Tribological Properties Of Hybrid Research Articles

Mechanical and Tribological Properties of Hybrid and Monolithic Reinforced Hypoeutectic Al–Si Matrix Composites

This study investigates the combined influence of Si element and reinforcing particles on the hardness and wear performance of aluminum matrix composites. The composites in focus include Fe‐based metallic glass (FMG) monolithic reinforced and FMG/SiC hybrid reinforced Al‐5 wt% Si matrix composites, fabricated through spark plasma sintering (SPS). A comprehensive investigation is carried out, encompassing the analysis of microstructural attributes and the examination of worn surfaces through field emission scanning electron microscopy (FESEM). Additionally, the study scrutinized two pivotal factors—hardness and density—recognizing their pivotal roles in determining the tribological performance of these composites. The experimental findings demonstrated the presence of an oxide protective layer on the worn surfaces of all specimens. Although, FMG/SiC hybrid reinforced Al‐5 wt% Si matrix composite possessed the highest hardness value, the best tribological performance is observed in Si‐bearing monolithic reinforced composite. The addition of Si to the matrix of monolithic reinforced composite facilitates improved densification behavior and enhances the distribution of reinforcing particles, resulting in a more stable and protective oxide layer in this specific sample. Furthermore, the study identifies a transition in the operative wear mechanisms from delamination to mild abrasion and adhesion with the inclusion of Si element.

Influence of sliding orientation on tribological properties of hybrid PTFE/Kevlar fabric composites.

A fabric liner is an ideal self-lubricating material that has been widely used in self-lubricating spherical plain bearings. To investigate the influence of sliding orientation on the tribological properties of fabric liners, samples were prepared for different fiber orientations relative to the sliding direction and wear tests were conducted under normal loads of 25 N to 200 N. Composite-90° (sliding along Kevlar fibers) shows the best friction and wear properties under loads of 50 N and 100 N, while composite-0° (sliding along PTFE fibers) exhibits the best tribological properties when the load increases to 200 N. Due to the formation of a PTFE transfer film, the friction coefficient even decreases during the stable wear stage. Although the dry sliding condition is controlled by a transfer film formed on the friction interface, the contact geometry generated by the interlacing fibers as well as sliding direction continue to dominate the tribological properties under a light load. The combination of a suitable heavy load and sliding along the PTFE fiber is conducive to the formation of a stable and continuous transfer film of debris. Accordingly, the lowest friction coefficient of 0.105 and the lowest wear depth of 0.056 mm are achieved for composite-0° under 200 N.

Influence of high temperature on the tribological properties of hybrid PTFE/Kevlar fabric composite

The tribological properties of PTFE/Kevlar fabric are extremely important for the service behavior of self-lubricating and maintenance-free joint bearings in aviation, aerospace and other fields that require high wear performance at different temperatures. This paper aims at investigating the influence of the ambient temperature on the tribological properties of hybrid PTFE/Kevlar fabric through reciprocating wear tests. The wear loss, surface damage morphology and tribo-chemical behaviors of PTFE/Kevlar at the temperature range of 25–200 °C are first analyzed. The wear mechanisms, damage behaviors and their transitions with the increase in the ambient temperature and reciprocating cycles are then systematically discussed. This information can provide a guide to master the range of safe use and the optimization of materials.

The tribological properties of single-layer hybrid PTFE/Nomex fabric/phenolic resin composites underwater

Abstract In this study, the tribological properties of hybrid polytetrafluoroethylene (PTFE)/Nomex fabric/phenolic resin composites were investigated under three operating conditions: dry sliding, dry sliding after soaking in water for 12 h, and water dripping lubrication. The friction coefficient (COF) was measured with a pin-on-disk tribometer. The wear surface was analyzed with a scanning electron microscope. The results show that water weakens the tribological properties of single-layer hybrid PTFE/Nomex fabric/phenolic resin composites. The fabric composites show slight abrasive wear with stable COF under dry sliding conditions, significant abrasive wear with oscillating COF after soaking, and destruction with severely oscillating COF under water dripping lubrication. Generally, water weakens the effect in two ways. The first is weakening the binding force between phenolic resin and Nomex fiber. The second is that Nomex fiber absorbs water and expands, which reduces its strength. Finally, the ideas to improve the tribological properties under water dripping lubrication are presented.

Assessment of flexural and wear properties of carbon/glass fiber hybrid composite

The weakness of individual fibers can be overcome by hybridization leading to improvement of mechanical and tribological properties. The present investigation aims to evaluate the flexural and tribological properties of hybrid carbon/glass fiber reinforced polymer (FRP) composites experimentally. The plain and hybrid composite with stacking sequence [C2G3]S were fabricated. The results revealed that the flexural stress and modulus of hybrid [C2G3]S composite increased by 48% and 76% respectively compared to plain glass FRP composite. The three body abrasion wear was conducted and specific wear rate (SWR) was measured as per design of experiment. By response Surface Methodology (RSM) the process factors to minimize SWR of hybrid composite were determined. The least SWR predicted for the hybrid [C2G3]S is 16.3209 × 10−3 mm3/Nm at 1100 m and 33.15 N. The hybrid composite creates opportunity to be used in different applications.

NTI-WEAR PROPERTIES OF MEDIUM CARBON STEEL AFTER CARBURIZING WITH SUBSEQUENT DIFFUSION CHROMIZING AND PVD TREATMENT

The paper discusses the results of research on the structure and tribological properties of hybrid layers produced on the surface of medium-carbon steel in hybrid treatment, combining gas carburizing process with the next treatment, i.e. diffusion chromizing and PVD treatment. A comparison was made of the structure and tribological properties of the layers obtained as a result of hybrid treatment with the layers produced in a single diffusion chromizing process. The studies of the layers concerned their structure, chemical composition, thickness, and hardness. Linear wear of the layers were performed by means of three-cylinder-cone method. It has been shown that the linear wear of samples with hybrid layers, produced on medium carbon steel, is less than 50% of samples with single carbide layers. This indicates very good anti-wear properties of hybrid layers.

Synergy of rice-husk filler on physico-mechanical and tribological properties of hybrid Bauhinia-vahlii/sisal fiber reinforced epoxy composites

In this research, the effect of rice husk fillers were investigated on physical, mechanical and sliding wear properties of on hybrid Bauhinia-vahlii-weight (BVW) and Bauhinia-vahlii-weight/sisal (BVWS) fibers reinforced hybrid composites. The rice husk content was hybridized by loading variation of 0, 2, 4 and 6wt% with 6wt% BVW and combined 6wt% BVW-Sisal fiber reinforced epoxy composites. The physical and mechanical properties like void fraction, water absorption, tensile strength, flexural strength, hardness, and impact energy in this research were found to be greatly influenced by rice-husk content. Moreover, the impact energy was found to be slightly decreased, owing to possible decrease in the deformability of the resin constituent. Rice husk filled BVWS composites exhibited improved tensile strength (34.42%), flexural strength (33%), and hardness (7.1%) as compared to BVW composites at all filler loading. The influence of selected control factors: sliding velocity, rice husk contents, normal load and sliding distance on specific wear rate of composites was investigated by Taguchi experimental design. Analysis of variance (ANOVA) was carried out to analyze the influence of each selected control factor on specific wear rate. The evaluated results demonstrate that rice husk content and sliding velocity were found to emerge the most noteworthy control factors among the others. Furthermore, the wear scars were analyzed by scanning electron microscopy to establish the governing wear mechanisms. This research established that the addition of rice husk fillers with optimum variation reflects the improvement in mechanical and wear performance of natural fiber based epoxy composites.

Effect of the graphite content on the tribological properties of hybrid Al/SiC/Gr composites processed by powder metallurgy

Purpose – The purpose of this paper is to understand the effect of graphite content on the properties of aluminum alloy/silicon carbide/granite (Al/SiC/Gr) composites. Design/methodology/approach – Hardness and wear tests were applied to the powder metallurgical composites, and microstructural characterization was conducted. Findings – Optimum graphite content for maximum wear resistance is reported as weight 6 per cent. Originality/value – Results of this study may help light weight Al/SiC/Gr composites to be used in different industrial applications.

Combined effect of air-plasma treatment and lubricant filling on the dry sliding wear behavior of hybrid PTFE/Nomex fabric/phenolic composite

Abstract Herein, we studied the combined effect of air-plasma treatment and lubricant filling on the dry sliding wear behavior of hybrid PTFE/Nomex fabric/phenolic composite. In this study, hybrid PTFE/Nomex fabric was firstly treated by air-plasma to improve the fabric–resin adhesion and tribological properties of hybrid PTFE/Nomex fabric/phenolic composite. Subsequently, polyfluo wax was employed as lubricant filler to further improve the anti-wear property of air-plasma treated fabric composite. The results of wear tests showed that polyfluo wax filled air-plasma treated fabric composite exhibited the optimal antiwear property and load-carrying capacity, compared to untreated and air-plasma treated fabric composites. The effects of the air-plasma treatment power and polyfluo wax content on the tribological behaviors of the fabric composites were also investigated.

Influence of weave structures on the tribological properties of hybrid Kevlar/PTFE fabric composites

The existing research of the woven fabric self-lubricating liner mainly focus on the tribological performance improvements and the service life raised by changing different fiber type combinations, adding additive modification, and performing fiber surface modification. As fabric composites, the weave structures play an important role in the mechanical and tribological performances of the liners. However, hardly any literature is available on the friction and wear behavior of such composites with different weave structures. In this paper, three weave structures (plain, twill 1/3 and satin 8/5) of hybrid Kevlar/PTFE fabric composites are selected and pin-on-flat linear reciprocating wear studies are done on a CETR tester under different pressures and different frequencies. The relationship between the tensile strength and the wear performance are studied. The morphologies of the worn surfaces under the typical test conditions are analyzed by means of scanning electron microscopy (SEM). The analysis results show that at 10 MPa, satin 8/5 performs the best in friction-reduction and antiwear performance, and plain is the worst. At 30 MPa, however, the antiwear performance is reversed and satin 8/5 does not even complete the 2 h wear test at 16 Hz. There is no clear evidence proving that the tensile strength has an influence on the wear performance. So the different tribological performance of the three weave structures of fabric composites may be attributed to the different PTFE proportions in the fabric surface and the different wear mechanisms. The fabric composites are divided into three regions: the lubrication region, the reinforced region and the bonding region. The major mechanisms are fatigue wear and the shear effects of the friction force in the lubrication region. In the reinforced region fiber-matrix de-bonding and fiber breakage are involved. The proposed research proposes a regional wear model and further indicates the wear process and the wear mechanism of fabric composites.

Effects of Weaves on the Tribological Properties of Hybrid Kevlar/PTFE Fabric Composites

Three weaves (plain, twill 1/3 and satin 8/3) of hybrid kevlar/PTFE fabric composites were selected for investigating the influence of weaves on the tribological properties. Pin-on-flat linear reciprocating wear studies were done on the three kinds of composites on a CETR Tester under pressure 20 MPa and frequency 13 Hz. The relationship between the tensile strength and the tribolog- ical performance of fabric composites was also examined. It was observed that though the friction coefficient of satin 8/3 was the lowest, the specific wear rate was also the highest. Plain weave, however, performed worse in friction-reduction while resulting best in antiwear performance. The tensile strength does not have an influence on the wear performance. So the different tribological performance of the three weaves of fabric composites may attribute to the different PTFE proportion in the fabric surface and adhesive wear. A model of wear process of fabric composites was proposed and supported by the Confocal Laser Scanning Microscope (CLSM) studies.

Surface Modification of CuS Nanoparticles and their Effect on the Tribological Properties of Hybrid PTFE/Kevlar Fabric/Phenolic Composite

Oleic acid-modified CuS nanoparticles were chemically synthesized. The tribological properties of surface modified and unmodified CuS nanoparticles as additives in the hybrid polytetrafluoroethylene (PTFE)/Kevlar fabric/phenolic composite were investigated in detail. The experimental results indicated that the incorporation of modified CuS nanoparticles improved the antiwear ability of the fabric/phenolic composite at varied loads and environmental temperatures. The reasons for the enhanced wear properties of the fabric/phenolic composite filled with surface-modified CuS nanoparticles were discussed based on the results of scanning electron microscopy and Fourier transform infrared spectroscopy.

The influence of plasma treatment on the tribological properties of hybrid PTFE/cotton fabric/phenolic composites

AbstractIn this study, the effects of air‐plasma and N2‐plasma treatment on the hybrid polytetrafluoroethylene (PTFE)/cotton fabric and a phenolic resin were investigated in detail. The tribological properties of the untreated and plasma‐treated hybrid PTFE/cotton fabric/phenolic composites were investigated. The results indicated that air‐plasma‐treated hybrid PTFE/cotton fabric/phenolic composites exhibited better antiwear and friction reduction properties. The combination of scanning electron microscopy and Fourier transform infrared spectroscopy analysis illustrated that hybrid PTFE/cotton fabric/phenolic composites treated with air‐plasma possessed more integrated structure and more functional groups, which plausibly contributed to the better tribological properties of the hybrid PTFE/cotton fabric/phenolic composites treated with air‐plasma. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers