bluuebunny/crossref_metadata_2025_split huggingface dataset:
The tribology of plastics — an overview
Authors: Wang Chenghe 
Published: July 2006

AbstractWith the widening use of plastics, it has become an urgent task to study their behaviour in friction systems. The present paper reviews the applications of plastics during the past decades and their function in friction systems. The paper analyses the basic differences between metals and plastics in structure and properties, and points out the limitations, or inapplicability, of using metal tribology to solve problems in plastic friction systems when even different kinds of high‐molecular materials have different shapes and applications.The paper also looks at the variety of plastic surfaces, and briefly presents the mechanism, theory, and calculation of the fiction, wear, and lubrication of plastics; theories of plastic wear are summarised. Also presented are the technical functions, simple application techniques, and economic benefits of plastic friction systems.
Determination of synthetic lubricant concentrations in soil during laboratory‐based biodegradation studies
Authors: Haigh Susan D. 
Published: July 2006

AbstractThe use of synthetic, biodegradable lubricants for two‐stroke engines has become widespread due to increased concern over the build‐up of hydrocarbons, derived from mineral oil‐based lubricants, in the aquatic environment. A method for assessing the biodegradation potential of new lubricants was developed by the Co‐ordinating European Council (CEC) for the Development of Performance Tests for Lubricants and Engine Fuels in 1982. However, this method deals only with the aquatic environment. The use of such lubricants in agricultural machinery led to a modification of the CEC method to assess the relative biodegradability of lubricants in soil. After incubation of oil‐treated soil in a simple and inexpensive incubation assembly, samples were extracted with solvent and the level of lubricant determined by infrared spectroscopy. The method was found to be both accurate and reproducible, giving excellent recoveries. It compared favourably with a gravimetric method and was so sensitive that it gave appreciable blank values from untreated soils owing to their content of long chain aliphatic natural products. The incubation and extraction methods were used successfully to assess the biodegradability of a range of synthetic lubricants in soil in comparison to a mineral oil‐based lubricant and a natural vegetable oil. The synthetic oils were found to degrade more rapidly and extensively than the mineral oil‐based lubricant but not as rapidly or extensively as the vegetable oil. Amendment with nitrate considerably enhanced the loss of all the oil tested, indicating the importance of nitrogen availability when assessing the inherent biodegradability of hydrocarbons in soil. As the data generated is from laboratory‐based studies the results do not necessarily translate directly to the field situation. However, the method is suitable for screening new materials and for comparative purposes.
Investigation of biomass formation during the biodegradation of ester base lubricants
Authors: Hund K. , Grolms U. , King J. M. H. , Bünemann T. 
Published: July 2006

AbstractComparative studies were performed to assess the biodegradation of the synthetic lubricant base stock, Priolube 3999, by P. putida using the CEC test method and manometric respirometry. Supplementary analyses demonstrated the production of a non‐readily biodegradable metabolite, trimethylol‐propane, the alcohol group of the candidate fluid. Evidence was obtained that indicated that a significant fraction of carbon added as test substance remained incorporated in the biomass. The implications of these results are discussed and modifications to the CEC test proposed.
Effects of solid lubricants in backward extrusion
Authors: Nakamura Tamotsu , Saiki Hiroyuki , Nkk Naoki Ikeuchi , Ishibashi Itaru 
Published: July 2006

AbstractIn the present paper, some solid lubricants were tested in backward extrusion friction tests with flat‐headed punches using aluminium at room temperature. The results showed that anti‐seizure ability was improved when wax was added to the solid lubricant samples. In addition, a water‐based graphite lubricant and an ultrahigh molecular weight polyethylene (UHMW‐PE) lubricant were tested using aluminium workpieces heated to 500°C. The lubricity of the UHMW‐PE lubricant was found to be superior to that of the graphite lubricant.
Tribological performance of PBT/PC/TPE ternary polymer alloy
Authors: Lin Heng Yao , Holmberg Kenneth , Säynätjoki Matti 
Published: July 2006

AbstractPolybutylene terephthalate (PBT)/Polycarbonate (PC)/thermoplastic elastomer (TPE) ternary polymer alloy (TPA) is one of a new generation of PBT based polymer alloys with good thermal conductive, mechanical, and physical properties. TPA‐59 was chosen as representative material factorially‐de‐signed experiment and has been studied, in the present work, to evaluate its potential as a tribological material. Its sliding, friction, and wear behaviour under unlubricated conditions was investigated with a pin‐on‐disc machine using various loads, sliding velocities, sliding distances, and disc surface roughnesses. The specific wear rates were found to be comparable to those of commercial materials currently used in bearings.
Structure—activity correlations for sulphur EP additives
Authors: Herdan J. M. , Valeanu Gabriela , Popescu A. 
Published: July 2006

AbstractA series of new sulphur compounds was synthesised. Mercaptoheterocycles and mercaptoethanol were reacted with C12‐C22 chloroacetates. Mercaptoethanol derivatives were subsequently reacted with trialkyl borates. The solubility of S‐methylcarbalcoxy derivatives in both mineral oil and synthetic esters strongly depended on the alkyl group length, the most soluble being the C12. C14 derivatives. Three tests were used to estimate the antiwear (AW) and extreme pressure (EP) performance of the sulphur compounds: a four ball machine, an LFW‐I machine, and a Falex tester. Despite some differences resulting from the test methods, the best EP characteristics were obtained with the 2‐mercaptobenzothiazole derivatives. This showed that even a strongly bonded sulphur atom, such as that of the thiazolic ring, participates in surface layer formation. Mercaptoethanol derivatives were less soluble in either mineral or ester‐based synthetic oils. Esterification of the hydroxyl groups with trialkyl borate improved their solubility and load carrying performance.
On sliding friction and wear of polyetheretherketone (PEEK) composites at elevated temperatures
Authors: Lu Z. , Friedrich K. , Küntzler B. 
Published: July 2006

AbstractThe friction and wear behaviour of polyetheretherketone (PEEK) composites, incorporating different amounts of short carbon fibres with different surface treatments, was studied under dry sliding conditions against smooth steel on a pin‐on‐disc apparatus at different temperatures. Wear of the composites was reduced considerably in all cases, but, whatever the surface treatment, wear increased with increasing temperature for all proportions off fibres. For minimum friction coefficient there was an optimum proportion of fibre volume fraction of about 10 vol.%. The effect of the fibre surface treatment was not significant for the tribological behaviour of the PEEK composites. To predict wear performance, a wear model proposed by Friedrich and Voss seemed to work properly, and, furthermore, a friction model was developed to predict the friction behaviour of PEEK composites with short carbon fibres.
An approach to characterisation of producibility and lubricity of reacted films under boundary lubrication
Authors: Jin Y. S. , Zhou C. H. 
Published: July 2006

AbstractBoundary oil films can be transformed into reacted films during an extremely short period of time under certain conditions of reactive dynamics. A comprehensive index R is introduced to characterise the producibility and lubricity of the reacted films. Index R, which is calculated using maximum and minimum friction coefficients in the formation process of the reacted films as well as from the reacting and maintaining periods of the films, is correlated to conditions of reactive dynamics, such as temperature, pressure, and velocity.
Reduction of the roll force during lubricated cold rolling of aluminium strips
Authors: Zhang S. , Lenard J. G. 
Published: July 2006

AbstractLubricants, especially blended for cold rolling of aluminium, have been studied in terms of their effects on the roll‐separating forces during the process. Synthetic and mineral oils, with and without additives, were investigated. Two general observations are made. The first concerns the roll force in the pass, averaged over the length of the workpiece. The second deals with the variation of the force as the process continues. In both cases, the roll‐separating forces change in noticeable ways, depending on the lubricant. Tests, designed to identify some of the causes of these changes, were conducted. It was found that the effect of the lubricants on the roll‐separating forces can be divided into three groups. The forces measured while using the synthetic ester based oil, with or without additives, decreased as the rolling process continued. The forces with the other base oils without additives increased slightly or remained essentially unchanged with additives. The changing lubrication conditions in the roll gap are expected to cause the variations of the roll forces.
A new engine oil optimised for ecologically sensitive operational areas
Authors: Baumann W. , Böhme W. , Hubmann A. , Zeiner W. 
Published: July 2006

AbstractIn recent years, environmental awareness and legislation have focused public attention on vehicle emissions. Consequently, more research has been devoted to emissions and pollution by lubricants. A number of studies has been carried out to understand lubricant‐related emissions and leak rates as well as the effects on fuel economy of using low viscosity grades of lubricant. The purpose of the present investigation was to develop for use in gasoline and diesel engines a crankcase lubricant which contained improved performance in engine cleanliness with fuel economy and a low rate of particle emissions. Emphasis was placed on low toxicology and rapid biodegradability because of the risk of unintentional emissions. Such a sophisticated lubricant is desirable not only for normal road vehicles but also and especially for use in ecologically sensitive areas.During the development of this lubricant, numerous laboratory tests were performed. In order to assess the quality and the fuel economy of the new lubricant, tests were carried out on an engine test rig and on a vehicle test bench. Field tests were run with various vehicles and stationary engines, using different fuel types. Unleaded gasoline, diesel fuels with a varying sulphur content, and rape seed oil methyl ester (RME) were used. This paper summarises the results of this investigation.
Effects of surrounding atmosphere on the formation of carbon films at 450°C
Authors: Zhou Chunhong , Jin Yuansheng , Wen Shizhu 
Published: July 2006

AbstractThe object of the present work is to present the results of research into the effects of surrounding atmosphere on the formation of carbon films by lubricating oil cracking at 450°C. The following six kinds of surrounding atmospheres were used: O2(5%), O2(95%), O2(70%), O2(50%), O2(20%) (with the remainders N) and air. Cr2O3 and Mo alloy coatings were selected as friction pair materials and a synthetic ester oil as lubricant. The experimental results on a SRV test machine showed that solid carbon films could be generated only in the atmosphere with a certain O2 content. No valid carbon films were generated in surrounding atmospheres rich in nitrogen and oxygen. Surface analyses with SEM, WDS, XPS and X‐ray diffraction indicated that graphite films with excellent solid lubricating effect resulted from the catalytic cracking of the hydrocarbon components in the lubricating oil at high temperature in the air atmosphere after the failure of fluid lubrication.
Improved maintenance and life extension of phosphate esters using ion‐exchange treatment
Authors: Phillips W. D. , Sutton D. I. 
Published: July 2006

AbstractThe present paper investigates the mechanism of degradation of triaryl phosphate esters and the methods that have been used to control this. A new chemical process, based on ion‐exchange resin treatment, is examined, including an evaluation of the behaviour of different resins in laboratory tests. Trial runs, notably in conjunction with a system of vacuum dehydration, have given extremely promising results.
Ester base stocks for synthetic lubricants
Authors: Vilics T. , Ciorbagiu F. , Ciucu B. 
Published: July 2006

AbstractThis paper reports on work on the synthesis and characterisation of mixtures of aliphatic adipates with complex esters based on polyols, adipic acid, and monohydroxy alcohols, in order to formulate new synthetic base stocks. The viscosity and pour point values of these mixtures are higher than those of adipates. Both of these physical properties become greater with the increasing molecular weight of the complex ester or of the ester's concentration in the mixture.
R‐134a compatible lubricants based on C4‐C6 esters of pentaerythritol and polyalkyleneglycol
Authors: Gryglewicz S. , Beran E. , Janik R. , Steininger M. 
Published: July 2006

AbstractThe results of work intended to produce inexpensive, synthetic lubricants compatible with R‐134a using waste carboxylic acids C4‐C6 as the base are presented in this paper.The suitability of the products synthesised was first evaluated considering their physical and chemical properties, and their thermostability determined by the standard Philipp test (sealed glass tube method). Two ester bases were then selected for further testing — a pentaerythritol esterified with C4‐C6 monocarboxylic acids and a polyalkyleneglycol similarly esterified with monocarboxylic acids C4‐C6.The base oils chosen were tested for their corrosive action on metals in the presence of water in different concentrations. The pentaerythritol ester proved to have the most advantageous properties at that stage. The results of the laboratory tests have been corroborated by trials conducted on real refrigerating compressor systems. Only the lubricant that was obtained using pentaerythritol esterified with monocarboxylic acids C4‐C6 as the base withstood the severe test.
Some experience with biodegradable lubricants
Authors: Legisa I. , Picek M. , Nahal K. 
Published: July 2006

AbstractA significant amount of lubricating oils and greases can enter the environment, producing contamination of both soil and water. Over the last few years, pressure on lubricant producers and consumers has caused them to seek a solution involving less environmentally harmful lubricants. In Croatia, a significant quantity of lubricants is disposed of without control, polluting soil and water; as a result, lubricant producers have looked seriously at biodegradable lubricating oils and greases.This paper presents information on development of some biodegradable hydraulic oils and lubricating greases based on lithium and calcium soaps, using synthetic esters and rapeseed oil, and presents their physical and chemical properties, and their applications.
Tribological behaviour of polymeric coatings lubricated with salt water
Authors: Mousa Mohamed O. 
Published: July 2006

AbstractIn many applications, such as marine industries, pumping of underground water, and in some chemical industries, sliding elements are lubricated with the process fluid (e.g. salt water). Therefore, the effect of salt water on the tribological behaviour of metallic friction couples has been a subject of study. In the present work, the influence of salt water solution (3 wt. % sodium chloride) on the tribological behaviour of some polymeric coatings is investigated, using a pin‐on‐disc testing machine, at different sliding speeds and normal loads. The coating consists of a base‐matrix of high‐density polyethylene (HDPE) and polyamide (PA6) with different concentrations of copper‐ and tin‐powder fillers. The effect of the formation of the oxide films, sodium hydroxide microlayers (NaOH) and the polymeric transformed films on the friction mechanism, is discussed. The results show that squeeze of the lubricant takes place in the presence of the NaCl‐solution; and, despite the relatively low viscosity of the lubricant, hydrodynamic pressure affected the friction mechanism at the sliding speed of 0.50 m/s, resulting in a significant reduction in the coefficient of friction. The value of the coefficient of friction seems also to be affected by the generation of sodium hydroxide, as well as the oxide films and material transfer layers. At a low speed (0.20 m/s), the PA6‐based composites with copper‐filler showed an optimal wear resistance at normal loads up to 15N.
Miscibility and stability of synthetic lubricants with HFC refrigerants
Authors: Wu Wei‐Te , Thomas Raymond H. P. 
Published: July 2006

AbstractThe phase‐out of CFC production and further regulations on HCFC are required because of their association with the depletion of stratospheric ozone. HFCs and their mixtures have evolved as long‐term replacements for CFCs and HCFCs. For air conditioning and refrigeration systems, new synthetic lubricants having miscibility with HFC refrigerants, similar to that of mineral oils with CFCs, have been developed. Data on the miscibility ofR‐32/125 and R‐125/143a with polyol ester lubricants are presented in this paper. In the temperature range of interest (−40°C to 60°C), we observed the upper immiscible region, lower immiscible region, as well as the coalescence of the two regions, for polyol ester lubricants with these HFC refrigerant mixtures. HFC‐143a is least miscible among the three pure HFC refrigerants. The stability of R‐32/125 and R‐125/143a with dry polyol ester lubricants is very good at 204° C. With high moisture content, hydrolysis of the lubricant occurs at high temperatures. The onset of significant hydrolysis of lubricant (B) takes place between 175°C and 200°C. Care must be exercised to maintain the dryness of polyol ester lubricants and refrigeration systems to prevent this occurring.
An investigation of the effect of the lubricant on the soluble organic fraction of particulate emissions from a DI diesel engine
Authors: Schramm Jesper , Hori Shigeo , Abe Tsugio 
Published: July 2006

AbstractThis paper looks at the effect of the lubricant on emissions of paniculate matter. A short literature review is presented, together with experimental results for an engine operating with a synthetic lubricant and a defined fuel. The influence of engine operating parameters such as engine load and speed on particulate matter (PM) emissions is discussed, based on measurement of the composition of the aliphatic fraction of the soluble organic fraction (SOF) of the PM. Based on the results from the experiments, which include some comparative data for a mineral‐based lubricant, it is concluded that the method that is generally used to estimate fuel and lubricant contribution to the SOF of the PM has to be reconsidered.
Structure effect of refrigeration polyolester oils for use in HFC‐134a compressors
Authors: Remigy J.‐C. , Nakache E. , Brechot P. D. 
Published: July 2006

AbstractA study of polyolester oils (POE) for compressors using an ozone‐friendly refrigerant is presented here. The effect of the chemical structure of POE was studied in relation to three lubricant properties: miscibility with HFC‐134a (CF3‐CH2F), lubricity (steel‐on‐steel and aluminium‐on‐steel contacts), and viscosity. The paper shows the strong structure effect of POE on miscibility and lubricity. Based on the data obtained, some model lubricants were blended, and the performance of these lubricants was assessed on refrigeration test rigs.
Synthesis and hydrolytic stability of aqueous antiwear agents of organic phosphate and organic thiophosphate
Authors: Feng Lin , De‐hua Tao , Zhi‐cai Wang , Cheng‐lei Li 
Published: July 2006

AbstractIn the present paper, the two aqueous antiwear agents, zinc salts of longchain polyoxyethylene glycol phosphate and of long‐chain polyoxyethylene glycol thiophosphate (ZOP and ZTP), have been synthesised. Using a fourball tester, their antiwear properties were investigated in high water‐based fluids. The four‐ball test results showed that the antiwear property of the ZOP additive was better than that of ZTP, while its load‐carrying capacity was slightly lower than that of ZTP. The effects of the addition of triethanolamine (TEA) and hydrolytic stability on their antiwear properties were also studied. The antiwear properties of ZOP and ZTP increased as a result of the addition of triethanolamine. The hydrolysis stability directly affected their antiwear properties. Lastly, the elemental composition of the wear‐scars were investigated using Auger Electron Spectroscopy (AES).
Test methods to judge the eco‐compatibility of lubricants
Authors: Szabó Julianna Bérci 
Published: July 2006

AbstractDiverse physical and chemical test methods are employed to evaluate important environmental characteristics of lubricants and lubricant related waste materials. The most important chemical tests are closely related to lubricant composition. The amount of aromatic and polycyclic aromatic hydrocarbons in base oils, as well as the potential amount of heavy metals in additives must be known. Among the biological tests, the most important are those dealing with biodegradation characteristics, but neither human nor ecotoxicity tests can be ignored.
Preparation and characterisation of oil‐containing POM/PU blends
Authors: Hu X. , Jiang L. 
Published: July 2006

AbstractPolyoxymethylene (POM), one of the major engineering thermoplastics, has high strength and stiffness, excellent chemical resistance and superior antifriction and wear resistance. It suffers, however, from poor impact resistance due to its higher crystallinity. In this study we have investigated how to improve the toughness of POM by blending polyurethane (PU) with POM using dual‐roller compaction. The influences of PU, silicone oil, a surfactant, and fillers such as ultra‐high molecular weight polyethylene (UHMWPE), polytetrafluoroethylene (PTFE), graphite and carbon black, on the mechanical properties of oil‐containing POM/PU blends and its self‐lubrication performance in dry sliding against AISI1045 steel are examined. The results show that blends of POM with 10 wt.% PU reached the maximum notched Izod‐impact strength. The best processing method for oil‐containing POM/PU blends, and the optimal compositions of modified POM/PU blends were also determined.
A tribological study of electrolytic nickel‐PTFE composite coatings
Authors: Assoul M. , Pena‐Munoz E. , Roizard X. 
Published: July 2006

AbstractThe potential for co‐depositing PTFE particles in a metal matrix by means of electrodeposition has led to a new generation of composites that show promising tribological properties. In the present work, a study has been made of the parameters of the coating process (type of current, current density, and concentration of PTFE in the electrolyte bath) in order to optimise the properties of coatings.
Polyalphaolefins — base fluids for modern heavy duty diesel oils
Authors: Benda R. , Plomer A. , Reboul P. 
Published: July 2006

AbstractA combination of environmental legislation and a need for improved economics currently presents both OEMs and fleet owners with a conflicting set of performance and operational requirements. These include lower emission and paniculate levels, fuel economy, longer drain/service intervals, and enhanced engine durability. Improved engine lubricants will play a crucial role in achieving these goals. The impact of base‐fluid composition and viscosity grade on emission/paniculate levels and fuel economy of a Euro II engine has been investigated. Polyalphaolefin‐based lubricants appear as an encouraging solution, as shown by our results centred on an SAE 5W40 grade.