scholarly journals Optimizing the tribological performance of DLC-coated NBR rubber: The role of hydrogen in films

Friction ◽  
2021 ◽  
Author(s):  
Changning Bai ◽  
Li Qiang ◽  
Bin Zhang ◽  
Kaixiong Gao ◽  
Junyan Zhang
Keyword(s):  
Surface Energy ◽  
High Hardness ◽  
Adhesive Force ◽  
Film Structure ◽  
Tribological Performance ◽  
Butadiene Rubber ◽  
Water Contact ◽  
Hydrogen Incorporation ◽  
Dlc Film ◽  
Impacted Load

AbstractDiamond-like carbon (DLC) films directly deposited on rubber substrate is undoubtedly one optimal option to improve the tribological properties due to its ultralow friction, high-hardness as well as good chemical compatibility with rubber. Investigating the relationship between film structure and tribological performance is vital for protecting rubber. In this study it was demonstrated that the etching effect induced by hydrogen incorporation played positive roles in reducing surface roughness of DLC films. In addition, the water contact angle (CA) of DLC-coated nitrile butadiene rubber (NBR) was sensitive to the surface energy and sp2 carbon clustering of DLC films. Most importantly, the optimum tribological performance was obtained at the 29 at% H-containing DLC film coated on NBR, which mainly depended on the following key factors: (1) the DLC film with appropriate roughness matched the counterpart surface; (2) the contact area and surface energy controlled interface adhesive force; (3) the microstructure of DLC films impacted load-bearing capacity; and (4) the generation of graphitic phase acted as a solid lubricant. This understanding may draw inspiration for the fabrication of DLC films on rubber to achieve low friction coefficient.

Tunnel electron photoemission in the nanoscale DLC film structure with electrostatic field localization

2017 ◽  
Author(s):  
Nikolay P. Aban'shin ◽  
Garif G. Akchurin ◽  
Yuri A. Avetisyan ◽  
Alexander P. Loginov ◽  
Denis S. Mosiyash ◽  
...  
Keyword(s):  
Electrostatic Field ◽  
Film Structure ◽  
Dlc Film ◽  
Electron Photoemission ◽  
Field Localization

The tribological performance of W-DLC in solid–liquid lubrication system addivated with Cu nanoparticles

2021 ◽  
Author(s):  
Dong shan Li ◽  
Ning Kong ◽  
Ruishan Li ◽  
Boyang Zhang ◽  
Yongshun Zhang ◽  
...  
Keyword(s):  
Test Temperature ◽  
Applied Load ◽  
Tribological Performance ◽  
Dominant Factor ◽  
Lubrication System ◽  
Cu Nanoparticles ◽  
Friction Test ◽  
Dlc Film ◽  
Test Conditions ◽  
Solid Liquid

Abstract Judicious selection of additives having chemical and physical compatibility with the DLC films may help improving the triboligical properties and durability life of DLC-oil composite lubrication systems. In this study, Cu nanoparticles were added to PAO6 base oil to compose a solid-liquid composite lubrication system with W-DLC film. The effects of nanoparticle concentration, test temperature and applied load on tribological performance were systematically studied by a ball-on-disk friction test system. The tribological results illustrated that Cu nanoparticles could lower the coefficient of friction (COF) and dramatically reduce the wear rates of W-DLC films. The optimal tribological behavior was achieved for the 0.1 wt.% concentration under 30 ℃ and the applied load of 100 N. The test temperature and applied load were vital influencing factors of the solid–liquid lubrication system. The bearing effect and soft colloidal abrasive film of spherical Cu nanoparticle contributed to the excellent tribological performance of the composite lubrication system under mild test conditions, meanwhile, the local delamination of W-DLC film and oxidation were the main causes of the friction failure under harsh test conditions. With test temperature and applied loads increase the degree of graphitization of the W-DLC film increased. In conclusion, there are several pivotal factors affecting the tribological performance of solid–liquid lubrication systems, including the number of nanoparticles between rubbing contact area, graphitization of the worn W-DLC films, tribofilms on the worn ball specimens and oxidation formed in friction test, and the dominant factor is determined by the testing condition.

scholarly journals High Loading Capacity and Wear Resistance of Graphene Oxide/Organic Molecule Assembled Multilayer Film

2021 ◽  
Vol 9 ◽  
Author(s):  
Li Chen ◽  
Gang Wu ◽  
Yin Huang ◽  
Changning Bai ◽  
Yuanlie Yu ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Multilayer Films ◽  
Thickness Measurement ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Film Structure ◽  
Silicon Substrates ◽  
Water Contact ◽  
Macro Scale

Taking advantage of the strong charge interactions between negatively charged graphene oxide (GO) sheets and positively charged poly(diallyldimethylammonium chloride) (PDDA), self-assembled multilayer films of (GO/PDDA)n were created on hydroxylated silicon substrates by alternating electrostatic adsorption of GO and PDDA. The formation and structure of the films were analyzed by means of water contact angle measurement, thickness measurement, atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). Meanwhile, tribological behaviors in micro- and macro- scale were investigated by AFM and a ball-on-plate tribometer, respectively. The results showed that (GO/PDDA)n multilayer films exhibited excellent friction-reducing and anti-wear abilities in both micro- and macro-scale, which was ascribed to the special structure in (GO/PDDA)n multilayer films, namely, a well-stacked GO–GO layered structure and an elastic 3D crystal stack in whole. Such a film structure is suitable for design molecular lubricants for MEMS and other microdevices.

MULTILAYERS DIAMOND-LIKE CARBON FILM WITH GERMANIUM BUFFER LAYERS BY PULSED LASER DEPOSITION

2017 ◽  
Vol 24 (02) ◽  
pp. 1750014 ◽  
Author(s):  
Y. CHENG ◽  
Y. M. LU ◽  
Y. L. GUO ◽  
G. J. HUANG ◽  
S. Y. WANG ◽  
...  
Keyword(s):  
Critical Load ◽  
Carbon Film ◽  
High Hardness ◽  
Buffer Layers ◽  
Diamond Like Carbon ◽  
Dlc Film ◽  
Diamond Like Carbon Film ◽  
Film Hardness ◽  
Protective Films ◽  
Germanium Substrate

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.

Addition of Cellulose Nanofibers to Control Surface Roughness for Hydrophobic Ceramic Coatings

2021 ◽  
Vol 21 (8) ◽  
pp. 4492-4497
Author(s):  
Eun Ae Shin ◽  
Gye Hyeon Kim ◽  
Jeyoung Jung ◽  
Sang Bong Lee ◽  
Chang Kee Lee
Keyword(s):  
Surface Roughness ◽  
Contact Angle ◽  
Surface Energy ◽  
Water Contact Angle ◽  
Ceramic Coating ◽  
Cellulose Nanofibers ◽  
Ceramic Coatings ◽  
Coating Material ◽  
Textured Surface ◽  
Water Contact

Hydrophobic ceramic coatings are used for a variety of applications. Generally, hydrophobic coating surfaces are obtained by reducing the surface energy of the coating material or by forming a highly textured surface. Reducing the surface energy of the coating material requires additional costs and processing and changes the surface properties of the ceramic coating. In this study, we introduce a simple method to improve the hydrophobicity of ceramic coatings by implementing a textured surface without chemical modification of the surface. The ceramic coating solution was first prepared by adding cellulose nanofibers (CNFs) and then applied to a polypropylene (PP) substrate. The surface roughness increased as the amount of added CNFs increased, increasing the water contact angle of the surface. When the amount of CNFs added was corresponding to 10% of the solid content, the surface roughness average of the area was 43.8 μm. This is an increase of approximately 140% from 3.1 μm (the value of the surface roughness of the surface without added CNFs). In addition, the water contact angle of the coating with added CNF increased to 145.0°, which was 46% higher than that without the CNFs. The hydrophobicity of ceramic coatings with added CNFs was better because of changes in the surface topography. After coating and drying, the CNFs randomly accumulated inside the ceramic coating layer, forming a textured surface. Thus, hydrophobicity was improved by implementing a rugged ceramic surface without revealing the surface of the CNFs inside the ceramic layer.

scholarly journals Superhydrophobic Self-Assembled Silane Monolayers on Hierarchical 6082 Aluminum Alloy for Anti-Corrosion Applications

2020 ◽  
Vol 10 (8) ◽  
pp. 2656 ◽  
Author(s):  
Amani Khaskhoussi ◽  
Luigi Calabrese ◽  
Edoardo Proverbio
Keyword(s):  
Aluminum Alloy ◽  
Surface Energy ◽  
High Water ◽  
Dip Coating ◽  
Aluminum Surface ◽  
Sliding Angle ◽  
Water Contact ◽  
Electrochemical Tests ◽  
Self Assembled ◽  
6082 Aluminum Alloy

In this work, a two-stage methodology to design super-hydrophobic surfaces was proposed. The first step consists of creating a rough nano/micro-structure and the second step consists of reducing the surface energy using octadecyltrimethoxysilane. The surface roughening was realized by three different short-term pretreatments: (i) Boiling water, (ii) HNO3/HCl etching, or (iii) HF/HCl etching. Then, the surface energy was reduced by dip-coating in diluted solution of octadecyltrimethoxysilane to allow the formation of self-assembled silane monolayers on a 6082-T6 aluminum alloy surface. Super-hydrophobic aluminum surfaces were investigated by SEM-EDS, FTIR, profilometry, and contact and sliding angles measurements. The resulting surface morphologies by the three approaches were structured by a dual hierarchical nano/micro-roughness. The surface wettability varied with the applied roughening pretreatment. In particular, an extremely high water contact angle (around 180°) and low sliding angle (0°) were evidenced for the HF/HCl-etched silanized surface. The results of electrochemical tests demonstrate a remarkable enhancement of the aluminum alloy corrosion resistance through the proposed superhydrophobic surface modifications. Thus, the obtained results evidenced that the anti-wetting behavior of the aluminum surface can be optimized by coupling an appropriate roughening pretreatment with a self-assembled silane monolayer deposition (to reduce surface energy) for anticorrosion application.

Preparation of Hydrophobic Nylon Fabric

2016 ◽  
Vol 11 (1) ◽  
pp. 155892501601100
Author(s):  
Jinmei Du ◽  
Lulu Zhang ◽  
Jing Dong ◽  
Ying Li ◽  
Changhai Xu ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Contact Angle ◽  
Surface Energy ◽  
Water Contact Angle ◽  
Sem Images ◽  
Water Contact ◽  
Carboxyl Content ◽  
Factors Affecting ◽  
Nylon Fabric ◽  
Butanetetracarboxylic Acid

Surface roughness and surface energy are two important factors affecting the hydrophobicity of nylon fabric. In this study, nylon fabric was treated for hydrophobicity with tetrabutyltitanate (TBT) and octadecylamine (OA) which were respectively responsible for increasing surface roughness and reducing surface energy. In order to enhance the hydrophobicity, In order to further enhance hydrophobicity by increasing available reactive sites, 1,2,3,4–butanetetracarboxylic acid (BTCA) was applied as a pretreatment to the nylon fabric It was found that the carboxyl content of nylon was increased by the BTCA pretreatment. SEM images showed that the TBT treatment produced small particles on nylon fabric which made surface rough. The water contact angle of nylon fabric treated with BTCA, TBT and OA was measured to be 134°, which was much greater than the water contact angle of nylon fabric treated only with OA. This indicated that the surface roughness resulting from the TBT treatment played an important role in improving hydrophobicity of the treated nylon fabric. The resistance to water penetration and the repellency of water spray of nylon fabric treated with BTCA, TBT and OA were respectively measured to be 27.64 mbar and 85 out of 100.

scholarly journals Effect of Zr Target Current on the Mechanical and Tribological Performance of MoS2–Zr Composite Lubricating Coatings

Coatings ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 80
Author(s):  
Wenlong Song ◽  
Zixiang Xia ◽  
Shoujun Wang ◽  
Qingge Zhang
Keyword(s):  
Mechanical Properties ◽  
Composite Coatings ◽  
Adhesive Force ◽  
Tribological Performance ◽  
Micro Hardness ◽  
Radio Frequency Magnetron Sputtering ◽  
Ion Plating ◽  
Surface Morphologies ◽  
Wear Modes ◽  
Mos2 Coating

To improve the tribological properties of pure MoS2 coating, the MoS2–Zr composite lubricating coatings were prepared on the WC/TiC/Co carbide surface utilizing radio frequency magnetron sputtering method combining with multiple arc ion plating technology. The effects of different Zr target currents on the surface morphologies, roughness, Zr content, adhesive force, thickness, microhardness and tribological behaviors of the composite coatings were systematically investigated. Results showed that the properties of MoS2 coating can be remarkably enhanced through co-deposition of a certain amount of Zr. As the Zr target current increased, the Zr content, surface roughness, thickness, and micro-hardness gradually increased, while the adhesive force of coatings increased first and then decreased. The friction behaviors and wear modes of the composite coatings both varied obviously with the increase of Zr current. The mechanism was mainly attributed to the different components and mechanical properties of the coatings caused by various Zr current.

scholarly journals Maleic Anhydride Modified Dicyclopentadiene Resin for Improving Wet Skid Resistance of Silica Filled SSBR/BR Composites

2020 ◽  
Vol 10 (13) ◽  
pp. 4478 ◽  
Author(s):  
Ruoming Huang ◽  
Qiwei Pan ◽  
Zhaohui Chen ◽  
Kunhao Feng
Keyword(s):  
Maleic Anhydride ◽  
Contact Angles ◽  
Styrene Butadiene Rubber ◽  
Skid Resistance ◽  
Butadiene Rubber ◽  
Maximum Enhancement ◽  
Water Contact ◽  
Tan Δ ◽  
Styrene Butadiene ◽  
Wet Skid Resistance

As commercial rubber in tires, silica-filled solution-polymerized styrene-butadiene rubber/butadiene rubber (SSBR/BR) compounds exhibited preferable wet skid resistance (WSR) properties, which could be further enhanced by the incorporation of some oligomeric resins. However, the untreated dicyclopentadiene (DCPD) resin shows a slight improvement in wet friction even if the good compatibility between DCPD and SBR owing to their common cyclic structures. For this problem to be addressed, we aimed to enhance its resin-silica interaction by reaction with maleic anhydride (MAH). In detail, the effect of MAH content on WSR, curing characteristics, physical-mechanical properties of the silica-filled SSBR/BR composites was investigated. When the MAH content is 4 wt% in the modified DCPD resin, the maximum enhancement of about 15% in tan δ values at 0 °C, as well as that of 17% in British pendulum skidding tester (BPST) index is obtained, indicating a desirable improvement in WSR. In addition of these two commonly used methods, water contact angles of the vulcanizates increase gradually with increasing MAH content, further confirming the remarkable performance of modified DCPD resin in WSR.

scholarly journals Superhydrophobic organosilicon-based coating system by a novel ultravoilet-curable method

2017 ◽  
Vol 7 ◽  
pp. 184798041770279 ◽  
Author(s):  
Baojiang Liu ◽  
Taizhou Tian ◽  
Jinlong Yao ◽  
Changgen Huang ◽  
Wenjun Tang ◽  
...  
Keyword(s):  
Contact Angle ◽  
Surface Energy ◽  
Silica Nanoparticles ◽  
Water Contact Angle ◽  
Cotton Fabric ◽  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Water Repellent ◽  
Step Method ◽  
Water Contact

A robust superhydrophobic organosilica sol-gel-based coating on a cotton fabric substrate was successfully fabricated via a cost-effective one-step method. The coating was prepared by modification of silica nanoparticles with siloxane having long alkyl chain that allow to reduce surface energy. The coating on cotton fabric exhibited water contact angle of 151.6°. The surface morphology was evaluated by scanning electron microscopy, and surface chemical composition was measured with X-ray photoelectron spectroscopy. Results showed the enhanced superhydrophobicity that was attributed to the synergistic effect of roughness created by the random distribution of silica nanoparticles and the low surface energy imparted of long-chain alkane siloxane. In addition, the coating also showed excellent durability against washing treatments. Even after washed for 30 times, the specimen still had a water contact angle of 130°, indicating an obvious water-repellent property. With this outstanding property, the robust superhydrophobic coating exhibited a prospective application in textiles and plastics.

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