Anti-Wear and Friction-Reducing Characteristics of Two Kinds of Ceramic Additives

2010 ◽  
Vol 139-141 ◽  
pp. 274-279
Author(s):  
Yu Zhou Gao ◽  
Jiang Tao Wang ◽  
Shi Yong Liu ◽  
Hui Chen Zhang

Two kinds of ceramic additives have been developed that one is the serpentine particles and another is a blend of serpentine particles and catalyst. The tribological properties of the addition of different additives are investigated through a series of friction and wear experiments. Wear surface and the composition of the tribofilm were examined by SEM, EDS and XPS. In case of single serpentine additive, tribo-film can be formed gradually on the worn metal surface. The friction coefficient is about 0.11. The tribofilm mainly consists of Mg and Si elements transferred from the additive. This can compensates part of wear mass loss, avoids the direct contact of the two rubbing surfaces, and thus effectively improves the anti-wear characteristics. In case of the blend oil additive, the tribo-film formed obviously on the worn surface in the initial stage and no obvious film at end of the test. However, the friction coefficient can lower even to 0.007~0.008 compared with the above experiment. The worn surface becomes very smooth. Chemical analysis shows that there is a very thin film of carbon concentration with thickness of 30~50nm on the worn surface. Existence of the very thin carbon-concentrated film and mirror-like surface generates super low friction coefficient.

Author(s):  
В.Ю. Фоминский ◽  
В.Н. Неволин ◽  
Д.В. Фоминский ◽  
Р.И. Романов ◽  
М.Д. Грицкевич

The results of a comparative study of the friction and wear of MoSx and MoSex thin film coatings that was carried out in an oxidizing medium (a mixture of argon and air) at a temperature of -100°C are presented. The films were obtained by pulsed laser deposition from MoS2, MoSe2, and Mo targets in vacuum and H2S. It was established that Se-containing coatings significantly exceeded the S-containing coatings in terms of wear resistance and provided a friction coefficient of ~ 0.09. The properties of MoSx films depended on the S concentration, which determines the local packing of atoms in the amorphous structure of the film. The coefficient of friction for MoS3 films after running-in turned out to be half as much as that for MoS2 films, and its value was 0.08.


2013 ◽  
Vol 315 ◽  
pp. 951-955 ◽  
Author(s):  
Samion Syahrullail ◽  
Jazair Yahya Wira ◽  
W.B. Wan Nik ◽  
Chiong Ing Tiong

In this paper, the effect of sliding speed on the anti-friction of RBD palm olein was investigated using four-ball tribotester. The speeds were varied from 800 to 1400 rpm. The normal load was set to 40 kg and the test oil was heated up to 75 °C before the experiments. The result showed that palm olein has low friction coefficient compared to additive-free paraffinic mineral oil.


Author(s):  
Y. Elaine Zhu ◽  
Steve Granick

The design of tribological interfaces is often motivated by a quest to minimize friction and wear. Among the many strategic design principles that have been developed to this end, the simple idea of decoupling frictional force from normal load is especially attractive. Recent work from this laboratory demonstrates that under certain conditions, it is possible to reduce this coupling significantly with the result that the friction coefficient appears to be very low. However, the materials design requirements to achieve this end are rather stringent. Furthermore, modern methods enable one under some conditions to measure directly the structure and motions of lubricants during tribological sliding.


Author(s):  
Eduardo Tomanik ◽  
Hiroshi Fujita ◽  
Shinya Sato ◽  
Eliel Paes ◽  
Ciro Galvao ◽  
...  

Chromium nitride (CrN) is the main protecting coating applied to top rings for gasoline and diesel engines, due to its excellent wear resistance, low friction and minor environmental impacts, especially in modern engines operating with low viscosity oils. Recently, diamond like carbon (DLC) coatings reported improved tribological performance, but at a higher cost. Therefore, in the present work, wear and friction of CrN and DLC coated rings were evaluated on reciprocating and floating liner engine tests running on 0W-20 and 0W-16 lubricant formulations, which additives tailored for different markets (Japanese, European and Emerging). DLC outperformed CrN for both friction and wear when running on lubricant formulations without molybdenum additives. On opposite, with high molybdenum content additives, CrN presented synergic effects that significantly reduced friction and wear, whilst DLC did not. Same comparison on floating liner engine tests demonstrated again superior performance of CrN by 9% reduction on friction losses, running on oils containing molybdenum additives, whilst DLC lowered 6%. From that, it can be estimated 0.4% fuel saving at urban conditions by combining Japanese lubricant oil formulation and CrN top rings.


2011 ◽  
Vol 687 ◽  
pp. 739-744 ◽  
Author(s):  
Fei Chen ◽  
Jia Qing Chen ◽  
Hai Zhou ◽  
Cheng Ming Li

At atmospheric pressure, Diamond-Like Carbon (DLC) thin films were deposited on the Ti6Al4V alloy surface by a DBD plasma gun at low temperature (<350°C), with CH4 as a precursor and Ar as dilution gas. The structure of the DLC thin film was analyzed by Laser Raman spectroscope and X-ray photoelectron spectroscopy. The surface morphology was observed through scanning electron microscopy. The adhesion between the DLC thin film and the substrate was investigated with the scribe testing. The friction and wear behavior of the DLC thin film under dry sliding against GCr15 steel was evaluated on a ball-on-disc test rig. The results show that it is feasible to prepare a DLC thin film of 1.0μm thickness by plasma gun. The surface roughness Ra is about 13.23nm. The DLC thin film has a good adhesion of critical load 31.0N. It has been found that the DLC thin film has excellent friction and wear-resistant behaviors. The friction coefficient of the Ti6Al4V substrate is about 0.50 under dry sliding against the steel, while the DLC thin film experiences much abated friction coefficient to 0.15 under the same testing condition.


2019 ◽  
Vol 293 ◽  
pp. 125-140
Author(s):  
Agnieszka Paradecka ◽  
Krzysztof Lukaszkowicz ◽  
Jozef Sondor

Low friction thin layers are an excellent alternative for conventional coatings. They provide increased life of the elements, to which they were applied, due to enhancing the hardness or chemical and electrochemical resistance. They help to avoid the cracks, oxidation, as well as possible structural changes during the element's work. However, they primarily improve tribological properties by increasing wear resistance and reducing the friction. This also applies to components operating under variable conditions such as load, speed, temperature. The presented article analyzes the properties of various low-friction thin layers deposited by vacuum methods on the steel substrates. DLC, TiC, MoS2, CrCN thin layers were chosen, as they achieve the lowest possible coefficient of friction. In the framework of this work the measurements of adhesion of the investigated layers to the substrate as well as the friction coefficient, chemical analysis, microstructure and topographic analysis of the low-friction layers were carried out.


MRS Bulletin ◽  
2008 ◽  
Vol 33 (12) ◽  
pp. 1159-1167 ◽  
Author(s):  
Kathryn J. Wahl ◽  
W. Gregory Sawyer

AbstractDirectly seeing into a moving contact is a powerful approach to understanding how solid lubricants develop low-friction, long-lived interfaces. In this article, we present optical microscopy and spectroscopy approaches that can be integrated with friction monitoring instrumentation to provide real-time, in situ evaluation of solid lubrication phenomena. Importantly, these tools allow direct correlation of common tribological events (such as variations in friction and wear) with the responsible sliding-induced mechanical and chemical phenomena. We demonstrate the utility of in situ approaches with applications to a variety of thin-film solid lubricants.


2011 ◽  
Vol 194-196 ◽  
pp. 454-457
Author(s):  
Zhen Jiang Ma ◽  
Ji Hui Yin ◽  
Yang Jiang

This article presents a research on friction and wear properties of titanium composite lubricating grease containing ultrafine PTFE particles by using scanning electron microscopy to observe surface morphology of the worn steel balls and EDS to analysis the main elements in the worn surface of steel ball. The results show that the compound titanium grease with 3% ultrafine PTFE has the best wear and friction reduction properties. Its friction coefficient decrease about 25.5%, the diameter of wear scar decrease about 23.2%. The appropriate amount of PTFE particles go into the frictional surface with the grease, form the PTFE particle layer on the frictional surface, which reduces the direct contact of metal to metal, effectively reduces the friction and wear.


2014 ◽  
Vol 697 ◽  
pp. 254-257
Author(s):  
Jie Lin Xu ◽  
Zeng Xiong Peng ◽  
Nan Wang ◽  
Shan Lin Xu

The scuffing of friction pair is a common phenomenon in conditions of high speed and pressure. It was researched on scuffing characteristics in this paper. By using UMT-3 friction and wear tester, the friction and wear characteristics of slipper pair material in hydraulic component were investigated, and the friction coeficient-speed curves in the different pressures were got, as well as the wear rate-speed curves. The worn surface morphology of pin specimen was photographed by SEM, and the formation mechanism of the worn surface was analyzed. The results suggested that: friction coefficient and wear rate would have a jump when the scuffing occurred, the friction and wear characteristics would be affected by the interaction of pressure (P) and speed (V) . The PV characteristic restricted the correlation between working pressure and speed.


2014 ◽  
Vol 936 ◽  
pp. 1025-1030 ◽  
Author(s):  
Yang Wang ◽  
Xiu Fang Cui ◽  
Guo Jin ◽  
Hai Peng Li ◽  
Wei Zheng ◽  
...  

Polytetrafluoroethylene (PTFE) is known as a solid material with high lubricating property and low friction coefficient. The application of PTFE is significant to improve the tribological properties of coating. In this paper, Scanning electron microscopy (SEM), Energy Dispersive Spectrometer (EDS), X-ray diffractometry (XRD), Microhardness test and friction and wear experiment are adopted to study the effects of PTFE content on the structure, morphology and properties of coating. The results show that the addition of PTFE particles can reduce spherical particle size and increase the hardness and friction properties of coating when typical cauliflower shaped druse and excellent interface binding characteristics are maintained. If the content of PTFE is too much, some area of coating is prone to powder hoarding which may lead to the decrease of coating density, hardness, and friction coefficient stability.


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