碳氮共渗钢干摩擦状态下磨损行为的研究

对20^#钢试进行C-N共渗热处理,经C-N共渗的试样进行干摩擦磨损试验,实验的载荷为2N到6N,滑动速度从8m/s到45m/s。摩擦磨损试验表明：在滑动速度为35m/s左右时,姓了从轻微磨损向严重磨损的转变,结合SEM、AES和XPS分析,磨损率的变化与磨损表面的氧化物形成与剥落、氧化物的类型转变（Fe2O3转变成FeO）有密切关系。     

聚四氟乙烯填充PA1010的摩擦磨损性能研究

以注塑成型法制备了聚四氟乙烯(PTFE)填充PA1010复合材料,利用M-2000磨损试验机测试了该复合材料与GCr15轴承钢对摩时的摩擦磨损性能,并用扫描电子显微镜(SEM)观察了试样磨损表面形貌.结果表明:PTFE填充PA1010可显著改善尼龙复合材料的摩擦磨损性能.w(PTFE)为25%时,复合材料的摩擦学综合性能最佳.复合材料的摩擦系数和磨损体积随施加载荷、滑动速度的增加分别呈现降低和增加的趋势.在200 N载荷下,复合材料磨损主要为磨粒磨损;在400 N载荷下,磨损表现为黏着磨损和磨粒磨损共同作用.在滑动速度为0.21 m/s时,材料摩擦表面因挤压发生塑性流变,其磨损机理为磨粒磨损;在滑动速度为0.84 m/s,复合材料因热疲劳和应力疲劳发生剥层,磨损机理转变为疲劳剥层磨损.     

炭／炭复合材料的摩擦磨损性能

选取由CVD预增密至一定密度，再进行树脂浸渍／炭化补充增密至1.85g/cm^3的炭／炭复合材料作摩擦环试样。测试了该试样在一系列刹车速度时的摩擦磨损性能，并对其摩擦面及磨屑进行了SEM,观察对摩擦面进行显微喇曼光谱分析。研究结果表明：炭／炭复合材料的摩擦磨损性能随刹车速度的变化而发生显著变化，在10m/s时出现最高峰，在25m/s出现亚高峰；磨损量随刹车速度的增加而增加，而氧化磨损在刹车速度为25m/s时开始大量产生，在28m/s时达最大值，其摩擦表面形貌，结构及磨屑亦有较大差别。刹车速度从5m/s升至20m/s，摩擦面石墨化度降低，石墨结构向无定型碳结构转变，但在高速时石墨化度反而升高，无定型碳结构又向石墨结构转变。     

炭／炭复合材料熔融渗Si研究

为了改善航空刹车副用炭／炭复合材料的摩擦磨损性能，对A，B2种试样进行了渗Si处理，在试样A的摩擦磨损试验中，其线性磨损由原来的42μm／次降低到17．56μm/次，摩擦因数较稳定，均为0．36，并且摩擦磨损曲线的线型较好；试样B渗Si后也比渗Si前的摩擦磨损曲线线型好，同时解决了摩擦时的振动问题，但随试样中所生成SiC含量的增加，其摩擦因数由0．40→0．34→0．30降低，静盘线性磨损是由2．0→21．21→69.33μm增加，对应的动盘线性磨损量也由1．4→23．12→52.85μm增加，并从摩擦磨损的机理上进行了分析，实验结果表明，摩擦磨损性能一方面受A，B2种试样的结构性能影响，另一方面是由渗Si后所生成SiC的性能和不同结构决定的。     

离子氮碳氧复合渗对45钢耐磨性能的影响

用离子氮碳氧复合渗处理的方法 ,在绝热式离子热处理炉上对 45钢试样进行处理。通过金相显微镜和X射线衍射仪观察了化合物层的显微组织和微观结构及在MPX 2 0 0型盘销式摩擦磨损试验机上进行纯滑动干磨损试验。结果表明 ,45钢经离子氮碳氧复合渗处理后 ,表层可获得化合物和氧化物的复合渗层 ,明显提高 45钢的耐磨性能。     

大口径弹带材料黄铜的磨损机理研究

为开发适用于高膛压发射条件的新型弹带材料,研究传统黄铜弹带材料的磨损机理。采用HSR-2M往复式摩擦实验机测试黄铜的摩擦磨损性能,并结合OM、SEM/EDS分析磨损黄铜的形貌和成分。结果表明,在30N载荷下,滑动速度按照200r/min、400r/min、600r/min次序增加时,黄铜的摩擦系数先增大后减小,磨损量在滑动速度为600r/min时急剧增大。滑动速度由200r/min提高到600r/min时,由于摩擦表面温度达到黄铜的熔点,黄铜的磨损机制由磨粒磨损转变为熔化磨损。     

纳米级镍粉改善润滑油摩擦磨损性能的研究

在MHK－500型环块摩擦磨损试验机上,研究了纳米级金属镍粉（直径在10～50nm）加入到矿物油中的润滑性能,结果表明：在低中滑动速度下（滑动速度分别为1．285m／s和2．57m／s）,加有纳米级镍粉的润滑油表现出优良的抗磨性能．     

C/C复合材料的摩擦磨损行为研究

利用HIT-1型球盘式摩擦磨损试验台,以C/C复合材料与GCr15钢为配副进行摩擦磨损实验。研究了C/C复合材料的摩擦系数与时间、载荷和速度的关系,分析了工况环境对摩擦系数的影响,获得了磨损量与载荷和速度的相关关系。结果表明:C/C复合材料的摩擦系数在摩擦磨损初期减小,随后在较小区间内平稳波动;摩擦系数在不同载荷条件下随速度变化趋势不同,当载荷为8 N时摩擦特性随速度变化最稳定,速度为0.576 m/s时摩擦特性随载荷变化最稳定;不同试验环境中摩擦性能呈现规律不同;C/C复合材料摩擦磨损过程中磨损率随速度缓慢增大,随载荷缓慢增大。     

纳米SiC颗粒作为润滑油添加剂的摩擦学性能研究

采用表面修饰法制备了聚合物包覆的纳米SiC颗粒，采用M-200环块试验机进行摩擦磨损试验，研究了表面修饰的纳米SiC颗粒添加荆对发动机润滑油(15W／40)减摩性能的影响，并利用扫描电子显微镜对磨块的磨损表面形貌进行观察，分析了润滑荆的减摩机理．结果表明：当滑动线速度为0．42m／s、载荷低于1000N时，纳米SiC颗粒的加入导致磨损失重的提高；当载荷提高到1300N时，纳米SiC颗粒的加入使磨损失重低于相同条件下以基础油作润滑剂的磨损失重；当滑动线速度为0．84m／s、载荷为1000N时，纳米SiC颗粒的加入使磨损失重为相同条件下以基础油作为润滑剂磨损失重的40％。     

纳米填料增强UHMWPE–橡胶水润滑摩擦学性能

为了研究水润滑条件下试验载荷和速度对纳米碳化硅填料（Nano–SiC）改性超高分子量聚乙烯（UHMWPE）–橡胶复合材料摩擦学性能的影响,通过高温混炼、热压成型制备Nano–SiC辅以聚四氟乙烯（PTFE）填充改性UHMWPE–橡胶复合材料;采用MRH–3型环–块摩擦试验机探究4种不同载荷条件下复合材料的摩擦磨损性能,采用光学显微镜（OM）、扫描电子显微镜（SEM）和非接触光学3维轮廓仪对试样微观磨损表面形貌分析,从微观层面探究改性复合材料的摩擦机理。试验结果表明：在定载变速条件下,速度由0.005 m/s升到0.541 m/s时,改性复合材料的动、静摩擦系数均呈现大幅下降趋势,摩擦系数波动归于平稳,黏–滑现象逐渐减弱直至消失。试验载荷和纳米粒子含量的变化与试样摩擦磨损程度呈负相关：在水润滑条件下,随着纳米粒子含量增加,摩擦系数与磨损率均出现明显降低,填充比例5%的复合材料摩擦学性能最佳,摩擦系数整体较UHMWPE–橡胶材料降低35%,磨损率降低46.6%,磨损表面形貌也随之发生改变;随着载荷的增加,复合材料的磨损率从1.25×10~(–6) mm~3/(N·m)降至0.40×10~(–6) mm~3/(N·m)。Nano–SiC的含量与工况载荷压力对摩擦磨损均存在一定影响,即填充适量Nano–SiC的UHMWPE–橡胶复合材料能减轻黏–滑现象,与一定工况压力下的对偶钢环组成的摩擦配副能有效改善摩擦性能,有利于减小水润滑轴承的磨损,增强传动系统服役寿命。     

Dry sliding wear behavior of Ti-6Al-4V alloy in air

0　ＩＮＴＲＯＤＵＣＴＩＯＮＴｉｔａｎｉｕｍａｌｌｏｙｓｈａｖｅｂｅｅｎｗｉｄｅｌｙｕｓｅｄｉｎａｅｒｏｓｐａｃｅｉｎｄｕｓｔｒｉｅｓｂｅｃａｕｓｅｏｆｔｈｅｉｒｈｉｇｈｓｔｒｅｎｇｔｈ ｔｏ ｗｅｉｇｈｔｒａｔｉｏａｎｄｅｘｃｅｌｌｅｎｔｃｏｒｒｏｓｉｏｎｒｅｓｉｓｔａｎｃｅ[1] .Ｈｏｗｅｖｅｒ ,ｔｈｅｉｒｐｏｏｒｗｅａｒｒｅｓｉｓｔａｎｃｅｐｒｅｖｅｎｔｓｔｈｅａｐ ｐｌｉｃａｔｉｏｎｓｏｆＴｉｔａｎｉｕｍａｌｌｏｙａｓｓｔｒｕｃｔｕｒａｌｍａｔｅｒｉａｌｓ[2 ] .Ｔｈｅｐｏｏｒｔｒｉｂｏｌｏｇｉ…     

Tribological Properties of MoSi2 Against AISI10045 Steel Under Sliding Friction

MoSi2 samples were prepared by a self-propagating high-temperature synthesis （SHS） and a hot-press technique. The sliding friction and wear properties of intermetallic MoSi2 against AISI10045 steel under dry friction and oil lubrication conditions were investigated with a MRH-5A type ring-on-block friction and wear tester. The elemental composition, microstructure and worn surface morphology of the MoSi2 material were observed and analyzed by means of scanning electron microscopy （SEM） and X-ray diffraction （XRD）. The synthetic parameter pv value reflecting friction work, was used to discuss the tribological properties of MoSi2 material. The results show that 1） oil lubrication can obviously improve the tribological properties of MoSi2, 2） the bigger the pv value, the greater the antifriction and the abrasive resistance of MoSi2 under oil lubrication, 3） with an increase in the pv value, the wear mechanism of MoSi2 material under dry sliding friction is the fatigue fracture and adhesive wear and 4） under oil lubrication the wear mechanism is mainly fatigue pitting.     

Dry Friction Characteristics of Ti-6Al-4V Alloy under High Sliding Velocity

Tribological behaviours of Ti-6Al-4V alloy pins sliding against GCr15 steel discs over a range of contact pressures （0.33-1.33 MPa） and sliding velocities （30-70 m/s） were investigated using a pin-on-disc tribometer under unlubricated conditions. The wear mechanisms and the wear transition were analyzed based on examinations of worn surfaces using SEM, EDS and XRD. When the velocity increases, the friction coefficient and the wear rate of the Ti-6Al-4V alloy show typical transition features, namely, the critical values of sliding velocities for 0.33 and 0.67 MPa are 60 and 40 m/s, respectively. The experimental results reveal that the tribological behaviours of Ti-6Al-4V alloys are controlled by the thermal-mechanical effects, which connects with the friction heat and hard particles of the pairs. A tribolayer containing mainly Ti oxides and V oxides is formed on the worn surface of Ti-6Al-4V alloy.     

Comparison of the Wear Behavior of UHMWPE Lubricated by Human Plasma and Brine

The effect of plasma and brine lubricants on the friction and wear behavior of UHMWPE were studied by using the geometry of a Si3N4 ball sliding on a UHMWPE disc under patterns of uni-directional reciprocation and bi-directional sliding motions. The worn surface and wear particles produced in these two lubricants were analyzed. Sliding motion pattern affected the friction coefficients lubricated with plasma, while seldom affected that lubricated with brine. UHMWPE lubricated with plasma showed about half of the wear rate of that lubricated with brine. The two rates were 0.75 pg/m and 2.19 pg/m for the two motion patterns, respectively. However, wear particles generated in plasma included a greater amount of small particles, compared to that in brine. In uni-directional reciprocation, the main wear mechanism is ploughing both in plasma and in brine. In bi-directional sliding modes, the significant characteristic is ripples on the worn surface in plasma, while there are oriented fibers on the worn surface in brine.     

Microstructure and wear resistance of electro-thermal explosion sprayed stellite coating used for remanufacturing

Electro-thermal explosion directional spraying was used to prepare the stellite coating on substrate of the AISI 1045 steel. The morphologies of cross-section and worn scar, porosity, distribution of elements, microhardness and wear resistance of the coating were determined by means of SEM, EDAX, micro-hardness tester and sliding wear tester. Because of the compact construction, good bonding and high hardness, the coating is characterized by good wear resistance. The results show that the mainly failure mode of the stellite coating is microplowing.     

The Wear Process of PTFE Coatings Under Vacuum Conditions

The wear process of PTFE coatings sliding against GCrlS-bearing steel ball under vacuum conditions was investigated, and the hardness of the PTFE coatings on both sides of wear track was measured. The experimental results showed that the friction coefficient of the PTFE coatings increases with the increase of sliding distance under different sliding velocities. And the friction coefficient of the PTFE coatings increases with the increase of sliding distance under different sliding loads. The wear rate of PTFE coatings decreases with the increase of sliding distance. And the majority of the wear produced during the whole wear process of PTFE coatings sliding against GCr-15 steel ball comes from the early period of friction. The hardness of PTFE coatings on both sides of wear track increases as the distance increases and distributes symmetrically around the wear track. Scanning electron microscope （SEM） was utilized to investigate the worn surface of PTFE coating, h was found that the worn surface of PTFE coating is characterized by sever plastic deformation and spalling of the PTFE coating. The edge of wear track is characterized by micro cracking.     

Wear mechanism for spray deposited Al-Si/SiC_p composites under dry sliding condition

Al-Si/15%SiCp(volume fraction) composites with different silicon contents were fabricated by spray deposition technique, and typical microstructures of these composites were studied by optical microscopy(OM). Dry sliding wear tests were carried out using a block-on-ring wear machine to investigate the effect of applied load range of 10-220 N on the wear and friction behavior of these composites sliding against SAE 52100 grade bearing steel. Scanning electron microscopy(SEM) and energy-dispersive X-ray microanalysis(EDAX) were utilized to examine the morphologies of the worn surfaces in order to observe the wear characteristics and investigate the wear mechanism. The results show that the wear behavior of these composites is dependent on the silicon content in the matrix alloy and the applied load. Al-Si/15%SiCp composites with higher silicon content exhibit better wear resistance in the applied load range. Under lower loads, the major wear mechanisms are oxidation wear and abrasive wear for all tested composites. Under higher loads, severe adhesive wear becomes the main wear mechanisms for Al-7Si/15%SiCp and Al-13Si/15%SiCp composites, while Al-20Si/15%SiCp presents a compound wear mechanism, consisting of oxidation, abrasive wear and adhesion wear.     

High Temperature Wear Characteristics of a New Hot Work Die Steel CH95

High temperature wear characteristics of a new hot work die steel CH95 doped with a small amount of rare earth （ Re ） and boron （ B ） have been investigated and compared with those of conventional die steel H11 at a series of temperatures and loads. Worn surfaces of CH95 steel and H11 steel were analyzed with a scanning electron microscope. It is found that high temperature mechanical properties of CH95 steel are much better than those of H11 steel. The oxide layer formed on the worn surface plays an important role in wear resistance at high temperature. When the load is less than 63 N, the surface oxide layer keeps integrated and the effect of load on high temperature wear is small. When the load is higher than 63 N, the supporting ability of matrix to the oxide layer decreases with the increase of load, which results in an increase of wear rate. Compared with H11 steel, the wear resistance of CH95 steel is much better and the worn surface of CH95 steel is smoother. It is easier for CH95 steel to form a compact and integrated surface oxide layer at high temperature than for Hll steel, which protects the worn surface and reduces wear.     

GF/MoS2改性PTFE密封唇片材料的力学及摩擦学性能

采用玻璃纤维(GF)微粉与MoS₂复合改性聚四氟乙烯(PTFE)密封唇片材料,考察复合材料的力学、干摩擦磨损性能及其磨损机理。结果表明:当GF质量分数为15%时,PTFE/GF试样的回弹率达到最大值92.5%,摩擦因数为0.29,相比纯PTFE有所增加,而磨损率大大降低,仅为1.8×10?6mm3/(N·m);在此基础上,当MoS₂添加量为5%时,PTFE/GF/MoS₂试样的回弹率略有降低,但仍然保持在90%以上,其摩擦因数为0.31,体积磨损率进一步降低到1.25×10?6mm3/(N·m)。磨损面SEM分析表明:纯PTFE呈现出严重的塑性变形和粘着磨损特征,而PTFE/GF主要表现为磨粒磨损行为;适当MoS₂含量的PTFE/GF/MoS₂试样在摩擦过程中磨粒磨损特征消失,仅有非常轻微的粘着磨损行为。