Effect of Friction Modifiers and Antiwear Additives on the Tribological Performance of a Hydrogenated DLC Coating

2010 ◽  
Vol 132 (3) ◽  
Author(s):  
T. Haque ◽  
A. Morina ◽  
A. Neville

There has been a lot of attention on the effect of lubricant additives on the friction at carbon coated surfaces. But only few papers have addressed the effect of additives on the durability of some diamondlike carbon DLC coatings. This paper presents a systematic study assessing the additive/additive and additive/surface interactions, and their influences on the durability of a low hydrogen-containing (15 at. % hydrogen) metal-free DLC coating (a-C:15H). In this study, lubricating oils containing a zinc dithiophosphate (ZDDP) antiwear additive and/or organomolybdenum friction modifiers (moly dimer and moly trimer) were used. Tribological tests were carried out in a pin-on-plate tribometer under boundary lubrication conditions. To understand the effect of additives, tribofilms formed on the wear tracks were analyzed using surface sensitive analytical techniques such as atomic force microscope, scanning electron microscopy, energy dispersive X-ray analysis, X-ray photoelectron spectroscopy, and Raman spectroscopy. Results showed that the ZDDP formed a zinc phosphate containing an ultrathin antiwear tribofilm, which offered excellent durability/wear protection to the a-C:15H coating. However, the antiwear performance of this additive was compromised when it was used with moly dimer or moly trimer. Surface analysis revealed that unlike steel surfaces, MoS2 formed on the DLC surfaces had negligible influence on friction, while the low friction DLC wear debris had strong influence on friction. Abrasive wear was found to be the dominating wear mechanism in the cases when additives showed poor wear protection on the a-C:15H coating.

Author(s):  
Tabassamul Haque ◽  
Ardian Morina ◽  
Anne Neville

Diamond Like Carbon (DLC) coatings are becoming very popular for automotive tribo-components as they can offer excellent tribological properties resulting in improved fuel economy and reducing dependence on harmful components of existing additives. The tribochemical interactions of low hydrogen containing DLC coating with lubricants, basically customised for ferrous materials, are yet to be well understood. In this work, an experimental study has been performed to understand the synergistic and antagonistic effects of low friction and antiwear additives on a 15 at. % hydrogen containing DLC coating. Surface sensitive analytical techniques, such as atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) were used to perform physical and chemical characterization of the tribofilms.


Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 201
Author(s):  
Elisangela Aparecida dos Santos de Almeida ◽  
Julio Cesar Giubilei Milan ◽  
César Edil da Costa ◽  
Cristiano Binder ◽  
José Daniel Biasoli de Mello ◽  
...  

In cold rolling, a textured roll can be used to imprint a desired surface topography onto the sheet during rolling. This work proposes the use of diamond-like carbon (DLC) coatings to protect the surface topography of the rolls in replacement of the carcinogenic hard chrome. For that, hydrogenated amorphous carbon (a-C:H) was deposited on plasma nitrided tool steel, both for ground and textured specimens. Changes in surface topography due to DLC coating were assessed using a confocal microscope. Coating adhesion was evaluated using the method VDI 3198. The specimens were characterized using X-ray diffraction (XRD), microhardness test and scanning electron microscopy (SEM). The coating was characterized using Raman spectroscopy (RS) and X-ray photoelectron spectroscopy (XPS). The results showed a soft multilayer coating consisting of a plasma nitrided layer for load support, a Si-rich interlayer to improve adhesion and an a-C:H top layer. DLC deposition reduced the roughness of the textured specimens. The coating resulted in relatively stable friction and good durability, with small damage and negligible wear even under dry sliding.


Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4531
Author(s):  
Mihaela-Ramona Buga ◽  
Adnana Alina Spinu-Zaulet ◽  
Cosmin Giorgian Ungureanu ◽  
Raul-Augustin Mitran ◽  
Eugeniu Vasile ◽  
...  

Porous silica-based materials are a promising alternative to graphite anodes for Li-ion batteries due to their high theoretical capacity, low discharge potential similar to pure silicon, superior cycling stability compared to silicon, abundance, and environmental friendliness. However, several challenges prevent the practical application of silica anodes, such as low coulombic efficiency and irreversible capacity losses during cycling. The main strategy to tackle the challenges of silica as an anode material has been developed to prepare carbon-coated SiO2 composites by carbonization in argon atmosphere. A facile and eco-friendly method of preparing carbon-coated SiO2 composites using sucrose is reported herein. The carbon-coated SiO2 composites were characterized using X-ray diffraction, X-ray photoelectron spectroscopy, thermogravimetry, transmission and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy, cyclic voltammetry, and charge–discharge cycling. A C/SiO2-0.085 M calendered electrode displays the best cycling stability, capacity of 714.3 mAh·g−1, and coulombic efficiency as well as the lowest charge transfer resistance over 200 cycles without electrode degradation. The electrochemical performance improvement could be attributed to the positive effect of the carbon thin layer that can effectively diminish interfacial impedance.


2022 ◽  
pp. 108818
Author(s):  
Elhadji Cheikh Talibouya Ba ◽  
Marcello Rosa Dumont ◽  
Paulo Sérgio Martins ◽  
Bárbara da Silva Pinheiro ◽  
Matheus Philippe Martins da Cruz ◽  
...  

2020 ◽  
Vol 73 (11) ◽  
pp. 1088
Author(s):  
Altafhusen Naikwade ◽  
Megha Jagadale ◽  
Dolly Kale ◽  
Gajanan Rashinkar

A new magnetic nanoparticle supported ionic liquid phase (SILP) catalyst containing perruthenate anions was prepared by a multistep procedure. The various analytical techniques such as FT-IR spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, thermogravimetric analysis, energy dispersive X-ray analysis, and vibrating sample magnetometer analysis ascertained the successful formation of catalyst. The performance of a magnetically retrievable SILP catalyst was evaluated in the selective oxidation of alcohols. The split test and leaching studies of the SILP catalyst confirmed its heterogeneous nature. In addition, the reusability potential of SILP catalyst was also investigated which revealed its robust activity up to six consecutive cycles.


1982 ◽  
Vol 36 (3) ◽  
pp. 290-296 ◽  
Author(s):  
Manuel Carvalho ◽  
Larry F. Wieserman ◽  
David M. Hercules

Wilkinson's catalyst, RhCl(PPh3)3 is a well known and widely used homogeneous hydrogenation catalyst. This catalyst was analyzed by ESCA which revealed that two rhodium species [Rh(I) and Rh(III)] were present, both for commercial preparations and for catalysts prepared in this laboratory. The ratio of Rh(I) to Rh(III) was 3:2 regardless of the source. A different method of synthesizing RhCl(PPh3)3 was used and produced a compound having only Rh(I) species. Additional analytical techniques such as elemental analysis, FT-IR, liquid chromatography, and 31P NMR were used to determine the origin of the higher binding energy peaks when Wilkinson's procedure was used to prepare RhCl(PPh3)3. Hydrogenation of cyclohexene was also performed to determine the effect of the higher binding energy species on catalytic activity.


2007 ◽  
Vol 546-549 ◽  
pp. 1571-1574
Author(s):  
L. Ji ◽  
N.L. Shi ◽  
Rui Yang

CVD (chemical vapor deposition) SiC continuous fiber is used as reinforcement of metal matrix composites because of its high strength, high stiffness and elevated temperature stability. In this work, anodic oxidation method was used to treat the surface of carbon coated SiC fiber. Then the surface of treated fiber was compared with untreated one by scan electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). SiC was detected on the surface of untreated carbon-rich coating. It is proved by XPS that SiC was transformed into SiO2 after treatment. About 100~200nm thick oxidation layer was detected on the surface of carbon-rich coating and the structure of double coatings formed. Because the surface of fiber became smooth and the tensile stress on it was relaxed after treatment, the tensile strength of fiber was improved by 8%~20% average and the dispersing ratio of it was reduced.


2018 ◽  
Vol 106 (4) ◽  
pp. 291-300
Author(s):  
Nidia García-González ◽  
Eduardo Ordoñez-Regil ◽  
María Guadalupe Almazán-Torres ◽  
Eric Simoni

AbstractThe interaction of salicylic acid with zirconium diphosphate surface and its reactivity toward uranium (VI) was investigated. The interaction of salicylic acid with zirconium diphosphate was firstly studied using several analytical techniques including atomic force microscopy, scanning electron microscopy and X-ray photoelectron spectroscopy. The sorption of uranium (VI) onto surface-modified zirconium diphosphate was evaluated by the classical batch method at room temperature. This study showed that the uranium (VI) sorption onto zirconium diphosphate is influenced by the presence of salicylic acid. A fluorescence spectroscopy study revealed the presence of a uranyl specie onto the modified solid surface. The spectroscopy results were then used to restrain the modeling of experimental sorption data, which are interpreted in terms of a constant capacitance model using the FITEQL code. The results indicated that interaction between the uranium (VI) and the surface of zirconium diphosphate modified with salicylic acid leads to the formation of a ternary surface complex.


Author(s):  
Atsushi Mukunoki ◽  
Tamotsu Chiba ◽  
Yasuhiro Suzuki ◽  
Kenji Yamaguchi ◽  
Tomofumi Sakuragi ◽  
...  

The authors describe progress in the development of low temperature vitrification with BiPbO2I (BPI) as a promising immobilization technique by which Iodine-129 is recovered by BiPbO2NO3 to form BPI, and then solidified into a lead-boron-zinc glass matrix (PbO-B2O3-ZnO) using a low temperature vitrification process. The microscopic structure of BPI glass was analyzed by various analytical techniques, such as XRD (X-ray diffraction), NMR (nuclear magnetic resonance analysis), and XPS (X-ray photoelectron spectroscopy), using several types of glass samples. The results obtained provide structural information on key elements in BPI glass and can be applied for modeling the structure of the BPI glass, simulated by molecular dynamics. The previous work suggested that the leaching behavior of iodine from BPI glass depended upon the chemical conditions of the solution. Further leaching tests using solutions under varying conditions were carried out in order to predict mechanisms of iodine leaching. Normalized elemental mass loss values of iodine in simulated seawater and bentonite pore water are almost the same as those of boron, showing that iodine dissolves congruently with BPI glass, whereas iodine dissolves incongruently in Ca(OH)2 solutions of pH 9 and 11. To demonstrate the feasibility of the BPI vitrification process, recovery tests of iodine from spent iodine filters were conducted and a prototype melting furnace was developed for scale-up tests of glass sample. It was found that more than 95% of iodine can be recovered from the spent iodine filter and that the prototype furnace can produce approximately 0.5 liters of homogeneous glass.


Author(s):  
Tassew Belete Bahru ◽  
Eyasu Gebrie Ajebe

The combination of nanotechnology with molecular biology, information technology and instrumentation, is opening the door to a new industrial age. The aim of this review article is to summarize the current knowledge of nanotechnology in synthesizing, identifying and characterization of nanomaterials using analytical techniques. Physical and chemical approach synthesis of nanomaterials befalls challenges in the development of analytical techniques used to characterize them. The major techniques include: Transmission Electron Microscopy, Scanning Electron Microscopy, Atomic Force Microscopy, Dynamic Light Scattering, X ray Photoelectron Spectroscopy, X-ray Diffraction, Single Phase Inductively Coupled Plasma Mass Spectroscopy, X ray Fluorescence Spectroscopy, Auger Electron Spectroscopy, X ray Absorption Fine Structure, Capillary Electrophoretic Separations, Magnetic nano particles coupled HPLC and Dynamic light scattering. Nanomaterials have been characterized for the extensive potential applications in optics, electronics, magnetics, and catalysts; chemical sensing, biomedicine, micro reactor, and they have been applied in food, biological, environmental and pharmaceuticals uses. In spite of the extended use of nano particles in diverse consumer products, there is a great concern over the unexpected impact or effects on humans due to exposure.


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