纳米金刚石粒子表面修饰及其摩擦学性能

通过纳米金刚石粒子与硫酸的酯化反应,合成了纳米金刚石粒子磺酸衍生物.采用傅立叶转换红外线光谱仪(FTIR)、飞行时间二次离子质谱仪(TOP-SIMS)对该改性物进行了结构表征.利用四球摩擦磨损试验机研究了化学修饰后纳米金刚石粒子在水基基础液的摩擦学行为.结果表明,纳米金刚石粒子磺酸衍生物在水基基础液中具有良好的分散稳定性;纳米金刚石粒子磺酸衍生物质量分数为0.1%时,可使水基基础液的承载能力提高10%,磨斑直径降低4.4%.     

纳米铜润滑添加剂在四球机上的摩擦学性能研究及机理探讨

用MRS-10J四球摩擦磨损试验机考察了N68基础油和添加了自修复纳米铜润滑添加剂NT1的N68NT1的摩擦学性能,用扫描电子显微镜（SEM）、x射线能量色谱仪（EDS）分析了钢球表面的磨斑形貌和组成,同时初步分析了纳米铜润滑添加剂的润滑机理.结果表明：自修复纳米铜润滑油添加剂NT1能显著改善N68基础油的摩擦学性能;在载荷为296 N、392 N、490 N,试验时间为30 min的试验条件下,摩擦副的摩擦因数同基础油的相比分别下降了33.8%、39.4%和55.5%;钢球的磨斑直径分别下降了46.5%、45.6%和32.5%;同N68相比,N68NT1的pB值提高了33.3%;这可能同摩擦过程中钢球表面上沉积膜的协同作用有关.     

纳米ZnS粒子作为润滑油添加剂摩擦学性能研究

采用均匀沉淀法制备了硬脂酸修饰的纳米ZnS粒子,用四球摩擦磨损试验机考察了其作为润滑油添加剂的摩擦学性能,并用扫描电子显微镜和X射线光电子能谱仪对磨斑进行了表面分析.结果表明:在一定添加量范围内,硬脂酸修饰的纳米ZnS粒子可明显改善基础油的摩擦学性能;在摩擦过程中,纳米ZnS粒子在摩擦表面的沉积和通过摩擦化学反应生成的化学反应膜,显著提高了基础油的抗磨减摩性能.     

纳米TiO2添加剂对低黏度润滑油成膜性能的影响

为改善低黏度润滑油的摩擦磨损性能和成膜性能,选用纳米TiO₂为添加剂,低黏度的聚α烯烃（PAO8、PAO10）和聚醚（PAG）作为基础油,在四球式摩擦磨损实验机上考察纳米TiO₂添加剂对润滑油摩擦磨损性能的影响,利用点接触光弹流润滑试验台,研究不同速度、载荷下和纳米TiO₂添加量对润滑油成膜性能的影响。结果表明:加入一定质量分数的纳米TiO₂添加剂能够明显提高润滑油的抗磨减摩性能,在PAO8、PAG和PAO10基础油中分别加入质量分数0. 3%、0. 05%和0. 3%的纳米TiO₂时,摩擦因数和磨斑直径均最小;综合比较摩擦因数和磨斑直径,纳米TiO₂在PAO8基础油中表现出最好的抗磨减摩性能,摩擦因数减小了约54. 5%,磨斑直径降低了约10. 4%;随着卷吸速度的增加,润滑油的最小膜厚也逐渐增加,在相同卷吸速度下,与纯基础油相比,添加一定质量分数纳米TiO₂添加剂的最小膜厚明显增加;随着纳米TiO₂粒子添加量...     

电镀废液回收纳米铜粉作为润滑添加剂的摩擦学性能研究

以化学还原法从电镀铜废液中回收的纳米铜粉为固体润滑油添加剂,在四球式摩擦磨损试验机上研究纳米铜粉的加入量对润滑油摩擦学性能的影响。采用SEM、EDAX等分析磨斑表面,初步探讨纳米铜粉抗磨减摩机制。结果表明:纳米铜粉的添加显著提高基础油的抗磨减摩性能,当纳米铜粉加入量为0.3%(质量分数)时,其摩擦因数和磨斑直径分别比基础油减小33.4%和19%。含纳米铜粉润滑油在高载荷下具有更好的抗磨减摩性能。纳米铜粉在摩擦过程中抗磨减摩机制主要为填充作用和沉积自修复膜作用机制。     

添加纳米磁性微粒的润滑油摩擦学行为研究

用化学方法制备纳米MnZnFe2O4磁性微粒，在四球摩擦磨损试验机和立式万能摩擦磨损试验机上考察了MnZnFe2O4纳米磁性微粒作为润滑油添加剂的抗磨减摩性能及对磨损表面的修复作用，并用扫描电子显微镜观察分析了磨斑表面形貌。实验表明，MnZnFe2O4纳米微粒添加剂可以显著提高基础油的承载能力，减小磨斑直径；磁性颗粒有利于加强吸附在摩擦副表面上形成物理吸附膜，并在摩擦表面形成自修复膜，对磨损表面具有一定的修复作用。     

含纳米PTFE颗粒润滑脂的润滑性能研究

在四球摩擦磨损试验机上考察纳米PTFE颗粒作为添加剂对复合钛基润滑脂摩擦磨损性能的影响,采用扫描电子显微镜分析试验钢球磨斑的表面形貌,并利用X射线光电子能谱仪检测磨斑表面化学元素的组成及状态。结果表明,在一定添加量范围内,纳米PTFE可以改善复合钛基润滑脂的摩擦磨损性能,其中纳米PTFE质量分数为3%时,复合钛基润滑脂具有最佳的抗磨、减摩性能,可使摩擦因数、磨斑直径分别降低约25.4%和18.9%。纳米PTFE颗粒在钢球表面发生摩擦化学反应,生成了一层金属氟化物,有效地抑制了摩擦表面的黏着磨损和接触疲劳。     

纳米Sn粒子的制备及其作润滑油添加剂的摩擦学性能研究

用化学还原法制备了表面经油酸修饰的纳米Sn粒子,并在透射电镜(TEM)下观测到所制备的纳米Sn粒子呈球形、平均粒径为20 nm。在MSR-10D四球摩擦磨损试验机上考察了纳米Sn粒子作为CF-4 15W/40润滑油添加剂的摩擦学性能,并在扫描电子显微镜(SEM)和能谱分析仪(EDS)上对钢球磨斑表面进行了形貌观测和表层成分分析。试验结果表明,纳米Sn粒子作为润滑油添加剂具有一定的减摩性能和较好的抗磨性能,当所添加的体积分数仅为0.1%时,添加纳米Sn粒子润滑油的摩擦力比基础油降低了16.64%,其磨斑直径比基础油减小了38.4%。分析认为,纳米Sn粒子通过隔离摩擦表面而改善了润滑油的减摩抗磨性能。     

纳米TiN对润滑油性能的影响及其在柴油发动机上的应用

控制纳米TiN添加量处于0.25%~1%范围内,利用MRS-10A四球摩擦试验机研究其对润滑油性能的影响。利用磨斑测量系统、激光共聚焦扫描显微镜OLS  1100和EDX能谱仪测试分析含纳米TiN润滑油的摩擦磨损及修复性能。在柴油发动机试验台上考察含有0.5%纳米TiN的润滑油对发动机运转性能的改善,在不同转速条件下检测润滑油添加剂对发动机外特性的影响。试验结果表明：含有0.5%纳米TiN的润滑油比基础油的抗磨减摩及自修复性能更好。纳米TiN润滑油添加剂能显著提高润滑油质量,减小发动机摩擦功,降低机油温度,改善发动机的运转性能,提高发动机的功率和转矩,降低耗油率,从而达到延长发动机的使用寿命和节约能源的目的。     

改性蒙脱石微粒在润滑油中分散稳定性对其摩擦学性能的影响

采用油胺、油酸、KH550、十六烷基三甲基溴化铵(CTAB)4种改性剂对经预处理的蒙脱石进行亲油性改性处理,研究分散剂添加量对改性蒙脱石在油液中分散稳定性的影响,并在四球摩擦磨损试验机上考察改性蒙脱石在油液中的分散情况对其摩擦学性能的影响。接触角与红外光谱分析结果表明,CTAB对蒙脱石的亲油性改性效果最优;吸光度测试结果表明,分散剂质量分数为6%时改性蒙脱石在油液中分散效果最佳。摩擦试验结果表明:蒙脱石在油液中的分散情况对其摩擦学性能影响很大,未添加分散剂的CTAB改性蒙脱石在基础油中分散不太稳定,摩擦因数相较于基础油仅降低了9.27%,加入分散剂后摩擦因数和磨斑直径相对于基础油分别降低了19.21%和40.29%。扫描电镜分析结果表明,在摩擦过程中蒙脱石微粒易沉积在磨损表面的低凹处,形成一层保护薄膜,起到降低接触面损伤和一定的修复作用,但蒙脱石微粒分散不好时则易发生团聚,增加表面磨粒磨损,降低其修复作用。     

Tribological Properties of Paraffinic Oil with Nanodiamond Particles

Friction accounts for a large amount of energy lost in mechanical systems and applications. Nanofluids, with particles less than 100 nm, added to a base fluid have been proven to be effective in reducing friction and wear. Diamond has superior mechanical, thermal, optical, electrical, and chemical properties. Therefore, nanodiamond holds a lot of promise for use in nanofluids. The tribological properties of oil-based nanofluids with spherical nanodiamond particles with the size of 3–10 nm in diameter were investigated using a ball-on-disk friction test by varying nanodiamond concentration, sliding velocity, normal load, and disk roughness. The friction testing was performed using a UMT-2 Micro Tribometer. Wear analysis was performed and chemical composition of the disk surface was examined using a WYKO 3D surface profiler and X-ray photoelectron spectroscopy. In general, the addition of nanodiamonds to oil leads to a reduction in the coefficient of friction but an increase in wear of the disk.     

Friction,Wear, and Scuffing Characteristics of Marine Engine Lubricants with Nanodiamond Particles

Many kinds of additives are generally added to engine lubricants to improve performance. These chemical additives are harmful to both humans and the environment. For this reason, the research trend in the lubricant industry is to reduce the use of chemical additives in engine oils. Carbon materials like nanodiamonds are candidates among many physical additives. Nanodiamond particles are round, very hard, chemically stable, and highly heat conductible. In this research, nanodiamond particles were uniformly dispersed in marine engine lubricants. A matrix synthesis method was used for dispersion with various concentrations. Friction and wear tests were performed to measure the friction and wear amounts, and scuffing tests were performed. The friction coefficients were decreased with the addition of nanodiamond particles. Due to their octagonal and almost spherical shape, the particles could act as rolling contact elements between two lubricated sliding surfaces. In addition, it was found that there was a proper concentration of nanodiamond to minimize the wear amounts, which was 0.3 wt%. From the scanning electron microscopy (SEM) analysis many agglomerated particles were found on the sliding surfaces with a high concentration of particles over 0.3%. The excessive amount of nanodiamonds acted as abrasive debris and ploughed the contact surfaces. Finally, as the concentration of nanodiamonds increased, the scuffing life increased due to a reduction in friction, and the rate of temperature increase was reduced due to the high heat conductivity of nanodiamonds.     

A comparison of tribological properties of evenly distributed and agglomerated diamond nanoparticles in lubricated high-load steel–steel contact

The tribological properties of evenly distributed and agglomerated nanodiamonds on steel contact surfaces were compared in ethylene glycol lubricated tests using a pin-on-disc tribometer with a steel counter ball. The nanodiamond distributions were studied on silicon and steel surfaces using scanning electron microscopy. Friction and wear decreasing effects were observed with both sprayed and agglomerated nanodiamonds. The average friction coefficient with pure ethylene glycol lubricated contacts decreased from 0.16 to 0.12 with agglomerated nanodiamonds when 100 N load was applied. A minimum for both disc wear rate (0.40×10⁻⁶ mm³/Nm) and ball wear rate (0.29×10⁻⁶ mm³/Nm) was observed with agglomerated nanodiamonds. One of the mechanisms of nanodiamond lubrication was observed to be the incorporation of nanodiamond particles in to the tribolayer.     

Nanodiamond-Based Nanolubricants: Investigation of Friction Surfaces

Synergistic compositions of detonation nanodiamond (DND) particles with polytetrafluoroethylene and molybdenum dialkyldithiophosphate were used in ring-on-ring, four-ball, and block-on-ring tests as an additive to polyalphaolefins and engine oils. Modest to significant reductions in the friction coefficients, wear, or both were observed. In the wear scars produced in the block-on-ring tests, the friction surfaces were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and profilometry. Significant polishing effects of the friction surfaces in lubricants containing DND were revealed in SEM observations and roughness measurements. The roughness of the scar surfaces produced in the presence of DND additives was about 35% lower than the roughness of the scars observed in pure oil experiments.     

Tribological Properties of Nanodiamond-Epoxy Composites

Owing to its superior mechanical properties, nanodiamond (ND) holds great potential to improve tribological characteristics of composites. In this study, we report on the wear and dry friction of epoxy-ND composites prepared from as-received and aminated ND across the length scale range from macro to nano. Comparison of macroscale, microscale, and nanoscale frictional behavior shows that ND is highly effective in improving the wear resistance and friction coefficients of polymer matrices across the different length scales. Although with both types of ND wear resistance and friction coefficients of epoxy-ND composites were significantly improved, aminated ND outperformed as-received ND, which we account to the formation of a strong interface between aminated ND and the epoxy matrix. This study also shows that agglomerates within epoxy-ND composites containing 25?vol.% ND were able to wear an alumina counterbody, indicating very high hardness and Young??s modulus of these agglomerates, that can eventually replace micron sized diamonds currently used in industrial abrasive applications.     

Wear mechanism of multiphase friction materials with different phenolic resin matrices

Wear of the brake friction materials with straight phenolic resin, silicon modified phenolic resin, or boron–phosphorous (B–P) modified phenolic resin was investigated. A simple formulation was used to produce friction material specimens and wear tests were carried out using a Krauss type friction tester. Friction stability and wear rate of the three friction materials were compared as a function of temperature up to 400 °C and the mechanisms associated with the wear processes at different temperature ranges were analyzed using Arrhenius type plots and worn surface morphology after tests. The results showed that the wear process below the critical temperature was mainly attributed to the gradual stripping of the heat affected surface layers of the friction material, while the wear rate at elevated temperatures was determined by the detachment of subsurfaces that was caused by the thermal decomposition of the resin. Among the three friction materials investigated in this study, the friction material containing B–P modified resin showed the best wear resistance and friction stability.     

磷酸酯偶联剂改性衬垫对自润滑关节轴承性能的影响

利用 Instron5944型电子万能材料试验机和自制的关节轴承摩擦磨损试验机,研究磷酸酯偶联剂接枝改性处理衬垫对自润滑关节轴承黏接性能和摩擦磨损性能的影响。结果表明：磷酸酯偶联剂接枝改性处理衬垫可以有效提高轴承衬垫的黏接性能;自润滑关节轴承的摩擦磨损性能与摆动频率呈现明显的相关性,摩擦因数和磨损量均随摆动频率的增大而减小,而摩擦温度随之升高;衬垫经改性处理的轴承摩擦因数、磨损量以及摩擦温升均明显降低,表明衬垫经改性处理后改善了自润滑关节轴承的摩擦学性能。     

不同润滑条件对纳米Al2O3改性UHMWPE摩擦磨损性能的影响

用MPV 2 0 0型摩擦磨损试验机对纳米Al2 O3改性超高分子量聚乙烯 (UHMWPE)塑料合金材料在不同润滑条件下 (干摩擦、水润滑 )进行了摩擦学性能测定 ,分别考察了载荷、速度以及运行时间等对材料摩擦学性能的影响。为纳米Al2 O3改性超高分子量聚乙烯塑料的实际应用提供理论指导     

纳米SiO2颗粒和玻璃微珠共混改性超高分子量聚乙烯复合材料的摩擦磨损性能

采用模压成型工艺制备了纳米SiO2颗粒和玻璃微珠共混改性的超高分子量聚乙烯复合材料;研究了相对滑动速度、载荷以及玻璃微珠含量对复合材料摩擦磨损性能的影响,并对磨损形貌和磨损机理进行了分析。结果表明:添加纳米SiO2颗粒和玻璃微珠可以提高复合材料的硬度、压缩弹性模量和摩擦磨损性能;相对滑动速度对复合材料摩擦因数和磨损率有很大的影响;载荷对复合材料的摩擦因数影响不明显,但磨损率随载荷的增加而增大;纳米SiO2颗粒和玻璃微珠混合改性后复合材料的磨损机理主要是粘着磨损和疲劳磨损。     

带式输送机树脂基摩擦片干式制动条件下摩擦学行为

采用热压烧结技术制备桐油改性酚醛树脂和腰果壳油改性酚醛树脂基摩擦片,通过CFT环块摩擦磨损试验机研究其在不同的制动速度、制动正压力下以及在瞬时制动时的摩擦因数以及磨损率的变化规律,采用扫描电镜(SEM)对试样摩擦后的表面形貌进行观察分析。结果表明,2种树脂基摩擦片摩擦因数以及磨损率变化规律具有一致性:摩擦因数均随着制动正压力与制动速度的增加而减小;磨损率随着制动速度的增加而减小,随着制动正压力的增加而增加。以桐油改性酚醛树脂为基体,碳纤维为增强纤维的摩擦片在瞬时制动时具有较稳定的摩擦因数,而且在不同制动正压力与制动速度下磨损率较低。