摩擦学性能的影响因素,提出了在今后研究与开发工作中应当重视的几个努力方向。     

碳纤维束间的摩擦磨损特性

为了对碳纤维束的磨损程度进行定量分析以及探索碳纤维束间摩擦磨损机制,采用自制的摩擦模拟实验装置,研究了摩擦次数、加载力、摩擦角度对碳纤维束摩擦损伤的影响。通过对比摩擦前后碳纤维束的拉伸断裂强力、毛羽量和表面浆膜形态评价了其磨损程度。结果表明:随着摩擦次数、加载力的增大,碳纤维束的磨损程度逐渐加剧;当摩擦角度在90°~30°范围变化时,碳纤维束的拉伸断裂强力随着角度的减小而小幅度下降;而当摩擦角度为0°时,碳纤维束的拉伸断裂强力急剧下降。同时,结合纤维束接触理论和黏性薄膜压痕法揭示了碳纤维束摩擦损伤机制,发现有效接触面积的变化是导致碳纤维束磨损程度改变的主要因素,且纤维束间的有效接触面积随加载力的增大而增大,随摩擦角度的增大而减小。      

纳米碳管的特性及其在摩擦磨损中的应用

纳米碳管具有超强的力学性能,极高的化学、热稳定性和独特的导电性,已得到广泛的应用.本文综述纳米碳管的结构、制备方法和应用,着重讨论纳米碳管在摩擦磨损中的研究进展及其应用.     

石墨改性热塑性聚酰亚胺复合材料的摩擦磨损性能

采用热压成型工艺制备石墨填充热塑性聚酰亚胺复合材料,考察了复合材料的力学性能及干摩擦和三种油润滑条件下的摩擦磨损性能;利用扫描电子显微镜和能谱仪观察分析材料磨损表面形貌和元素分布.结果表明:石墨的加入降低了复合材料的弯曲强度和拉伸强度,干摩擦条件下复合材料摩擦系数随着石墨含量的增大稳步降低最终保持在0.1左右;石墨含量为30%时复合材料磨损率仅为纯树脂的2.9%;油润滑条件下复合材料的摩擦系数相比干摩擦降低了一个数量级;三种润滑油均能在偶件表面形成稳定吸附膜,由于润滑油性质的差异导致材料摩擦磨损性能有所不同.     

磁流变弹性体的制备及其摩擦磨损特性测试

磁性弹性体不但具有显著的粘附特性还是一种可控的磁致摩擦材料,可以在仿生机器人手足以及离合器踏板等诸多新型领域获得应用。为了探究磁流变弹性体的摩擦性能,通过混合-固化-冷却的步骤制备了不同体积分数的各向同性和各向异性磁流变弹性体。利用了球盘式摩擦磨损机进行摩擦因素测试,并在环境扫描电镜下观察磨损后的颗粒排列方式以及基体的破损程度。实验结果表明,各向同性和各向异性弹性体随着磁性颗粒含量的增加,颗粒之间的间隙减少,最终形成团状,摩擦因素随之下降。此外,各向异性弹性体基体的破坏程度更加剧烈,颗粒之间形成基能团,摩擦因素相应较低。各向异性弹性体在摩擦磨损过后基体会出现严重的波纹,这也说明了磨损波纹以及磨痕的密集程度也是导致摩擦因素变化的原因。     

热喷涂技术在摩擦磨损领域应用研究

该文综述了热喷涂技术在摩擦磨损领域应用的研究现状及进展,主要论述了喷涂方法、喷涂工艺、喷涂材料、涂层结构、涂层处理及喷涂涂层的磨损机理等方面在摩擦磨损领域的研究与进展,通过上述几方面的讨论与分析,总结了热喷涂涂层在摩擦磨损领域具体的应用情况,分析和总结了热喷涂涂层在摩擦磨损领域应用失效的主要原因和形式,并提出了提高热喷涂技术在摩擦磨损领域应用能力的方法和措施。     

PTFE基复合材料摩擦磨损特性研究

用机械共混、冷压成型自由烧结的方法制备了PTFE基复合材料;用M-2000型磨损试验机测试了在干摩擦定载荷条件下各试样的磨损性能;用扫描电子显微镜(SEM)对磨损试样的表面形貌进行了观察和分析.结果表明:在实验条件下,复合材料的抗磨性能,随青铜粉用量的增大逐渐增强,当青铜粉的用量大于20vol.%后,抗磨损性能增强的趋势明显减缓,在干摩擦条件下复合材料主要发生粘着磨损和磨粒磨损,且随青铜粉用量的增加,磨粒磨损也越明显.研究发现,当青铜粉:氧化镉:二硫化钼为20:6:4(体积比)时,复合材料的摩擦磨损性能最佳.     

半金属摩阻材料中铜纤维摩擦磨损行为的研究

用扫描电子显微镜(SME)和X-射线能谱分析法(EDX)对铜纤维增强的半金属摩阻材料与灰铸铁对偶滑摩后的摩擦表面进行了分析,研究了摩阻材料中铜纤维的摩擦磨损行为.结果表明,在摩擦磨损过程中,摩阻材料摩擦表面上铜的分布更加弥散化,并且铜纤维具有集铁作用,因而摩阻材料摩擦表面上形成了富铁贫铜表面工作层;铜能从摩阻材料摩擦表面转移到对偶摩擦表面,故对偶摩擦面上分布一定量铜,这是摩擦副具有稳定摩擦系数和良好耐磨性的关键因素;铜纤维取向对摩阻材料摩擦磨损行为有显着影响.     

三种NiAl材料的室温摩擦磨损性能

测试二元NiAl合金、NiAl-Al2O3-TiC原位内生复合材料以及NiAl-Cr(Mo)-Hf共晶合金的室温摩擦磨损性能,研究了磨损机制.结果表明:NiAl材料的抗磨损性能与材料的硬度和断裂韧性成正比,在磨损过程中硬质陶瓷颗粒能有效地传递应力和起到支撑作用,减轻材料的磨损.因此NiAl-Al2O3-TiC复合材料的抗磨损性能最好,在相同工况下其磨损率为NiAl-Cr(Mo)-Hf共晶合金的1/4-3/4和二元NiAl合金的1/20-1/10.摩擦系数随着三种NiAl材料硬度的提高而降低.三种NiAl材料的室温干摩擦磨损过程受控于塑性变形,其磨损机制主要是磨粒磨损机制,随着载荷的增加,磨损表面依次呈现出塑性变形、显微剥落和粘着磨损特征,磨损机制的改变对磨损率和摩擦系数具有重要的影响.     

高硅铝合金的摩擦磨损性能

采用喷射沉积技术和热挤压致密化技术制备Al-22Si和Al-27Si(质量分数)两种高硅铝合金,研究两种合金在不同载荷下的摩擦行为和磨损机理。结果表明,与铸态合金相比,喷射沉积技术制备的高硅铝合金具有晶粒细小、成分均匀的组织特征;在载荷为30,45,60和75 N下,Al-22Si合金的磨损以粘着磨损和氧化磨损为主;Al-27Si合金在低载荷下以粘着磨损为主,在高载荷下的磨损行为时粘着磨损和磨粒磨损的混合磨损机制。含有较高硅含量的Al-27Si合金具有相对小的摩擦系数和磨损率。随着载荷增大,两种合金的磨损量逐渐增大。     

Nanoscale friction and wear maps

Friction and wear are part and parcel of all walks of life, and for interfaces that are in close or near contact, tribology and mechanics are supremely important. They can critically influence the efficient functioning of devices and components. Nanoscale friction force follows a complex nonlinear dependence on multiple, often interdependent, interfacial and material properties. Various studies indicate that nanoscale devices may behave in ways that cannot be predicted from their larger counterparts. Nanoscale friction and wear mapping can help identify some 'sweet spots' that would give ultralow friction and near-zero wear. Mapping nanoscale friction and wear as a function of operating conditions and interface properties is a valuable tool and has the potential to impact the very way in which we design and select materials for nanotechnology applications.     

C/C复合材料特性对其摩擦磨损性能的影响

在MM-2000环-块摩擦试验机上研究了制备工艺、石墨化度、密度、纤维取向等材料特性对其摩擦磨损性能的影响。研究结果表明，采用化学气相渗透(CVI) 浸渍工艺制备并经过多次浸渍增密且石墨化后的材料具有优良的摩擦磨损特性。石墨化后试样的密度越大，其摩擦磨损性能也越好。一般情况下在载荷适中时，垂直试样的摩擦系数要大于平行试样，而体积磨损量却小于平行试样。C／C复合材料比高强石墨材料更适宜用作航空发动机轴间密封材料。     

Sliding friction and wear behavior of Fe-based bulk metallic glass in 3.5% NaCl solution

The corrosion wear behaviors of a Fe-based bulk metallic glass Fe_66.7C_7.0Si_3.3B_5.5P_8.7Cr_2.3Al_2.0Mo_4.5 against Si₃N₄ ceramic ball was studied in a 3.5% NaCl solution and using a unidirectional tribometer with the ball-on-disk configuration. During friction process, the Fe-based BMG showed tribochemical reaction with the 3.5% NaCl solution. Wear occurred mainly through an abrasive wear mechanism and corrosive wear effects. The overall average friction coefficient was in the range of 0.18 to 0.25 according to the test conditions and slightly decreased with increasing load. The wear resistance of the BMG was better than that of the conventional bearing steel, demonstrating the potential of the BMG as a viable engineering alloy for anti-corrosive wear applications.     

Sliding friction and wear of structural ceramics

Further analysis has been performed on SiC and partially stabilized ZrO₂ specimens employed in a previous study of sliding friction and wear. Wear volumes have been measured, wear debris has been studied by X-ray diffraction and transmission electron microscopy, and comparative X-ray diffraction studies have been performed on worn and unworn surfaces. There is no correlation between the wear during running-in and the steady-state coefficient of friction established by this process. ZrO₂-ZrO₂ friction couples wear much faster than SiC-SiC couples, which in turn wear faster than ZrO₂-SiC couples. In these last couples wear occurs mostly on the ZrO₂ member, but does not measurably promote the tetragonal to monoclinic phase transformation. Adding graphite to SiC reduces the wear of SiC-SiC couples somewhat, but improving their initial surface finish has the opposite effect. All wear debris exhibited a bimodal particle-size distribution, which observation can be rationalized with the wear surface topographies reported previously.     

Sliding friction and wear of structural ceramics

A study has been made of the unlubricated sliding friction and wear behaviour of various like and unlike combinations of four materials -sintered-SiC, graphitized SiC, siliconized SiC and a Y₂O₃-stabilized ZrO₂ — in air at room temperature under dynamic conditions approximating the motion of a piston in the cylinder of an idling automotive engine. The steady state friction coefficient _f is largely independent of the initial surface finish, but is in all cases unacceptably high (0.25 _f 0.50) for engine applications. When the running-in process involves smoothing of the wear surfaces, the coefficient of friction decreases asymptotically towards its steady state value; and when running-in involves roughening, this coefficient usually increases asymptotically as the wear surfaces develop their steady state topographies. Friction couples containing siliconized SiC were the only exceptions to this pattern of behaviour. In every case the high steady state friction is accompanied by considerable wear. The results suggest that ceramic components will not be used unlubricated in reciprocating situations.     

Tribological characteristics of thin films and applications of thin film technology for friction and wear reduction

Thin film deposition technologies based on chemical and physical vapor deposition are now well established to improve the wear resistance of cutting tools. Although severe tribological conditions occur here, coated tools perform exceptionally well. Despite this, the growth in use of thin film deposition technology is slow in the general mechanical industry. In part, this is due to lack of data on the tribological characteristics of bodies coated with thin films.In this paper, tribological test data gathered in a systematic program of sliding and rolling contact tests are presented to demonstrate the usefulness of thin film coatings for wear protection and friction reduction. Samples coated by reactive magnetron sputtering were tested in sliding and rolling contact tests at low and high speeds and at varying contact stresses. These results are presented and used to identify the primary consideration guiding the choice of coating materials, coating properties, film thickness needed etc. A newly developed film-to-substrate adhesion strength test is also briefly described and the results obtained are cited. It is shown that film material selection and coating process selection have a reasonable physical basis.