摘要:

AbstractIt is generally agreed that contact pressure and sliding speed are the predominant factors for the prediction of wear of ultrahigh‐molecular‐weight polyethylene (UHMWPE) in joint prostheses. A new parameter for predicting the wear of UHMWPE has been introduced with a wear test in vitro. The parameter is the time of exposure to a lubricating liquid on a bearing surface. A pin‐on‐disc machine was designed such that the exposure time of a CoCrMo alloy disc to a lubricating liquid could be varied. The specific wear of UHMWPE was increased by a decrease in the exposure time, even if the contact pressure and the sliding speed were held constant. The parameter is able to account for the contact pressure set in the experiment (2.0–20.0 mPa), and clarifies the conditions under which the specific wear of UHMWPE is fou

ISSN:0265-6582    

DOI:10.1002/jsl.3000190402

出版商:John Wiley&Sons, Ltd    

年代:2003

数据来源: WILEY

摘要:

AbstractResearch on the boundary lubrication performance of two perfluoropolyether (PFPE) thin films in the presence of passirated 440C stainless steel is presented. The study used a standard ball‐on‐disc (BoD) tribometer operating in dry nitrogen and a vacuum spiral orbit tribometer (SOT). Stainless steel surfaces were passivated using one of four techniques: a high‐temperature and low‐temperature chromic acid bath, a tricresyl phosphate (TCP) soak, or UV/ozone treatment for 15 min. After passivation, each BoD disc had a 400 Å film of Krytox® 16256 (PFPE) applied to it. The lives of these films were quantified by measuring the number of sliding cycles before an increase in friction occurred. The lubricated life of the 440C couple was not altered as a result of the various passivation techniques. The resulting surface chemistry of each passivation technique was examined using X‐ray photoelectron spectroscopy. The SOT was used to examine the effects of the TCP treatment on the lubricated life of another PFPE, Brayco® 815Z, under rolling conditions. None of the passivation techniques were found to increase dramatically the oxide film thickness or lub

ISSN:0265-6582    

DOI:10.1002/jsl.3000190403

出版商:John Wiley&Sons, Ltd    

年代:2003

数据来源: WILEY

摘要:

AbstractThe lubricating ability of a grease depends on both the base oil and the thickener. As a result of their intrinsic properties and/or because of their com‐patibility with thickeners and specific additives, base fluids have different influences upon the properties of grease formulations. It is well known that mineral oils are the most widely used lubricant bases due to their inherent lubricity and lower cost, but recent environmental concern has led to consideration of the use of vegetable oils and readily biodegradable synthetic fluids as raw materials in lubricating grease formulations. As well as the base materials, the additives for biodegradable greases should also be biodegradable. This requirement limits the kind of products that may be used in environmentally friendly greases.This paper presents comparative data concerning the tribological and physico‐chemical properties of biodegradable greases formulated with certain vegetable oils, such as rape seed oil, castor oil, and soybean oil or their mixtures, and synthetic esters. The improvement of the load‐carrying properties of biodegradable greases and the antioxidative effect of some suitable additives have also been studied, and the results are presented

ISSN:0265-6582    

DOI:10.1002/jsl.3000190404

出版商:John Wiley&Sons, Ltd    

年代:2003

数据来源: WILEY

摘要:

AbstractPolyalphaolefin (PAO) fluids have become widely accepted as high‐performance lubricants and functional fluids due to certain inherent, and highly desirable, characteristics. One of these characteristics is their low toxicity, which, combined with excellent viscometrics and lubricity, have made low‐viscosity PAO fluids an important component in lubricant formulations.Typical data found in product specifications for lubricants are the kinematic viscosity and the viscosity index. These values do not give enough information with which to choose the optimum lubricant for a lubricated contact. In mechanical systems, rolling, sliding, and rolling/sliding contacts occur, and lubricants have to work optimally under these operating conditions.In this study the rolling‐contact fatigue lives (L50and L10) of PAOs of different viscosities were experimentally determined. The tests were carried out using a four‐ball machine. Wear tests were also carried out using another four‐ball tester in order to measure the wear‐scar diameter and the flash temperature parameter. The lubricants were characterised by infrared spectroscopy, and the pitting of the balls was observed using scanning electron

ISSN:0265-6582    

DOI:10.1002/jsl.3000190405

出版商:John Wiley&Sons, Ltd    

年代:2003

数据来源: WILEY

摘要:

AbstractShort glass fibre‐reinforced polyamide 6 and polyamide 11 (PA 6 and PA 11) with and without a solid lubricant of polytetrafluoroethylene and metal powders (e.g., bronze) and copper as fillers were formulated and characterised for their compositional and mechanical properties. A tribological evaluation of these composites' abrasive wear was carried out by abrading a polymer pin against 80 grade (175 um) silicon carbide (SiC) paper under single‐pass conditions at various loads. It was observed that the fibre reinforcement reduced the abrasive wear resistance of virgin polymers. A combination of fibre and particulate fillers was further detrimental in this respect. Efforts were made to correlate the wear performance with the ductility factor, fracture toughness, and fracture energy in the case of PA 6 and its composi

ISSN:0265-6582    

DOI:10.1002/jsl.3000190406

出版商:John Wiley&Sons, Ltd    

年代:2003

数据来源: WILEY

ISSN:0265-6582    

DOI:10.1002/jsl.3000190407

出版商:John Wiley&Sons, Ltd    

年代:2003

数据来源: WILEY

ISSN:0265-6582    

DOI:10.1002/jsl.3000190408

出版商:John Wiley&Sons, Ltd    

年代:2003

数据来源: WILEY

ISSN:0265-6582    

DOI:10.1002/jsl.3000190409

出版商:John Wiley&Sons, Ltd    

年代:2003

数据来源: WILEY

ISSN:0265-6582    

DOI:10.1002/jsl.3000190401

出版商:John Wiley&Sons, Ltd    

年代:2003

数据来源: WILEY