【作者】 刘仁德；

【导师】 陶德华； 赵源；

【作者基本信息】 上海大学 ， 机械设计与理论， 2005， 博士

【摘要】 鉴于不含硫、磷元素的有机金属盐抗磨剂具有独特的摩擦学性能,开发高效的、环境友好的、油溶性有机金属盐类润滑添加剂越来越引起人们的重视。本论文对一系列油溶性有机羧酸金属盐（如环烷酸的稀土、锡、锌、镍、锰、钴、铅和铜盐及油酸亚锡、烷基水杨酸稀土等）的摩擦学特性进行了考察。研究表明它们大多具有良好的摩擦学性能,且稀土和锡盐之间具有摩擦学协同效应。通过能谱分析探讨了摩擦表面上的金属氧化物和还原金属对摩擦化学的作用机理。分析结果表明这些盐类在摩擦过程中的分解产物绝大部分为金属氧化物,而单质金属很难发现。为了进一步提高添加剂性能,并考察单质金属在摩擦过程中的真实贡献,文章以微乳化化学还原法成功地制备出表面修饰纳米金属粒子（包括纳米稀土、纳米铜和纳米铅）,并考察了它们的摩擦学性能与作用机理。此外,还对纳米稀土作为新型环保发动机油添加剂的应用前景进行了初步探讨。 所制备的表面修饰纳米金属粒子的团粒径均在40nm以下,其中金属核的粒径在10nm以下,它们在基础油中呈透明状液体,有极好的油溶性,在苯、甲苯等有机溶剂中有良好的分散性和分散稳定性。 纳米稀土添加剂具有优异的摩擦学性能。其最佳添加量为3.0%,此时最大无卡咬负荷（pB=647N）是基础油的3.30倍,磨斑直径(D_30min^294N=0.29mm)为基础油的45.3%,摩擦系数是基础油的87.5%。且它具有比二烷基二硫代磷酸锌（ZDDP）和环烷酸稀土（REN）更加优良的抗磨能力。在196、294、392和490N载荷条件下,纳米稀土的抗磨性能分别为ZDDP的1.24、1.52、1.37和1.15倍。能谱分析显示纳米稀土在边界润滑条件下促进了摩擦表面的氧化反应,其润滑保护膜中除了纳米单质稀土沉积膜外,还存在有因摩擦化学反应而生成的高价态铁的氧化物（主要为Fe₃O₄和Fe₂O₃）和稀土氧化物所组成的化学反应膜,这种厚度甚至超过24nm的复杂保护膜的出现是其具有优良摩擦学性能的主要原因。 采用纳米稀土添加剂试制出一种新型的不含硫、磷元素的环保发动机油,对其摩擦学性能和高温氧化安定性进行了初步的实验室考察,结果表明其抗磨和减摩性能明显优于市售成品油,其高温氧化安定性也达到了SF级发动机油的要求。 表面修饰纳米铜和纳米铅添加剂也具有一定的抗摩和极压性能。它们抗磨能力与相应有机羧酸金属盐的基本相当,但承载能力更高。能谱分析显示,纳米铜更多还原

【Abstract】 Since sulfur/phosphorus-free organo-metal compounds own particular tribological properties, it is an increasing tendency for scientists to develop oil-soluble, environmentally friendly and high effective lubrication additives. The tribological behaviors of a series of oil soluble organo-metal salts, such as rare-earth naphthenate （REN）, rare-earth alkylsalicylate （REA）, stannous naphthenate （SN）, stannous oleate （SO）, zinc naphthenate, nickle naphthenate, manganese naphthenate, cobalt naphthenate, lead naphthenate and copper naphthenate, are invested in this paper. Analytical results show that most of them possess good tribological properties and there are synergistic effects between orgno rare-earth and orgno-tin compounds. Auger electron spectrum （AES） ans X-ray photoelectron spectrum （XPS） analyses are used to study the contributions of metal oxides and elementary metals produced on the rubbed surface. It is found that most of the decompounded products of organo metal additives are metal oxides during the friction and wear process. In order to improve the tribological effects of such additives and invest the contribution of elementary metals in the friction process, surface modified nano metal particles, such as nano rare-earth, nano-copper and nano-lead, are prepared through micro-emulsification chemical reduce method, and their tribological characteristics and mechanisms are studied in this paper. Furthermore, the foreground of nano rare-earth used as additive of novel environmentally acceptable engine oil are evaluated too.The diameters of surface-modified nano-metal particles are below 40 nm, and the sizes of elementary metal nucleus of the particles are less than 10 nm. They show excellent oil solubilities and good dispersibilities in organic solvents such as benzene and toluene.Surface modified nano rare-earth additive exhibits excellent tribological properties in white oil. When the concentration of the additive is 3.0%, its load-carrying capability （P_B= 647N） increases to 3.30 times that of base stock, and its wear scar diameter (WSD, D^294N_30min =0.29 mm) value and friction coefficient reduce to45.3% and 87.5% that of base stock respectively. It exhibits better anti-wear capability than that of zinc dialkyldithiophosphate （ZDDP） and REN. At the load of 196, 294, 392 and 490 N, the anti-wear capability of nano rare-earth additive is 1.24> 1.52> 1.37 and 1.15 times that of ZDDP respectively. Surface analysis of worn scar indicates that nano rare-earth can accelerate the oxydation of the metal surface during the friction process. It is found that there are not only nano rare-earth particles but also rare-earth oxides and ferreous oxides composed mainly by Fe3O4 and Fe2O3 on the rubbed surface. The main reason of the excellent tribological performance of nano rare-earth additive attributes to the formation of such a complicated protection film that is even more than 24 nanometers in depth.Novel environmentally friendly engine oil with sulfur and phosphorus free is trial manufactured by using nano rare-earth as anti-wear additive, and its tribological behavior and oxidation stability are also invested in this paper. The experimental results show that its anti-wear and firction-reducing capabilities and oxidation stablility in high temperature are better than those of commercial products.Surface modified nano-copper and nano-lead additives also show certain anti-wear and load-carrying capacities. Their anti-wear capabilities are as good as that of corresponding organo metal salts, while their load-carrying capabilities are better. Surface analysis finds that there is a deposit elementary metal film that is 10-13 nm in depth formed on the worn surface under the boundary lubrication condition, which is the main reason to their good tribological properties.Oil soluble rare-earth alkylsalicylate, stannous naphthenate and stannous oleate are synthesized for the first time, and their tribological performances and tribochemistry reaction mechanisms are also invested in this paper.Rare-earth alkylsalicylate exhibits excellent load-carrying and anti-wear capabilities and good friction-reducing capability. When its concentration is 4.0%, itsWSD value （D294N 30min =0.3 lmm） and friction coefficient reduce to 48.4% and 78.0%that of base oil respectively, and its load-carrying capability （j）u = 598N) increases to 3.05 times that of base oil. Compared with ZDDP, rare-earth alkylsalicylate showsbetter anti-wear effect under the selected range of loads. At the load of 196, 294, 392 and 490 N, the WSD value of rare-earth alkylsalicylate is 87.1%, 70.5%, 61.5% and 46.7% that of ZDDP respectively.Analyses of AES and XPS show that there is a boundary film formed by organo metals, ferrous oxides, rare-earth oxides and elementary rare-earth on the worn surface. But the concentration of oxygen in the friction surface lubricated by organo rare-earth is far less than that lubricated by nano rare-earth additive. Such a rare-earth enrichment lubrication film is the main reason of good tribological performance of organo rare-earth compound.Both stannous oleate and stannous naphthenate show good load-carrying, anti-wear and friction-reducing capabilities under moderate and low load. Analytical results of worn scar surfaces indicate that there is a boundary lubricating film containing Sn and Fe elements formed on the rubbed surface. And Sn element exists as SnO and SnC>2 while the Fe element exists as ferreous oxides and organo-ferreous in the boundary film. It is their combined effects that lead to the good performance of organo-tin compounds.Analytical results show that there are lubrication synergisms existed in the anti-wear and friction-reducing capabilities between stannous naphthenate and rare-earth naphthenate. In the load range of 196—549 N, the WSD value and friction coefficient of the complex of rare-earth naphthenate and stannous naphthenate are less than that of lubricant containing only rare-earth naphthenate or stannous naphthenate. Analytical results of AES and XPS indicate that there is a boundary lubricating film containing organo metal, ferreous oxides, rare-earth oxides, rare-earth and tin oxides formed on the friction surface. The alloy effect between rare-earth and tin may be the main reason of the synergistic effect of organo rare-earth and organo-tin compounds.There are good oil solubility and excellent tribological properties in the combined additive RES2 containing rare-earth and tin When the concentration ofRES2 is 3.0%, its WSD value （D^n = 0 31mm） and friction coefficient reduce to 516% and 74 1% that of base stock respectively, and load-carrying capability {/)? —更多还原