Tribochemical Reactions of Si Incorporated Diamond-Like Carbon Films During the Initial Transient Period

1997 ◽  
Vol 498 ◽  
Author(s):  
Myoung-Geun Kim ◽  
Kwang-Ryeol Lee ◽  
Kwang Yong Eun
Keyword(s):  
Friction Coefficient ◽  
Auger Spectroscopy ◽  
Carbon Films ◽  
Diamond Like Carbon ◽  
Ambient Atmosphere ◽  
Friction Mechanism ◽  
Initial Transient ◽  
Tribochemical Reactions ◽  
Transient Period ◽  
Oxide Debris

ABSTRACTTribochemical reactions between Si incorporated diamond-like carbon (Si–DLC) films and steel ball were investigated during initial stage of tribo-test. The films were deposited by r.f.–PACVD using mixtures of diluted silane (SiH4:H2=10:90) and benzene gases. Si concentration in the film was varied from 0 to 10 at.% by adjusting the diluted silane fraction in the reaction gases. A rotating type ball-on-disk wear rig was employed for the tribo-test in ambient atmosphere. When the Si concentration was less than 5 at.%, initial transient period of high friction coefficient was commonly observed. After the transient period, the friction coefficient becomes lower with increasing contact cycles. The initial transient period becomes shorter and the starting and maximum friction coefficients in transient period decreased with increasing Si concentration. Composition of the debris on the wear scar surface was analyzed by Auger spectroscopy at various stages in the initial transient period. We observed that when the friction coefficient increased in earlier stage of the transient period, iron and oxygen was observed in the debris. However, decrease in the friction coefficient in the later stage of the transient period was associated with the formation of silicon rich oxide debris. This result supports the friction mechanism of Si-DLC films that the formation of Si rich oxide debris results in low friction coefficient in ambient atmosphere.

scholarly journals Key Role of Transfer Layer in Load Dependence of Friction on Hydrogenated Diamond-Like Carbon Films in Humid Air and Vacuum

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1550 ◽  
Author(s):  
Yunhai Liu ◽  
Lei Chen ◽  
Bin Zhang ◽  
Zhongyue Cao ◽  
Pengfei Shi ◽  
...  
Keyword(s):  
Applied Load ◽  
Carbon Films ◽  
Diamond Like Carbon ◽  
Low Friction ◽  
Transfer Layer ◽  
Humid Air ◽  
Friction Mechanism ◽  
Sharp Drop ◽  
Practical Applications ◽  
Load Dependence

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.

Effect of RF Negative Bias on the Structure and Performance of Diamond-Like Carbon Films in ECR Plasma

2013 ◽  
Vol 423-426 ◽  
pp. 756-761
Author(s):  
Li Jun Sang ◽  
Qiang Chen ◽  
Zhong Wei Liu ◽  
Zheng Duo Wang
Keyword(s):  
Friction Coefficient ◽  
Electron Cyclotron Resonance ◽  
Crystalline Silicon ◽  
Carbon Films ◽  
Diamond Like Carbon ◽  
Negative Bias ◽  
Film Property ◽  
Ecr Plasma ◽  
Peak Intensity ◽  
Stretching Vibration

Diamond-like carbon films (DLC) were deposited on single crystalline silicon surface under different RF negative bias in microwave electron cyclotron resonance (ECR) plasma source. The chemical structure and morphology were characterized by Fourier transformation infrared spectroscopy (FTIR) and atomic force microscopy (AFM). The friction coefficient of films was measured to examine the film property later. The results show that the smooth and compact deposited films were typical hydrogenated diamond-like carbon with CHn stretching vibration in 2800-3000cm-1. It is noticed that with the increase of RF bias on the substrate the peak intensity for C-H stretching vibration in spectrum between 2800cm-1~3000cm-1 increased at the beginning and then decreased, which caused the friction coefficient of the film being smaller and then larger in reverse. In 50W RF biased power one can obtain the maximum-CHn peak intensity and the minimum friction coefficient.

The Effect of CNT Content on the Tribological Properties of CNTs Doped Diamond-Like Carbon Films

2015 ◽  
Vol 642 ◽  
pp. 231-235
Author(s):  
Che Hung Wei ◽  
Jui Feng Yang ◽  
Chao I Wang
Keyword(s):  
Friction Coefficient ◽  
Critical Load ◽  
Internal Stress ◽  
Tribological Properties ◽  
Chemical Vapor ◽  
Carbon Films ◽  
Diamond Like Carbon ◽  
Element Analysis ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Diamond-like carbon (DLC) films is useful in many applications. To improve the tribological properties in DLC, we spin coat the multi-walled carbon nanotubes (CNTs) with different solution on (100) silicon. DLC was deposited by plasma enhanced chemical vapor deposition (PECVD) with C2H2and H2. The results show that the ID/IGratio is increasing with higher CNTs content while the friction coefficient and critical load are decreasing with larger CNTs contents. The decreasing friction coefficient results from graphitation on the surface due to higher sp2content. The decreasing critical load is attributed to higher internal stress. The effect of friction coefficient and CNT concentration on stress distribution is studied by a nanoscratch finite element analysis. The results indicate that low friction coefficient and high CNT concentration will reduce the stress magnitude in the film. Therefore, the decreasing friction coefficient in CNT doped DLC film with increasing CNT concentration should reduce stress in the film and is good for adhesion. The discrepancy between friction coefficient and critical load is explained in terms of high internal stress during deposition. A surface treatment on CNT before deposition to reduce internal stress is currently under investigation.

Ultra-low friction mechanism of highly sp3-hybridized amorphous carbon controlled by interfacial molecule adsorption

2018 ◽  
Vol 20 (35) ◽  
pp. 22445-22454 ◽  
Author(s):  
Jing Shi ◽  
Tiandong Xia ◽  
Chengbing Wang ◽  
Kun Yuan ◽  
Junyan Zhang
Keyword(s):  
Amorphous Carbon ◽  
Carbon Materials ◽  
Carbon Films ◽  
Nanocrystalline Diamond ◽  
Diamond Like Carbon ◽  
Low Friction ◽  
Friction Mechanism ◽  
Molecule Adsorption

The friction behaviors of highly sp3-hybridized carbon films, including ultra-nanocrystalline diamond and diamond-like carbon materials, strongly depend on atmospheres.

Micromechanical Behaviour of Amorphous Hydrogenated Silicon Carbide Films

1993 ◽  
Vol 308 ◽  
Author(s):  
J. Meneve ◽  
R. Jacobs ◽  
F. Lostak ◽  
L. Eersels ◽  
E. Dekempeneer ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Friction Coefficient ◽  
Wear Rate ◽  
Chemical Vapour ◽  
Diamond Like Carbon ◽  
Ambient Atmosphere ◽  
Low Friction ◽  
Hydrogenated Silicon ◽  
Amorphous Hydrogenated Silicon ◽  
Low Wear

ABSTRACTAmorphous hydrogenated silicon carbide (a-Si1-xCx:H) films (x = 0.65 to 1) were deposited by radio frequency plasma assisted chemical vapour deposition (RF-PACVD). Their friction and wear properties were investigated by means of a conventional ball-on-disk apparatus. The results were correlated with film mechanical properties. It was found that adding silicon to a-C:H (also called diamond-like carbon (DLC)) films reduces the hardness, elastic modulus and internal stress values by 15 to 30 %. Scratch testing induces film spallation from stainless steel substrates at low loads (1 N). In the low normal load (1 N) ball-on-disk tests under humid N2 conditions, a-Si1-xCx:H films (0.7 < x < 0.9) combine a very low wear rate of both the film and the counterbody with a steady state low friction coefficient below 0.1. For higher loads (5 and 10 N), however, this low friction coefficient only lasts for a relatively short time. In this case, the harder diamond-like carbon films perform tribologically better because of their higher wear resistance, low wear rate of the counterbody and generally low friction coefficients between 0.15 and 0.35 in a humid ambient atmosphere. In a dry N2 atmosphere, pure DLC films perform tribologically better than a-S1-xCx:H films in all respects.

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 ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Surface Passivation ◽  
Carbon Film ◽  
Diamond Like Carbon ◽  
Surface Wear ◽  
Sliding Velocity ◽  
Transfer Layer ◽  
Friction Mechanism ◽  
Dlc Film ◽  
Practical Engineering

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.

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