电化学机械光整加工表面形貌研究

提出了用于圆柱表面精密光整的夹心式电化学机械加工装置核心部件设计方案,探讨了主要工艺参数对表面质量影响规律。对采用这种新型加工方法所产生表面的轮廓高度特性、间距特性、形状特性、轮廓峰分布及表面波纹度进行了试验研究,结果表明电化学机械光整表面轮廓以高频小振幅波度为主要成分。     

摩擦表面形貌表征的研究现状与发展趋势

摩擦表面形貌反映材料的磨损状态,对材料表面摩擦形貌的分析是研究其磨损失效形式的一种重要方法。介绍国内外关于表征摩擦形貌主要方法的研究现状,分析各种方法的优点及局限性,并提出摩擦表面形貌表征方法的可能发展趋势。分形和小波变换应用于摩擦表面形貌的表征具有一定的优点,但对于摩擦过程中摩擦表面形貌与材料磨损状态的动态表征具有较大的局限性。因此,需要开发一种能及时准确地反映材料摩擦状态的摩擦表面形貌表征方法。     

铜/铬青铜摩擦副磨损表面形貌与电弧的相互作用关系

为探究载流摩擦磨损过程中摩擦副磨损表面形貌与电弧的相互作用关系,在HST-100高速载流摩擦磨损试验机上以铜/铬青铜为摩擦副进行载流摩擦磨损试验。用三维形貌仪测量磨损表面粗糙度,并通过扫描电子显微镜分析试验后销试样表面形貌。结果表明:起始表面粗糙度在磨损初期对电弧能量、摩擦因数有影响,在磨损中后期其影响并不显著;表面粗糙度与燃弧率有一定的正相关性,表面粗糙度较大时,燃弧率与电弧能量较大,表面粗糙度降低,燃弧率与电弧能量也随之降低;质量磨损率呈现"U"形变化,摩擦因数则先降低后升高;磨损初期,磨损机制主要是黏着磨损,没有明显的电弧侵蚀作用,磨损中后期,电弧侵蚀越发严重,出现电弧烧蚀坑,并造成熔融堆积。     

脉冲电化学加工现状与进展

介绍了脉冲电化学加工(PECM)的机理,综述了PECM/PECMM的国内外技术现状及研究进展,详细阐述了脉冲电化学加工的工艺模型和复合加工技术,并展望了今后的发展前景和重点研究方向。     

20 vol％SiCp/Al复合材料—硬质合金摩擦磨损表面形貌研究

以YG6X硬质合金为对磨材料,借助MMUD-5摩擦磨损试验机研究了载荷、转速和温度对20vol%SiC_p/Al复合材料干滑动摩擦磨损性能的影响,并采用SH-4000M扫描电镜和VHX-2000三维超景深光学显微镜对试样的摩擦磨损带进行观察。结果表明:当载荷小于150N时,表面质量较好,只有轻度涂覆现象;当载荷大于200N时,随着载荷的增加,表面质量越来越差,表面磨损主要为犁沟和剥离;在较低转速下,表面磨损主要是剥离和犁沟;在较高速度下,材料表面因较高的温度产生塑性形变,出现了裂纹和粘着磨损;当温度超过100℃后,磨损表面产生塑性变形,且随着温度升高,表面磨损由犁沟和剥离转变成粘着磨损和颗粒拔出等损伤。     

脉冲电化学及脉冲电化学机械光整加工工艺

介绍了脉冲电化学光整加工及脉冲电化学机械光整加工原理和工艺特点,分析了电化学加工表面和机械加工表面的微观几何形貌对零件的机械性能和使用寿命的影响,表明电化学加工表面的优越性,并对其精度特性进行了分析.     

砂轮约束磨粒喷射精密光整加工表面功率谱分析和摩擦磨损特性研究

对砂轮约束磨粒喷射精密光整加工微观形貌进行功率谱分析和摩擦磨损特性研究。利用平面磨床M7120对精磨后45#钢工件材料进行喷射精密光整加工;用TALYSURF5轮廓仪测量加工后的微观几何参数值;用扫描电镜观察表面微观形貌变化;用功率谱密度函数评价磨削加工和光整加工表面的微观形貌特征;利用MG-2000型销-盘式高速高温摩擦磨损试验机研究表面形貌对摩擦磨损的影响。结果表明,磨粒喷射精密光整加工均化和改善了工件表面的波纹度,降低了工件表面粗糙度值,提高了工件表面的形状精度;光整加工表面摩擦因数和磨损量与磨削加工表面相比明显降低,表面质量明显改善,从而提高了零件的使用寿命和精度保持性,摩擦磨损实验结果和功率谱密度分析相吻合。     

电化学修形对齿轮表面微观几何形貌的影响

对电化学修形前后齿面微观不平度高度特征参数和形状特征参数进行了测量和统计计算,研究了电化学加工表面平滑化对齿面摩擦、齿面闪温及润滑状态的影响。     

微观摩擦与表面形貌相关性的试验研究

针对微机电系统存在的问题，阐述了微摩擦的测试方法以及表面形貌对微机械中摩擦性能的影响，试验研究了表面形貌对介于宏观和微观之间摩擦行为的影响。试验用研磨的方法在硅片表面制作了不同宽度的条纹，通过UMT微摩擦测试仪研究了在不同速度和载荷下氮化硅陶瓷球和试样间的摩擦行为。试验表明，在硅片上制作出合适的条纹有助于降低摩擦系数，在低载低速下出现了测力梁突然释放弹性变形能的情况，使得摩擦力和载荷不稳定，而且随着表面条纹间距增大，这种现象的频率也越来越高，并通过理论分析解释了这些现象。     

夹心式复合加工表面形貌特征

对夹心式电化学机械复合光整加工设备进行了改进，通过工艺试验广泛地搜集了大量试验数据，确定了较合理的工艺参数。依据试验数据，多角度地研究了电化学机械复合光整加工的表面形貌特点，并从理论上深入讨论了电化学机械复合光整加工表面形貌对工件工作性能的影响，最后得出的结论为：电化学机械复合光整加工对工件原始表面的低频成分有较大程度的降低，而对高频成分影响较小，有明显的阳极整平作用，被加工工件表面的尖峰状凸起被去除，工件表面呈现出微观“高原型”，表面轮廓不平度高度特性参数大幅度降低，工件表面轮廓分布集中，且呈负偏态，轮廓偏斜度为负值，轮廓支承长度率曲线陡峭，工件的表面质量得到综合改善，这对提高零件的抗接触变形能力、改善摩擦、磨损性能、降低工件的磨合时间、提高工件的精度保持性、延长工件的寿命均有利。     

齿轮光整加工工艺及其新进展

提出了齿轮的表面质量对其使用性能和寿命有重要影响的观点，论述了齿轮精加工及光整加工的现状，详细介绍了非传统齿轮光整加工的原理及其表面质量特征，试验结果表明：齿面光整加工后寿命大幅度提高，噪声大幅度降低。     

45钢的摩擦磨损特性实验研究

采用自制的销盘式干滑动摩擦磨损试验机,研究了45钢配副的摩擦磨损特性.结果表明:材料的磨损率随着速度、载荷的增加而增大;摩擦系数随着速度、载荷的增加而减小.磨损机理主要为磨粒磨损和粘着磨损.     

脉冲电化学齿轮齿面光整加工实验研究

将脉冲电化学加工原理应用于齿轮齿面光整加工，建立了移动式成形阴极脉冲电化学齿面光整加工实验装置；研究了工作电流密度、阴极移动速度、扫描次数、电解液流速等工艺参量对加工质量及效率的影响，获得了较优的工艺参数；以模数为3mm、齿数为33的直齿圆柱齿轮为实例进行了光整加工实验研究。结果表明，该工艺不仅能在短时间内将齿面粗糙度大幅度降低，而且能显著增加齿面的光亮性。     

Aspheric surface finishing by fixed abrasives

This paper presents a method for the finishing of aspheric surfaces using fixed abrasives. The strategy is to remove a specified amount of material from the surface. The method assumes concentric tool paths perpendicular to the axis of the surface. The key parts of the method are: (1) efficient computation of the material removal profile for each tool path and (2) optimisation of the feed rate for the tool paths. Simulation results are included to illustrate the proposed method, which suggest that the method is potentially useful for aspheric surface finishing.     

Advances in friction and wear mechanisms

This review considers what inferences regarding the mechanism of wear can be derived from recent investigations into the functioning of machine elements operating under conditions representative of engineering practice. Among the subjects discussed are particle analysis, surface texture effects, stress system, thermal effects, chemical aspects of wear, and ehd effects     

Relationship between wear of friction materials and dissipated power density

Specific tribometric tests showed both the effect and relevance of the power dissipated by friction upon the transition from mild wear to severe wear for friction materials. The dissipated power density could be viewed as an important variable either to identify the critical wear characteristics of friction materials or to make comparisons among different types of friction materials. The scanning electron microscopy analysis showed some correspondence between the sliding surface morphology after the friction tests and the wear rate obtained. Moreover, the phenomena observed are related to known mechanochemical wear mechanisms.     

Fine friction cutting: a useful wear process

Friction cutting of metals was first reported almost 160 years ago. This review concentrates on its latest development, the slitting of nickel-chromium, titanium and ferrous alloys by toothless, water-cooled, mild steel discs spinning with a rim speed between 50 and 100 ms⁻¹. Slits an thin an 0.25 mm can be produced with little surface damage.Slitting occurs by adhesive wear. When oxidation leading to a mild wear state can be prevented, area slitting rates greater than 10 mm² s⁻¹ can be achieved: this is the case with nickel-chromium and titanium alloys and with soft or hardened stainless and tool steels. Oxidation cannot be prevented with carbon steels and most cast irons, so these metals cannot in general be slit usefully by fine friction cutting     

脉冲电化学光整加工工艺参数数据库设计

利用数据库技术建立了脉冲电化学光整加工表面质量参数与各主要工艺参量之间的复杂非线性关系,总结了脉冲电化学光整加工的基本工艺规律,为实现脉冲电化学光整加工的自动化控制做好铺垫。     

Interfacial potential barrier theory of friction and wear

An interfacial potential barrier theory to calculate friction and wear is proposed by considering the micro interaction of frictional surfaces. The theory suggests that the performance of friction and wear depends on the magnitude and distribution of the interfacial potential barrier on contact surfaces. The calculation methods of the interfacial potential barrier and standard interfacial potential barrier are then studied and the formulas to calculate the friction force, friction coefficient, and quantity of adhesion wear are derived based on the theory. With its independence and stability, the standard interfacial potential barrier can be used as an index to describe the frictional performance of materials. The calculation results of the friction force with some existing experimental data are consistent with the experimental results performed with an ultra high vacuum atomic-force microscope, which proves that the theory and method are feasible. __________ Translated from Tribology, 2007, 27(1): 54–59 [译自: 摩擦学学报]     

Plate-like wear particle formation in a lubricated ball-on-plate friction pair

The mechanism of formation of plate-like wear particles in a ball-on-plate lubricated friction pair has been examined for wear constants of K < 10⁻¹⁰ (mm³ mm⁻¹ N⁻¹). The plate Vicker's hardness was 2.80–3.00 kN/mm², the sliding speed 1.74 m s⁻¹ and the load 50 N. The following mechanism is suggested: scratching of the surface and formation of ridges at the scratch border, lateral deformation of ridges and formation of thin sheets, and cracking and separation of plate-like particles from these sheets.