scholarly journals Influence of nitrogen on the tribological properties of a-C:H layers on the polycarbonate substrates

2008 ◽  
Vol 2 (2) ◽  
pp. 69-73 ◽  
Author(s):  
Rafal Nowak ◽  
Stanislawa Jonas

Polycarbonate (PC) possesses many commercial applications. However, PC is still limited to non-abrasive and chemical-free environments due to its low hardness, low scratching resistance and high susceptibility to chemical attacks. To overcome this limitation, PC can be coated by hydrogenated amorphous carbon layers. The a-C:H layers have very attractive properties such as high hardness, infrared transparency, chemical inertness, low friction coefficients, and biocompatibility. Addition of nitrogen in the structure allows lowering internal stress and improve tribological properties of a-C:H layers. In this work, a-C:N:H layers were deposited from mixture CH4/N2 gases by RF PECVD method. Effects of the nitrogen incorporation on structure and tribological properties of deposited layers were investigated. The structure of layers were characterized by Fourier Transform Infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The friction coefficient, wear resistance of a-C:H:N layers were estimated by tribometer in ball-on-disc configuration. The IR spectra of the obtained layers have demonstrated a presence of nitrogen bonded both to carbon and to hydrogen. A formation of the following bonds has been confirmed: -C?N, -NH2, -C?NH2, >C=NH. They are all typical for a-C:N:H layers. The tribological tests have shown that the layers reduce the friction coefficient of the polycarbonate (up to 50 %) and considerably improve wear resistance.

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 719
Author(s):  
Yuki Hirata ◽  
Ryotaro Takeuchi ◽  
Hiroyuki Taniguchi ◽  
Masao Kawagoe ◽  
Yoshinao Iwamoto ◽  
...  

Amorphous boron carbon nitride (a-BCN) films exhibit excellent properties such as high hardness and high wear resistance. However, the correlation between the film structure and its mechanical properties is not fully understood. In this study, a-BCN films were prepared by an arc-sputtering hybrid process under various coating conditions, and the correlations between the film’s structure and mechanical properties were clarified. Glow discharge optical emission spectroscopy, X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, and Raman spectroscopy were used to analyze the structural properties and chemical composition. Nanoindentation and ball-on-disc tests were performed to evaluate the hardness and to estimate the friction coefficient and wear volume, respectively. The results indicated that the mechanical properties strongly depend on the carbon content in the film; it decreases significantly when the carbon content is <90%. On the other hand, by controlling the contents of boron and nitrogen to a very small amount (up to 2.5 at.%), it is possible to synthesize a film that has nearly the same hardness and friction coefficient as those of an amorphous carbon (a-C) film and better wear resistance than the a-C film.


2011 ◽  
Vol 695 ◽  
pp. 417-420 ◽  
Author(s):  
Hyun Hwi Lee ◽  
Seung Ho Kim ◽  
Bhupendra Joshi ◽  
Soo Wohn Lee

Oxide ceramics such as alumina and zirconia are industrially utilized as cutting tools, a variety of bearings, biomaterials, and thermal and corrosion-resistant coatings due to their high hardness, chemical inertness, high melting point, and ability to retain mechanical strength at elevated temperatures. In this research, the effect of other ceramic additives (TiO2) and h-BN within alumina(α-Al2O3) and yttria-stabilized tetragonal (Y-TZP) composite was studied with respect to the mechanical and tribological properties. The lowest coefficient of frction of 0.45 was observed for the ZTA ceramic composite with hBN-TiO2. The highest hardness, fracture toughness and flexural strength were obtained as 15.7GPa, 5.2MPam-1/2, 712MPa, respectively.


Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 635 ◽  
Author(s):  
Fang Han ◽  
Huaixing Wen ◽  
Jianjian Sun ◽  
Wei Wang ◽  
Yalong Fan ◽  
...  

This paper concerns a comparative study on the tribological properties of Si3N4-10 vol% hBN bearing on GCr15 steel under seawater lubrication and dry friction and fresh-water lubrication by using a pin-on-disc tribometer. The results showed that the lower friction coefficient (around 0.03) and wear rate (10−6 mm/Nm) of SN10/GCr15 tribopair were obtained under seawater condition. This might be caused by the comprehensive effects of hydrodynamics and boundary lubrication of surface films formed after the tribo-chemical reaction. Despite SN10/GCr15 tribopair having 0.07 friction coefficient in the pure-water environment, the wear mechanismsits were dominated by the adhesive wear and abrasive wear under the dry friction conditions, and delamination, plowing, and plastic deformation occured on the worn surface. The X-ray photoelectron spectroscopy analysis indicated that the products formed after tribo-chemaical reaction were Fe2O3, SiO2, and B2O3 and small amounts of salts from the seawater, and it was these deposits on the worn surface under seawater lubrication conditions that, served to lubricate and protect the wear surface.


2013 ◽  
Vol 734-737 ◽  
pp. 2369-2372
Author(s):  
Lei Lei Gao ◽  
Jin Zhong Zhang

A commercial Mg alloy was prepared through equal channel angular extrusion (ECAE) process. The effect of ECAE on mechanical and tribological properties of the alloy was investigated. Experimental results showed that the hardness and strength of the alloy with ECAE were higher than that of the alloy without ECAE and increased with the increase pass number. The friction coefficient and wear resistance of the alloy after ECAE were significantly improved.


2009 ◽  
Vol 60-61 ◽  
pp. 270-273
Author(s):  
Guang Gui Cheng ◽  
Jian Ning Ding ◽  
Biao Kan ◽  
Zhen Fan

In order to analyze the effect of proceeding on the mechanical and tribological properties of DLC films. Three DLC films samples on single silicon wafers were prepared by CVD method. The changed bias voltages were 300V, 350V, 450V separately. The structure and topography of prepared films were studied by Raman spectroscopy and atomic force microscopy (AFM), respectively. The hardness and elastic modulus together with friction coefficient of DLC films were measured by Tribolab system. According to the Raman spectra, the G and D peak shift to left with the increasing of bias voltage. Nano indent showed that the hardness (H) of the DLC films decreases from 19.63GPa to 18.12GPa with the increasing of bias voltages, and the value of elastic modulus (E) is also behaving the same trend as H from 157.95GPa to 146.95GPa. Friction coefficients of the three samples were measured by nano-scratch method under the constant normal load of 1000uN and the slide velocity of 3 um/sec, the corresponding friction coefficient is 0.0804 for DLC300, 0.0508for DLC350 and 0.0594 for DLC450 separately, which indicates that high hardness materials may not necessarily the perfect frictional material, but compound properties of hardness and elastic modulus


2016 ◽  
Vol 674 ◽  
pp. 239-243
Author(s):  
Gai Zhao ◽  
Qi Hua Wang ◽  
Irina Hussainova ◽  
Qing Jun Ding

Polyimide (PI) composites have been widely used in a space science due to extraordinary properties, such as excellent mechanical and electrical properties, good thermal stability and chemical inertness, as well as high wear resistance. However, atomic oxygen (AO), as one of the main radiated constituents in low earth orbit, had an important influence on the structrural and tribological properties of the polyimide matrix. To investigate the mechanism of AO erosion on polyimide, MoS2/Al2O3/PI composites were fabricated by means of a hot-press molding technique and irradiated by AO in a ground-based simulation system. The chemical composition change of the irradiated surface was examined by X-ray photoelectron spectroscopy (XPS). Then, the friction and sliding wear behavior against GCr15 steel balls were evaluated in a ground-based simulation facility using ball-on-disk tribology test rig. The worn morphologies and radiated surfaces of the materials were observed by Scanning electron microscope (SEM) to reveal the wear mechanism. Experimental analysis indicated that oxidation induced by AO irradiation and degradation of PI molecular chains on the composite’ surface results in change in chemical composition and formation of “carpet-like” structures. Affected layer, gradually formed during the process of irradiation, plays an important role for wear performance of the materials increasing friction coefficient and wear rate. Incorporation of Al2O3 nanofibers and MoS2 nanoparticles is shown to be favourable for AO resistance, which is helpful for improvement in wear resistance of the PI.


2010 ◽  
Vol 33 ◽  
pp. 483-486
Author(s):  
Hai Dong Yang ◽  
Xi Quan Xia ◽  
Zhen Hua Qing

The method of “cutting instead of grinding” on hardened steel is always attractive to engineers. To gain this aim the tool material must first be found. C3N4 is a new kind of super hard material and has comparable properties with diamond in high hardness, wear-resistance, low friction coefficient and thermal conductivity. A number of dry-cutting tests were carried out by C3N4-film coated tool on hardened steel, proved the coating tool is suitable for hard dry cutting.


2010 ◽  
Vol 450 ◽  
pp. 189-193 ◽  
Author(s):  
Ji Hui Yin ◽  
Jian Jun Qu ◽  
Bao Yu Song ◽  
Dai Zhong Su

Tribological properties of the urea grease containing nano-silica were investigated with a four-ball tester, and its noise characteristics were evaluated with a BVT-1 bearing vibration tester. The results showed that the nano-silica has good effects on friction and wear resistances, the urea grease with 3% nano-silica has the least value of friction coefficient, and the urea grease with 2% nano-silica showed the best wear resistance. A proper amount of nano-silica can decrease the noise of the urea grease, and when lubricated by the grease with 1% nano-silica, the bearing achieved its lowest noise level as well as the best velocity values of both intermediate and high frequencies.


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.


1997 ◽  
Vol 505 ◽  
Author(s):  
Q. Wei ◽  
R. J. Narayan ◽  
A. K. Sharma ◽  
S. Oktyabrsky ◽  
J. Sankar ◽  
...  

ABSTRACTWe have investigated the microstructure and tribological properties (wear resistance) of diamondlike carbon (DLC), DLC doped with Cu and DLC doped with Ti deposited by a sequential pulsed laser ablation of two targets onto Si(100) substrates. The composition of these films was determined by Rutherford backscattering spectroscopy and X-ray photoelectron spectroscopy(XPS). Raman spectroscopy and detailed analysis of the electron diffraction pattern of the films showed typical features of DLC with a structure dominated by sp3 bonded carbon. Wear resistance measurements made on these samples by means of the “crater grinding method” showed that DLC + 2.75%Ti has the highest wear resistance, while that of undoped DLC has the lowest among the samples. The improvement of wear behavior of the doped films was attributed to the reduction of internal compressive stress due to the presence of more compliant atoms, as indicated by the G-peak position shift to smaller Raman shift. The XPS studies showed the evidence for the formation of Ti- C bonding in the Ti doped films. Thus we expect metal-doped DLC coatings can have better tribological properties than the undoped, highly stressed DLC coatings.


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