scholarly journals Perspectives of the Friction Mechanism of Hydrogenated Diamond-Like Carbon Film in Air by Varying Sliding Velocity

Coatings ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 331 ◽  
Author(s):  
Yunhai Liu ◽  
Bin Zhang ◽  
Lei Chen ◽  
Zhongyue Cao ◽  
Pengfei Shi ◽  
...  

The purpose of the present work is to probe the friction mechanism of hydrogenated diamond-like carbon (H-DLC) film in air by varying sliding velocity (25–1000 mm/s). Friction tests of Al2O3 ball against H-DLC film were conducted with a rotational ball-on-disk tribometer. As the sliding velocity increases, both the friction coefficient and the surface wear of H-DLC film decrease, reach the minimum values, and then increase in the high sliding velocity region. Based on the observed results, three main friction mechanisms of H-DLC film—namely graphitization mechanism, transfer layer mechanism, and passivation mechanism—are discussed. Raman analysis indicates that the graphitization of worn surface on the H-DLC film has a negligible contribution to the variation of the friction coefficient and the surface wear. The origin of the sliding velocity dependence is due to the synergistic interaction between the graphitized transfer layer formation and the surface passivation. The present study will not only enrich the understanding of friction mechanism of H-DLC films in air, but will also help to promote their practical engineering applications.

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Narin Sunthornpan ◽  
Shuichi Watanabe ◽  
Nutthanun Moolsradoo

Elements-added diamond-like carbon films for biomedical applications were investigated. The aim of this work was to study the effects of the elemental contents (silicon and silicon-nitrogen) in a DLC film on its properties for biomedical applications. Pure DLC, Si-DLC, and Si-N-DLC films were prepared from C2H2, C2H2 : TMS, and C2H2 : TMS : N2 gaseous mixtures, deposited on an AISI 316L substrate using the plasma-based ion implantation (PBII) technique. The structure of films was analyzed using Raman spectroscopy. The chemical composition of films was measured using energy dispersive X-ray spectroscopy (EDS). The average surface roughness of films was measured by using a surface roughness tester. The hardness and elastic modulus of films were measured by using a nanoindentation hardness tester. The friction coefficient of films was determined using a ball-on-disk tribometer. The surface contact angle was measured by a contact angle measurement. The corrosion performance of each specimen was measured using potentiodynamic polarization. The biocompatibility property of films was conducted using the MTT assay cytotoxicity test. The results indicate that the Si-N-DLC film shows the best hardness and friction coefficient (34.05 GPa and 0.13, respectively) with a nitrogen content of 0.5 at.%N, while the Si-DLC film with silicon content of 14.2 at.%Si reports the best contact angle and corrosion potential (92.47  and 0.398 V, respectively). The Si-N-DLC film shows the highest cell viability percentage of 81.96%, which is lower than the uncoated AISI 316L; this is a considerable improvement. All specimens do not demonstrate any cytotoxicity with approximate viabilities between 74% and 107%, indicating good biocompatibilities.


2011 ◽  
Vol 44 (11) ◽  
pp. 1296-1303 ◽  
Author(s):  
Takeshi Yamaguchi ◽  
Junji Ando ◽  
Takuya Tsuda ◽  
Naoko Takahashi ◽  
Mamoru Tohyama ◽  
...  

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1550 ◽  
Author(s):  
Yunhai Liu ◽  
Lei Chen ◽  
Bin Zhang ◽  
Zhongyue Cao ◽  
Pengfei Shi ◽  
...  

The friction of hydrogenated diamond-like carbon (H-DLC) films was evaluated under the controlled environments of humid air and vacuum by varying the applied load. In humid air, there is a threshold applied load below which no obvious friction drop occurs and above which the friction decreases to a relatively low level following the running-in process. By contrast, superlubricity can be realized at low applied loads but easily fails at high applied loads under vacuum conditions. Further analysis indicates that the graphitization of the sliding H-DLC surface has a negligible contribution to the sharp drop of friction during the running-in process under both humid air and vacuum conditions. The low friction in humid air and the superlow friction in vacuum are mainly attributed to the formation and stability of the transfer layer on the counterface, which depend on the load and surrounding environment. These results can help us understand the low-friction mechanism of H-DLC film and define optimized working conditions in practical applications, in which the transfer layer can be maintained for a long time under low applied load conditions in vacuum, whereas a high load can benefit the formation of the transfer layer in humid air.


2017 ◽  
Vol 24 (02) ◽  
pp. 1750014 ◽  
Author(s):  
Y. CHENG ◽  
Y. M. LU ◽  
Y. L. GUO ◽  
G. J. HUANG ◽  
S. Y. WANG ◽  
...  

Multilayer diamond-like carbon film with germanium buffer layers, which was composed of several thick DLC layers and thin germanium island “layers” and named as Ge-DLC film, was prepared on the germanium substrate by ultraviolet laser. The Ge-DLC film had almost same surface roughness as the pure DLC film. Hardness of the Ge-DLC film was above 48.1[Formula: see text]GPa, which was almost the same as that of pure DLC film. Meanwhile, compared to the pure DLC film, the critical load of Ge-DLC film on the germanium substrate increased from 81.6[Formula: see text]mN to 143.8[Formula: see text]mN. Moreover, Ge-DLC film on germanium substrates had no change after fastness tests. The results showed that Ge-DLC film not only kept high hardness but also had higher critical load than that of pure DLC film. Therefore, it could be used as practical protective films.


2007 ◽  
Vol 127 ◽  
pp. 245-250 ◽  
Author(s):  
Mitsuyasu Yatsuzuka ◽  
Yoshihiro Oka ◽  
Akifumi Tomita ◽  
Noritaka Murata ◽  
Mitsuaki Hirota

Diamond-like carbon film (DLC) with an interlayer of plasma sprayed tungsten-carbide (WC) was prepared on an aluminum alloy substrate (A5052) by a hybrid process of plasma-based ion implantation and deposition using hydrocarbon gas. Typical thicknesses of DLC and WC films were 1 μm and 100 μm, respectively. The hardness and friction coefficient of DLC were typically 15 GPa and 0.15, respectively. The durability of DLC/WC/A5052 system was evaluated from the measurement of the friction coefficient by a ball-on-disk friction tester in which the loaded ball was drawn repeatedly across a sample and the load was increased with each traverse. For the DLC/A5052 system, which has no WC interlayer, the DLC film was broken quickly because of distortion of the substrate. For the DLC/WC/A5052 system, on the other hand, the DLC film was excellent in durability for long running. The wear rate of rubber rotor to the metal rotor was measured by a roller-pitching-type wear testing machine, showing large reduction in wear rate using DLC-coated metal rotor.


2013 ◽  
Vol 745-746 ◽  
pp. 60-65
Author(s):  
Nan Yu Ma ◽  
Dan Zeng ◽  
Yu Jie Huang ◽  
Jun Wei Di ◽  
Mu Sen Li

Ag nanoparticles (NPs) have prominent local surface plasma resonance effect (LSPR), and Ag NPs exhibit sharpest and strongest bands among all metals. Diamond-like carbon (DLC) film have good biological compatibility and also have high transmissibility in the visible and near-infrared region. A new LSPR interface between Ag NPs and ultra-thin DLC film was formed by Plasma Enhanced Chemical Vapor Deposition. The morphologies and properties of the Ag NPs coated with DLC film were studied with SEM and AFM. The results indicated that the thickness of DLC film increased with the deposition time. LSPR peak became sharper after depositing for 1 or 2 min. DLC film was prior to nucleate on the surface of Ag NPs, and it has high content of sp2 bonds near the interface. The sensitivity of new LSPR interface deposited for 20s was about the half of the sensitivity of bare Ag NPs and the sensitivity significantly decreased with deposition time. This result is helpful to understand the behavior of the new LSPR interface and to improve its sensitivity.


2017 ◽  
Vol 749 ◽  
pp. 70-75
Author(s):  
Xia Zhu ◽  
Kazuki Kubo ◽  
Hiromichi Toyota ◽  
Shinfuku Nomura ◽  
Yukiharu Iwamoto ◽  
...  

Diamond-like-carbon (DLC) films are promising as coating materials. Ion plating, an excellent method in terms of adhesiveness, step coverage, and deposition rate, can form not only pure metal films but also oxide films, nitride films, and carbonized films. In this study, which aimed to form a DLC film with good adhesiveness and a diamond crystal structure, a DLC film, with a SiC interlayer formed by ion plating with introduction of tetramethylsilane (TMS), was formed. It was experimentally revealed that as the interlayer thickness increases, the crystal structure in the DLC film becomes more diamond rich, and the adhesiveness of the DLC film and substrate is thereby improved.


2008 ◽  
Vol 1138 ◽  
Author(s):  
Yasuharu Ohgoe ◽  
Haruki Matsuo ◽  
Kazuhiro Nonaka ◽  
Toshiyuki Yaguchi ◽  
Kazuya Kanasugi ◽  
...  

AbstractIn this study, we focus on effect of diamond-like carbon (DLC) coating on scaffold for tissue engineering. DLC film was deposited on segmented polyurethane (SPU) scaffold sheet which consists of micro SUP fibers. Structural and compositional effects of the DLC film coating were investigated on cell growth as an investigation of biological response. The surface composition, morphology, structures, and wettability of the DLC film coating was estimated by using X-ray photoelectron spectrometer (XPS), Scanning Electron Microscope (SEM), Ar-laser Raman spectrophotometer (Raman), and contact angle measurement. And then, human umbilical vein endothelial (HUV-EC-C) cells were grown on the DLC coated scaffold sheet. The results presented here suggest that DLC film coating is promising approach to improve biological for tissue engineering.


2001 ◽  
Vol 685 ◽  
Author(s):  
Anatoli A. Evtukh ◽  
Volodimir G. Litovchenko ◽  
Yurii M. Litvin ◽  
Dmitrii V. Fedin ◽  
Yurii V. Rassamakin ◽  
...  

AbstractThe main requirements to electron field emission cathodes are their efficiency, stability and uniformity. In this work we combined the properties of porous silicon layers and diamond-like carbon (DLC) film to obtain emission cathodes with improved parameters. The layered structures of porous silicon and DLC film were formed both on flat n-Si surface and silicon tips created by chemical etching. The conditions of the anodic and stain etching of silicon in HF containing solution under the illumination have been widely changed. The influence of thin (≤10nm) DLC film coating of the porous silicon layer on electron emission has been investigated. The parameters of emission efficiency such as field enhancement coefficient, effective emission areas and threshold voltages have been estimated from current-voltage dependencies to compare and characterize different layered structures. The improvement of the emission efficiency of silicon tip arrays with porous layers coated with thin DLC film has been observed. These silicon-based structures are promising for flat panel display applications.


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