摘要:

AbstractAn epoxy‐based nanocomposite containing a low concentration of nanometric TiO2(4 vol. %), graphite powder (7.21 vol. %), and 2–14 vol. % aramid particles was developed as a coating material. The mechanical and tribological performance of the composites was investigated. The epoxy filled only with TiO2possessed significantly improved impact strength and flexural properties, whereas the further incorporation of graphite and aramid particles had a deleterious effect on most of the mechanical properties, except the modulus. The tribological behaviour of the composites was tested in sliding and fretting modes. Under sliding conditions, the addition of nanometric TiO2alone significantly improved the wear resistance and decreased the coefficient of friction compared to the neat epoxy. The sliding wear and friction behaviour was further enhanced with the incorporation of graphite and aramid particles. Contrary to the sliding wear behaviour, the fretting wear and friction behaviour was worse for the epoxy filled only with TiO2, but was significantly enhanced by the incorporation of graphite and aramid particles. The optimum aramid particle content for sliding and fretting wear of the epoxy‐based nanocomposite was determined as 10 v

ISSN:0265-6582    

DOI:10.1002/jsl.3000210402

出版商:John Wiley&Sons, Ltd    

年代:2005

数据来源: WILEY

摘要:

AbstractA novel, potential ashless S—N‐style additive, 2‐(N,N‐dibutylamino)‐4,6‐bis‐(dibutyldithiocarbamate)‐1,3,5‐triazine (DBTT), was synthesised and its synergistic tribological effect with a traditional additive, tricresyl phosphate (TCP), in rape seed oil was evaluated using a four‐ball tester. The results show that the load‐carrying capacity of the vegetable oil could be improved greatly by the presence of the TCP and/or DBTT additives; at certain mass ratios TCP and DBTT show a good synergistic effect in improving the tribological performance of the base oil. The elemental composition and chemical nature of antiwear films generated at a steel interface were investigated using Kevex energy dispersive X‐ray analysis and X‐ray photoelectron spectroscopy. Scanning electron microscopy was also used to study the rubbed surface morphology. It was found that FeS, organosulphur compound, sulphate, phosphate, and nitrogen‐containing compounds were present in the comple

ISSN:0265-6582    

DOI:10.1002/jsl.3000210403

出版商:John Wiley&Sons, Ltd    

年代:2005

数据来源: WILEY

摘要:

AbstractOne of the most important aspects of a hydraulic fluid used in mobile systems (e.g., excavators, wheel loaders) is the viscometric behaviour of the fluid at low temperatures. It has been found that the pour point of the base fluid does not predict this behaviour satisfactorily, and, as a result, the Swedish standard for these products (SS155434) requires that the kinematic viscosity of a hydraulic fluid remains stable at low temperatures (−20 or −30°C) during a period of 72 h.However, in rheological studies under dynamic conditions, it has now been found that certain oleochemically derived esters do not show Newtonian flow behaviour at these low temperatures. The authors have found not only a shear‐dependent behaviour of these esters but also a time‐dependent behaviour, especially after (high) energy input from an external source to simulate pumping of the fluid.Given the non‐Newtonian behaviour of these esters, the kinematic viscosity test method with an Ubbelohde tube was found to be inappropriate for the determination of the low‐temperature viscosity because this method assumes Newtonian behaviour. Dynamic viscosity measurements at higher shear rates (e.g., cold cranking simulator) resulted in much better reproducibility and may offer the best method o

ISSN:0265-6582    

DOI:10.1002/jsl.3000210404

出版商:John Wiley&Sons, Ltd    

年代:2005

数据来源: WILEY

摘要:

AbstractNew fluorinated greases based on perfluoropolyether (PFPE) fluids and perfluorinated polymer thickeners were prepared. Both the type of fluid (branched and linear PFPE) and the thickener (polytetrafluoroethylene, PTFE) were varied, and different oil/thickener ratios were also evaluated. The greases were characterised in terms of penetration, oil separation, and wear. Some relationships regarding the influence of both the amount and the type of thickener used were found. Torque values of ball bearings lubricated with these greases were investigated at low temperature and at high bearing speed. Specifically, the use of a new PTFE grade obtained through micro‐emulsion polymerisation technology allowed the formulation of greases with a substantially reduced amount of thickener. These greases show improved antiwear properties as well as lower friction coefficients under high‐speed conditions, thus paving the way to their use in applications not generally fulfilled by fluorinated grea

ISSN:0265-6582    

DOI:10.1002/jsl.3000210405

出版商:John Wiley&Sons, Ltd    

年代:2005

数据来源: WILEY

摘要:

AbstractIn this paper the available technologies for the preparation of oils, fats and their derivatives using oil seeds as a starting material are discussed. Currently, 15 million tonnes per year of fatty products are used for industrial purposes, and their applications are discussed with particular reference to biodiesel, biolubricants, biosolvents, and printing inks. For each product, the discussion concerns the state of the art as well as the prospects for the future, and existing barriers to development. Also, the problem of glycerol production in terms of both economic significance and new outlets for surplus production is discussed. The paper ends with a brief overview of recent trends in research in the field of chemical and technical utilisation of vegetable oils.

ISSN:0265-6582    

DOI:10.1002/jsl.3000210406

出版商:John Wiley&Sons, Ltd    

年代:2005

数据来源: WILEY

ISSN:0265-6582    

DOI:10.1002/jsl.3000210407

出版商:John Wiley&Sons, Ltd    

年代:2005

数据来源: WILEY

ISSN:0265-6582    

DOI:10.1002/jsl.3000210408

出版商:John Wiley&Sons, Ltd    

年代:2005

数据来源: WILEY

ISSN:0265-6582    

DOI:10.1002/jsl.3000210409

出版商:John Wiley&Sons, Ltd    

年代:2005

数据来源: WILEY

ISSN:0265-6582    

DOI:10.1002/jsl.3000210401

出版商:John Wiley&Sons, Ltd    

年代:2005

数据来源: WILEY