X-ray photoelectron spectroscopy and Fourier transform-infrared studies of transition metal phosphate glasses

Khawaja, E. E.; Durrani, S.M.A.; Al-Adel, F.; Salim, M.A.; Hussain, M. Sakhawat

doi:10.1007/bf00352154

Cited by 37 publications

(24 citation statements)

References 25 publications

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“…For the above mentioned experiments in Section 3.2 XPS analysis was conducted and the oxygen peaks are plotted. This approach has extensively been demonstrated in literature [37][38][39][40][41][42][43][44][45]. It supports the fact that when higher water concentration is present in the oil at higher values of humidity and lower temperature, the tribofilm formed on the surface consists of shorter polyphosphates due to the depolymerisation of the longer polyphosphates chains [7,10].…”

Section: Effect Of Relative Humidity On Tribochemistrysupporting

confidence: 65%

Study of the interfacial mechanism of ZDDP tribofilm in humid environment and its effect on tribochemical wear; Part I: Experimental

Parsaeian

Eijk

Nedelcu

et al. 2017

Tribology International

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Wear performance of any tribological system can be influenced in a complex way by water contamination. Water can be the cause of steel corrosion which, in turn, can accelerate wear. It can decompose the additives in the oil and create a more corrosive environment which leads to the higher wear in the system. A key novelty of this study is to investigate the effect of relative humidity and the tribochemical changes on the tribological performance and tribofilm characteristics of boundary lubricated systems by means of designing a humidity control system integrated to the Mini Traction Machine (MTM) and Spacer Layer Interferometry Method (SLIM) for the first time. The system is capable of simulating rolling-sliding conditions continuously where lubricant can be contaminated with water. This paper is the first part of a two-part study and the theoretical aspects of the work is the subject of the second part of this investigation. It was observed that humidity hinders the tribofilm formation, especially at higher values of relative humidity and lower temperatures and it can significantly affect the wear process. The correlation between tribofilm thickness, water concentration, temperature and wear of the system was studied. The experimental results suggest that the higher the humidity, the higher the wear of the system and it is more noticeable at lower temperatures where the tribofilm in thinner. The surface chemistry of zinc polyphosphates was investigated as a function of humidity.

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Section: Effect Of Relative Humidity On Tribochemistrysupporting

confidence: 65%

Study of the interfacial mechanism of ZDDP tribofilm in humid environment and its effect on tribochemical wear; Part I: Experimental

Parsaeian

Eijk

Nedelcu

et al. 2017

Tribology International

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“…The possibility of distinguishing phosphate glasses of different chain lengths by XPS is known to be based on the calculation of the ratio between the BO and NBO peaks, which is used for fitting the O 1s signal. This procedure has been extensively reported in the literature in the case of both silicate and phosphate glasses [36,38,39,41,43,44,[76][77][78]. In the present work, the O 1s signal was fitted with two peaks: the NBO component was found at 532.3±0.1 eV for all samples, whereas the position of the BO turned out to be slightly dependent on the composition.…”

Section: Ft-ir Analysismentioning

confidence: 95%

Chain-length-identification strategy in zinc polyphosphate glasses by means of XPS and ToF-SIMS

et al. 2012

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The surface chemistry of amorphous zinc polyphosphates of different compositions (ranging from zinc metaphosphate to zinc orthophosphate) has been investigated by means of X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary-ion mass spectroscopy (ToF-SIMS). The identification of the chain length of zinc polyphosphates by XPS was on the basis of the integrated intensity ratio of the bridging (P-O-P) and nonbridging (P = O and P-O-M) oxygen peaks used for fitting the oxygen 1s signal, the shift of the P 2p(3/2) signal towards lower binding energies and the modified Auger parameter towards higher values as the zinc content increases. The discrimination of the polyphosphate chain lengths was also achieved by ToF-SIMS, by comparing the intensities of selected characteristic phosphate fragments. Both techniques appear to be suitable for the investigation of polyphosphate glasses in applications such as tribology, where there is a need to identify the chain length present in the outermost monolayer of the film. Fourier-transform infrared (FT-IR) spectroscopy was used to characterize the bulk compounds. The FT-IR studies showed that long-chain structures linked through P-O-P bonds predominate in the metaphosphate composition, while when the zinc content is increased, the chains become shorter, ultimately being replaced by PO(4) monomers in the orthophosphate composition.

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“…The ratio of bridging oxygen to non-bridging oxygen in the polyphosphate glass was calculated by dividing the intensity of BO and NBO peaks obtained from XPS analysis. This approach has been extensively used in literature [42][43][44][45][46][47][48][49][50]. Also the binding energy difference between the Zn3s and P2p peaks in the XPS spectra was used to give complementary information.…”

Section: Chemistry Of the Tribofilmmentioning

confidence: 99%

A new insight into the interfacial mechanisms of the tribofilm formed by zinc dialkyl dithiophosphate

Parsaeian

Ghanbarzadeh

Eijk

et al. 2017

Applied Surface Science

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Understanding the true interfacial mechanisms involved in the growth of tribofilms generated by Zinc Dialkyl Dithiophosphate (ZDDP) is important because it is the most widely used antiwear additive and there is legislative pressure to find efficient environmentally-friendly replacements. The main focus of this study is to investigate the durability of the ZDDP tribofilm and correlate it to the chemical and physical properties of the glassy polyphosphates.A novel experimental method has been developed to study the effect of lubricant temperature and contact load on tribofilm growth and durability. Results show that physical parameters such as temperature and pressure significantly influence the tribofilm durability. XPS analyses were carried out before suspending the test and after changing the oil to assess the difference in chemical structure of the tribofilm before and after stopping the test. The chemical analyses suggest that there are different chemical properties across the thickness of the tribofilm and these determine the durability characteristics.

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X-ray photoelectron spectroscopy and Fourier transform-infrared studies of transition metal phosphate glasses

Cited by 37 publications

References 25 publications

Study of the interfacial mechanism of ZDDP tribofilm in humid environment and its effect on tribochemical wear; Part I: Experimental

Study of the interfacial mechanism of ZDDP tribofilm in humid environment and its effect on tribochemical wear; Part I: Experimental

Chain-length-identification strategy in zinc polyphosphate glasses by means of XPS and ToF-SIMS

A new insight into the interfacial mechanisms of the tribofilm formed by zinc dialkyl dithiophosphate

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