【作者】 俸颢；

【导师】 毛大恒；

【作者基本信息】 中南大学 ， 机械设计及理论， 2007， 博士

【摘要】 研究开发高性能高温润滑脂，对满足设备的高温润滑要求具有重要意义。本文以新型润滑材料WS₂亚微米粒子作为高性能高温润滑脂的添加剂，对其在润滑脂中所起的抗磨、减摩、抗极压等作用进行了实验研究和高温轴承台架试验，并用电子探针显微镜和俄歇电子能谱仪等对摩擦表面进行了分析。针对润滑脂中亚微米粒子的微观分散问题，引入了超声波分散技术。根据试验结果对WS₂亚微米粒子在高温润滑脂中的润滑机理和超声波对润滑脂中亚微米粒子的分散作用机理进行了分析，并研制出两种达到国际先进水平的高性能WS₂高温润滑脂。本文的主要研究结果有：1．通过实验发现WS₂亚微米粒子能大大提高两种主要高温润滑脂：复合锂基润滑脂和复合磺酸钙基润滑脂的抗磨、减摩、抗极压等摩擦学性能。在滚动轴承用润滑脂中添加适量WS₂亚微米粒子，能有效降低轴承在高温环境下工作时的摩擦因数，降低能耗，并能减少润滑脂消耗，延长润滑脂的工作寿命。并发现WS₂亚微米粒子的润滑性能大大优于石墨和MoS₂。2．发现亚微米粒子的最佳添加量与润滑脂的皂纤维结构有关。在复合锂基润滑脂中，由于部分WS₂亚微米粒子被封锁在皂纤维所组成的网状结构中，没有发挥润滑作用，故最佳添加量较大，为1.5％左右；在复合磺酸钙基润滑脂中，由于WS₂亚微米粒子主要是和团状皂纤维混合，大部分发挥了润滑作用，故最佳添加量较小，为1％左右。3．发现在较低的温度下，润滑脂中所含的WS₂亚微米粒子除了依靠晶体内部层间滑移减少摩擦外，主要依靠在金属摩擦表面形成WS₂吸附膜，以起到润滑作用。吸附膜的覆盖比例和厚度是影响润滑效果的关键，由于WS₂吸附膜比同等条件下MoS₂生成的吸附膜覆盖比例大，且更厚，故在比MoS₂具有更好抗磨、减摩和抗极压性能。4．发现在较高的温度下，润滑脂中所含的WS₂亚微米粒子主要依靠在摩擦副表面发生摩擦化学反应，生成化学反应膜，以降低摩擦，减少磨损。在钢-钢摩擦中，这层化学反应膜的形成过程为：在摩擦热作用下，WS₂分解生成W和S负离子(S^2-)，然后W扩散沉积在金属表面，同时S与基体金属Fe作用生成FeS等抗磨、减摩的成分。这层化学反应膜不仅阻止了摩擦表面之间的直接接触，而且拥有很高的承载能力，使得由剪切应力引起的弹性变形和塑性变形局限于润滑膜区域，因而有效地抑制了摩擦表面的粘着磨损和接触疲劳，起到保护摩擦表面的作用。化学膜的厚度是影响润滑效果的关键，由于这种化学膜的厚度远大于同等条件下MoS₂生成的反应膜，故比MoS₂具有更好抗磨、减摩和极压性能。同时给出了反应膜厚度与工作温度的关系，指出反应膜厚度随工作温度的升高首先增加，当达到一定极限时，开始下降。5．发现WS₂亚微米粒子在轴承润滑脂中高温工作下产生的少量氧化生成物WO₃为粒径小于100nm的球状微粒，能在润滑过程中产生“滚珠轴承”效应，具有良好的摩擦学性能。6．首次将超声波分散技术引入对润滑脂中亚微米固体添加剂的分散中来，证实采用超声波能够产生声流搅拌并引起润滑脂中空化泡崩溃而产生瞬时高压，实现亚微米固体添加剂在润滑脂中微观上的均匀分布，提高了润滑脂的润滑性能。7．以WS₂亚微米粒子为主要添加剂，并引入超声波均化技术，研制出高性能WS₂复合锂基润滑脂和高性能WS₂复合磺酸钙基润滑脂，其性能基本达到国外同类先进高性能高温润滑脂产品的水平，部分指标甚至要优于国外产品。在工厂的实际应用情况表明，自行研制的高性能WS₂润滑脂在高温下工作情况良好，能够满足生产实践的需要，已部分取代进口同类产品，并出口到多个国家和地区，取得了较大的经济效益，值得在高温工作场合下推广运用。更多还原

【Abstract】 Research and development of high performance high temperature grease has important significance to lubricate the equipment at high temperature. In this paper, a new lubricating material-WS₂ submicron particle is used as additive of high performance high temperature grease and its effects on anti-wear, antifriction and extreme pressure in grease are researched and the high temperature bearing bed test is carried out, the friction surface is analyzed with EPMA and AES. To solve the problem of the microscopic dispersing the submicron particles in grease, Ultrasonic method is used. According to the results, lubrication mechanism of WS₂ submicron particle in high temperature in grease and disperse mechanism of ultrasonic dispersing to submicron particle in grease are analyzed, and two kinds of high performance WS₂ high temperature grease which approach international advanced level are presented.Main research findings of this paper are as follows:1. The results of experiment show that WS₂ submicron particle can enhance the tribology property, including anti-wear, antifriction and extreme pressure, of two main high temperature grease-lithium complex grease and complex calcium sulfonate grease. Adding proper WS₂ submicron particle into the grease used in rolling bearing can reduce the friction factor, consumption, wastage of grease and prolong the working life of grease. It is also found that the lubrication property of WS₂ submicron particle is much better than that of graphite and MoS₂.2. The best proportion of submicron particle is related to soap’s fibre structure of grease. In lithium complex grease, some WS₂ submicron particle is blocked in reticular soap fibre and is not into lubrication, so the best percent should be higher and is about 1.5%; In calcium sulfonate complex grease, WS₂ submicron particle is only mixed with nodular soap fibre and is all into lubrication, so the best percent should be lower and is about 1%.3. It is discovered that, under a lower temperature, the metal is lubricated mainly by WS₂ adsorption membrane which is formed between metal friction surfaces besides crystal interior layer slipping of WS₂ submicron particle in the grease. The adsorption membrane cover proportion and thickness are the key to affect the lubrication effect, because WS₂ adsorption membrane cover proportion is higher and WS₂ adsorption membrane is thicker than that of MoS₂ under the same condition.4. It is discovered that, under a higher temperature, the friction and wear are reduced mainly by chemical film which is produced by the friction chemical reaction of friction pairs’ surface. In the steel-steel friction, the forming process of this chemical film is: the WS₂ is decomposed into W and S^2- with friction heat. then the W spreads and deposits on metal surface, simultaneously the anti-wear and antifriction ingredients, such as FeS is produced by reaction of S and substrate metal Fe, not only is the direct contact between friction surface prevented, but also the metal has higher beating capacity, which limits the elastic deformation and plastic deformation caused by shear stress to lubricating film region. Thus effectively restrains the friction surface coherence to wear and to contact wearily, so the friction surface is well protected. Chemical film thickness is the key factor to lubrication effect. Because the chemical film is much thicker than the film produced by MoS₂ under the same condition, and has better antiwear, antifriction and extreme pressure performance. Meanwhile, the relation between chemical film thickness and working temperature is presented, which shows that the chemical film becomes thicker as the working temperature rises, and start to drop when it achieves a certain temperature.5. It is discovered that, a little oxidized resultant WO₃ which is produced by WS₂ submicron particle in beating grease under high working temperature, is smaller than 100nm spherical particle, can act as ball bearing and has good friction performance.6. For the first time, ultrasonic dispersion technique is introduced to disperse submicron solid additive in grease. Ultrasonic wave have the sonic flow to stir and cause grease cavitation soaks the collapse to produce the instantaneous high pressure, disperses submicron solid additive in grease equably at micro level, and enhances the lubricating properties of grease.7. Take WS₂ submicron particle as the main additive, introduce ultrasonic dispersion technique, and develop high performance WS₂ lithium complex grease and high performance WS₂ calcium sulfonate complex grease, which can achieve the advanced level at whole performance, some performances excels overseas same kind products. Indicated in the factory practical application situation, independently develops high performance WS₂ grease puts down work in the high temperature makes the situation be good, can meet the requirement of production practice, has replaced some import grease, and has exported to some countries and areas, owing to good economical benefits, is worthy to extending use in the high temperature working conditions.更多还原