纯钛在去离子水和生理盐水中的复合微动腐蚀特性

在高精度液压式微动试验机上,采用球/平面接触方式,进行了纯钛(TA2/TA2)在干态、去离子水和生理盐水中的切向与径向复合微动试验.在动力学分析的同时,结合光学显微镜和扫描电镜(SEM)对磨痕进行了分析研究.结果表明:在去离子水和生理盐水中,复合微动载荷-位移曲线呈现准梯形和椭圆形2阶段特征;相同载荷条件下,2种介质中微动腐蚀的材料损失小于干态;生理盐水中摩擦耗散能比去离子水中大.在2种介质条件下,TA2的复合微动磨损表现为腐蚀磨损、磨粒磨损和剥层共同作用的机制.     

基于时变摩擦主减速器动态特性研究

针对汽车主减速器在高速条件下破坏失效等问题,考虑主减速器动态效应和弹流润滑摩擦的基础上,引入时变摩擦概念,建立完善后的汽车主减速器动态特性模型,研究了弧齿锥齿轮和准双曲面齿轮动态特性变化规律。分析结果表明,弧齿锥齿轮输入转速变化对摩擦因数变化范围影响程度比准双曲面齿轮较大;弧齿锥齿轮输入扭矩变化对摩擦因数影响程度比准双曲面齿轮较大;弧齿锥齿轮动态摩擦因数对X方向上的啮合力变化趋势影响明显,准双曲面齿轮X方向上的变化相对Y、Z方向较为明显,但与常摩擦因数作用下的结果大致相同。     

铝合金表面Ni-SiC复合镀层的摩擦磨损性能

通过复合电沉积技术,在铝合金表面得到了不同SiC粒子含量的Ni-SiC复合镀层,研究了在干摩擦和液态石蜡润滑摩擦条件下载荷与SiC粒子体积分数对Ni-SiC复合镀层摩擦磨损性能的影响。结果表明:无论在干摩擦或润滑摩擦条件下,加入SiC粒子后的复合镀层其耐磨性均优于纯镍镀层,并随载荷的提高耐磨性下降。在干摩擦条件下,镀层中的SiC粒子体积分数在5.8％时复合镀层耐磨性最好;在润滑摩擦条件下,随镀层中SiC粒子体积分数提高,复合镀层耐磨性均提高。     

锌和锡锌半流体脂磨损自修复效应研究

研究了用微米级锌粉与Li基脂、VG32号油混合制备的锌半流体脂和同时加入锡、锌2种微粒的复合半流体脂.考察了在锌半流体脂和锡锌复合半流体脂下钢一铜摩擦副摩擦磨损的特性.研究结果表明,锌脂和锡锌复合脂在钢-铜摩擦作用下均能在铜试样上形成较厚的自修复涂层,锌涂层厚度约为10μm,锡锌复合涂层厚度约为20 μm.锌涂层的减摩抗磨性能比无锌涂层有所改善,而锡锌复合涂层的摩擦学性能较好.     

载荷对硅酸盐/纳米铜复合添加剂摩擦学性能的影响

以含有硅酸盐/纳米铜复合添加剂的N68基础油为润滑介质,分别在100、150和200 N载荷条件下进行了摩擦磨损试验.结果表明,硅酸盐/纳米铜复合添加剂能够显著提高N68基础油的承载能力.随着试验时间的延长,下试样出现了"零磨损".与100和200 N载荷下结果相比较,载荷为150 N的摩擦环境缩短了摩擦副的磨合期,更适合于添加剂润滑作用的发挥.     

离子轰击热处理技术对轴承钢摩擦学性能的影响

为提高轴承钢的摩擦磨损性能,采用离子轰击热处理技术在GCr15轴承钢的表面生成渗硫层、渗氮层和硫氮复合渗层.在球一盘摩擦磨损试验机上对比研究轴承钢原始表面、渗硫表面,渗氮表面与硫氮复合处理表面在油润滑下的摩擦磨损性能.利用显微硬度计分析不同表面的硬度;利用扫描电镜观察不同处理表面和磨损表面的形貌;利用X射线光电子能谱仪分析磨损表面边界润滑膜化合物的价态并研究元素随深度的变化.研究表明,GCr15轴承钢表面通过渗硫、渗氮、硫氮复合处理后在油润滑条件下摩擦磨损性能都可以得到比较明显的提高.轴承钢基体对渗硫层的支持作用有限,影响硫化层作用的发挥.高硬度的渗氮层在较低载荷下可以起到很好的减摩抗磨作用.硫氮复合处理盘由于在较软的共渗层下面存在高硬度的渗氮层,可以对表面的软质层提供更强的支持,在较苛刻的工况下,硫氮复合盘的摩擦学性能显得更加突出.     

调制周期对纳米多层类石墨薄膜力学性能及摩擦学性能的影响

采用等离子增强多靶磁控溅射系统在溅射沉积类石墨(Graphite-like carbon,GLC)薄膜过程中交替掺杂金属W制备了6种纯GLC子层和W-GLC子层交替堆垛的纳米多层GLC薄膜。薄膜调制周期分别为300 nm、180 nm、90 nm、40 nm、15 nm以及8 nm共6种。研究了调制周期对薄膜力学性能和摩擦学性能的影响。结果表明:各纳米多层GLC薄膜均具有良好的力学性能与摩擦学性能,且随着调制周期的减小,薄膜的力学性能与摩擦学性能均大幅提高,并表现出显著的协同效应。纳米多层GLC薄膜中WC或W_2C纳米晶的弥散强化效应和纳米多层膜的界面效应是薄膜具有优异力学性能的主要原因,而薄膜在摩擦对偶表面形成的厚实致密的富碳转移膜又确保了薄膜具有良好的摩擦学性能。当调制周期减小至8 nm时,薄膜的硬度高达35.13 GPa,结合强度为45.28 N,H/E为0.109 5,H~3/E~2为0.375,且在"100 r/min,12 N"条件下连续摩擦480 min,平均摩擦因数仅为0.002,磨损率低至9.0×10~(-18)m~3/(N·m),综合性能极为优异。     

硅镁型复合纳米添加剂的摩擦学及自修复性能研究

用化学方法制得粒径约为40 nm的硅镁型复合纳米添加剂,分别采用四球摩擦磨损试验机、环-块摩擦磨损试验机和齿轮试验机考察了其作为矿物油添加剂的抗磨减摩性能及对磨损表面的修复作用.用扫描电子显微镜、粗糙度测定仪以及X射线光电子能谱仪等对摩擦副磨损表面进行了分析,并探讨其修复作用机制.结果表明:制备的硅镁型复合纳米添加剂具有优良自修复性能,可以很好覆盖磨损表面,能显著降低磨损表面的粗糙度.其自修复作用机制是由于硅镁型复合纳米粒子在摩擦表面形成沉积并在接触区的高温高压下熔融铺展形成低剪切强度的表面膜, 由于这层膜的剪切强度比较低,可以减少摩擦界面的粘着磨损,故表现出良好的减摩抗磨和自修复性能.     

MoS_2基复合润滑薄膜的制备及其摩擦性能

采用磁控溅射法在不锈钢基体上制备了MoS2/Ni复合润滑薄膜,研究了添加DLC(类金刚石薄膜)中间层对于MoS2/Ni复合薄膜的影响,探讨了复合润滑薄膜的减摩机理;使用EDS与XRD测定了复合薄膜的主要成分和物相结构,使用多功能摩擦试验机测定了薄膜的摩擦因数.结果表明:复合薄膜的主要成分为MoS2和Ni;薄膜中主要晶面为平行于基面的(002)晶面;复合薄膜的摩擦因数在0.06～0.18之间变化,且在高速重载的环境下具有更低的摩擦因数和更高的摩擦稳定性;中间层的加入进一步降低了复合薄膜的摩擦因数,达到0.04左右.     

BN-C-硅油超微/纳米高温润滑胶体及其性能研究

为了制得一种新的超微/纳米复合胶体,基于纳米六方氮化硼对硅油的润滑性改善作用机制以及六方氮化硼(h-BN)和石墨(C)的相似性质,通过将h-BN和C混合后高能球磨,然后真空烧结,最后与硅油混合后重新进行球磨细化,制备出BN-C-硅油复合胶体.探讨了该胶体的结构形态、润滑机制以及摩擦盘表面粗糙度对其润滑性能的影响.研究表明:该胶体在较宽温度范围内具有良好的润滑性,无论在常温还是高温下,该胶体的摩擦因数显著低于BN-硅油胶体和纯硅油;BN-C-硅油胶体的润滑性能受摩擦副粗糙度的影响,粗糙度值越小,胶体的摩擦因数越小.结合汗腺式金属陶瓷烧结体(干摩擦因数为0.25)的结构特点,研究了该复合胶体的应用,结果表明浸渍该胶体后可得到200 ℃下干摩擦因数为0.13的高温自润滑金属陶瓷.     

水润滑复合橡胶轴承的摩擦学特性试验研究

以自来水为润滑介质 ,用 MPV- 2 0 0型摩擦磨损试验机分别研究了载荷、速度、运行时间等对 30 mm× 5 0mm复合橡胶轴承的摩擦系数和磨损率的影响 ,结果表明 :在较高载荷和较低转速下 ,形成了水膜动压润滑 ,轴承的摩擦系数和磨损率都较低。对作用机理进行了系统的分析 ,为水润滑橡胶轴承的实际应用提供理论依据     

稀土化合物改性复合材料在油润滑下的摩擦学性能

以竹纤维为增强相,通过稀土化合物改性制备一种树脂基复合材料;采用环块式摩擦磨损实验,研究稀土化合物改性复合材料在油润滑状态下载荷、转速对试样摩擦学性能的影响,以及稀土化合物改性对复合材料试样摩擦学性能的影响;比较干摩擦状态和油润滑状态下复合材料的摩擦学性能,观察和分析试样磨损表面形貌,探讨其磨损机制。实验结果表明:油润滑条件下,稀土化合物改性复合材料的摩擦因数和磨损率都随着载荷的增大而增加;较高载荷下摩擦因数随着转速的增大先增加后减小,而磨损率则呈现逐步增加的趋势;稀土化合物的改性使竹纤维和基体界面结合更为紧密,提高摩擦因数的同时降低了磨损率;在油润滑作用下,试样磨损由干摩擦时的磨粒磨损和疲劳磨损转变成为轻微的疲劳磨损;在油润滑状态下,复合材料处于边界润滑状态,故摩擦因数和磨损率均低于干摩擦。     

烟炱对电接触磨损的影响

选用常见的铜作为电接触材料,将烟炱溶液喷洒于试样表面,进行不同载荷下的电接触微动试验,用3D形貌仪和SEM对磨痕形貌进行分析。结果表明:载荷对材料的电接触性能影响显著,接触电阻与法向载荷成反比,即增加载荷可改善摩擦副的电接触性能;接触区域的有效导电面积是有限的,故载荷达到某一值后,随着载荷的增加,接触电阻不再有明显的下降趋势;小载荷下,烟炱的加入恶化了摩擦副的电接触性能,随着载荷的增加,这种恶化作用逐渐减小;摩擦因数随着载荷的增加而降低,载荷较低时(2～6 N),摩擦因数曲线可见明显的上升期、跑合期、下降期、稳定期;而载荷较高时(8～10 N),只有上升期和稳定期;大载荷下,触头接触区域匹配良好,摩擦副表面迅速达到了平衡点,摩擦因数较稳定。在电化学的作用下烟炱颗粒在摩擦副表面形成固体膜,起到减摩抗磨的作用。     

Biotribological properties of Ti/TiB2 multilayers in simulated body solution

Ti/TiB₂ multilayers with various modulation ratios were prepared by magnetron sputtering on biomedical titanium alloy Ti6Al4V. The tribological properties of the multilayers sliding against ultra-high molecular weight polyethylene under lubrication with Hank׳s solution were also investigated. The results demonstrated that the tribological properties strongly depended on the modulation ratios of multilayers. The coefficient of friction of multilayers with a modulation ratio of 1:5 was 0.1, a reduction by 28.6%; the wear volume loss of UHMWPE decreased by almost one order of magnitude compared to that of Ti6Al4V alloy, exhibiting excellent anti-friction and anti-wear properties. The oxidation wear of Ti6Al4V alloy could be restrained effectively and converted to abrasion wear and/or adhesive wear by the laminate structures in the multilayers, suggesting that this material may serve as a potential candidate for the surface modification of artificial joints.     

摩擦改进剂对改善燃油经济性的影响研究

采用四球机试验,考察了钼胺化合物、二烷基二硫代氨基甲酸钼、无灰型摩擦改进剂与摩擦因数的关系以及它们之间的复配作用。结果表明：摩擦改进剂（FM）降低摩擦因数的效果与其化学结构有关;加入量提高,摩擦因数的改善效果明显;不同化学结构的摩擦改进剂复配使用,可以减低整个温度区的摩擦因数。     

Synthesis and tribology of aluminium hexoxylborate as an antiwear additive in lubricating oil

An oil-soluble compound containing aluminium and boron has been synthesized. The tribological properties of the compound in SN500 oil were evaluated on a four-ball and block-on-ring test apparatus. The results showed that the wear resistance and load-carrying capacity of the oil were improved, and the friction coefficient was decreased. Evidence of deposition was found in the wear scar by SEM. It is concluded that this deposition provided the oil with its good wear resistance properties.     

催化剂对蛇纹石粉体减摩抗磨性能的影响

采用UMT 3摩擦磨损试验机,在高接触压力下考察蛇纹石粉体及其与催化剂组合作为润滑油添加剂对45#钢的减摩抗磨作用.结果表明:在高接触压力下,润滑油中添加蛇纹石粉体后摩擦因数和磨损量都变大;相对于蛇纹石粉体,以蛇纹石和某种催化剂组合作为润滑油添加剂,可有效地降低摩擦因数和磨损量,并提高摩擦因数的稳定性.     

Water Lubrication of Silicon Nitride in Sliding

Several studies have shown that the coefficient of friction of self-mated silicon nitride in water decreases from an initially high value to about 0.002 after a certain run-in period. Since the worn surfaces become extremely smooth, the low friction is attributed to the initiation of hydrodynamic lubrication by a thin water film at the interface. The possibility of mixed lubrication, i.e., hydrodynamic lubrication by water and boundary lubrication due to the presence of colloidal silica on the wearing surfaces, has also been proposed. The purpose of our study is to investigate the influence of load, speed, and surface roughness on the duration of the run-in period. The results confirmed that a low coefficient of friction is obtained following a run-in period when a wear scar of sufficient size is developed to reduce the contact stress. The run-in period, during which the coefficient of friction is fairly high, was shorter for smoother surfaces and at higher loads and speeds. The low friction behavior was found to be unstable and occasional high friction spikes were observed. The surfaces of the wear tracks and wear scars contained a series of striations parallel to the sliding direction and exhibiting plastic deformation, delamination and fracture. The striations that appeared to be associated with the high friction spikes, could form as a result surface film breakdown. Although these results are consistent with the proposed mechanisms of hydrodynamic lubrication or mixed lubrication, it is proposed that the low friction behavior may be also related to fundamental interactions between two hard and elastically deforming surfaces covered with hydrogen-terminated oxide films.     

Response Characteristics of the Potential-Controlled Friction of ZrO<Subscript>2</Subscript>/Stainless Steel Tribopairs in Sodium Dodecyl Sulfate Aqueous Solutions

In this article experimental results have been presented on response characteristics of the potential-controlled friction of ZrO₂/stainless steel sliding contacts in sodium dodecyl sulfate (SDS) aqueous solutions. Two methods for modifying interfacial potential, by using an electrochemistry station and a signal generator, respectively, of the ball-on-disk contacts, are described firstly. Then friction tests under steady and dynamic potential conditions are reported. From the steady potential experiment result, a potential range in which friction coefficient varies with potential quasi-linearly has been found. The potential range is within the electrochemical window of the system, and neither hydrogen nor oxygen evolution happens. When interfacial potential is modulated within the potential range in the form of a triangular or a sinusoidal wave, by using either an electrochemistry station or a signal generator, friction coefficient varies in the same form between lower and higher levels, as long as the frequency of the applied potentials is lower than a break frequency. When the interfacial potential is changed abruptly from the open circuit potential down to a negative value, a response time ranging between 0.2 and 1.5 s, depending on the magnitude of the potential and the SDS concentration, is observed for friction coefficient to increase from the lower level of about 0.1 to the higher level of about 0.45. When the interfacial potential is elevated suddenly to 0 V by shorting or to a small positive value, friction coefficient can recover from the higher level to the lower level within a short time, 0.5–2 s, depending on the SDS concentration, which is much shorter than the recovery time of friction in the case of just switching-off the voltage. At last, effect of solution temperature on the response time of friction to stepwise changes in potential is also presented.     

复合润滑结构表面在油润滑下的减摩性能*

为研究不同表面处理方式对巴氏合金/45钢配副表面减摩性能的影响,采用热压固化工艺将六方氮化硼封装于表面织构内,制备复合润滑结构表面;在油润滑下进行销-盘磨损试验,使用递归定量分析（Recurrence quantification analysis,RQA）参数划分磨损过程;研究复合润滑结构表面在磨合期和正常磨损期的减摩性能,并与纯织构表面减摩性能进行对比。结果表明：复合润滑结构表面拥有较低摩擦因数和显著减摩效果,其减摩性能优于纯织构表面;相比无织构表面,复合润滑结构表面在磨合期内的平均摩擦因数下降77.9%,在正常磨损期内的平均摩擦因数下降73.5%且磨合期的时长缩减75.0%;较大织构孔径的复合润滑结构表面的减摩效果更好且磨合期更短;纯织构和复合润滑结构表面的减摩效果均在较高速度和载荷下更显著;各试样表面在磨合期的摩擦因数越低,对应进入正常磨损期后就越低。