S-N型润滑添加剂的合成及其摩擦学性能研究

合成一种新型环境友好型、无灰、非磷极压抗磨剂——含羟基二烷基二硫代氨基甲酸衍生物(DDCSD)。采用红外光谱仪对其结构进行表征,利用热分析仪考察其热稳定性,使用四球试验机及SRV考察其在复合锂基润滑脂中的摩擦学性能,并用扫描电子显微镜及X射线光电子能谱分析摩擦表面形貌及表面化学成分。结果表明,DDCSD具有良好的热稳定性,能有效提高基础脂的抗磨、减摩及极压性能,可作为多功能润滑油脂添加剂ZDDP的替代品。这是由于DDCSD在摩擦过程中发生化学吸附及摩擦化学反应,在金属表面上形成了一层具有抗磨减摩性能的边界润滑膜,从而起到抗磨减摩的作用。     

Tribological properties of grey cast iron lubricated using organic compounds containing Mo and ZnDTP additives

The lubricating effectiveness of organic compounds containing Mo and ZnDTP in different ratios in poly‐alpha‐olefin (PAO) was investigated using an Optimol SRV‐IV (Optimol Instruments, Munich, Germany) reciprocating friction and wear tester. The morphologies of the worn surfaces were observed using a scanning electron microscope with energy‐dispersive X‐ray spectroscopy. The chemical states of several typical elements on the worn surfaces of grey cast iron discs were examined by means of X‐ray photoelectron spectroscopy (XPS). The results indicated that the grey cast iron discs exhibited different friction‐reducing and wear‐resistance capabilities when lubricated with PAO containing MoDTP and ZnDTP additives in different ratios. The lowest frication coefficient is only 0.072. XPS analyses indicated that ZnDTP + MoDTP and ZnDTP + MoDTC formed different chemical products. Copyright © 2012 John Wiley & Sons, Ltd.     

Benzimidazolyl phosphates as anti‐wear additives in poly(ethylene glycol) for steel/steel contacts

Four novel benzimidazolyl phosphates (BPs) were synthesized and evaluated as anti‐wear additives in poly(ethylene glycol) for steel/steel contacts. The friction experiments were carried out on an Optimol SRV‐I oscillating reciprocating friction and wear tester (SRV) both at room temperature and high temperature. The worn surfaces of the steel discs were analysed by JSM‐5600LV scanning electron microscope and PHI‐5702 multifunctional X‐ray photoelectron spectrometer. It was indicated that poly(ethylene glycol) with 2 wt% BP additives had better friction‐reducing and anti‐wear properties than the commercial lubricant additive, tricresyl phosphate. Excellent tribological performance of BPs could be ascribed to the formation of high quality boundary films that consisted of the ordered adsorption films and tribo‐chemical reaction films. Copyright © 2013 John Wiley & Sons, Ltd.     

Tribological performance of poly(sodium 4‐styrenesulphonate) as additive in water–glycol hydraulic fluid

The tribological behaviour of poly(sodium 4‐styrenesulphonate) (PSS) as additive in the base fluid of water–glycol hydraulic fluid was evaluated with four‐ball machine and Optimol SRV‐IV (Optimol Instruments, Munich, Germany) oscillating friction and wear tester, and its viscosity‐enhancing performance was also investigated. The results show that PSS exhibits excellent friction‐reducing and anti‐wear properties in the base fluid and can significantly improve the latter's welding load and viscosity. The worn surfaces were characterised by scanning electron microscope and X‐ray photoelectron spectroscopy. The analytical results of typical elements on the worn surfaces demonstrate that PSS molecules adsorb on the rubbing surface and form a stable chemically absorbed film through the interactions between the sulphonate anions and surface metallic atoms during the sliding process, which contributed to improve the tribological properties of the base fluid. Copyright © 2012 John Wiley & Sons, Ltd.     

A study on tribological behaviours of ZDDP in polymer thickened lubricating greases

Zinc Dialkyl Dithiophosphate (ZDDP) is a well‐known multifunctional additive for soap based lubricating greases. Polymers are being studied for their performance as lubricating grease thickeners and rheology modifiers. In this work the tribological study of ZDDP was carried out in polypropylene (PP), maleated polypropylene (mPP) and linear low density polyethylene (PE) thickened lubricating greases. Performance of lithium grease was taken as a reference. The tribological properties were evaluated using a four ball tester for EP properties and Optimol SRV‐III machine for coefficient of friction. The mechanism of action of ZDDP in polymer greases was established through analysis of the worn surface of steel balls with scanning electron microscope (SEM) and energy dispersive x‐ray spectroscopy (EDAX). The results show that the performance of ZDDP depends on the thickener system. The antiwear and EP property exhibited by ZDDP varies from polymer to polymer. Poor performance was observed with PP type thickener whereas performance in PE and lithium grease was comparable. Copyright © 2015 John Wiley & Sons, Ltd.     

Tribological performance of an ionic liquid as a lubricant for steel/aluminium contacts

The wear and friction behaviour of an ionic liquid 1‐ethyl‐3‐hexylimidazolium tetrafluoroborate (L206) was investigated as a lubricant for steel/aluminium contacts using an Optimol SRV® oscillating friction and wear tester. The elemental composition and chemical nature of the antiwear films generated on the aluminium surface were analysed using a scanning electron microscope with a Kevex energy dispersive X‐ray analyser attachment (SEM/EDS) and X‐ray photoelectron spectroscopy (XPS). A low friction coefficient (˜0.05) was recorded when lubricating with L206; a small amount of water (5 wt. %) in L206 effectively reduced the wear volume and greatly increased the microhardness of the aluminium alloy, but had little effect on the friction coefficient. The SEM/EDS results showed that severe corrosive wear occurred on the aluminium alloy when lubricating with neat L206, which could be avoided by the addition of water in L206. The XPS results indicated that the species AlF₃, Al₂O₃, AlO(OH), and Al(OH)₃ formed during friction; there was no indication of boron on the worn surfaces.     

冠醚化合物对钢/铜和钢/铝摩擦副的抗磨减摩性能研究

本文利用ＳＲＶ摩擦磨损试验机研究了省代苯并－１５－冠醚对钢／铜、钢／铝摩擦副的摩擦磨损性能的影响。结果表明,溴代苯并－１５－冠－５冠醚对钢／铜摩擦副起到减摩抗磨作用,对钢／铝摩擦副起到加速腐蚀磨损的作用。利用ＸＰＳ对磨痕表面进行了分析,发现铜和铝磨痕上发现了Ｂｒ,金属溴化物的生成减少了铜的摩擦和磨损,但却由于腐蚀而加速了铝合金的磨损。     

Chemical structure of phosphazenes in relation to the tribological properties of a steel‐on‐steel system

The tribological behaviours of a steel‐on‐steel contact lubricated by three different fluids: (i) tetrakis(3‐trifluoromethylphenoxy)‐bis(4‐fluorophenoxy)‐cyclotriphosphazene (X‐1P), (ii) a synthetic bridged cyclotriphosphazene, and (iii) linear phosphazene derivative as base fluids were comparatively investigated on an Optimol SRV oscillating friction and wear tester. The results show that X‐1P records the lowest friction coefficient, and linear phosphazene oligomer gives the lowest wear volume loss of the steel among the investigated lubricants. Moreover, the bridged cyclotriphosphazene shows much better anti‐wear ability than cyclotriphosphazene (X‐1P) at both room and elevated temperatures. The worn surfaces were analysed by means of scanning electron microscopy, energy dispersive spectrometry and X‐ray photoelectron spectroscopy. The results demonstrate that the protective layer originated from the tribochemical reaction together with the adsorbed boundary lubricating layer containing organic F‐containing compounds; nitrogen oxide and FeF₂ played an important role in improving the friction and wear behavior of the steel‐on‐steel system. Copyright © 2009 John Wiley & Sons, Ltd.     

Study on the tribological properties of surfactant-modified MoS2 micrometer spheres as an additive in liquid paraffin

Tribological properties of MoS₂ micrometer spheres modified by self-prepared surfactant as an additive in liquid paraffin (LP) are studied and compared with those of the commercial colloidal MoS₂ on a four-ball tester and an Optimol SRV oscillating friction and wear tester. The worn surfaces are examined with SEM and XPS, respectively. Results show that MoS₂ micrometer sphere is a much better extreme-pressure additive and anti-wear and friction-reducing additive in LP than the commercial colloidal MoS₂. The boundary lubrication mechanism can be deduced as an effective chemical adsorption protective film formed by the long chain alkyl and active elements (S and N) in the prepared surfactant and tribochemical reaction film composed of the tribochemical reaction products of the additive. Moreover, sliding and rolling frictions exist simultaneously in the MoS₂ micrometer spheres /LP lubricating system, which also do more contributions to the good tribological properties.     

The Preparation and Tribological Investigation of Ni–P Amorphous Alloy Nanoparticles

Amorphous Ni–P alloy nanoparticles were synthesized by chemical reduction of nickel acetate in water reacted with sodium hypophosphite under stirring. The nanoparticles were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). Results of XRD and TEM showed that nanoparticles have an average diameter 100 nm. And XPS analysis indicated that part of the surface of Ni–P amorphous alloy nanoparticles was oxidized. The tribological properties of the prepared Ni–P nanoparticles as an additive in lithium grease were evaluated with a four-ball friction and wear tester. The worn surfaces of the lubricated GCr15 steel were analyzed by means of XPS and scanning electron microscopy (SEM). The lubricating mechanisms were discussed on the basis of XPS and SEM analyses of the worn steel surfaces. The results show that these nanoparticles as a grease additive can effectively enhance the friction-reduction and antiwear ability of lithium grease. Tribochemical reactions were involved for steel–steel frictional pair lubricated with the lithium grease containing amorphous Ni–P alloy nanoparticles, with the formation of a boundary lubricating and protecting film composed of additives of lithium grease and tribochemical reaction products (iron phosphate, iron oxides, nickel oxide, nickel, etc.) of the lubricants. This contributes to improve the tribological properties of the lithium grease.     

修饰ZnS纳米粒子的减摩抗磨性能研究

利用SRV摩擦磨损试验机考察了粒径约为4nm的二烷基二硫代磷酸（DDP）修饰ZnS纳米粒子作为润滑油添加剂的磨擦学性能，并采用XPS对其摩擦表面进行了研究。结果表明：添加修饰ZnS纳米粒子在摩擦过程中会发生摩擦化学反应，形成一层边界润滑膜，该膜可有效提高十四烷的减摩抗磨和承载能力。     

Tribological behaviour of protic ionic liquids with ammonium salts modified LABSA as lubricants and additives

Two typical protic ionic liquids with ammonium salts modified linear alkylbenzene sulfonic acid (LABSA) were synthesised, and their tribological behaviours used as both lubricants compared with PAO10 and additives in PAO10 were evaluated with an Optimol SRV‐I oscillating reciprocating friction and wear tester. The results show that the two novel protic ionic liquids with ammonium salts modified LABSA exhibited excellent friction‐reducing and anti‐wear properties as lubricants and can also significantly improve the tribological performance of the base fluids as friction modifier additives. The worn surfaces were characterised by scanning electron microscope and X‐ray photoelectron spectroscopy, indicating that the excellent anti‐wear and friction‐reducing performance could attributed to the boundary lubrication films that could contain both the tribochemical film composed of organic amine decomposed from the protic ionic liquids with ammonium salts and the stable chemical absorbed film through the interactions between the sulfonate anions and surface metallic atoms during the sliding process. Copyright © 2012 John Wiley & Sons, Ltd.     

The tribological behaviors of some rare earth complexes as lubricating additives Part 1. An investigation of the friction-reducing behaviors and an XPS study of the tribochemical characteristics

Several rare earth coordination compounds of 8-hydroxyquinoline and of di-n-hexadecyldithiophosphate were synthesized. The burnished films of these coordination compounds on a GCr15 bearing steel (SAE 52100 steel) disc were prepared. The friction-reducing behaviors of the burnished films were evaluated on a DF-PM friction tester. The friction-reducing behaviors of these complexes as additives in a lithium grease were examined on an SRV fretting wear tester. The binding energies of some typical elements in the complexes before and after friction were determined on an X-ray photoelectron spectrometer. It was found that these coordination compounds could form a quite complete burnished film on a GCr15 bearing steel surface. The lowest friction coefficient was obtained with respect to the burnished film of neodymium di-n-hexadecyldithiophosphate (NdDDP), while a decreased friction coefficient was reached with respect to the burnished film of rare earth 8-hydroxyquinolinate, as compared with the non-burnished friction pairs. Besides, the SRV fretting wear test results revealed that NdDDP in lithium grease exhibited better antiwear and extreme pressure properties than zinc di-n-butyldithiophosphate (ZDDP), while the antiwear and extreme pressure performance of rare earth 8-hydroxyquinolinates is comparable to that of ZDDP. The related results will be published in a following part of this work. The XPS results indicated that tribochemical reactions were involved in the wear process of these coordination compounds as lubricants or as lubricating additives. Here in the first part of this work, the friction-reducing behaviors of the burnished films and of the additives in a lithium grease are dealt with, while the XPS study of the tribochemical characteristics of these complexes is also reported.     

Tribological characteristics of bisphenol S bis(diphenyl phosphate) as a high‐performance antiwear additive in lubricating greases at elevated temperature

Bisphenol S bis(diphenyl phosphate) (BSDP) was synthesised and characterised, and its tribological behaviours as additives in polyurea grease and lithium complex grease were evaluated for steel/steel contact at 200 °C. The results indicated that BSDP could dramatically reduce the friction and wear of sliding pairs in the base grease of polyurea, and the tribological performances of BSDP in polyurea grease were significantly superior to the normally used molybdenum disulfide‐based additive package. Furthermore, BSDP in polyurea grease has better tribological behaviour than that in lithium complex grease at a constant load of 100 N. X‐ray photoelectron spectroscopy analysis indicated that boundary lubrication films composed of Fe(OH)O, Fe₂O₃, Fe₃O₄ and FePO₄ compounds containing the P–O bonds and nitride compounds were formed on the worn surface, which resulted in excellent friction reduction and antiwear performance. Copyright © 2016 John Wiley & Sons, Ltd.     

Effect of Ag nanoparticles additive on the tribological behavior of multialkylated cyclopentanes (MACs)

Monodisperse Ag nanoparticles with a particle size of about 6–7 nm and low volatile multialkylated cyclopentanes (MACs) lubricant were prepared. The effect of Ag nanoparticles as additive in MACs base oil on the friction and wear behavior of MACs was investigated. The friction and wear test of a steel disc sliding against the same steel counterpart ball was carried out on an Optimal SRV oscillating friction and wear tester. The morphology and elemental distribution of the worn surface of both the steel ball and steel disc and the chemical feature of typical element thereof were examined using a JEM-1200EX scanning electron microscope (SEM) equipped with a Kevex energy dispersive X-ray analyzer attachment (EDS) and X-ray photoelectron spectroscope (XPS), respectively. Friction and wear test indicates that the wear resistance and load-carrying capacity of MACs base oil were markedly raised and its friction coefficient changed little when 2% Ag nanoparticles were added in it. Results of SEM/EDS and XPS show that Ag nanoparticles were deposited on the friction pair surfaces to form low shearing stress metal Ag protective film in rubbing process.     

Friction and wear behaviors of aluminum-on-steel under the lubrication of grease containing a complex of lanthanum dialkyldithiocarbamate and phenanthroline

A complex of lanthanum dialkyldithiocarbamate and phenanthroline was synthesized, and its lubricating and antiwear behaviors as an additive in lithium grease were evaluated using a Timken tester with a SAE52100 steel ring sliding under an A1 2024 block. As a comparison, the wear behavior of a steel-on-steel system under the lubrication of the same grease was also investigated under the same test conditions. The protective film formed on the rubbed surface of aluminum was investigated by both XPS and AES. Results of friction and wear tests indicate that this rare earth complex possess good antiwear ability for aluminum, and its antiwear and friction reduction properties for the aluminum-on-steel system is even superior to that for the steel-on-steel system. The results of AES and XPS analyses illustrate that the prepared La complex as an additive in lithium grease forms a protective film containing lanthanum oxide, aluminum sulphide, and an organic compound containing sulfur and nitrogen on the rubbed surface of aluminum.     

Friction and wear behaviour of Sialon/ (Ca,Mg)‐Sialon with lubrication by coated PbS nanoparticles as oil additives

The friction and wear behaviour of Sialon/(Ca,Mg)‐Sialon with lubrication by liquid paraffin containing PbS nano‐particles coated with dialkyldithiophosphate or oleic acid as additives was investigated using an SRV ball‐on‐disc test rig. It was found that the addition of such nanoparticles reduced the friction coefficient of the friction couple irrespective of the concentration of the additive and the wear volume of (Ca,Mg)‐Sialon, especially under relatively high loads such as 150 N or more. X‐ray photoelectron spectroscopy and electron probe microanalysis revealed that a tribochemical film composed of PbSO₄, PbS₂O₃, PbSO₃, etc., was formed on the worn surface, and contributed to the lubricity of the PbS nanoparticles.     

Effect of tetraalkylphosphonium based ionic liquids as lubricants on the tribological performance of a steel-on-steel system

A series of asymmetrical tetraalkylphosphonium ionic liquids were synthesized and evaluated as a new kind of lubricant for the contact of steel/steel using an Optimol SRV oscillating friction and wear tester in ambient condition. The phosphonium ionic liquid shows excellent tribological performance when being used as the lubricating oil, and is superior to the conventional high temperature lubricants X-1P and perfluoropolyether (PFPE) in terms of anti-wear performance and load-carrying capacity. The chemical compositions of the boundary film generated on different contact surfaces were analyzed on a scanning electron microscope with a Kevex energy dispersive X-ray analyzer attachment (SEM/EDS) and X-ray photoelectron spectrometer (XPS). The friction–reduction and anti-wear mechanism of tetraalkylphosphonium as the lubricant were proposed to originate from the active elements P in the tetraalkylphosphonium ionic liquids reacting with the fresh surface to form a reaction film onto specimen surface, an extreme-pressure film with lower shearing strength, which leads to lower friction coefficient, and good wear resistance.     

Tribological evaluation of α, -diimidazoliumalkylene hexafluorophosphate ionic liquid and benzotriazole as additive

Ionic liquids of α, -diimidazoliumalkylene hexafluorophosphate were synthesized. The tribological properties of the synthetic ionic liquid and the ionic liquid contained additive for contacts of steel/steel were investigated by Optimol SRV oscillating friction and wear tester under ambient conditions. The synthetic ionic liquid presented low friction coefficients and small wear volumes, especially under higher temperatures. The ionic liquid doped with benzotriazole (BTA) showed excellent anti-wear ability. The worn surfaces and chemical nature of the boundary films generated on the metal surfaces were analyzed by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). SEM results showed slight abrasion on the worn surfaces and XPS results indicated the formation of FeF₂, FeF₃, Fe₃O₄, and FePO₄ by the tribochemical reactions of ionic liquid with iron during the sliding process.     

The mechanism of synergism between ZDDP and CeF3 additives

The interaction of zinc dialkyldithiophosphate (ZDDP) with cerium fluoride and cerium dioxide in lithium grease has been studied for friction, wear, and EP characteristics on a four-ball and SRV tester. The combination of ZDDP and cerium trifluo-ride has been shown to be beneficial in reducing wear, especially over a long period of friction and with increasing EP load. The test results show that adding cerium dioxide to lithium grease does not improve the antiwear and friction performance of the paste. The analytical results of X-ray photoelectron spectrum (ESCA, XPS) reveal that ZDDP inhibits the decomposition of cerium fluoride and improves its film-forming property. The wear scar reaches a minimum at an atomic concentration ratio of 3P:2Zn:1S:25F, and an atomic concentration ratio of 2S:2P:1Zn:4F gives the highest EP load. The scratch test results show that combining ZDDP with cerium trifluoride improves the tenacity of the surface film. The stabilisation of cerium trifluoride by ZDDP is proposed.