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1.
Y. Song  M. Zou  Y.A. Wang 《Thin solid films》2010,518(14):3801-1083
Hydrophobic micro/nano-engineered surfaces (MNESs) with good adhesion and frictional performances were fabricated by the combination of aluminum-induced crystallization (AIC) of amorphous silicon (a-Si) and octadecyltrichlorosilane (OTS) coating. The AIC of a-Si technique was used to produce silicon micro/nano-textured surfaces, while an OTS self-assembled monolayer was used to lower the surface energies of the textured surfaces. The wetting properties of the MNESs were studied using a video-based contact angle measurement system. The adhesion and friction properties of the MNESs were investigated using a TriboIndenter. This study shows that the adhesion and frictional performances of all MNESs are significantly improved compared to untreated silicon substrate surfaces, and the adhesion and frictional performances of the OTS-modified textured surfaces strongly correlate to their surface wetting property, i.e., the larger the water contact angle, the better the adhesion and frictional performances of the OTS-modified textured surfaces.  相似文献   

2.
A new micromechanical model describing the sliding friction wear of polycrystalline solids is proposed. The model is consistent with a hypothesis suggested previously, according to which the transition from intensive to moderate wear (for the nonconforming bodies in sliding friction contact) is related to attaining a definite, sufficiently small shear strain rate at the friction surface, depending on the absolute value of the normal force applied to the friction contact. In addition, the model explains some well-known empirical relationships between the wear intensity and friction coefficient for steel on steel in a wide range of loads and pressures in the friction contact.  相似文献   

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4.
龚乾江  徐祥  杨明 《复合材料学报》2017,34(10):2171-2181
采用干法热压成型工艺制备高摩复合材料,研究了基体材料腰果壳油改性酚醛树脂(CPR)与丁晴橡胶(NR)的质量比和新型高性能填料(主要成分为石墨粉Al2O3、MoS2、Fe粉)含量对高摩复合材料摩擦磨损性能的影响规律。在摩擦磨损试验机上测试了高摩复合材料的摩擦磨损性能,利用激光共聚焦显微镜、扫描电镜对摩擦表面形貌、磨屑进行观察和分析,借助EDS测定摩擦表面成分的变化。结果表明,随着CPR与NR质量比的增加,高摩复合材料的耐热性能、结合性能大幅提高,且具有较好的摩擦磨损性能。当高性能填料含量较低时,磨损表面出现大量连续的真实接触面,磨损机制为磨粒磨损和黏着磨损;当高性能填料含量较高时,真实接触面积减少,磨损表面剥落严重,并出现较多的裂纹,其主要磨损形式转变为磨粒磨损和疲劳磨损。随着高性能填料含量的增加,摩擦表面的元素从均匀分布逐渐转变为局部富集,磨粒的尺寸逐渐变大。  相似文献   

5.
The potential use of fluorinated, polyacrylonirtile-based, high strength carbon fibers as reinforcement for a fluorocarbon polymer, namely poly (vinylidene fluoride) (PVDF), was investigated by means of the single fiber pull-out test. The apparent interfacial shear strength as a measure of practical adhesion was determined and the fracture and friction behavior of the model composites characterized.It was shown that the fracture behavior of the model composites is predominately brittle in nearly all cases. Fluorination of carbon fibers has a positive impact on the adhesive strength to PVDF. The apparent interfacial shear strength increases with increasing degree of fiber surface fluorination and becomes maximal at a degree of fiber fluorination (F/C-ratio) of around 0.8, determined by ESCA, which is close to that of PVDF. This result points to the fact that the increased practical adhesion is due to a physical compatibilization between the fluorinated fibers and the surrounding PVDF matrix. It was found that, even though the interfacial shear strength increases with increasing degree of fiber surface fluorination, the friction between fluorinated carbon fibers and the surrounding PVDF decreases.  相似文献   

6.
In this work,the high temperature friction mechanism of the tetrahedral amorphous carbon(ta-C)film was elucidated.The multilayer ta-C film with alternating hard...  相似文献   

7.
《材料科学技术学报》2019,35(7):1261-1269
High depth-to-width ratio friction stir welding is an attractive method for the joining demands of aluminum profiles, which is sparked with its extremely low heat input and high mechanical performance. In this study, the joint formation mechanism was studied by a numerical model of plastic flow combined with experimental approaches. A fluid-solid-interaction algorithm was proposed to establish the coupling model, and the material to be welded was treated as non-Newtonian fluid. The thread structure and the milling facets on tool pin promoted drastic turbulence of material. The thread structure converged the plasticized material by its inclined plane, and then drove the attached material to refill the welds. The milling facets brought about the periodic dynamic material flow. The thread structure and the milling facets increased the strain rate greatly under the extremely low heat input, which avoided the welding defects. The condition of the peak temperature of 648 K and the strain rate of 151 s−1 attributed to the lowest coarsening degree of precipitate. The tensile strength of the joint reached 265 MPa, equivalent to 86% of base material. The amelioration via the material flow model inhibits the welding defects and optimizes the parameter intervals, providing references to extracting process-structure-property linkages for friction stir welding.  相似文献   

8.
Minimization of the amount of salmon adhering to the can wall after emptying is one of the convenience requirements of consumers of canned salmon. In order to achieve this, the mechanism by which salmon adheres to cans needs to be understood. The aim of this study was to provide such knowledge for polymer‐coated cans. The results indicate that gelatin, derived from salmon collagen, and myofibrillar proteins are the major proteins involved in sticking of salmon to the polymer‐coated can wall. Furthermore, it was shown that mainly hydrogen bonds are formed between the salmon proteins and the polymer surface. Therefore, making the surface more apolar can prevent sticking of salmon to polymer‐coated cans. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

9.
The nanotribological characterization of carbon nanotubes is fundamental for the exploration of new sliding applications. In this study, a comprehensive investigation of adhesion, friction and wear of a multiwalled nanotube (MWNT) tip, and SWNT (single-walled nanotube) and MWNT arrays has been carried out. A nonlinear response of the MWNT tip is observed when the tip is brought into and out of contact with various surfaces. A nonlinear response occurs due to the buckling of the nanotube and its subsequent sliding on the surface. In addition to the role of surface chemistry, it can also explain the relatively high value of the coefficient of friction obtained on different surfaces, as compared to that of Si and Si(3)N(4) tips. The adhesion and friction studies carried out on SWNT and MWNT arrays using Si tips show that SWNT arrays, compared to MWNT arrays, exhibit lower values, possibly due to lower van der Waals forces as a result of lower packing density and higher flexibility. The wear tests conducted with the MWNT tip and a Si tip on a gold film, at two normal loads, show less damage of the surface when the MWNT tip is used because of the MWNT acting as a compliant spring, absorbing part of the load. Wear tests conducted with a Si tip on SWNT and MWNT arrays show that the arrays do not wear. The tip wear and the friction force in the SWNT array are lower, because of lower adhesion and higher flexibility of the SWNTs, which causes less opposition to the motion of the tip.  相似文献   

10.
The effects of the fluid friction acting on the endfaces of the revolving vane (RV) machine, where the cylinder rotates together with the rotor, are investigated analytically with closed form solutions. It was found that the endface losses of the RV machine are generally affected by both the relative velocity and the eccentricity between the rotor and the cylinder. The endface loss of an RV machine with the simply supported bearing arrangement is found to be always lower than that with the cantilever arrangement.When compared to a similar rotary machine but with a stationary cylinder, the RV machine used in this study exhibits a 95% decrease in the endface loss, while in the wider practical dimensions range, an RV machine consistently shows at least a 50% lower in endface loss.These findings supply more proof to the claim of the suitability of the employment of the RV mechanism in high-speed and high-pressure applications.  相似文献   

11.
高硅铝合金的摩擦磨损性能   总被引:1,自引:0,他引:1  
朱学卫  王日初  王小锋  彭健 《功能材料》2015,(8):8063-8066,8071
采用喷射沉积技术和热挤压致密化技术制备Al-22Si和Al-27Si(质量分数)两种高硅铝合金,研究两种合金在不同载荷下的摩擦行为和磨损机理。结果表明,与铸态合金相比,喷射沉积技术制备的高硅铝合金具有晶粒细小、成分均匀的组织特征;在载荷为30,45,60和75 N下,Al-22Si合金的磨损以粘着磨损和氧化磨损为主;Al-27Si合金在低载荷下以粘着磨损为主,在高载荷下的磨损行为时粘着磨损和磨粒磨损的混合磨损机制。含有较高硅含量的Al-27Si合金具有相对小的摩擦系数和磨损率。随着载荷增大,两种合金的磨损量逐渐增大。  相似文献   

12.
基于轮轨之间的摩擦耦合自激振动引起钢轨波磨的观点,论文建立了车辆稳态通过小半径曲线时由轮对-钢轨-轨枕组成的轮轨系统有限元弹性振动摩擦自激振动有限元模型,用ABAQUS软件对该模型的运动稳定性进行了分析,重点研究了轮轨摩擦系数和蠕滑力-蠕滑率曲线负斜率对轮轨系统摩擦自激振动的影响。计算结果显示,轮轨摩擦系数对轮轨摩擦自激振动有重要影响,当控制摩擦系数 时可以消除钢轨磨耗型波磨,蠕滑力-蠕滑率曲线负斜率对钢轨波磨有显著影响。  相似文献   

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14.
《材料科学技术学报》2019,35(6):1027-1038
Defect-free dissimilar Al/zinc coated steel and Al/AlSi coated steel welds were successfully fabricated by refill friction stir spot welding. However, Al alloy and uncoated steel could not be welded under the same welding condition. Al-Zn eutectic layer formed at the Al/zinc coated steel interface showed non-uniformity in thickness and nanoscale intermetallic (IMC) produced was discontinuous. The bonding formation between the Al-Zn layer and the surrounding materials was attributed to a liquid/solid reaction mechanism. Bonding formation at Al alloy and AlSi coated steel interface was attributed to a solid/solid reaction mechanism, as the joining process did not involve with melting of base metals or AlSi coating materials. Kissing bond formed at the weld boundary acted as a crack initiation and propagation site, and the present study showed that weld strength of Al 5754/AlSi coated steel was greatly influenced by properties of original IMC layer.  相似文献   

15.
In this paper, the comparative tribological property of 9Cr18 friction pair used for aerospace components was investigated using a ball-on-disc tester in four different service conditions: in air, in vacuum, and with or without MoS2-based film. The results indicate that the friction coefficients of the 9Cr18 couplings with MoS2 solid lubrication or in vacuum are much lower than those in the conditions of dry friction or atmosphere, with relatively flat ground trace surfaces. While the friction coefficients of usual materials of friction pairs in vacuum are higher than those in atmosphere, it is shown in our study that the abnormal performance may be induced by the surface hardenability of dry friction transition and the lubrication effect of the MoS2-based film. At the same time, the tribological mechanism of the pair is considered as well.  相似文献   

16.
In this study, rubber compounds were produced in varying proportions of carboxylated acrylonitrile butadiene rubber (XNBR) and natural rubber (NR) and the parameters such as cure characteristics, wear behavior against various surfaces at different normal loads, and frictional works were tested. The tensile strength and dynamic co-efficient of friction of sample containing 80 wt.% of XNBR was high compared to other samples by 2% and 10% respectively. The results of XNBR and NR vulcanizates under normal pressure ranging from 43 to 118 kPa were reported. Based on these results the relationship between normal load and dynamic co-efficient of friction has been proposed. It was also observed that sample containing 80 wt.% of XNBR exhibits lesser volume loss than compared to other samples.  相似文献   

17.
从金属橡胶材料的干摩擦阻尼产生的机理入手,提出了一种全新的金属橡胶非线性干摩擦结构单元力学模型, 该结构单元由一对带有轴向和径向两个方向的弹性元件构成,它们既表示了金属丝之间的摩擦特性,同时也表示了螺线卷线匝在受力变形时的弹性特征。以建立的金属橡胶材料力学模型为基础, 采用多个摩擦副单元串联组成的结构,深入研究了线匝的摩擦接触, 通过对结构单元组成系统的计算机模拟仿真,对金属橡胶元件在不同载荷作用下的滞迟回线进行了深入地分析和研究,在静态载荷作用下,研究了结构单元的摩擦系数、结构单元的摩擦角对金属橡胶结构摩擦耗能的影响,在动态载荷作用下,研究了载荷的幅值、载荷的频率、载荷的初始相位对摩擦耗能的影响, 此项研究工作大大减少了静态和动态试验方面的工作。  相似文献   

18.
Abstract

Friction welding of high strength aluminium alloys was considered in the current study. The mechanism of bond formation in dissimilar alloy welding was compared to similar alloy welding. The differences in flow properties between two different alloys of aluminium lead to uneven deformation behaviour while welding. Since flow behaviour directly affects bond formation and strength, it is important to understand its behaviour. Rods of aluminium alloys AA 2024 and AA 6061 were welded to themselves and to each other denoting similar and dissimilar weld systems. Burn-off length, which is one of the important parameters in friction welding was varied in steps to see how it affects the bond formation. The flash geometry of the welds was observed to interpret the flow differences. Reasons for variations in bond formation were discussed with the help of fracture surfaces.  相似文献   

19.
The effects of alumina (Al2O3) as an abrasive on brake friction performance and friction layers of nonmetallic brake friction materials were evaluated. Five experimental compositions containing from 0 to 14.6 vol% alumina were tested (Al2O3—0, 3.4, 5.6, 9.0, and 14.6 vol%). The experimental results indicated that alumina enhances friction coefficient and improves wear performance. The formation and development of friction layers were characterized using X-ray fluorescence spectrometry and scanning electron microscopy with energy dispersive X-ray analysis. Phenomena of baryte film and transferred iron-containing film formed on the friction surfaces were observed. Baryte films were detected on specimens containing from 0 to 5.6 vol% alumina. Iron-containing films were detected on surfaces of all alumina-containing specimens but not on the material without alumina. The role of abrasive in nonmetallic friction materials was studied in relation to formulation, friction performance, and friction surfaces.  相似文献   

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