Friction and wear properties of TiCN coatings sliding against SiC and steel balls in air and water

The TiCN coatings were deposited on WC cemented carbides using enhanced cathodic arc magnetron sputtering. The topography of TiCN coatings were observed using scanning electron microscopy (SEM), the composition and structure of TiCN coatings were analyzed by energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The friction and wear properties of TiCN coatings sliding against SiC and steel balls in air and water were investigated using ball-on-disk tribometer. The results showed that the TiCN coatings had a strong (111) preferred orientation. The friction coefficient and the specific wear rates of the TiCN/SiC tribopairs in air were higher than those in water. When the TiCN coatings slid against SiC balls in water, the friction coefficient and the specific wear rates first decreased, and then increased with the normal load, but decreased linearly with the sliding velocity. The lowest friction coefficient of 0.171 was obtained at 3 N and 0.4 m/s, while the lowest specific wear rate of the TiCN coatings was 2.3 × 10^− 6mm³/Nm at 6 N and 0.1 m/s. The TiCN coatings were worn out when the normal loads were higher than 6 N. When the TiCN coatings slid against the SUJ2 and SUS440C balls in water, the friction coefficient increased to 0.271 and 1.026 respectively. The EDS analysis showed that Fe and O elements existed on the wear track. This indicated that the tribochemical reaction occurred at the friction contact area.     

The effect of strontium on the microstructure and wear properties of A356–10%B4C cast composites

This study was undertaken to investigate the effect of strontium (0.5%) as a modifier on the microstructure and dry sliding wear behavior of A356–10%B₄C particulate metal matrix composite (PMMC). The composite ingots were made by stir casting process. In this work, composite were characterized by scanning electron microscope equipped with energy dispersive spectrometer (EDS), and dry sliding wear experiment were performed in a pin-on-disc wear tester against a DIN 100Cr6 steel disc at speed of 0.5 ms⁻¹ and normal loads of 20, 40 and 60 N. The obtained results showed that 0.5%Sr was needed to modify of silicon eutectic in A356–10%B₄C cast composite. Also, the wear results showed that the addition of strontium to MMCs can lead to reduction of wear rate through strong bonding (between B₄C and matrix) and silicon particle modification. Formation of compact transfer layer has been identified on the entire surface of the pins at the applied load of 60 N. It is suggested that the transfer layer which was formed under an applied load of 60 N can act as a protective layer and helps to reduce wear rate.     

Role of zirconia filler on friction and dry sliding wear behaviour of bismaleimide nanocomposites

This paper discusses the friction and dry sliding wear behaviour of nano-zirconia (nano-ZrO₂) filled bismleimide (BMI) composites. Nano-ZrO₂ filled BMI composites, containing 0.5, 1, 5 and 10 wt.% were prepared using high shear mixer. The influence of these particles on the microhardness, friction and dry sliding wear behaviour were measured with microhardness tester and pin-on-disc wear apparatus. The experimental results indicated that the frictional coefficient and specific wear rate of BMI can be reduced at rather low concentration of nano-ZrO₂. The lowest specific wear rate of 4 × 10⁻⁶ mm³/Nm was observed for 5 wt.% nano-ZrO₂ filled composite which is decreased by 78% as compared to the neat BMI. The incorporation of nano-ZrO₂ particles leads to an increased hardness of BMI and wear performance of the composites shows good correlation with the hardness up to 5 wt.% of filler loading. The results have been supplemented with scanning electron micrographs to help understand the possible wear mechanisms.     

Three-body abrasion on wear and frictional performance of treated betelnut fibre reinforced epoxy (T-BFRE) composite

This work aims to investigate the wear and frictional behaviour of a new epoxy composite based on treated betelnut fibres subjected to three-body abrasion using different abrasive particle sizes (500 μm, 714 μm and 1430 μm) and sliding velocities (0.026–0.115 m s⁻¹) at constant applied load (5 N) using a newly developed Linear Tribo Machine. The worn surfaces of the composite were studied using scanning electron microscope. The work revealed that the predominant wear mechanism of treated betelnut fibre reinforced epoxy (T-BFRE) composite sliding against grain sands was plastic deformation, pitting and pullout of betelnut fibres. The composite exhibited higher values in frictional coefficient when it was subjected against coarse sand. Besides, the abrasive wear of the composite is depending on the size of abrasive particles and sliding velocity. Higher weight loss is noticed at high sliding velocities. The specific wear rate for the composite subjected to three different sand particles follow the order of: coarse > grain > fine sands respectively.     

Study on friction and sliding wear behavior of woven S-glass fiber reinforced vinylester composites manufactured with different comonomers

The effect of variations in sliding velocity and applied normal load on the friction and sliding wear behavior of glass–vinylester composite (G–V) is studied by measuring the weight change and observing the surface features of worn specimens using scanning electron microscopy (SEM). The G–V composites were manufactured with Bi-directional woven S-glass fibers (65 wt%) reinforced with vinylester resin with different comonomers. Friction and wear experiments were carried at ambient conditions on a Pin on disc machine arrangement. The wear in the experiment was determined from the weight loss measured after running against steel disc at sliding velocities of 1, 2, 3, and 4 m/s and applied normal load of 10, 20, 30, and 40 N. The experimental findings show increase in specific wear rate with increase the applied load. Specific wear rate was maximum for the sample A (Styrene as Comonomer), intermediate for sample B (Methyl acrylate as comonomer), and least for sample C (Butyl acrylate as comonomer). It was also observed that increasing normal load and sliding velocity the coefficient of friction decreases. The scanning pictures show features like tendency for the matrix to adhere towards the fiber, debris formation, network of cracks, agglomeration of debris, and broken fibers depending on the load and velocity employed.     

Wear characteristics of hybrid aluminium matrix composites reinforced with graphite and silicon carbide particulates

This investigation studies the dry sliding wear behaviour of Al matrix composites reinforced with Gr and SiC particulate up to 10%, to study the effect of % reinforcement, load, sliding speed and sliding distance on stir cast Al–SiC–Gr hybrid composites, Al–Gr and Al–SiC composites. Parametric studies indicate that the wear of hybrid composites has a tendency to increase beyond% reinforcement of 7.5% as its values are 0.0242 g, 0.0228 g and 0.0234 g respectively at 3%, 7.5% and 10% reinforcement. The corresponding values are 0.0254 g, 0.0240 g and 0.0242 g in Al–Gr composites and 0.0307 g, 0.0254 g and 0.0221 g in Al–SiC composites, clearly indicating that hybrid composites exhibit better wear characteristics. Increase of speed reduces wear and increase of either load or sliding distance or both increases wear. Statistical analysis has revealed interactions among load, sliding speed and sliding distance in composites with Gr particulates.     

Friction and wear behavior of carbon nanotubes reinforced polyamide 6 composites under dry sliding and water lubricated condition

The friction and wear behavior of carbon nanotube reinforced polyamide 6 (PA6/CNT) composites under dry sliding and water lubricated condition was comparatively investigated using a pin-on-disc wear tester at different normal loads. The morphologies of the worn surfaces and counterfaces of the composites were also observed with scanning electron microscopy (SEM). The results showed that CNTs could improve the wear resistance and reduce the friction coefficient of PA6 considerably under both sliding conditions, due to the effective reinforcing and self-lubricating effects of CNTs on the PA6 matrix. The composites exhibited lower friction coefficient and higher wear rate under water lubricated condition than under dry sliding. Although the cooling and boundary lubrication effect of the water contributed to reduce the friction coefficient of the composites, the adsorbed water lowered the strength of the composites and also inhibited the formation of transfer layers on the counterfaces resulting in less wear resistance. With the increasing normal loads, the friction coefficient of the composites increased under the dry sliding and decreased under the water lubricated condition, owing to inconsistent influences of shear strength and real contact areas. The specific wear rate of the composites increased under both sliding conditions.     

Dry sliding wear behavior of spray deposited AlCuMn alloy and AlCuMn/SiCp composite

The dry sliding wear behavior of spray-deposited Al-Cu-Mn alloy and its composite reinforced with 13 vol.% SiC particles have been studied in the applied load of 5–400 N (corresponding normal stress is 0.1–8 MPa). It showed that SiC particle-reinforced AlCuMn composite produced by spray deposition process exhibited an improved wear resistance at the entire applied load range in comparison to the monolithic alloy. However, this improvement was not significant in the overall load range. With increasing the applied load, the wear rate of the composite and the monolithic alloy exhibited four different regions, therefore the wear was dominated by different wear mechanism. The former three regions all belonged to mild wear. The transition from mild to severe wear occurred at the similar critical load for both the composite and the monolithic alloy. For both the composite and the monolithic alloy, with increasing applied load, the dominant wear mechanism exhibited successively: oxidative mechanism, delamination mechanism, subsurface-cracking-assisted adhesive mechanism and adhesive mechanism.     

Sliding wear of Al2O3P/6061 Al composite

The mild sliding wear behaviour of a 15 vol % Al₂O_3P/6061 Al composite has been investigated by using a pin-on-disc reciprocating sliding machine. The composite has been shown to exhibit an excellent wear resistance as compared to the unreinforced matrix alloy. The wear rate of the composite under dry wear conditions with a 12N load is approximately one tenth of that in the 6061 aluminium alloy. The wear rate of the composite under lubrication with 15W/40 gear oil under a 100N load is only one thousandth ofthat in the 6061 aluminium alloy.The dry wear resistance of an over-aged sample is shown here to be better than a peak aged or under-aged sample when the composite was aged at 160°C. The coefficient of friction of the composite was approximately 0.5–0.6 under dry conditions and 0.07 in lubricated wear experiments.In the initial stage, the worn surface of the composite under dry conditions is primarily composed of ploughed grooves and ductile tear. The composite makes a conducting contact with the steel pin. The worn surface is composed of compacted powder and the contact potential gradually increases when the period of the wear experiment goes beyond 2 h.     

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.     

Study on the effects of nanoparticulates of SiC,Al2O3, and ZnO on the mechanical and tribological performance of epoxy-based nanocomposites

In this research work, mechanical and tribological characteristics of ortho cresol novalac epoxy (OCNE)-based nanocomposites filled with nanoparticulates of SiC, Al₂O_3, and ZnO have been investigated. Also, in these investigations, the influence of wear parameters such as applied normal load, sliding velocity, filler contents, and sliding distance have been explored. The experimental plan for four factors at three levels using face centered composite design (CCD) has been employed by the response surface methodology (RSM) technique. The friction and wear tests were carried out using a pin on disc wear test apparatus under dry sliding conditions. The hardness and flexural strength of nano ortho cresol novalac epoxy composites filled with nano (SiC, Al₂O_3, and ZnO) particulates increases with an increase in the filler contents. Whereas, the tensile strength of these nanocomposites increases with an increase in the filler contents from 1 to 2 wt%, and with a further increase in filler contents the tensile strength decreases. The results of the study also showed that (2 wt%) filler contents bring superior mechanical and tribological properties. The lowest coefficient of friction and specific wear rate were found with nano Al₂O₃-filled composites. Also, the wear mechanisms of these nanocomposites were studied using a scanning electron microscope (SEM) equipped with an EDS analyzer.     

Effect of addition of graphite particulates on the wear behaviour in aluminium–silicon carbide–graphite composites

Aluminium matrix composites with multiple reinforcements (hybrid AMCs) are finding increased applications because of improved mechanical and tribological properties and hence are better substitutes for single reinforced composites. Few investigations have been reported on the tribological behaviour of these composites with % reinforcement above 10%. The present study focuses on the influence of addition of graphite (Gr) particulates as a second reinforcement on the tribological behaviour of aluminium matrix composites reinforced with silicon carbide (SiC) particulates. Dry sliding wear tests have been performed to study the influence of Gr particulates, load, sliding speed and sliding distance on the wear of hybrid composite specimens with combined % reinforcement of 2.5%, 5%, 7.5% and 10% with equal weight % of SiC and Gr particulates. Experiments are also conducted on composites with % reinforcement of SiC similar to hybrid composites for the sake of comparison. Parametric studies based on design of experiments (DOE) techniques indicate that the wear of hybrid composites decreases from 0.0234 g to 0.0221 g as the % reinforcement increases from 3% to 7.5%. But the wear has a tendency to increase beyond % reinforcement of 7.5% as its value is 0.0225 g at.% reinforcement of 10%. This trend is absent in case of composites reinforced with SiC alone. The values of wear of these composites are 0.0323 g, 0.0252 g and 0.0223 g, respectively, at.% reinforcement of 3%, 7.5% and 10% clearly indicating that hybrid composites exhibit better wear characteristics compared to composites reinforced with SiC alone. Load and sliding distance show a positive influence on wear implying increase of wear with increase of either load or sliding distance or both. Whereas speed shows a negative influence on wear indicating decrease of wear with increase of speed. Interactions among load, sliding speed and sliding distance are noticed in hybrid composites and this may be attributed to the addition of Gr particulates. Such interactions are not present in composite reinforced with SiC alone. Mathematical models are formulated to predict the wear of the composites.     

Tribological behavior of aluminum-CNT coated metal composite under dry and water lubricated conditions

Carbon nanotubes are considered the best material in the field of composites because of their mechanical and tribological properties. In this study, carbon nanotubes coated metal was dispersed in aluminum, the base metal, to improve the wettability between aluminum and carbon nanotubes. The friction and wear behaviors of the aluminum-carbon nanotube coated metal, which is a nickel and copper composite, were investigated using a pin-on-disk wear tester under dry sliding and water lubricated conditions and evaluated using SEM and EDX analysis. All the results demonstrated that the addition of the carbon nanotubes coated metal significantly improved the wettability of CNTs in the aluminum. And the distribution of CNTs prevented the propagation of micro cracks on the surface of the aluminum base metal sample, resulting in enhanced friction characteristics and wear resistance of the nano composite. The composite exhibited lower friction coefficient and wear resistance under the water lubricated condition than the dry sliding condition. Although the lubrication and cooling effect of water contributed to the reduction of the friction coefficient of the composite, the separation of wear particles from the sliding surface changed the wear type from three-body to two-body, resulting in very high wear rate. Also the concentration of oxide under water lubricated condition contributed to the increase of the wear rate because the amount of oxide film removed in terms of thickness exceeded the critical thickness of real contact area.     

Tribological properties of powder metallurgy – Processed aluminium self lubricating hybrid composites with SiC additions

In this experimental study, aluminium (Al)-based graphite (Gr) and silicon carbide (SiC) particle-reinforced, self-lubricating hybrid composite materials were manufactured by powder metallurgy. The tribological and mechanical properties of these composite materials were investigated under dry sliding conditions. The results of the tests revealed that the SiC-reinforced hybrid composites exhibited a lower wear loss compared to the unreinforced alloy and Al–Gr composites. It was found that with an increase in the SiC content, the wear resistance increased monotonically with hardness. The hybridisation of the two reinforcements also improved the wear resistance of the composites, especially under high sliding speeds. Additionally, the wear loss of the hybrid composites decreased with increasing applied load and sliding distance, and a low friction coefficient and low wear loss were achieved at high sliding speeds. The composite with 5 wt.% Gr and 20 wt.% SiC showed the greatest improvement in tribological performance. The wear mechanism was studied through worn surface and wear debris analysis as well as microscopic examination of the wear tracks. This study revealed that the addition of both a hard reinforcement (e.g., SiC) and soft reinforcement (e.g., graphite) significantly improves the wear resistance of aluminium composites. On the whole, these results indicate that the hybrid aluminium composites can be considered as an outstanding material where high strength and wear-resistant components are of major importance, predominantly in the aerospace and automotive engineering sectors.     

炭纤维增强聚醚醚酮复合材料在水润滑下的摩擦学行为

考察了炭纤维及PTFE增强PEEK复合材料在干摩擦和水润滑下的摩擦学性能,并研究了该复合材料在两种条件下的磨损机理.结果表明,干摩擦下复合材料的摩擦系数和磨损率随负荷的增加不断减小;水润滑下复合材料的摩擦系数随负荷的变化不大,磨损率随负荷的增加而增大.干摩擦下,复合材料的磨损以粘着磨损和磨粒磨损为主.水润滑条件下,磨损表面比较光滑,仅有微切削的痕迹,磨损方式以轻微磨粒磨损为主.干摩擦条件下,摩擦对偶表面仅有轻微的犁沟形成,表面形成一层薄而均匀且结合紧密的转移膜.水润滑下,对偶表面犁沟较深,犁削作用明显,转移膜的形成被明显抑制.水的冷却作用使得向摩擦对偶的粘着转移明显减轻,同时由于摩擦表面吸附水膜的边界润滑作用,显著改善复合材料的摩擦磨损性能.     

Effect of sliding distance on the wear and friction behavior of as cast and heat-treated Al–SiCp composites

The present investigation aims to evaluate the effect of sliding distance on the wear and friction behavior of as cast and heat-treated Al–SiCp composites using pin-on-disc wear testing machine, giving emphasis on the parameters such as wear rate and coefficient of friction as a function of sliding distance (0–5000 m) at different applied pressures of 0.2, 0.6, 1.0 and 1.4 MPa, and at a fixed sliding speed of 3.35 m/s. Characterizing the alloy and composites in terms of microstructure, X-ray diffraction analysis, microhardness and wear surface analysis. The results revealed that the heat-treated composite exhibited superior wear properties than the base alloy, while the coefficient of friction followed an opposite trend. Moreover, the wear rate of the composite is noted to be invariant to the sliding distance and increased with applied pressures. Microstructure of composite shows fairly uniform distribution of SiC particles in the metallic matrix. The hardness value of heat-treated composite increased 20–30% by addition of SiC particles to the alloy, intermetallic phases like Al₂Mg₃ and Al₂CuMg, etc., were obtained from X-ray analysis. The wear mechanism of the investigated materials was studied through worn surfaces examination of the developed wear tracks.     

镍基复合材料在水环境中的摩擦学性能及磨损机理研究

本文考察了Ni-SiC-石墨系复合材料在水环境中的摩擦学性能,并研究其磨损机理.结果表明:复合材料在水环境中的摩擦系数比干摩擦降低了一半左右,磨损率仅为干摩擦下的1/15,水环境中,负荷和速度的变化对摩擦系数的影响不大,摩擦系数基本保持在0.28～0.32之间,磨损率随负荷和滑动速度的增加而不断增加.磨损表现为机械微切削;摩擦副表面吸附水的边界润滑作用以及水的冷却作用使材料容易耗散摩擦热,塑性变形减小,严重粘着磨损明显减轻.水的存在使不锈钢偶件更容易发生氧化,同时暴露于磨损表面的SiC以及由于水的渗透而导致与基体脱粘的SiC,易被氧化生成SiO2,进而SiO2发生水合反应在磨擦对偶表面生成不均匀的SiO2·nH2O水合反应膜,起到了一定的减磨润滑作用,显著降低摩擦系数和磨损率.     

Effect of SiC content and sliding speed on the wear behaviour of aluminium matrix composites

In the present study effect of SiC content and sliding speed on the wear behaviour of aluminium alloy and composite was studied using pin-on-disc apparatus against EN32 steel counterface. These tests were conducted at varying SiC particles in 10, 15 and 25 wt.% and sliding speeds of 0.52, 1.72, 3.35, 4.18 and 5.23 m/s for a constant sliding distance of 5000 m. The results revealed that as the SiC content increases the wear rate and temperature decreases, but reverse trend can be observed for coefficient of friction. All these facts can be discussed on the basis of prevailing wear mechanism.     

Comparative analysis of wear behavior of garnet and fly ash reinforced Al7075 hybrid composite

Al7075 hybrid composites reinforced with varying weight percentage (0 wt.%, 5 wt.%, 10 wt.%, 15 wt.%) of each of garnet and fly ash were fabricated and characterized for their comparative wear assessment. The sliding wear test was conducted on a reciprocating tribometer in dry medium under the working conditions of applied normal load (2 N, 4 N, 6 N, 8 N), sliding velocities (0.04 m/s, 0.08 m/s, 0.12 m/s, 0.16 m/s), sliding distance (20 m, 40 m, 60 m, 80 m) and working temperature (25 °C, 50 °C, 75 °C, 100 °C). The experiments were performed as per steady‐state condition and Taguchi (L₂₅) orthogonal array design to evaluate specific wear rate of the Al7075 hybrid composites. The finding of results indicated that the wear rate was decreased with the increase in the filler content in both the case of garnet and fly ash reinforced Al7075 hybrid composites. The results from Taguchi experiments suggested that the filler content and load were the most significant factors affecting wear behavior of composites while temperature and sliding distance are the least significant factors. Also, the garnet reinforced Al7075 hybrid composite indicated less specific wear rate as compared to that of fly ash reinforced Al7075 hybrid composite.     

Effect of matrix alloy and influence of SiC particle on the sliding wear characteristics of aluminium alloy composites

This article presents an effect of matrix alloy and influence of SiC particle on the sliding wear characteristics of high strength aluminium alloys AA7010, AA7009 and AA2024, composites was examined under varying applied pressure and a fixed sliding speed of 3.35 m/s. The results revealed that the wear resistance of the composite was noted to be significantly higher than that of the alloy and is suppressed further due to addition of SiC particles. The overall observation among the matrix alloys, AA7010 alloy shows maximum wear resistance than that of the other, and can withstand the seizure pressure up to 2.6 MPa. The wear mechanism was studied through worn surfaces and microscopic examination of the developed wear tracks. The wear mechanism strongly dictated by the formation and stability of oxide layer, mechanically mixed layer (MML) and subsurface deformation and cracking. The overall results indicate that the high strength aluminium alloys and composite could be considered as an excellent material where high strength and wear resistance components are prime importance especially designing for structural applications in aerospace and general engineering sectors.