Auger and X-Ray Photoelectron Spectroscopy Study of the Tribocontact Surface after Laser Modification

2016 ◽  
Vol 870 ◽  
pp. 298-302 ◽  
Author(s):  
A.V. Sidashov ◽  
A.T. Kozakov ◽  
S.I. Yaresko

The samples of the tool steel P6M5 were modified by means of laser irradiation (hereinafter - LO). The chemical composition of the sample surface before and after the LO was studied using the Auger and X-ray photoelectron spectroscopy (hereinafter - AES and XPS respectively). It was found that while the steel is exposed to LO, the thick oxide layer consisting mainly of the Fe2O3 oxide is formed. It was established that the modification with LO leads to increasing of wear resistance and durability of the R6M5 steel because of a double reduction of the friction coefficient.

2008 ◽  
Vol 23 (2) ◽  
pp. 43-50 ◽  
Author(s):  
Alexander Veleshko ◽  
Irina Veleshko ◽  
Anton Teterin ◽  
Konstantin Maslakov ◽  
Labud Vukcevic ◽  
...  

An X-ray photoelectron spectroscopy study of uranium sorption by spherically-granulated chitosan in sulphate solutions, as well as the study of the nature of the U(VI) - chitosan interaction was carried out in this work. The X-ray photoelectron spectroscopy analysis showed that the uranyl - chitosan interaction results in the formation of complexes with aminogroup nitrogen, and possibly chitin ring oxygens and free hydroxyl groups in the equatorial plane. Under the UHV in the spectrometer chamber, the uranyl-amin and uranyl-hyroxide bonds were shown to break and tetravalent uranium compounds were shown to form on the sample surface. Hydroxyl groups were shown to evaporate. The calculated DG0 = -1,3 kJ/mol can be an evidence of several concurrent processes, some of which require energy, as well as of the formation of a surface chemical compound.


2012 ◽  
Vol 134 (4) ◽  
Author(s):  
C. Serrar ◽  
P. Guiraldenq

The wear-fatigue rupture of Ni88P11.78Co0.12Fe0.10 (NiP) and Ni80.55Cr15.25B4.20 (NiCrB) glasses prepared by planar–flow casting have been studied using a test under simultaneous constant and cyclic loading generated by an eccentric rotation ceramic antagonist. For better apprehending the phenomena related to the structural state changes of samples before and after tests, structural characterization by x-ray diffraction, mechanical characterization by measuring Vickers microhardness (HV 0.1) and chemical composition by X-ray photoelectron spectroscopy (XPS) analysis have been carried out on as-quenched and worn dull side ribbons. Rupture surfaces, in S–N curves, have been measured by scanning electron microscope. Wear-fatigue contact tests consist to impose, simultaneously, a traction strain and cyclic normal stresses which generate traction, compression, rolling, bending and shearing. All results obtained from the two selected glasses (NiP and NiCrB) are systematically compared with those of a nickel pure crystalline foil (Ni). We evaluate mainly the wear mechanism, the mode and the typical rupture surface observed in NiP, NiCrB and Ni specimens. We specify the conditions of obtaining these rupture surfaces which often present in smooth plane, veining and “chevrons” patterns. All results show a great wear and fatigue resistance for the two metallic glasses compared to Ni. The NiCrB wear resistance is superior to that of NiP, while the difference in their fatigue limit is not clearly distinct. The reasons for the differences in wear and fatigue behavior will be discussed in relation to the metallic glass thermal stability, chemical composition, microhardness and surface rupture topography.


Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3588
Author(s):  
Jiayi Chen ◽  
Yansong Liu ◽  
Jiayue Zhang ◽  
Yuanlin Ren ◽  
Xiaohui Liu

Lyocell fabrics are widely applied in textiles, however, its high flammability increases the risk of fire. Therefore, to resolve the issue, a novel biomass-based flame retardant with phosphorus and nitrogen elements was designed and synthesized by the reaction of arginine with phosphoric acid and urea. It was then grafted onto the lyocell fabric by a dip-dry-cure technique to prepare durable flame-retardant lyocell fabric (FR-lyocell). X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FTIR) analysis demonstrated that the flame retardant was successfully introduced into the lyocell sample. Thermogravimetric (TG) and Raman analyses confirmed that the modified lyocell fabric featured excellent thermal stability and significantly increased char residue. Vertical combustion results indicated that FR-lyocell before and after washing formed a complete and dense char layer. Thermogravimetric Fourier-transform infrared (TG-FTIR) analysis suggested that incombustible substances (such as H2O and CO2) were produced and played a significant fire retarding role in the gas phase. The cone calorimeter test corroborated that the peak of heat release rate (PHRR) and total heat release (THR) declined by 89.4% and 56.4%, respectively. These results indicated that the flame retardancy of the lyocell fabric was observably ameliorated.


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