蒙脱土/Cu复合纳米的制备及其摩擦学性能研究

共混制备蒙脱土与Cu(MMT/Cu)复合纳米粒子,将其添加到150N基础油中,以45#钢为摩擦副,利用MMU-10G摩擦磨损试验机考察其摩擦学性能,使用EPMA-1600电子探针、金相显微镜、Genesis能谱仪进行试样磨损面形貌观察和组成元素分析。结果表明:MMT/Cu复合纳米粒子作为润滑油添加剂具有优异的减摩效果和抗磨性能,与基础油相比,添加了MMT/Cu复合纳米粒子的油样使摩擦副的平均摩擦因数下降52%,摩擦副试样失重减少55%,这是由于MMT/Cu复合纳米粒子在摩擦表面生成了自修复膜层。     

表面修饰ZrO2纳米颗粒对液体石蜡抗磨性能的影响

采用原位修饰方法制备了双烷基二硫代磷酸盐(DDP)表面修饰的ZrO2纳米颗粒,利用四球摩擦磨损试验机考察了ZrO2/DDP复合纳米微粒用于添加剂的摩擦学行为。用扫描电子显微镜(SEM)和能量散射谱仪(EDS)观察、分析了磨斑表面形貌,并探讨了复合纳米微粒添加剂的润滑作用机制。摩擦磨损结果表明,ZrO2/DDP复合纳米微粒添加剂具有优良的抗磨损性能,能显著提高液体石蜡的失效载荷;表面分析结果表明,在摩擦过程中ZrO2/DDP复合纳米微粒聚集在边界润滑膜中,对磨损表面起到修复作用。     

W18Cr4VCo5钢表面PCVD复合陶瓷涂层的摩擦学研究

用等离子体化学气相沉积(PCVD)技术对挤压模具钢表面进行复合陶瓷强化处理，用环一块摩擦磨损试验模拟金属挤压的磨损过程，研究了复合陶瓷表面强化涂层的摩擦磨损特性。用俄歇电子能谱(AES)、X射线衍射(XRD)和扫描电镜(SEM)分析了表面涂层的元素分布、相结构和磨痕形貌。结果表明，W18Cr4VCo5钢表面PCVD陶瓷涂层具有显著减摩抗磨能力。     

精密下料中圆形锤头棒料摩擦副的摩擦学性能分析

针对精密下料中存在的圆形锤头棒料摩擦副磨损严重问题，借助WTM-2E型可控气氛摩擦磨损试验仪，研究了不同转速和不同质量分数纳米MoS2添加剂下的GCr15钢块45钢柱摩擦副的摩擦磨损性能。结果表明：随着上摩擦副(45钢柱)的转速增加，磨损行程变长，摩擦因数和磨损量呈减小趋势，磨损表面形态由黏着磨损转变为磨粒磨损。采用声发射技术对摩擦副表面磨损状态进行实时监测，定量确定出质量分数为0.5%的纳米MoS2添加剂的减摩抗磨效果最佳。     

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。     

坡缕石载铜复合纳米润滑添加剂的制备及摩擦学性能研究

使用化学还原法制备坡缕石载铜复合纳米颗粒,以铸铁HT200作为摩擦副,采用MMU-10G摩擦磨损试验机研究该纳米颗粒作为润滑添加剂的摩擦学行为,使用EPMA-1600电子探针、金相显微镜、Genesis能谱仪进行试样磨损面形貌观察和组成元素分析。实验结果表明:该纳米复合颗粒作为润滑添加剂具有优异的减摩效果和良好的抗磨性能,与基础油150N相比,平均摩擦因数下降66.2%,对应的摩擦副试件磨损失重减少80.9%,在试件表面生成由纳米坡缕石和纳米铜共同组成的自修复膜。     

蛇纹石纳米粒子对ZL109铝合金活塞微弧氧化膜层摩擦性能的影响

配制蛇纹石纳米粒子分散液,选定不同质量浓度分散液加入电解液中,分别对ZL109铝合金试件进行微弧氧化处理,制备蛇纹石纳米粒子复合微弧氧化陶瓷膜。通过测厚仪和显微硬度计对复合陶瓷膜进行检测得到表面性能最佳的试件,并在摩擦磨损试验机上考察该试件的摩擦学性能;通过分析其截面形貌和磨损前后表面形貌,探讨其摩擦机制。结果表明,蛇纹石纳米颗粒的加入使微弧氧化复合陶瓷层的膜厚增加、硬度升高,且蛇纹石纳米颗粒存在最佳添加量,使复合陶瓷膜试件具有较高的厚度和硬度;蛇纹石纳米颗粒的加入降低了复合陶瓷膜摩擦因数,改善其磨损性能。在摩擦过程中,蛇纹石对表面孔隙进行了填充,使表面的粗糙度减小;同时,蛇纹石在摩擦形成了类似薄膜的块状,起到了自修复的作用。     

气缸套表面微造型与微纳米颗粒填充对摩擦学性能的影响

研究气缸套试样表面微造型技术和微纳米颗粒填充技术对缸套-活塞环摩擦副摩擦学性能的影响。在富油和贫油2种工况下,探究表面微造型和微纳米颗粒填充技术对摩擦副的摩擦因数和抗黏着磨损时间的影响。试验结果表明:在富油工况下,表面两端微造型和蛇纹石二硫化钼微纳米颗粒复合填充气缸套试样的摩擦因数最小,比机械珩磨气缸套试样的摩擦因数降低了13.99%;在贫油工况下,表面全部微造型和蛇纹石二硫化钼微纳米颗粒复合填充气缸套试样的抗黏着磨损时间最长,比机械珩磨气缸套试样的抗黏着磨损时间延长了85.79%;在试验过程中,表面微坑中的微纳米颗粒的溢出率会随着时间的延长而逐渐下降,最后趋近于0。     

PA66/Si_3N_4纳米复合材料的摩擦磨损性能

采用双螺杆挤出机熔融共混和注射成型方法制备了PA66/Si3N4纳米复合材料.研究了纳米Si3N4添加量对复合材料的力学性能和摩擦磨损性能的影响.通过对试样磨损表面及其对摩副表面上转移膜的扫描电子显微镜(SEM)观察和X射线光电子能谱(XPS)分析,探讨了其磨损机制.结果表明,纳米Si3N4的加入降低了基体的拉伸强度和弯曲强度,但是在PA66中加入适量的纳米Si3N4颗粒后,摩擦过程中有利于生成较均匀的转移膜,从而降低摩擦因数.同时磨屑里的纳米Si3N4镶嵌到试样摩擦表面,使表面得到局部增强,从而提高其耐磨性能.     

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.     

Tribological properties of solid lubricants (graphite, h-BN) for Cu-based P/M friction composites

Cu-based P/M friction composites containing graphite at weight fractions in the range of 0%, 2%, 5%, 8%, 10%, corresponding to the hexagonal boron nitride (h-BN) at weight fractions in the range of 10%, 8%, 5%, 2%, 0%, were fabricated by a P/M hot press method, respectively. The effects of graphite and h-BN on tribological properties of Cu-based P/M friction composites were investigated on a block-on-ring tester. Worn surfaces, microstructures and wear debris of the composites were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Results indicate that lubrication effects of graphite are superior to those of h-BN. With the increase of graphite content wear rates were decreased significantly. Added graphite with low contents of h-BN can stabilize friction and wear properties of Cu-based P/M friction composites.     

Sliding friction and wear of alumina-reinforced zirconia-toughened mullite composites

The friction and wear characteristic of self-mated alumina-reinforced zirconia-toughened mullite (ZTM/A) composites has been investigated using a block-on-ring tribometer in different lubricants at varying loads. Load-dependent wear transitions were observed for these ceramics. The wear transition was usually accompanied by an abrupt change of friction coefficient and wear rate. The addition of Al₂O₃ effectively reduces the wear rate of ZTM/A composites before the wear transition in water and at middle loads in machine oil. Scanning electron microscope (SEM) micrographs show that the main pre-transition wear mechanism of ZTM/A composites is plastic deformation, ploughing and occasionally grains pulling out, while fracture is the dominant mechanism of post-transition. Al₂O₃ can restrain the t→m phase transformation of zirconia to some extent and improve the resistance of these materials to wear by fracture, ploughing and plastic deformation.     

Comparative study of micro- and nano-ZnO reinforced UHMWPE composites under dry sliding wear

This is a comparative study between ultra-high molecular weight polyethylene (UHMWPE) reinforced with micro-zinc oxide (ZnO) and nano-ZnO under different filler loads. These composites were subjected to dry sliding wear test under abrasive conditions. The micro- and nano-ZnO/UHMWPE composites were prepared by using a hot compression mould. The wear and friction behaviours were monitored using a pin-on-disc (POD) test rig. The pin-shaped samples were slid against 400 grit SiC abrasive papers, which were pasted, on the stainless steel disc under dry sliding conditions. The worn surfaces and transfer film formed were observed under the scanning electron microscope (SEM). Experimental results showed that UHMWPE reinforced with micro- and nano-ZnO would improve the wear behaviour. The average coefficient of friction (COF) for both micro- and nano-ZnO/UHMWPE composites were comparable to pure UHMWPE. The weight loss due to wear for nano-ZnO/UHMWPE composites are lower compared to micro-ZnO/UHMWPE and pure UHMWPE. The optimum filler loading of nano-ZnO/UHMWPE composites is found to be at 10 wt%. The worn surface of ZnO/UHMWPE composites shows the wear mechanisms of abrasive and adhesive wear. Upon reinforcement with micro- and nano-ZnO, the abrasive and adhesive wear of worn surfaces transited from rough to smooth.     

Dry-Sliding Tribological Properties of Cu/AlMgB14 Composites

In this paper, Cu/AlMgB₁₄ composites with by weight percent, 5, 10 and 20 % of the AlMgB₁₄ (referred to CA-5, CA-10 and CA-20) were fabricated by hot-press sintering method. The mechanical and dry-sliding tribological properties of the three composites were investigated. The results indicated that the densities of the Cu/AlMgB₁₄ composites were lower than copper, whereas the hardness higher. The friction and wear behaviors of the composites were strongly dependent on the AlMgB₁₄ content. The friction coefficient was in the range of 0.73–1.0 for CA-5, but it was always steady at about 0.2 for CA-10 and CA-20. Accordingly, the increase in the AlMgB₁₄ concentration can improve the wear resistance of the composites.     

Dry Sliding Friction and Wear Characteristics of Cu-Sn Alloy Containing Molybdenum Disulfide

The wear and sliding friction response of a hybrid copper metal matrix composite reinforced with 10 wt% of tin (Sn) and soft solid lubricant (1, 5, and 7 wt% of MoS₂) fabricated by a powder metallurgy route was investigated. The influence of the percentages of reinforcement, load, sliding speed, and sliding distance on both the wear and friction coefficient were studied. The wear test with an experimental plan of six loads (5–30 N) and five sliding speeds (0.5–2.5 m/s) was conducted on a pin-on-disc machine to record loss in mass due to wear for two total sliding distances of 1,000 and 2,000 m. The results showed that the specific wear rate of the composites increased at room temperature with sliding distance and decreased with load. The wear resistance of the hybrid composite containing 7 wt% MoS₂ was superior to that of the other composites. It was also observed that the specific wear rates of the composites decreased with the addition of MoS₂. The 7 wt% MoS₂ composites exhibited a very low coefficient of friction of 0.35. The hardness of the composite increased as the weight percentage of MoS₂ increased. The wear and friction coefficient were mainly influenced by both the percentage of reinforcement and the load applied. Wear morphology was also studied using scanning electron microscopy and energy-dispersive X-ray analysis.     

载荷对激光选区烧结Cf/SiC复合材料摩擦磨损性能的影响

通过激光选区烧结技术和液相渗硅工艺制备了碳纤维增强碳化硅（Cf/SiC）复合材料。试样组织由C、SiC和Si三相组成,其密度和弯曲强度分别为2.89±0.01 g/cm3和237±9.8 MPa。采用UMT TriboLab多功能摩擦磨损试验机研究了Cf/SiC复合材料在不同载荷(10 N, 30 N, 50 N和70 N)条件下的摩擦学特性。研究结果表明：载荷较小(10 N)时,Cf/SiC复合材料的磨损由微凸起和SiC硬质点造成,磨损机制为磨粒磨损;载荷为30 N时,复合材料的摩擦磨损综合性能最好,其平均摩擦因数为0.564,磨损率低(5.24×10-7 cm3/（N·m）),主要磨损机制为犁削形成的磨粒磨损和黏结磨损。载荷增大到70N时,材料磨损严重,磨粒脱落形成凹坑,产生裂纹,其磨损率(8.68×10-7 cm3/（N·m）)高,磨损机制主要为脆性剥落。     

Friction and wear of carbon nanohorn-containing polyimide composites

Polyimide (PI)-based composites containing single-wall carbon nanohorn aggregate (NH) were fabricated using the spark plasma sintering (SPS) process. For comparison, composites with carbon nanotube (NT) and traditional graphite (Gr) were also fabricated. The NH was produced using CO₂ laser vaporization and a graphite target and the NT was produced by a chemical synthesis method. We evaluated the friction and wear properties of the PI-based composites with a reciprocating friction tester in air using an AISI 304 mating ball. NH drastically decreased the wear of PI-based composites; the specific wear rate of composite with NH of only 5 wt% was of the order of 10⁻⁸ mm³/Nm, which was two orders of magnitude less than that of PI alone. The wear reduction ability of NT seemed to be slightly inferior to that of NH, although it was considerably better than that of Gr. NH and NT lowered the friction of composites. The friction coefficient of composite with 10 wt% NH was less than 0.25, although it was slightly higher than that of composite with 10 wt% Gr. There was no clear difference in the friction reduction effect of NH and NT. The further addition of Gr to composites with NH or NT rather deteriorated the antiwear property of composites, although the friction coefficient was slightly reduced. The transferred materials existed on the friction surface of the mating ball, sliding against composites with three types of carbon filler. These transferred materials seemed to correlate with the low friction and wear properties of composites.     

Tribological Behavior of Particles and Fiber-Reinforced Hybrid Nanocomposites

This article discusses the mechanical performance of alumina nanoparticles and randomly distributed short glass/carbon fiber-reinforced hybrid composites through microhardness and wear test. The open mold casting method was adapted to prepare the test coupons. The wear and friction behavior of composites sliding against hardened ground EN 32 steel in a pin-on-disc configuration is evaluated on a wear and friction tester. The microhardness properties of the neat epoxy, alumina nanoparticles, and alumina nanoparticle–embedded glass/carbon fiber–reinforced hybrid composites were determined. The morphology of the worn composites was analyzed with a scanning electron microscope. It was found that the particles as fillers contributed significantly to improve the mechanical properties and wear resistance of the polymer composites. This is because the fillers contributed to enhance the bonding strength between the fiber and the epoxy resin. Moreover, the wear and friction resistance of the glass/carbon fiber composites was increased by increasing the filler weight in the composite materials.     

Dry Sliding Wear Behavior of Palmyra Shell Ash–Reinforced Aluminum Matrix (AlSi10Mg) Composites

High strength, light weight, ease of fabrication, excellent castability, and good wear resistance make aluminum alloy composites suitable for commercial applications. In this work, a silica-rich ash particle (palmyra shell ash) was reinforced with aluminum alloy (AlSi10Mg) composites and its mechanical and tribological properties were studied. The aluminum alloy was reinforced with 3, 6, and 9 wt% of palmyra shell ash particles, and its dry sliding wear behavior was studied using a pin-on-disc machine under different loading conditions. The result shows that the dry sliding wear resistance of Al–palmyra shell ash composites was almost similar to that of fly ash– and rice husk ash–reinforced Al-alloy composites and these composites exhibit better wear resistance compared to unreinforced alloy. The palmyra shell ash particle weight fraction significantly affects the wear and friction properties of the composites. Scanning electron microscopic examination of the worn surface reveals that at various loads palmyra shell ash particles act as load-bearing constituents and the wear resistance of the reinforced palmyra shell ash with a size range of 1–50 µm was superior to that of unreinforced alloy. Mechanical properties (hardness and tensile strength) were also studied and it was observed that the reinforced Al-alloy showed a significant increase in mechanical properties.     

纳米HA增强PVA-H复合材料的摩擦学性能研究

利用四球试验机考察了纳米羟基磷灰石（HA）粉体增强PVA-H人工软骨材料与不锈钢球进行对磨时的摩擦磨损性能，采用扫描电子显微镜（SEM）观察并分析了磨损表面的微观形貌。试验结果表明：加入适量的纳米HA（质量分数1％）能有效地降低复合材料的摩擦因数，但更多的添加量反而增加复合材料的摩擦冈数；SEM图像表明，纯PVA-H的表面有较严重的磨损痕迹和磨屑，而HA粒子的加入可以降低复合材料表面的磨损情况。