摘要:

AbstractThe combination of scanning friction force microscopy (SFFM) and lock‐in techniques leads to dynamic SFFM (DSFFM) and provides great advantages in friction force studies with sub‐micrometre resolution. In this paper are presented measurements on thin adsorbed organic films on polymers (polymer blend of 75% poly(allylaminehydrochloride) (PAA) and 25% poly(diallyl‐dimethylammonium chloride) (PDDAC)) and on mica (as a reference). The amplitude and phase response as a function of the excitation amplitude can be explained on hard surfaces by a simple static and dynamic friction model. This model allows us further to distinguish static friction forces and kinetic friction forces in a quantitative way. Furthermore, we demonstrate the use of these spectra to determine the correct modulation amplitude of the excitation to achieve the optimal friction contrasts directly. Polymer data suggest that the viscoelastic shear flow under the atomic force microscope (AFM) tip is responsible for the shape of the phase and amplitude spectrum. Lastly, we demonstrate that DSFFM is a useful technique for surface characterisation in situations where SFFM may not be ade

ISSN:0265-6582    

DOI:10.1002/jsl.3000180102

出版商:John Wiley&Sons, Ltd    

年代:2001

数据来源: WILEY

摘要:

AbstractProgress in the technology of magnetic media has brought about a remarkable increase in recording density. The most important factor determining the utility of magnetic disks is durability against head wear, and this durability is controlled by several factors. The present paper discusses the tribology of these media, particularly from the viewpoint of boundary lubrication. In that context there are two characteristic features of this lubrication regime: specific standard lubricants (fluoropolyethers such as Z‐DOL and perfluo‐ropolyethers such as Z‐15) and the newer application of these lubricants in the form of films only a few nanometers thick Advanced phosphazene‐type fluorinated compounds are of most interest at present, so these compounds are discussed in more detail. The emphasis is on X‐1P lubricant used either alone or as an additive for fluoro‐ and perfluoropolyethers deposited on protective diamond‐like ca

ISSN:0265-6582    

DOI:10.1002/jsl.3000180103

出版商:John Wiley&Sons, Ltd    

年代:2001

数据来源: WILEY

摘要:

AbstractThe results described in this paper represent a contribution towards finding feedstocks, such as monocarboxylic acids, for the production of polyolester base oils. The research has shown that it is possible to obtain a mixture of monocarboxylic (butyric, valeric, and caproic) acids from the waste stream produced by the catalytic oxidation of cyclohexane to cyclohexanone in the industrial production of caprolactam. The mixture of C4—C6carboxylic acids separated from this waste by distillation was used to esterify neopentyl alcohols such as trimethylolpropane (TMP) and pentaerythritol (PE). Thus, polyolester synthesis was strongly dependent on the choice of suitable catalyst and the neturalisation of unreacted acids. Polyolester oils obtained from TMP or PE with monocarboxylic C4—C6acids have better physicochemical properties than conventional mineral oils, namely ISO 10 or ISO 22, including higher viscosity indices, higher flash points, lower pour points, and lower volatilities. In addition, the polyolesters tested are readily biodegradable under the conditions of the CEC‐L‐33‐T‐82 test and the Zahn

ISSN:0265-6582    

DOI:10.1002/jsl.3000180104

出版商:John Wiley&Sons, Ltd    

年代:2001

数据来源: WILEY

摘要:

AbstractA new high‐pressure viscometer that can measure viscosity at pressures up to 0.8 GPa has been developed in the authors' laboratory. The ‘modulus equation’ has been used to compare the behaviour of mineral and synthetic lubricants. Among the oils investigated there was one ester that biodegraded rapidly both before and after ageing in a long‐term test‐rig operation. To facilitate a comparison or application of the results to other oils, an analysis of the correlation between the viscosity—pressure coefficient and the kinematic viscosity measured at atmospheric pressure has been provided. A prediction of lubricant film thickness based on high‐pressure viscosity data is compared with film thickness measurements in a r

ISSN:0265-6582    

DOI:10.1002/jsl.3000180105

出版商:John Wiley&Sons, Ltd    

年代:2001

数据来源: WILEY

ISSN:0265-6582    

DOI:10.1002/jsl.3000180106

出版商:John Wiley&Sons, Ltd    

年代:2001

数据来源: WILEY

ISSN:0265-6582    

DOI:10.1002/jsl.3000180107

出版商:John Wiley&Sons, Ltd    

年代:2001

数据来源: WILEY

ISSN:0265-6582    

DOI:10.1002/jsl.3000180101

出版商:John Wiley&Sons, Ltd    

年代:2001

数据来源: WILEY