环氧树脂基复合涂层摩擦磨损性能研究

研究了不同质量分数石墨、碳纤维、纳米ZrO2对环氧树脂(EP)涂层摩擦磨损性能的影响,并用扫描电子显微镜观察了涂层磨损表面形貌并探讨了磨损机理。结果表明:石墨质量分数为20%时复合涂层的磨损率仅为纯EP的7.75%;纳米ZrO2质量分数为4%时复合涂层的磨损率为纯EP的30%;纳米ZrO2与碳纤维以及石墨的协同作用提高了EP的摩擦磨损性能。EP复合涂层的磨损机理以粘着磨损、磨粒磨损以及疲劳磨损为主。     

Tribological properties of hydrogenated amorphous carbon under dry and lubricated conditions

Diamond-like carbon (DLC) coatings are considered as potential surface coatings for many engineering applications including gears and engine parts. It is important to know whether conventional extreme pressure (EP) additive-containing oil can work with DLCs and provide tribological performance as effective as they provide on steel surfaces. This study examines the friction and wear properties of hydrogenated amorphous carbon (a-C:H) under dry, base oil (BO)- and fully formulated gear oil (FF)-lubricated conditions. Pronounced graphitisation occurs due to rubbing under dry condition and provides low friction but promotes wear. However, BO and FF greatly suppress graphitisation and wear. Tribofilms formed from FF in a-C:H/steel contact appear to exhibit superior antiwear properties than those formed in steel/steel contact.     

Tribological and corrosion performance of epoxy resin composite coatings reinforced with graphene oxide and fly ash cenospheres

In this work, a novel graphene oxide (GO)-fly ash cenospheres (FACs) hybrid fillers was introduced to improve the wear and corrosive resistance of epoxy resin (ER) composite coatings. The tribological behavior and the corrosion performance of three kinds of coatings (pure ER, GO/ER and GO-FACs/ER coatings) were studied and the reinforced mechanisms of coatings filled by different fillers were analyzed. The friction coefficient and wear rate of the ER coatings were decreased with the addition of GO-FACs hybrids. The scanning electron microscope images showed that the dispersibility and compatibility of GO-FACs hybrids were effectively improved compared with that of GO sheet. The water contact angle examination indicated that the hydrophobicity of the GO-FACs/ER coatings increased. The electrochemical impedance spectroscopy (EIS) results demonstrated that the GO-FACs/ER coatings have better anticorrosion performance compared with the pure ER coatings and the GO/ER coatings. The hydrophobic surface and the well dispersed fillers constitute the dual barrier to resist the corrosion medium.     

Microstructural and mechanical characteristics of graphene oxide-fly ash cenosphere hybrid reinforced epoxy resin composites

An experimental investigation into the influence of incorporation of graphene oxide (GO) and fly ash cenospheres (FACs) on the mechanical properties of epoxy resin (EP) composites. Two fillers were studied: GO-FAC hybrid and single GO. The GO-FAC hybrid was synthesized using a solution blending method, and characterized by FTIR, XRD, and scanning electron microscope (SEM). The modified EP composite specimens were prepared by adding different contents of GO and GO-FAC hybrid. The investigation showed that the FACs were successfully carried on the GO layer. The experimental data indicated that the addition of GO-FAC hybrid effectively improved the tensile property and the wear resistance of the EP composites, superior to the addition of single GO samples. The best tensile properties and lowest wear rate of EP composites were obtained when the hybrid content was 0.5 wt %. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 47173.     

EP/氧化石墨烯–硬脂酸丁酯微胶囊复合材料

采用种子微悬浮聚合法制备了聚苯乙烯/氧化石墨烯复合囊壁包覆硬脂酸丁酯微胶囊润滑材料(MGO–Micro LMs),以MGO–Micro LMs为润滑填料,环氧树脂(EP)为基体材料,采用浇注成型工艺制备了EP/MGO–Micro LMs复合材料。采用滑动摩擦磨损试验仪评价了MGO–Micro LMs对EP基体材料摩擦学性能的影响;采用扫描电子显微镜对磨损面的微观形貌进行表征,并探究了其磨损机理。结果表明,MGO–Micro LMs能够显著地降低EP的摩擦系数和磨损量,当MGO–Micro LMs质量分数为20%时,EP/MGO–Micro LMs复合材料的摩擦系数为0.138 44,磨损量减少了约42.3%,磨损机理主要为磨粒磨损。     

Tribological properties of polyimide coatings filled with PTFE and surface‐modified nano‐Si3N4

Polyimide (PI) coatings filled with PTFE and nano‐Si₃N₄ were prepared by a spraying technique and successive curing. Nano‐Si₃N₄ particles were modified by grafting 3‐aminopropyltriethoxysilane to improve their dispersion in the as‐prepared coatings. Friction and wear performances and wear mechanisms of the coatings were evaluated. The results show that the incorporations of PTFE and modified nano‐Si₃N₄ particles greatly improve the friction reduction and wear resistance of PI coating. The friction and wear performance of the composite coating is significantly affected by the filler mass fraction and sliding conditions. PI coating incorporated with 20 wt % PTFE and 5 wt % modified nano‐Si₃N₄ displays the best tribological properties. Its wear rate is more than one order of magnitude lower and its friction coefficient is over two times smaller than that of the unfilled PI coating. Differences in the friction and wear behaviors of the hybrid coatings as a function of filler or sliding condition are attributed to the filler dispersion, the characteristic of transfer film formed on the counterpart ball and the wear mechanism of the coating under different sliding conditions. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40410.     

SiAlON–epoxy nanocomposite coatings: Corrosion and wear behavior

In this study, epoxy powder as a matrix was combined with different contents of silicon–aluminum–oxygen–nitrogen (SiAlON) nanoparticles using a planetary ball mill. Pure epoxy and nanocomposite powders were applied on the surface of plain carbon steel components by the electrostatic spraying method. Curing of the coatings was done in an oven or microwave for the appropriate time. The coating structure and morphology of the SiAlON nanoparticles were studied by scanning electron microscopy and transmission electron microscopy, respectively. The corrosion properties of the coatings were assessed by immersion, Tafel polarization, and electrochemical impedance spectroscopy tests in 3.5% NaCl solution. The results show that addition of 10 wt % SiAlON nanoparticles markedly increases the corrosion resistance of epoxy coatings. Thus, it can be inferred that the corrosion rate of these coatings is 15 to 18 times lower than that of pure epoxy samples and 8 to 11 times lower than coatings with 20 wt % SiAlON. The higher corrosion resistance of nanocomposite coatings can be attributed to the barrier properties of SiAlON nanoparticles. The tribological performance of the coatings was studied with the pin‐on‐disk test. The results of wear testing show that the samples containing 10 wt % SiAlON provide about five times more wear resistance than pure ones and about two times more than coatings with 20 wt % SiAlON. However, the coefficient of friction for nanocomposite coatings is reduced about 50% compared to the pure sample. Also, the curing process in either regime (oven or microwave) has the same effect on the corrosion and wear properties, and the coatings are completely crosslinked. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43855.     

Microstructural,mechanical and tribological properties of suspension plasma sprayed YSZ/h-BN composite coating

Brittleness, relative high friction coefficient and wear rate limit the applications of ceramic coatings as wear-resistant layers. However, because embedding additives with ceramic matrix has demonstrated to be an effective way to improve coating performances, different contents and size of h-BN were added into an YSZ suspension. Afterwards, the YSZ/h-BN composite coatings were manufactured by suspension plasma spray and their tribological analysis indicated that: i) the reduction of the friction coefficient and wear rate can be achieved by incorporating h-BN into YSZ coating. ii) finer h-BN particle is more helpful to enhance the tribological properties of the coating. iii) the optimum content is dependent on h-BN particle sizes. iv) when the contents and the size of the h-BN inclusion increase, the probability distribution of the micro-hardness can become bi-modal. Three worn surface conditions were summarized and their wear mechanisms were discussed as well.     

Effect of solid lubricants on tribological behavior of glass fiber reinforced polyamide 6

The tribological properties of glass fiber reinforced polyamide 6 (GF/PA6, 15/85 by weight) and its composites filled with solid lubricants were investigated. The main purposes of this article were to study the hybrid effect of solid lubricants with glass fiber as well as the synergism of combined solid lubricants, the wear mechanisms were studied by SEM. The results showed that graphite impaired the tribological properties of GF/PA6, but the tribology behavior of graphite filled GF/PA6 composite could be significantly improved by polytetrafluroethylene (PTFE) or/and ultrahigh molecular weight polyethylene (UHMWPE), and the GF/PA6 composite filled with 5 wt % graphite, 5 wt % PTFE together with 5 wt % UHMWPE exhibited the lowest friction coefficient and wear rate, which was almost a reduction in friction coefficient by 37% and in wear rate by 34% contrast to GF/PA6. The effect of load was also studied, and the results showed that the friction coefficient was virtually not affected by load, while the wear rate all increased with increasing load. POLYM. COMPOS., 34:1783–1793, 2013. © 2013 Society of Plastics Engineers     

Double layer aligned-graphene nanosheets/styrene-butadiene rubber composites: Tribological and mechanical properties

We enhanced tribological and mechanical properties of styrene-butadiene rubber (SBR) by designing double layer aligned-graphene nanosheets (aligned-GNSs)/SBR composites with one-step emulsion polymerization preparation method. The composites consisted of two layers, one is the SBR layer and the other is aligned-GNSs/SBR layer, in which the graphene nanosheets (GNSs) regularly aligned. The resulted composites exhibited mega increase of tribological property as well as mechanical property. With the increase of GNSs contents from 0.5 to 5 wt %, both the friction coefficient and volume wear rate steadily declined, and the mechanics dramatically increased. Such as 59% decrease of friction coefficient and 1778% increase of the initial tensile modulus when the addition of GNSs is 5 wt %. The above results are mainly due to the well aligned-GNSs in SBR, which can take full advantage of the unique properties of GNSs two-dimensional materials. The detailed mechanisms of improving tribological and mechanical properties were discussed in the study. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 46939.     

Tribological application of carbon nanotubes in a metal-based composite coating and composites

Ni-P-carbon nanotube (CNT) composite coating and carbon nanotube/copper matrix composites were prepared by electroless plating and powder metallurgy techniques, respectively. The effects of CNTs on the tribological properties of these composites were evaluated. The results demonstrated that the Ni-P-CNT electroless composite coating exhibited higher wear resistance and lower friction coefficient than Ni-P-SiC and Ni-P-graphite composite coatings. After annealing at 673 K for 2 h, the wear resistance of the Ni-P-CNT composite coating was improved. Carbon nanotube/copper matrix composites revealed a lower wear rate and friction coefficient compared with pure copper, and their wear rates and friction coefficients showed a decreasing trend with increasing volume fraction of CNTs within the range from 0 to 12 vol.% due to the effects of the reinforcement and reduced friction of CNTs. The favorable effects of CNTs on the tribological properties are attributed to improved mechanical properties and unique topological structure of the hollow nanotubes.     

硼化钽增强聚醚醚酮复合涂层的制备及性能评价

采用阴极电泳沉积技术在纯钛基板表面沉积聚醚醚酮（PEEK）/硼化钽（TaB₂）复合涂层。采用透射电子显微镜、扫描电子显微镜、X射线衍射仪和摩擦磨损试验机等方式对电泳沉积液分散性、PEEK/TaB₂复合涂层表面形貌、微观结构、结晶行为、摩擦学性能和生物学性能进行表征。结果表明，通过调节电泳沉积参数可以制备形貌均匀、具有一定厚度的PEEK/TaB₂复合涂层，在390 ℃热处理后，涂层均匀致密无孔隙；热处理可以提高PEEK/TaB₂涂层的结晶性能，TaB₂颗粒的加入使PEEK涂层获得更高的结晶度；添加较低含量的TaB₂颗粒时，复合涂层在小牛血清（fetal bovine serum，FBS）介质中表现出良好的摩擦学性能，与纯PEEK涂层相比，磨损率分别下降了48.1 %，69.1 %；但过量TaB₂颗粒在PEEK基质中出现明显的团聚现象， 摩擦系数和磨损率呈现上升趋势；细胞实验表明，TaB₂良好的生物活性促进了样品表面细胞增殖。     

Effect of MoS2/PTFE coatings on performance of Si3N4/TiC ceramics in dry sliding against WC/Co

To enhance the tribological performance of Si₃N₄/TiC ceramics, MoS₂/PTFE composite coatings were deposited on the ceramic substrate through spraying method. The micrographs and basic properties of the MoS₂/PTFE coated samples were investigated. Dry sliding friction experiments against WC/Co ball were performed with the coated ceramics and traditional ones. These results showed that the composite coatings could significantly reduce the friction coefficient of ceramics, and protect the substrate from adhesion wear. The primary tribological mechanisms of the coated ceramics were abrasive wear, coating spalling and delamination, and the tribological property was transited from slight wear to serious wear with the increase of load because of the lower surface hardness and shear strength. The possible mechanisms for the effects of MoS₂/PTFE composite coatings on the friction performance of ceramics were discussed.     

Structural and tribological characterization of amorphous and crystalline titanium-nickel coatings

The interest in titanium-nickel (TiNi) alloys has increased with the discovery of the versatile properties of these alloys. In this study, the structural, mechanical and tribological properties of amorphous and crystalline TiNi coatings were investigated. The TiNi coatings were deposited with magnetron sputtering system. The crystallization process was conducted in a vacuum heat treatment furnace. The structural properties of the coatings were investigated with XRD, SEM and EDS analyses. Micro-hardness and pin-on-disc wear tests were used to obtain the mechanical and tribological properties of the coatings. AISI D2 steel, AISI 52100 steel, Aluminum 2024 alloy and copper were used as substrate materials, hence the effects of different substrates were also investigated. The highest coating hardness was obtained as 8.5?GPa and the lowest coefficient of friction value was obtained as 0.18. The tribological tests showed that the amorphous and crystalline TiNi coatings have different coefficient of friction and wear rate and using different substrate affects these properties.     

Influence of surface modification of carbon nanotube on microstructures and properties of polyamide 66/multiwalled carbon nanotube composites

The melt‐mixing polyamide 66 (PA66) composite samples that incorporated pure, acid‐ and amine‐functionalized multiwalled carbon nanotubes (MWCNTs) were prepared in order to enhance mechanical and frictional properties of PA66 composites. The homogeneous dispersion of amine‐functionalized MWCNTs (D‐MWCNTs) in PA66 matrix was observed from the significantly uniform morphology of tensile fractured surface of the composites. Differential scanning calorimetry measurement indicates that D‐MWCNTs acted as effective nucleation agent for PA66 matrix and the crystallinity of PA66 was increased. The fracture stress and tensile modulus of the composites were significantly improved with the incorporation of D‐MWCNTs, owing to the good dispersion of D‐MWCNTs. Compared with PA66, the PA66 composites with 1.0 wt% D‐MWCNTs were improved considerably in both wear and friction properties owing to the change of the tribological mechanisms. The good dispersion of D‐MWCNTs in PA66 and good interface compatibility between D‐MWCNTs and PA66 favored the formation of a thin layer on the contact surfaces during wear and friction test, which played an important role in reducing wear and friction of the composite and in suppressing the transverse cracks. These results prove the importance of D‐MWCNTs in a positive change of the mechanical and frictional properties of PA66 composites and suggest the applicability prospect of PA66/D‐MWCNTs composites in engineering components.POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers     

Wear-resistant ceramic coatings deposited by liquid thermal spraying

As a surface strengthening and surface modification technology of materials, liquid thermal spray technology has been used in many fields, such as wear and friction reduction, corrosion resistance, and high-temperature oxidation resistance. This article reviews the progress of liquid thermal sprayed coating in wear resistance as well as friction reduction in recent years. The influences of microstructure, composition, phase structure and mechanical properties on the tribological properties of typical coatings (including ceramic coatings and multiphase composite coatings) are investigated. The tribological properties of the coating are determined by the coating characteristics (including microstructure, porosity, mechanical properties, etc.) and the service conditions (working temperature, lubrication state, etc.). Typical ceramic wear-resistant coatings include Al₂O₃, YSZ, HA coatings, etc. The tribological properties of the coating can be significantly improved through process optimization and heat treatment. The comparison of nanostructured and microstructured ceramic-based coating reveals that nanostructured coating reduces wear by absorbing stress. The interaction between different constituent phases improves wear resistance and reduces wear in composite coatings. Finally, various challenges faced by liquid thermal spray are pointed out, and future research focuses are proposed.     

Submicrometer characterization of surfaces of epoxy‐based organic–inorganic nanocomposite coatings. A comparison of AFM study with currently used testing techniques

Surface properties (morphology, hardness) of transparent colorless epoxy‐based organic–inorganic nanocomposite coatings were investigated by atomic force microscopy, optical and scanning electron microscopy, nanoindentation, and the Persoz pendulum test. Friction and wear coefficients were obtained from tribological experiments. The influence of mechanical properties and the size, shape, and concentration of additives (colloidal silica particles and montmorillonite sheets) on the measured surface characteristics are discussed. It was found that the highest surface hardness (assigned by nanoindentation, pendulum test or expressed as the scratch resistance) exhibited materials with the glass‐transition temperature close to 20°C. Microcopy techniques revealed that surface morphology is influenced by both types of admixtures: on the nanometer scale by colloidal silica particles and on micrometer scale by montmorillonite platelets. Already 1 wt % of montmorillonite increased friction coefficients and wear resistance without distinctive changes of tensile properties. However, the addition of ? 20 wt. % of silica nanoparticles was necessary for the increase of wear and scratch resistances. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:5763–5774, 2006     

Correlation between nanoindentation response and wear characteristics of CrN-based coatings deposited by an Arc-PVD method

The examination of the existing relationships between nanoindentation responses and tribological properties of the nanostructured CrN, Cr(CN), and (CrTi)N coatings was the matters to be considered in this research. A cathodic arc physical vapor deposition machine was therefore implemented to apply the chosen coatings on the DIN 1.2510 tool steel substrate. Moreover, an X-ray diffraction and a field emission scanning electron microscope were utilized in order to show the features regarding microstructure and morphology of these very coatings. The mechanical and tribological behavior of the coatings was expected to be assessed with the use of a nanoindentation and pin-on-disc wear tests. According to the obtained result, the wear resistance and hardness value of the (CrTi)N coating were proved to be much better than those of the CrN and Cr(CN). Linear equations were proposed between wear rate/hardness and friction coefficient/hardness to evaluate the correlation between mechanical and tribological properties. The presence of a quadratic equation between the friction coefficient and the plastic deformation index was also discovered.     

Epoxy composite reinforced with three‐dimensional polyimide fiber felt: Fabrication and tribological properties investigation

Novel epoxy (EP) composite reinforced with three‐dimensional (3D) polyimide (PI) fiber felt (PI_3D/EP) is first fabricated by vacuum assisted resin transfer molding. The tribological behaviors of pure EP and PI_3D/EP composite under dry sliding and water lubricated condition are comparatively studied. Results indicate that both wear rates and friction coefficients of PI_3D/EP composite are lower than those of pure EP. The wear resistance of PI_3D/EP composite is 9.8 times higher than that of pure EP under dry sliding of 1.5 MPa and 0.76 m s^?1 while a 27‐fold increase is achieved under water lubricated condition. The wear mechanisms of PI_3D/EP composite are investigated based on tribological testing results and scanning electron microscopy observations. The PI fiber felt provides strong 3D structure supports to sustain most of the loads on the composite, improving the mechanical and tribological properties significantly. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44160.     

A comparative investigation of the tribological behavior and scratch response of polyester powder coatings filled with different solid lubricants

Employing coatings is one of the most effective methods to reduce friction and protect contacting surfaces from wear. The deposition of protective coatings from thermosetting polymer powders has witnessed a rapid growth as an ecological, economic and energy efficient technology. During the last few decades, many new deposition techniques have been developed, and more and more tribological coatings have been made available. In this context, our present investigation tried, firstly to analyze the friction and wear behavior of electrostatically sprayed polyester powder coatings deposited on an aluminum substrate and secondly to focus on the response of these thermosetting coatings to micromechanical deformation under scratch test loading. The effect of graphite and hexagonal boron nitride (hBN) solid lubricant fillers on the friction and wear behavior of polyester composite coatings was evaluated using a reciprocating tribometer under dry friction condition. The experimental findings show that the additions of graphite or hBN are effective in enhancing the wear life of polyester powder coatings. Meanwhile, under the same sliding conditions, the wear results revealed that the polyester coating filled with only 10 wt.% of graphite has a higher anti-wear ability compared to the polyester coating filled with the same weight fraction of hBN. Thus, the two reinforcing polyester matrix fillers play an important role in reducing the plastic deformation of the coatings and enhance the formation of thick third body between the sliding parts as the fraction of solid lubricant increases from 0 wt.% to 10 wt.%. From the scratch analyses, we deduced that coatings scratch behavior is severely affected by the kind and amount of fillers inside the polyester matrix. In fact, the best friction characteristic and scratch resistance are observed in the case of polyester coatings filled with very low amount of hBN (5 wt.%).