掺铬类石墨碳膜在润滑油条件下的摩擦学性能研究

发布时间：2019-05-06 19:55

【摘要】：工业实践证明,固体润滑涂层及液体润滑剂能十分有效地减小运动副的摩擦和磨损。新兴起的类石墨碳膜具有良好的减摩耐磨效果,但其热稳定性差、磨损不易补给限制了其使用范围,若与液体润滑剂复合使用则能起到取长补短的作用。目前对固液复合润滑技术的研究才刚起步,迄今国内尚未见到有关类石墨碳膜在固液复合润滑条件下的摩擦行为的研究报道。本文采用闭合场非平衡磁控溅射离子镀制备了掺铬类石墨碳膜。用球-盘摩擦磨损试验仪,在三类润滑油(石蜡基润滑油、合成润滑油、机械油)条件下对掺铬类石墨碳膜与未镀膜(基体材料)进行摩擦磨损实验。通过改变载荷和滑动速度,考察不同润滑油与掺铬类石墨碳膜的复合作用,探明了载荷、滑动速度对复合润滑体系的影响。利用光学显微镜、扫描电子显微镜、电子能谱、激光共聚焦显微镜对摩擦表面磨痕进行检测和观察,探讨固液复合润滑条件下的摩擦磨损机理。另外还研究了润滑油添加剂(MoDTC、ZDDP)对复合润滑体系的摩擦特性的影响。掺铬类石墨碳膜与润滑剂复合润滑的摩擦磨损性能的研究结果表明:液体润滑剂对掺铬类石墨碳膜的摩擦磨损性能起到改善的作用。润滑油条件下掺铬类石墨碳膜比未镀膜(基体材料)的比磨损率低,摩擦因数高。机械油条件下掺铬类石墨碳膜的摩擦因数随载荷的增加而减小,在160N时15#(机械油的一种)条件下掺铬类石墨碳膜具有最低的摩擦因数和比磨损率。合成润滑油条件下复合润滑的摩擦磨损性能与润滑油的粘度相关,低粘度的合成润滑油(PAO-4)具有更低的摩擦因数和比磨损率。石蜡基润滑油条件下掺铬类石墨碳膜摩擦因数则随载荷的增加先减小后增加,120N时摩擦因数、比磨损率最低。研究发现滑动速度对复合润滑体系的磨损性能几乎不影响。在研究添加剂对固液复合润滑体系摩擦磨损性能的影响中发现,润滑油中加入添加剂MoTDC后摩擦界面出现部分薄膜剥落,未起到延长薄膜使用寿命的作用。加入添加剂ZDDP后摩擦因数与比磨损率减小,摩擦界面磨痕轻微,磨损程度得到改善,呈现出良好的减摩耐磨性能。
[Abstract]:It has been proved in industrial practice that solid lubricating coating and liquid lubricant can reduce the friction and wear of moving pairs effectively. The newly developed graphite-like carbon film has good anti-friction and wear-resistant effect, but its thermal stability is poor, wear is not easy to replenish its use range, if used in combination with liquid lubricants, it can play a role of taking advantage of each other. At present, the research on solid-liquid composite lubrication technology has just started, so far, there is no research report on the friction behavior of graphite-like carbon film under solid-liquid composite lubrication condition. Chromium-doped graphite carbon films were prepared by closed-field unbalanced magnetron sputtering ion plating. The friction and wear experiments of chromium-doped graphite carbon film and uncoated (matrix material) were carried out under the condition of three kinds of lubricating oil (paraffin-based lubricating oil, synthetic lubricating oil, mechanical oil) by using a ball-disk friction and wear tester. The effects of load and sliding velocity on the composite lubrication system were investigated by changing the load and sliding velocity of different lubricating oil and chromium-doped graphite carbon film. The friction and wear mechanism under solid-liquid lubrication was investigated by means of optical microscope, scanning electron microscope, electron spectroscopy and laser confocal microscope. In addition, the effect of lubricating oil additive (MoDTC,ZDDP) on the friction characteristics of the composite lubrication system was also studied. The friction and wear properties of chromium-doped graphite carbon film and lubricant were studied. The results show that liquid lubricant can improve the friction and wear properties of chromium-doped graphite carbon film. The specific wear rate of chromium-doped graphite carbon film is lower and the friction coefficient is higher than that of uncoated graphite carbon film under lubricating oil condition. The friction coefficient of chromium-doped graphite carbon film decreases with the increase of load under the condition of mechanical oil. The friction coefficient and specific wear rate of chromium-doped graphite carbon film at 160N 15 # (one of mechanical oil) conditions are the lowest. The friction and wear performance of composite lubricating oil under synthetic lubricating oil condition is related to the viscosity of lubricating oil. Low viscosity synthetic lubricating oil (PAO-4) has lower friction coefficient and specific wear rate. Under the condition of paraffin-based lubricating oil, the friction coefficient of chromium-doped graphite carbon film decreases first and then increases with the increase of load, and the specific wear rate is the lowest at 120N. It is found that the sliding velocity has little effect on the wear performance of the composite lubrication system. In the study of the effect of additives on the friction and wear properties of solid-liquid composite lubrication system, it was found that after the additive MoTDC was added to the lubricating oil, some thin film spalling appeared at the friction interface and did not prolong the service life of the film. After adding the additive ZDDP, the friction coefficient and specific wear rate decrease, the friction interface wear mark is slight, the wear degree is improved, and the friction-reducing and wear-resisting property is good.
【学位授予单位】：陕西理工学院
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TH117

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