Sn-Ag-Cu系高温自润滑材料的摩擦学特性

采用真空压力浸渗复合技术将熔融固体润滑剂熔渗到微孔金属陶瓷基体中,制备熔渗型Sn-Ag-Cu系高温自润滑复合材料;利用XP-2型高温摩擦磨损销盘型试验机考察其高温摩擦磨损性能,采用SEM和XRD分析其磨损表面形貌、成分,探讨其高温自润滑机制。研究结果表明:制备的自润滑复合材料在600℃高温下具有较低的摩擦因数和磨损率,这是因为在高温摩擦磨损过程中熔渗于基体材料中的固体润滑剂在高温、摩擦热和应力的作用下从微孔中析出,并在摩擦界面形成由Cu_3Sn、Cu_αSb_γ、Fe_3Sn、Ag_3Sn等金属间化合物组成的润滑膜。该润滑膜使材料具有良好高温自润滑性能,其中的Ag元素对摩擦因数的影响较大。     

PTFE/7075铝合金镶嵌型自润滑材料的摩擦学行为

采用模压／烧结工艺制备了PTFE／7075铝合金镶嵌型自润滑复合材料,在往复式摩擦磨损试验机上进行了摩擦磨损试验,用扫描电镜观察了复合材料磨损后的表面形貌,并探究了其磨损机理。结果表明:在试验条件下,稳态后摩擦温度为51℃,摩擦因数为0．087,磨损率为0．38×10-3mm3／(Nm),和非镶嵌型PTFE基复合材料相比,导热性和耐磨性大大提高,而摩擦因数无明显增加;稳定磨损阶段主要表现为粘着磨损,同时伴有轻微磨粒磨损,磨损后期局部呈现疲劳特征。     

青铜粉对聚四氟乙烯基复合材料摩擦学性能影响的研究

通过向聚四氟乙烯材料加入不同质量比的青铜粉和氧化铅制备了3种自润滑复合材料,并与不加青铜粉的填充氧化铅的聚四氟乙烯材料进行实验研究,研究了青铜粉及其含量对聚四氟乙烯基复合材料摩擦学性能的影响,并探讨了填料的减磨机理。结果表明:在干摩擦条件下,在一定范围内,随着青铜粉含量的增加,填充氧化铅的PTFE基材料的摩擦磨损性能有所降低;在油润滑条件下,填充氧化铅的PTFE基材料的摩擦磨损性能相对干摩擦有所提高,且在一定范围内,随着青铜粉含量的增加,填充氧化铅的PTFE基材料的摩擦磨损性能有所提高;填料的减磨机理与“第三体”有关,而“第三体”又与材料的基体组分有关。     

镶嵌型固体自润滑材料的研究与应用

本文介绍了金属基镶嵌型固体润滑自材料的加工方法及摩擦磨损性能特点,并对其摩擦进行了初步探讨。试验结果表明：此种材料具有较低的摩擦系数和良好的减摩耐磨性能;用该材料制成的煤矿提升设备中箕斗上使用的镶条其寿命可大幅度提高。镶嵌型固体２自润滑材料制作工艺简单、成本低廉、经济效益明显,具有很大的推广应用价值。     

石墨铝基自润滑材料的制备及性能表征

以石墨为固体润滑剂,铝为基体材料,添加硅、铜、铁等元素作为强化成分,添加Cr3C2、粉煤灰来提高自润滑材料的耐磨性,通过液态铸造法制备铝基自润滑材料。借助MM-200磨损试验机研究不同石墨含量以及粉煤灰的添加对铝基复合材料摩擦磨损性能的影响;在Olympus金相显微镜下观察材料显微组织;用S-3000N扫描电子显微镜对材料拉伸断口和磨损表面进行观察。结果表明:随着石墨含量的增加,摩擦因数逐渐降低,磨损率逐渐升高,抗拉强度、硬度都逐渐降低;粉煤灰的加入使得初生硅得到细化,自润滑材料的强度上升,摩擦因数得到进一步的改善。     

粉末冶金铝基固体自润滑材料

铝基固体自润滑材料由于其优异的物理性能和摩擦性能受到人们的广泛关注,本文从铝基体研究和固体润滑剂两方面介绍了其研究概况,并指出了发展铝基固体自润滑合金的重大意义。     

聚四氟乙烯的摩擦磨损特性

聚四氟乙烯(PTFE)具有突出的低摩擦特性,特别是在低速、高负荷时,它的摩擦系数可低到0.04,是到目前为止所发现的摩擦系数最低的一种固体物质。然而,PTFE的耐磨性却很差。通过填充、增强改性或其它复合工艺手段,PTFE能用作自润滑的摩擦零部件。用PTFE作为固体润滑剂去改性多种塑料,可以获得显著的摩擦学效果。本文综述了PTFE的摩擦磨损机理及其在不同滑动速度、负荷、环境温度等参数下的摩擦学行为。文中还搜集了各种填充剂及其含量对PTFE摩擦磨损特性的影响等。     

干摩擦条件下碳纤维填充聚苯酯基复合材料摩擦学性能研究

采用碳纤维填充聚苯酯基复合材料制备出一种性能优异的新型自润滑复合材料.利用干摩擦条件下碳纤维填充聚苯酯基复合材料与配副材料的摩擦磨损试验,通过对接触表面形貌、磨损量、摩擦因数等特征参数的采集与分析,研究内外部因素的变化对碳纤维填充聚苯酯基固体润滑材料摩擦磨损性能的影响,探讨碳纤维增强聚苯酯基自润滑复合材料的磨损机理.     

熔渗型宽温域复合固体润滑剂设计及其摩擦学性能研究

设计一种可用于300~800℃宽温度范围润滑的熔渗型Pb-Sn-Ag-RE复合固体润滑剂。基于润湿试验研究不同组分与配比对其润湿性能的影响;采用高频感应熔渗工艺,制备出熔渗型高温自润滑复合材料;利用XP-5型高温摩擦磨损试验机考察其摩擦磨损性能,运用扫描电子显微镜(SEM)和X射线衍射仪(XRD)分析磨损表面形貌、成分及结构。结果表明:不同组分组成对基体的润湿性有很大的影响,在Pb-Sn系固体润滑剂中添加Ag、RE既能提高其对母材的润湿性能,又能改善自润滑材料的摩擦磨损性能;熔渗Pb-Sn-Ag-RE复合固体润滑剂制备的复合材料具有良好的高温自润滑性能,其600℃下的平均摩擦因数约为0.28。     

对偶件表面微结构取向对PTFE基自润滑轴承材料摩擦性能的影响

研究了聚四氟乙烯(PTFE)基自润滑轴承材料与45#钢对摩时,对偶件45#钢表面微结构取向对PTFE基自润滑轴承材料摩擦学性能及转移膜的影响。结果表明:对偶件表面微结构取向与摩擦方向的夹角为0°和90°时,形成的转移膜较为均匀,且磨损量较小;夹角45°时,形成的转移膜不完整,且磨损较大。     

Influence of Ultrasonic Modified Liners on the Adhesive and Tribological Performances of Self-Lubricating Radial Spherical Plain Bearings

For self-lubricating spherical plain bearings, poor interface bonding strength between the polytetrafluoroethylene (PTFE)/aramid fabric hybrid woven liners and the outer rings can influence the full play of tribological performance of the self-lubricating liner. To solve this problem, the liners were modified by ultrasonic treatment. The adhesive performances of the modified and unmodified liners and the tribological performance of the self-lubricating radial spherical plain bearings with two kinds of liners were tested and compared. Results show that ultrasonic modification can improve the bonding performance of the liners significantly; compared to unmodified liners, the modified liners can decrease the friction coefficient, wear loss, and friction temperature of the bearings, which shows that ultrasonic modification can improve the tribological performance of self-lubricating spherical plain bearings. Bearings with modified liners only produced slight adhesive wear, but bearings with unmodified liners produced moderate adhesive wear and slight abrasive wear during test procedures.     

GF/PTFE自润滑纤维复合材料磨损性能热衰退研究

针对高频摆动关节轴承摩擦热对自润滑纤维复合材料摩擦磨损性能的影响,研制了高频使用条件下的玻璃纤维增强聚四氟乙烯(GF/PTFE)自润滑纤维复合材料,利用MYB～500高频高载摆动摩擦磨损试验机,对其进行不同摩擦温度下的摩擦磨损性能测试,研究摩擦热作用下材料自润滑性能和磨损性能衰退特征,分析磨损产物和摩擦表面以及不同摩擦温度下材料的磨损机理。结果表明,摩擦热对材料自润滑性能影响显著,适当的摩擦温度范围能够保证材料的自润滑性能,摩擦温度和摩擦因数之间互为耦合作用,对材料的磨损性能具有一定的影响;高摩擦热作用于自润滑过程及机理的改变,造成材料的磨损性能衰退现象。因此,不同温度下材料的磨损特征具有明显的差异化,其中低摩擦温度下(60～120℃)材料自润滑性能优异,磨损率很低;140℃摩擦温度条件下材料摩擦磨损性能开始衰退;材料在高摩擦温度下(140～180℃)的磨损初期自润滑性能良好、磨损轻微,而中后期磨损严重。微观分析表明,低摩擦温度下材料的磨损机理以轻微粘着和疲劳磨损为主;高摩擦温度下材料的磨损以片状剥落、纤维剪切破坏为主,且磨损面局部损伤特征明显,磨损严重。     

聚四氟乙烯/聚苯酯耐磨自润滑保持架材料的研究

采用聚苯酯填充改性聚四氟乙烯,制备出具有较好耐磨性和自润滑性的保持架复合材料。研究发现聚苯酯添加量为20%时,径向拉伸强度为17.3 MPa,邵氏硬度为64.0,干摩擦系数为0.248 5,耐磨性较纯聚四氟乙烯提高6倍;控制烧结过程降温速率,并在结晶速率最大的温度区保温1 h,径向拉伸强度提高27.2%,耐磨性提高1.7%。     

高频摆动自润滑关节轴承故障分析与改进验证

对高频摆动工况下自润滑关节轴承GE20-1的故障分析显示:织物自润滑衬垫和内圈球面镀硬铬涂层耐磨损性能不佳,出现偏磨现象;磨损严重处衬垫磨穿,内圈球面涂层仅剩1～2μm.为提升轴承耐磨损性能,采用了PTFE纤维面密度约20.1％的CD2#衬垫与内圈球面硬质合金涂层相组合的改进方案,改进轴承GE20-2经1500 h寿命...     

聚合物合金的摩擦磨损特性的研究

作者采用了聚合物共混技术研制了ＰＣ＋ＰＴＦＥ，ＰＣ＋ＰＴＦＥ＋ＰＰＳ两类聚合物合金，并对这些材料的摩擦学特性及其机理进行了研究。结果表明，ＰＴＦＥ的添加不仅可以提高ＰＣ的耐磨性，而且还可降低其摩擦系数；适量的ＰＰＳ的添加具有减摩抗磨作用。聚全物及其合金的摩擦特性可由粘着摩擦理论解释，其磨损过程主要受粘着，磨粒和疲劳机理控制。     

Self-Lubricating Cold-Sprayed Coatings Utilizing Microscale Nickel-Encapsulated Hexagonal Boron Nitride

It is often beneficial to modify surfaces to gain desirable properties such as improved wear and friction resistance. Self-lubricating coatings can improve the performance of contacting surfaces and extend component lifetimes by reducing the coefficient of friction and/or improving resistance to specific wear modes. With these goals in mind, self-lubricating coatings of hexagonal boron nitride (hBN) particles in a deposited nickel matrix were investigated and optimized for friction and wear. These self-lubricating coatings were created via high-velocity particle consolidation or cold spray using micrometer-sized hBN powder encapsulated by nickel and nickel phosphorous alloys. Relatively thick nickel encapsulation via electrolesss Ni plating was required to aid in coating bonding/formation by “tricking” the hBN into acting as monolithic Ni during deposition. Once deposited on aluminum substrates, the coatings were analyzed and found to exhibit enhanced mechanical and tribological properties such as high bond strength and microhardness, a relatively low coefficient of friction, and improved reciprocating wear behavior relative to pure cold-sprayed Ni coatings. Furthermore, the encapsulation process was found to be both scalable and amenable to relatively small hBN particles.     

Evaluation of the Machinability of Nickel-Base,Inconel 718, Alloy with Nano-Ceramic Cutting Tools

The machinability of difficult-to-cut aerospace alloys can be enhanced by the rapid development of cutting tool materials that can withstand machining at high-speed conditions. The performance of nano-grain size ceramic tool materials were evaluated when machining nickel base, Inconel 718, in terms of tool life, tool failure modes and wear mechanisms as well as component forces generated under different roughing conditions. Comparison tests were carried out with commercially available ceramic tool materials of micron-grain composition.

The test results show that the micron grain size commercially available tool materials generally gave the longest tool life. The dominant failure mode is nose wear, while some of the nano-ceramic tools were rejected mainly due to chipping at the cutting edge. This suggests that physical properties and mechanical stability of the cutting edge of the ceramic tools influence their overall performance. It is also evident that chemical compositions of the tool materials played a significant role in their failure. The alumina base ceramics are more susceptible to premature fracture than the silicon nitride base ceramics with higher fracture toughness.     

深过冷Ni-Pb-Cu固体自润滑材料摩擦行为研究

采用深过冷快速凝固方法制备了均质N i-Pb-Cu偏晶合金,用扫描电镜对其组织进行了观察,在摩擦试验机上对其试样进行了摩擦性能测试,并分析了其摩擦磨损机制。结果表明:制备的N i-Pb-Cu偏晶合金其凝固组织为硬基体上均匀地分布着软质点;N i-Pb-Cu合金的摩擦学特性随过冷度的提高而呈上升趋势,从而在理论上证实采用深过冷技术制备难混熔偏晶合金固体自润滑材料是可行的;N i-Pb-Cu偏晶合金与45#钢的磨损为磨屑磨损、粘着磨损。     

Influence of solid lubricants and fibre reinforcement on wear behaviour of polyethersulphone

Polyethersulphone (PES), is an amorphous, brittle and high temperature engineering thermoplastic. Two composites of PES containing short glass fibres (GF) and solid lubricants viz. PTFE and MoS₂; and two composites containing short carbon fibre (CF) [30% and 40%] were selected for the present studies. Compositional analysis of selected materials was done with various techniques such as gravimetry, solvent extraction and thermal analysis viz. thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). These materials were studied for adhesive and abrasive wear performance by sliding against a mild steel disc and silicon carbide abrasive paper respectively, under different loads. It was observed that GF reinforcement along with incorporation of solid lubricants (PTFE and MoS₂) enhanced the wear performance of PES by an order of two. In the case of solid lubricants, PTFE proved to be more beneficial than MoS₂. CF reinforcement, however, proved to be the most effective in enhancing wear performance of PES. PES reinforced with 40% CF exhibited a specific wear rate in the order of 10⁻¹⁶m³/Nm which is considered to be very good for the thermoplastic composite. In the case of abrasive wear behaviour, however, incorporation of fibres or solid lubricants deteriorated the performance of the neat matrix. SEM was employed to investigate the wear mechanisms.     

Tribological behaviour of new chemically bonded PTFE polyamide compounds

Topic of the study is the formation of new PTFE polyamide materials by reactive extrusion. The new type of formed PTFE polyamide compound shows very good material properties. Recently it has been revealed that carboxylic acid groups exhibit a very high reactivity under polyamide melting conditions. PTFE micro powders functionalized by carboxylic acid groups are the base for the block copolymer formation in polyamide melts under defined process conditions. Such functionalized micro powders are formed from virgin PTFE by electron irradiation in the presence of oxygen. These new PTFE polyamide materials can be processed easily using commercial (common) process equipment like twin-screw extruders and injection molding. Many experimental investigations have been performed under dry sliding friction on PA 6, PA 6.6 and PA 12 compounds with PTFE weight portions between 3.3 and 50%. They show low coefficients of friction and low specific wear rates. The wear resistance of newly developed PTFE polyamide compounds is comparable with commercially available mechanically or physically produced PTFE and PEAK compounds.