粉末冶金零件生产用润滑剂的性能改进与选择

在粉末冶金零件生产中,压制成形与脱模过程中都需要进行润滑,最常用的方法是将润滑剂添加于金属粉末的预混合粉中。润滑剂的类型不仅影响粉末的压制性能,而且影响混合粉的其他性能和零件的生坯与烧结性能。评述了最常用的润滑剂的使用性能,并介绍最近20多年来粘结剂/润滑剂系统的性能改进与进展。     

添加剂对航空润滑油橡胶相容性的影响

采用满足MIL-PRF-23699F规范中航空发动机润滑油要求的季戊四醇酯为基础油，研究了3种抗氧剂和3种极压抗磨剂对航空润滑油橡胶相容性的影响。结果表明：磷酸酯极压抗磨剂使丁腈橡胶的体积变化率增大，其他添加剂对丁腈橡胶的体积变化率无显著影响；极压抗磨剂对氟橡胶的体积变化率几乎没有影响，而抗氧剂使氟橡胶的体积变化率有微弱的减小；胺类添加剂在酯类润滑油中对氟橡胶拉伸性能无显著影响；酸性磷酸胺极压抗磨剂使硅橡胶体积发生收缩，使氟硅橡胶的体积变化率减小；酸性磷酸胺极压抗磨剂与硅橡胶和氟硅橡胶可发生化学反应，使橡胶的拉伸性能大幅下降。     

Catalytic polymerization of 1-decene using a silicon-bridged metallocene system

The polymerization of 1-decene catalyzed by rac-Me₂Si(1-indenyl)₂ZrCl₂/AlⁱBu₃/[C₆H₅NH(CH₃)₂][B(C₆F₅)₄] system with hydrogen has been carried out in the paper. The influence of reaction conditions on catalytic activity and polymer properties was investigated. High activity (17.2 × 10⁶ g molZr^?1 h^?1) was observed under the optimized reaction conditions. The introduction of hydrogen enhances the catalytic activity of the metallocene system. The ¹H NMR spectra revealed the polymerization mechanism with the presence of hydrogen. The ¹³C NMR spectra of poly(1-decene) indicated that the polymer has a very tactic side chain structure, showing potential application of the system in the commercial production of lubricant base oil.     

Performance analysis of a fully textured hybrid circular thrust pad bearing system operating with non-Newtonian lubricant

The present paper deals with the theoretical investigation of the influence of dimple geometry on fully textured hybrid thrust pad bearing and operating with non-Newtonian lubricant. The modified Reynolds equation which governs the flow of non-Newtonian lubricant in the clearance space has been solved using Finite Element Method. The simulated results indicate that the values of load carrying capacity, frictional power loss, maximum pressure and fluid film stiffness coefficient are significantly affected by the behavior of lubricant. The results presented in the study are expected to aid in determining the optimum value of dimple diameter and depth for the optimum bearing performance.     

Performance of supercritical carbon dioxide sprays as coolants and lubricants in representative metalworking operations

This paper investigates the cooling and lubrication properties of supercritical carbon dioxide (scCO₂) sprays as potential substitutes for aqueous emulsions and straight oils used in the metalworking industry today. Sprays of rapidly expanding scCO₂ act to cool and lubricate machining and forming processes by delivering a mixture of dry ice and lubricant deep into the cutting/forming zone. In this work, experiments with turning, milling, drilling, thread cutting, and thread forming were performed with scCO₂ and other metalworking fluids (MWFs) to evaluate their relative performance with respect to tool wear and machining torque. Observations reveal that scCO₂–MWFs are more effective in removing heat from the tool-workpiece interface than conventionally delivered (flood) aqueous MWFs as well as other gas-based MWF sprays. In addition, scCO₂–MWFs delivered in lubricant-expanded phase, where scCO₂ is used to increase volume of lubricant in the spray field, are shown to provide better lubricity than straight oils and oil-in-air minimum quantity lubrication (MQL) sprays. As a result, scCO₂–MWFs can reduce tool wear and improve machining productivity in a wide range of manufacturing operations leading to appreciable improvements in the economics of manufacturing. Also given that CO₂ is a recovered waste gas that is non-toxic, scCO₂–MWFs can improve the environmental and worker health performance of manufacturing operations.     

聚α-烯烃合成油及其加氢工艺的研究进展

聚α-烯烃合成油是所有合成润滑油基础油中性能最优异的一种,具有黏度指数高、低温性能和高温氧化安定性好、抗燃性好及挥发性低等优点,是未来应用广泛的合成基础油,市场需求持续增加。综述聚α-烯烃基础油及其加氢工艺、加氢精制催化剂的研究现状。传统聚α-烯烃合成油生产工艺有乙烯齐聚法和石蜡裂解法等,潞安煤制油工艺和天然气制油工艺等新工艺也开始兴起。加氢精制工艺对提高聚α-烯烃合成油的质量起着至关重要的作用,北京燕化聚华工贸有限公司两段加氢精制工艺和中国石油兰州润滑油厂聚α-烯烃合成油加氢精制处理工艺均极大改善了聚α-烯烃合成油的质量。聚α-烯烃合成油加氢精制效果很大程度取决于加氢精制催化剂性能,要求加氢精制催化剂具有较高的选择性和较好的稳定性。     

Tribological Properties of Functionalized Ionic Liquids Containing Ester-group as Lubricants for Steel-Steel System

A series of functionalized ionic liquids (ILs) containing ester-group were synthesized and their tribological properties as lubricants for steel-steel contact were studied and compared with a non-functionalized ionic liquid and perfluoropolyethers (PFPE). The morphology and chemical composition of the worn scars were analyzed by scanning electron microscopy and X-ray photoelectron spectroscopy, respectively, and the possible lubrication mechanism of ILs was discussed. As a result, all ILs demonstrated a better lubricity and a much higher load-carrying capacity than PFPE used as lubricants for the steel-steel tribomates system. The functionalized ILs with ester-group showed slightly worse friction reducing ability than their nonfunctionalized counterparts at relatively lower loads owing to their higher viscosity, but then exhibited better antiwear ability because the ester group they contained had not only physical but also strong chemical reactions with the freshly exposed steel surface and formed chemical adsorption boundary films on the worn surface during friction process. Under high loads, some tribochemical reactions took place between the active elements, such as fluorine which were released from the ILs, and fresh metal surfaces of rubbing pairs to form the admixture reaction films, which were mainly composed of ferric fluoride mixed with ferric oxide, leading to lower friction coefficients and good wear resistance.     

复合Al_2O_3-SiO_2纳米颗粒的摩擦学性能研究

以硅烷偶联剂为改性剂对复合Al2O3-SiO2纳米颗粒进行原位改性,实现其在润滑油中均匀稳定的单分散。将改性后的复合Al2O3-SiO2纳米颗粒分别按质量分数为0、0.05%、0.1%、0.5%、1.0%的量加入到润滑油中制成试样,进行四球试验和止推圈试验。对摩擦实验中的摩擦系数、磨斑直径、磨损量、摩擦副表面形貌进行分析。结果表明:当复合Al2O3-SiO2纳米颗粒添加质量分数为0.5%时,摩擦系数和磨斑直径最小,止推圈的磨损量出现负磨损,摩擦表面的磨痕明显的变浅、变窄。说明摩擦过程中,复合Al2O3-SiO2纳米颗粒沉积在摩擦副表面,形成一层保护膜有效的保护了摩擦表面,抗磨减摩作用显著。     

平整废液芬顿试剂氧化试验研究

平整废液是带钢冷精轧过程中产生的一种废液,是一种较难处理的高浓度有机废水,其生化性较差,传统的生物处理难以奏效,对于此类废水,国内外尚无成熟的处理工艺。采用芬顿（Fenton）氧化工艺对某公司生产的平整液进行了试验研究,研究了初始pH值、硫酸亚铁投加量、H2O2投加量以及混凝pH值等因素对COD去除效果的影响。通过试验研究,确定了反应温度、初始pH值、FeSO4和H2O2投加量等最佳处理工艺条件。在最佳处理条件下,COD去除率可达56%,同时BOD5/COD由0.17提高到0.48,废水的可生化性得到明显改善,可以满足后续生化处理的进水要求。     

润滑剂含量对钛粉高速压制性能的影响

采用高速冲击压机压制钛粉,研究润滑剂含量对压坯性能的影响.结果表明:加入适量的润滑剂可以提高钛粉成形时的质量能量密度,从而获得更高密度的压坯.当润滑剂加入量为0.3%(质量分数)时,钛粉成形的最大质量能量密度为0.192 KJ/g,压坯密度为4.38 g/cm3,相对密度为97.4%.此外,适量的润滑剂能提高钛粉压制过...