Optimization of tribological parameters in abrasive wear mode of carbon-epoxy hybrid composites

Abrasive wear performance of fabric reinforced composites filled with functional fillers is influenced by the properties of the constituents. This work is focused on identifying the factors such as filler type, filler loading, grit size of SiC paper, normal applied load and sliding distance on two-body abrasive wear behaviour of the hybrid composites. Abrasive wear tests were carried on carbon fabric reinforced epoxy composite (C-E) filled with filler alumina (Al₂O₃) and molybdenum disulphide (MoS₂) separately in different proportions, using pin-on-disc apparatus. The experiments were planned according to Taguchi L18 orthogonal array by considering five factors, one at two levels and the remaining at three levels, affecting the abrasion process. Grey relational analysis (GRA) was employed to optimize the tribological parameters having multiple-response. Analysis of variance (ANOVA) was employed to determine the significance of factors influencing wear. Also, the comparative specific wear rates of all the composites under dry sliding and two-body abrasive wear were discussed. The analysis showed that the filler loading, grit size and filler type are the most significant factors in controlling the specific wear rate of the C-E composite. Optimal combination of the process parameters for multi performance characteristics of the composite under study is the set with filler type as MoS₂, filler loading of 10 wt.%, grit size 320, load of 15 N and sliding distance of 30 m. Further, the optimal parameter setting for minimum specific wear rate, coefficient of friction and maximum hardness were corroborated with the help of scanning electron micrographs.     

Mechanical and three-body abrasive wear behaviour of three-dimensional glass fabric reinforced vinyl ester composite

The mechanical and three-body abrasive wear behaviour of two- and three-dimensional E-glass woven fabric reinforced vinyl ester composites were studied in this article. The mechanical properties were evaluated using universal testing machine as per ASTM D-638. Three-body abrasive wear tests were conducted using rubber wheel abrasion tester (RWAT) under different abrading distances at two loads, wherein the wear volume loss were found to increase and that of specific wear rate decrease. The results indicate that the three-dimensional glass woven fabrics in vinyl ester (G_3D–V) have significant influence on wear under varied abrading distance/loads. Further, it was found that G_3D–V composite exhibited lower wear rate compared to two-dimensional glass woven fabric reinforced vinyl ester (G_2D–V) composite. The worn surface features, as examined through scanning electron microscope (SEM), show ruptured glass fiber in G_2D–V composite compared to G_3D–V composites.     

Abrasive wear behaviour of hard powders filled glass fabric–epoxy hybrid composites

The effect of incorporation of tungsten carbide (WC) and tantalum niobium carbide (Ta/NbC) powders on three-body abrasive wear behaviour in glass fabric–epoxy (G–E) composites was investigated and findings are analysed. A vacuum assisted resin transfer moulding (VARTM) technique was employed to obtain a series of G–E composites containing different fillers (WC and WC + Ta/NbC). Dry sand rubber wheel abrasion test was carried out at 200 rpm speed. The effect of different loads (22 and 32 N) and abrading distances (from 135 to 540 m) on the performance of the wear resistance were measured. The wear volume loss of the composites was found increasing with the increase in abrading distances and under the same conditions the specific wear rate decreases. The hard powders filled G–E composite systems exhibit lower wear volume loss and lower specific wear rate as compared to unfilled G–E composite system. The features of worn surfaces of the specimen were evaluated at higher and lower abrading distances at load of 32 N were using scanning electron microscope (SEM) and results indicate more severe damage to matrix and glass fiber in unfilled composite system as compared to hard powder filled composites.     

Study of Abrasive Wear Volume Map for PTFE and PTFE Composites

The potential of this work is based on consideration of wear volume map for the evaluation of abrasive wear performance of polytetrafluoroethylene (PTFE) and PTFE composites. The fillers used in the composite are 25% bronze, 35% graphite and 17% glass fibre glass (GFR). The influence of filler materials, abrasion surface roughness and applied load values on abrasive wear performance of PTFE and PTFE composites were studied and evaluated. Experimental abrasive wear tests were carried out at atmospheric condition on pin-on-disc wear tribometer. Tests were performed under 4, 6, 8 and 10 N load values, travelling speed of 1 m/sec and abrasion surface roughness values of 5, 20 and 45 μm. Wear volume maps were obtained and the results showed that the lowest wear volume rate for PTFE is reached using GFR filler. Furthermore, the results also showed that the higher is the applied load and the roughness of the abrasion surface, the higher is the wear rate. Finally it is also concluded that abrasive wear process mechanism include ploughing and cutting mechanisms.     

Effect of organoclay addition on the two-body abrasive wear characteristics of polyamide 6 nanocomposites

Polymer clay nanocomposites (PCN) exhibit improved mechanical properties due to nanolevel dispersion of clay in the polymer matrix. They also exhibit good tribological performance under dry sliding conditions. Abrasive wear behaviour of these materials would be different from dry sliding behaviour as the mechanisms of the both are entirely different. Hence the abrasive wear behaviour of these materials needs to be investigated. The abrasive wear characteristics of polyamide 6 nanocomposites, with 1, 3 and 5% (wt.) clay prepared by melt intercalation technique, under two-body abrasive wear conditions have been reported. Abrasive wear tests were conducted using a pin-on-disc tribometer containing an abrasive counterface. All the polyamide nanocomposites investigated exhibited a low abrasive wear resistance compared with pristine Nylon. The wear performance of the nanocomposites was correlated with the mechanical properties. Dominant ploughing and cutting wear were observed in polymer clay nanocomposites. The amount of clay present alters the wear mechanism.     

Evaluation of the friction and wear properties of PTFE composites filled with glass and carbon fiber

The aim of the research article is to study the mechanical and two‐body abrasive wear behaviour of glass/carbon fiber reinforced PTFE composites. The measured wear volume loss increases with increase in abrading distance. The results showed that the highest specific wear rate is for glass fiber reinforced PTFE composite with a value of 8.1×10^–6 mm³/Nm and the lowest wear rate is for carbon fabric reinforced vinyl ester composite with a value of 7.2×10^–6 mm³/Nm. Mechanical properties were evaluated and obtained values are compared with the wear behaviour. The worn surface features have been examined using scanning electron microscope (SEM). Photomicrographs of the worn surfaces revealed higher percentage of broken glass fiber as compared to carbon fiber.     

Abrasive wear of FeCr (M7C3–M23C6) reinforced iron based metal matrix composites

Abstract

The effects of volume fraction, particle size, and sintered porosity of FeCr (M₇C₃–M₂₃C₆) particulates on the abrasive wear resistance of powder metallurgy (PM) Fe alloy metal matrix composites have been studied under different abrasive conditions. It was seen that the abrasive wear rate of the composites increased with an increase in the FeCr volume fraction in tests performed with 80 grade SiC abrasive paper, but it decreased for tests conducted with 220 grade SiC abrasive paper. Furthermore, the wear rates decreased with an increase in FeCr size for composites containing the same amount of FeCr. Hence it is deduced that Fe alloy composites reinforced with larger size FeCr particles are more effective against abrasive wear than those reinforced with smaller ones. At the same time the results show that the beneficial effects of hard FeCr particulates on wear resistance far outweighed the detrimental effects of sintered porosity in the PM metal matrix composites. In addition, the fabrication of composites containing soft particles such as graphite or copper favours a reduction in the coefficient of friction, and increases the matrix hardness of the composite. For this reason graphite and copper were used in the matrix in different amounts to test their effect on the wear resistance. Increase in graphite and copper volume fraction allowed the formation of additional phases, which had high hardness and wear resistance. It was also found that the wear rate of the composites decreased considerably with graphite and copper addition.     

Abrasive Wear Volume Maps for PA6 and PA6 Composites Under Dry Working Condition

In this study the wear volume map is obtained and considered for evaluation of the abrasive wear performance for polyamide (PA6) and PA6 composites. Polyamide composites were tailored using 25 wt.% glass bead, 20 wt.% talc and 30 wt.% wollastonite fillers. In this work, the influence of filler materials, abrasion surface roughness and applied loading values on abrasive wear performance of PA6 and PA6 composites were evaluated. Experimental abrasive wear tests were carried out at atmospheric condition using pin-on-disc rig arrangement. Tests were performed under 4, 6, 8 and 10 N load values, traveling speed of 1 m/s and abrasion surface roughness values of 5, 20 and 45 μm. Wear volume maps were obtained and the results showed that the lowest wear volume rate for PA is reached using glass bead filler. Furthermore, the results also showed that the higher is the applied load and the roughness of the abrasion surface, the higher is the wear rate. Finally it is also concluded that abrasive wear process mechanism include ploughing mechanism and delimitation of filler tips.     

Polymere Hochtemperatur-Verbundwerkstoffe für Anwendungen als Gleitelemente

High temperature polymer composites for applications as sliding elements Polymeric composites are nowadays frequently used for applications in which friction and wear are critical issues. Quite often, they also have to operate at elevated temperatures, so that the use of high temperature polymers is needed. This overview decribes on the example of sliding elements that can be used e.g in textile drying machines, how matrix, fiber and filler components of the composites can affect their friction and wear properties under sliding conditions against steel counterparts. As a good solution for a composite operating as a sliding element under extrem conditions, polyetheretherketone (PEEK) with 10 weight% of each, short carbon fibers, graphite filler, and polytetrafluoroethylene (PTFE) particles is suggested.     

新型填料对高摩复合材料摩擦磨损性能影响及机制

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。     

Study on the friction and wear behavior of basalt fabric composites filled with graphite and nano-SiO2

To improve the friction and wear behavior of basalt fabric reinforced phenolic composites, single graphite or nano-SiO₂ and both of them were incorporated. The tribological properties of the resulting composites under different sliding conditions were investigated systematically on a model ring-on-block test rig. The friction and wear mechanisms of the composites were studied through analyzing the worn surfaces and transfer films by a scanning electron microscopy (SEM). Experimental results showed that graphite (Gr) was more beneficial than nano-SiO₂ in improving the tribological properties of basalt fabric composites (BFC) when they were singly incorporated. It is well worth noting that the friction and wear behavior of the filled composites was improved further when nano-SiO₂ and graphite were added together, indicating that there was a synergistic effect between them. Tribological tests under different sliding conditions revealed that the BFC/Gr/SiO₂ composites seemed to be more suitable for tribological applications under higher sliding speed and load.     

Mechanical and abrasive wear characterization of bidirectional and chopped E-glass fiber reinforced composite materials

Bi-directional and chopped E-glass fiber reinforced epoxy composites are fabricated in five different (15, 20, 25, 30 and 35) wt% in an epoxy resin matrix. The mechanical characterization of these composites is performed. The three body abrasive wear behavior of fabricated composites has been assessed under different operating conditions. Abrasive wear characteristics of these composites are successfully analysed using Taguchi’s experimental design scheme and analysis of variance (ANOVA). The results obtained from these experiments are also validated against existing microscopic models of Ratner-Lancaster and Wang. It is observed that quite good linear relationships is held between specific wear rate and reciprocal of ultimate strength and strain at tensile fracture of these composites which is an indicative that the experimental results are in fair agreement with these existing models. Out of all composites fabricated it is found that tensile strength of bi-directional E-glass fiber reinforced composites increases because of interface strength enhancement. Chopped glass fiber reinforced composites are observed to perform better than bi-directional glass fiber reinforced composites under abrasive wear situations. The morphology of worn composite specimens has been examined by scanning electron microscopy (SEM) to understand about dominant wear mechanisms.     

Wear rate and fracture toughness of porous particle-filled phenol composites

We experimentally investigated the effects of filler volume fraction of the phenol composites filled with porous particles on the fracture toughness and the wear rate against a smooth metal surface under multi-pass condition. Porous particles, made from rice husks, of various volume fractions from 0 to 0.5 were added to phenol resin as carbon filler. For the reported results of adhesive wear under multi-pass condition, we correlated the bulk parameters associated with the fracture toughness to the wear rate. We found an empirical power–law relation between the reciprocal of the product of stress and strain at rupture in bending test and the wear rate with various filler volume fractions. We also proposed the modified mixture law of the wear rate by taking account of the area fraction of transfer layer, which can provide a good prediction of the filler volume fraction dependence.     

Role of micro/nano fillers on mechanical and tribological properties of polyamide66/polypropylene composites

The objectives of this research article is to evaluate the mechanical and tribological properties of polyamide66/polypropylene (PA66/PP) blend, graphite (Gr) filled PA66/PP, nanoclay (NC) filled PA66/PP and NC plus short carbon fiber (NC + SCF) filled PA66/PP composites. All composites were fabricated using a twin screw extruder followed by injection molding. The mechanical properties such as tensile, flexure, and impact strengths were investigated in accordance with ASTM standards. The friction and sliding wear behaviour was studied under dry sliding conditions against hard steel on a pin-on-disc apparatus. Scanning electron micrographs were used to analyze the fracture morphologies. From the experimental investigation, it was found that the presence of NC and SCF fillers improved the hardness of PA66/PP blend. Further, the study reveals that the tensile and flexural strength of NC + SCF filled PA66/PP was higher than that of PA66/PP blend. Inclusion of micro and nanofillers reduced the wear rate of PA66/PP blend. The wear loss of the composites increased with increasing sliding velocity. The lowest wear rate was observed for the blend with nanoclay and SCF fillers. The wear rates of the blends with micro/nanofillers vary from 30–81% and lower than that of PA66/PP blend. The wear resistance of the PA66/PP composites was found to be related to the stability of the transfer film on the counterface. The results have been supplemented with scanning electron micrographs to help understand the possible wear mechanisms.     

稀土处理玻璃纤维填充PTFE复合材料的滑动磨损性能

研究了不同玻璃纤维表面处理对PTFE复合材料在干摩擦条件下滑动磨损性能的影响,并借助扫描电子显微镜(SEM)分析了磨损机理。结果表明:在干摩擦条件下,经表面处理玻璃纤维填充的PTFE复合材料的摩擦系数和摩擦表面温度比未经处理玻璃纤维填充的PTFE复合材料的低,且减磨性能优于未经处理的;而稀土处理玻璃纤维填充的PTFE复合材料的摩擦系数和摩擦表面温度最低,减磨性能最好;未经处理玻璃纤维填充的PTFE复合材料和偶联剂处理玻璃纤维填充的PTFE复合材料都发生了剧烈的粘着转移;偶联剂与稀土处理玻璃纤维填充的PTFE复合材料的磨损机理主要是明显的磨粒磨损;稀土处理玻璃纤维填充PTFE复合材料的磨损形式主要是粘着转移和轻微的磨粒磨损。     

Carbon fiber knitted fabric reinforced copper composite for sliding contact material

A novel carbon fiber knitted fabric reinforced copper (C/C–Cu) composite was fabricated by a pressureless infiltration technique. The microstructure of the composite was characterized by scanning electron microscopy, X-ray diffraction and energy dispersive spectroscopy. The mechanical, electrical and tribological properties of the C/C–Cu composite were compared with those of a carbon/copper contact strip. The experimental results showed that the C/C–Cu composite formed an interpenetrating network structure. It exhibited a high bending strength of 186 MPa, excellent impact strength of 4.7 J/cm² and a particularly low electrical resistivity of 0.58 μΩ m, giving it advantages over the C/Cu strip in terms of both mechanical and electrical properties. Friction and wear experiments were conducted for the C/C–Cu composite and the C/Cu strip on a hemisphere pin-on-block apparatus, using cooper pins against polished specimens in dry sliding conditions. It was found that the C/C–Cu composite exhibited greater wear resistance than the C/Cu strip and did less damage to the copper pin.     

Development of a new inexpensive green thermoplastic composite and evaluation of its physico-mechanical and wear properties

In the present study an attempt has been made to use turmeric spent (TS) as reinforcing filler to fabricate polypropylene (PP) green composite for load bearing and tribological applications. PP/TS composites were fabricated using varying amounts of TS viz, 10%, 20%, 30% and 40% (w/w) by twin screw extrusion method. The fabricated PP green composites were evaluated for physico-mechanical and tribological properties. Experimentally obtained tensile values were compared with theoretically predicted values using different theoretical models. Tensile modulus of composites increased from 1041 to 1771 MPa with the increase in filler addition from 0 to 40 wt.%. Flexural strength and flexural modulus of composites were improved after incorporation of TS into PP matrix. The water absorption characteristics of composites were determined. The effect of abrading distances viz., 150, 300, 450, and 600 m and different loads of 23.54 and 33.54 N at 200 rpm on the abrasive wear behaviour were studied using dry sand/rubber wheel abrasive test rig. The TS filler lowered the abrasion resistance of PP/TS composites. The wear volume loss and specific wear rate as a function of abrading distance and load were determined. The surface morphology of tensile fractured green composites and their worn surface features were examined under scanning electron microscope.     

炭布/树脂复合摩擦材料的湿式摩擦学性能

基于炭布优异的摩擦磨损性能、 自润滑性能以及低密度等特点, 将其应用于湿式摩擦材料中, 以适应高转速、 大压力或润滑不充分等极端工况。分别以1 K、 3 K和6 K碳布为增强体, 制备出三种炭布/树脂复合摩擦材料, 研究了其湿式摩擦学性能。结果表明: 随着纤维束内单丝数量的增加, 摩擦材料的瞬时制动稳定性降低, 动摩擦系数减小, 但是耐磨性能提高。所有摩擦材料的磨损率小于1.10×10^-5 mm³/J, 表现出较好的耐磨性能, 并且对偶材料的磨损率很小, 仅为0.40×10^-5 mm³/J。磨损主要表现为纤维断裂、 拔出及树脂脱粘等形式, 但是在磨损表面没有形成大尺寸磨屑和明显的"第三体"磨粒, 导致摩擦材料和对偶材料的磨损率较小。     

Assessment of mechanical and three-body abrasive wear peculiarity of TiO<Subscript>2</Subscript>- and ZnO-filled bi-directional E-glass fibre-based polyester composites

This paper is about the development of bi-directional E-glass fibre-based polyester composites filled with zinc oxide (ZnO) and titanium dioxide (TiO₂) fillers, respectively. The mechanical characterization of these composites is performed. The three-body abrasive wear characteristic of fabricated composites has been assessed under different operating conditions. For this, the three-body abrasion test is done on dry abrasion test rig (TR-50) and analysed using Taguchi’s experimental design scheme and analysis of variance. The results obtained from these experiments are also validated against existing microscopic models of Ratner–Lancaster and Wang. A good linear relationship is obtained between specific wear rate and the reciprocal of ultimate strength and strain at tensile fracture of these composites. It indicates that the experimentally obtained results are in good agreement with these existing models. It is found that the tensile strength decreases with filler loading, while hardness, flexural strength, inter-laminar shear strength and impact strength are increased. TiO₂-filled composites were observed to perform better than ZnO-filled composites under abrasive wear situations. The wear mechanism is studied in correlation with the SEM micrograph of the worn-out surface of composites. Performance optimization of composites is done by using VIKOR method.     

The tribological behavior of nanometer and micrometer TiO2 particle-filled polytetrafluoroethylene/polyimide

The friction and wear properties of micrometer and nanometer TiO₂ particle-filled polytetrafluoroethylene (PTFE)/polyimide (PI) composites were studied in this paper. The effect of filler contents (0.5%, 1%, 1.5%, 2%, 3%, 5% and 7 vol.%) on the tribological properties was examined. The transfer films and the worn surfaces of the PTFE/PI composites filled with micrometer and nanometer TiO₂ particles were investigated by using a scanning electron microscope (SEM). Experimental results show that anti-wear properties of the PTFE/PI composites can be improved greatly by filling nanometer TiO₂ particles. The wear rate of 1.5% nanometer TiO₂ filled composite is the lowest, which is about 52% lower than that of PTFE/PI. In the case of micrometer TiO₂ filler, the friction coefficient and wear rates increase with increasing filler volume fractions under identical test conditions. It was also found that the wear mechanism of micrometer TiO₂ particle-filled PTFE/PI is mainly severe adhesion and abrasive wear, while that of nanometer TiO₂ particle-filled PTFE/PI is mainly slight abrasive wear.