Two-body Abrasion Research Articles

Tribological Properties of Recycled Polyvinyl Butyral (rPVB) and Glass-Fiber-Reinforced Polyamide Blends in Dry and Microabrasive Contacts

As a contribution of recycling of polymers in the automotive industry, recycled polyvinyl butyral (rPVB) from automotive windshields is being explored as a solid lubricant reinforcement for improving lubricity of engineering polymers. This work aims to evaluate the tribological behavior (coefficient of friction [CoF] and wear resistance) of polyamide 6 (PA6) and glass-fiber-reinforced polyamide 6 (PAGF) blended with rPVB as solid lubricant under two-body and three-body abrasive conditions. The different polymer blends were produced by adding recycled polyvinyl butyral (rPVB) into a matrix of either a commercial polyamide 6 (PA6) or a commercial 30% glass-fiber reinforced polyamide 6 (PAGF). The tribological tests were conducted in an instrumented microabrasion tester for generating wear and measuring the coefficient of friction (CoF) in both dry and microabrasion conditions. In the dry condition, rPVB was effective in reducing the CoF for both PA6 and PAGF. Two-body abrasion was found as the predominant wear pattern in the dry condition. On the other hand, in the microabrasion condition, the additions of rPVB were not totally effective since they produced a wear resistance increase for PAGF but a reduction for PA6, which was ascribed to a notable decrease in toughness for PA6 when adding rPVB. Well-defined plowing traces and several SiC particles embedded in the scars were the predominant patterns in all the materials. In both PA6 and PAGF, CoF increased with the rPVB additions.

Influence of boriding on the tribological behavior of AISI D2 tool steel for dry deep drawing of stainless steel and aluminum

Deep drawing of stainless steel and aluminum is a widely adopted method for manufacturing various industrial goods. However, the wear damage produced to die tools is a recurring problem in these processes. While lubricants are often employed to lubricate and reduce die wear, dry deep drawing is the current best alternative for meeting green manufacturing demands. Hence, enhanced solid lubricants or surface treatments for dies are highly required. This study aims to evaluate and compare the tribological behavior of a heat-treated AISI D2 steel and a boriding AISI D2 tool steel against stainless steel (AISI 304) and aluminum alloy (AA 6061 T6) in the absence of lubricant. The boride coating was formed on the AISI D2 steel by the closed-pack boriding technique, resulting in a tooth-saw morphology with an overall thickness of 33.6 μm. X-ray diffraction analysis confirmed the presence of FeB, Fe2B, and Cr2B3 phases on the surface of the borided AISI D2 tool steel. Notably, the boriding treatment led to a significant increase in the surface hardness of the tool steel, reaching a value of 20.7 GPa. The coefficient of friction (CoF) behavior and wear were evaluated by pin-on-disk tests, simulating conditions similar to those found in cold deep drawing operations. The wear surfaces were analyzed by optical profilometry and scanning electron microscopy (SEM). The results suggest boriding as a suitable treatment to reduce wear damage on the surface of deep drawing dies used for stainless steel and aluminum forming processes in the absence of lubricant. Two-body abrasion and adhesion were identified as the main wear mechanisms in AISI D2 steel against stainless steel and aluminum, with a significant amount of oxidation observed when aluminum was tested. Additionally, a reduction of approximately 20 % in the CoF was observed when employing borided tool steel against stainless steel. However, there was an observed increase of around 75 % in the CoF when the borided tool steel was tested against aluminum.

Wear of the ultrahard B4C–SiC–TiB2 ceramic composite in unlubricated sliding contact with ceramic counter-parts

The wear performance of the ultrahard B4C–SiC–TiB2 ceramic composite was investigated in unlubricated sliding contact in various friction pairs with other ceramics of very different mechanical properties (diamond, Y2O3-stabilised ZrO2, Al2O3, Si3N4, and borosilicate glass) under otherwise identical contact conditions. It was found that this composite is, due to its ultra-high hardness (∼35(1) GPa), a promising material for tribological applications (sliding-wear resistance of the order of 105–108 (N·m)/mm3) that undergoes only very mild two-body abrasion against diamond (∼6.5(7)·10−9 mm3/(N·m)) and mild three-body abrasion against ZrO2, Al2O3, Si3N4, and borosilicate glass (10−6–10−7 mm3/(N·m)). It was also found that the B4C–SiC–TiB2 composite wore faster against Si3N4 (∼3.1(3)·10−6 mm3/(N·m)) than against Al2O3 (∼1.8(3)·10−6 mm3/(N·m)), next against borosilicate glass (∼1.1(1)·10−6 mm3/(N·m)), and finally slowest against ZrO2 (∼7.2(6)·10−7 mm3/(N·m)), a trend that was justified based on the consideration that its three-body abrasion is a complex phenomenon conditioned by the abundance and hardness of the wear debris, the formation and coherence of protective tribolayers (either oxide or material transfer), and the effective contact pressure acting on the wear debris. Finally, implications arising from the study are presented.

Effect of abrasive grit grade on the abrasion wear behaviour of long banana-jute fibers reinforced hybrid epoxy composites

The effect of abrasive grit geometry on two-body abrasion wear behavior of long banana and jute fiber reinforced epoxy composites has been investigated. Epoxy (EP), Epoxy/4 wt% Banana fiber (BF)/4 wt%Jute fiber (JF) (EP8), Epoxy/8 wt%BF/8 wt%JF (EP16), Epoxy/12 wt%BF/12 wt% JF (EP24), and Epoxy/16 wt% BF/16 wt%JF (EP32) were the composite materials systems used for the investigation. These composites were processed and fabricated using hand—lay-up technique. The two body abrasion wear test was carried out in accordance with ASTM G99 under the influence of different SiC grit particles (180, 320, 400, and 600 SiC grit). The test was conducted at a room temperature under the abrasion load of 10 N and abrasion speed of 1 m s−1 over a distance of 100 m. The findings of the experiments revealed that wear response of composites depends on pressure, geometry of abrasion particles and their composition. The wear volume loss and specific wear rate decreases with increase in the rank of grit grade. Further, 16 wt% of fibers in composites exhibits the superior abrasion wear resistance. But the higher volume fraction of natural fibers in composites impaired the abrasion wear resistance. Higher rank of grit number was associated with the lesser wear volume loss because of the change in wear mechanism from abrasion to adhesion. In comparison to epoxy based composites, EP16 composite shows superior wear resistance. SEM images were used to examine the worn surfaces.

Effect of the degree of densification on the unlubricated sliding-wear behaviour of monolithic B4C ceramics

The unlubricated sliding-wear behaviour of monolithic B4C ceramics with densification degree from ∼62 % up to ∼99.1 %, and therefore hardness from ∼7.9 GPa up to ∼35.3 GPa, was investigated. It was found that the specific wear rate decreases somewhat asymptotically by one order of magnitude (from 10–7 down to 10–8 mm3/(N m)) with the increase of densification degree/hardness. This is because, while wear always occurred by abrasion, below a certain threshold of densification/hardness it took place predominantly in brittle mode by fracture-dominated three-body abrasion and above that threshold predominantly in ductile mode by plasticity-dominated two-body abrasion. Finally, it was found that over-sintering of monolithic B4C ceramics above their near-full densification condition is impractical and could even be detrimental for tribological applications.

Particle type effect on mechanisms of surface texturing in reducing wear

The tribological behavior of tungsten carbide-textured samples with different particle types (silica, alumina and diamond) and sizes (5 and 25 µm) are investigated. Pin-on-disk experiments are conducted. Surface texture can effectively reduce the friction coefficient and wear rate of the sample with different particle types and sizes. When the lubricant has silica particles, the friction reduction efficiency of texture is the lowest. Softer particles are more likely to be crushed, making it easier to enter the friction interface and fill into the texture. The wear resistance increases with decreasing particle hardness. The particles will cause three-body and two-body abrasion. Small particles (5 µm) are more likely to enter the friction interface and roll more easily than larger particles (25 µm), causing more three-body abrasion. As the hardness of the particles increases, they are more likely to press against the surface of the specimen as they roll, leading to more three-body abrasion. Compared with untextured samples, textured samples can store particles and lubricant and thus have less three-body abrasion and two-body abrasion. This study provides new ideas for reducing the friction and wear of samples in water containing different particle types and sizes.

Evaluation of abrasive wear resistance of self-fluxing Ni-base coatings by scratch testing

"Abrasion wear is one of the most dominant types of wear in many applications, causing over 50% of all wear failures [1]. The abrasive wear phenomenon could be classified regarding several aspects: a) the position of the abrasive particles: two-body abrasion if they are fixed, or three-body abrasion if they are free to slide and/or roll, b) the stresses involved: gouging abrasion, high-stress abrasion (grinding) and low-stress abrasion (scratching), c) the surface appearance: ploughing, cutting, fatigue and fracture (cracking). In this study was approached the possibility of abrasion wear resistance evaluation of selffluxing Ni-base coatings by scratch testing. Materials used in tests were: three self-fluxing Ni-base coatings deposited on low-alloyed steel substrate using flame spraying process (referred to as S1, S2 and S3). The wear of the samples and the friction coefficient were investigated with scratch tester and analyzed in correlation with their mechanical properties. "

Tribological performance of thermal sprayed coatings under abrasive conditions

In this work, the tribological behaviour of thermally sprayed titanium and chromium ceramic-based coatings was investigated under abrasive conditions. Their structure was studied by a scanning electron microscope (SEM), while their hardness was evaluated using a microhardness tester. To study the strength of these ceramic coatings under abrasion conditions, reciprocating sliding experiments were carried out in a high-precision (10 mN resolution, 1000 Hz data acquisition) pin-on-disk apparatus and by using a Ø6 mm corundum ball to generate high contact pressures (1.5 GPa). To thoroughly investigate the friction evolution of the tribo-system, three-dimensional mapping of the tangential friction forces (triboscopy) was performed. Following the abrasion experiments, the wear of these coatings was measured using confocal microscopy. The obtained friction and wear results were compared to state-of-the-art materials and coatings that are currently being used in various industrial applications. From this comparison, it was found that the titanium and chromium ceramic-based coatings have comparable if not better tribological properties for the given conditions. The main wear mechanism was mainly two-body abrasion due to the surface roughness of the counter-material, as well as three-body abrasion due to the formation of debris at the interface.

Study on abrasive wear pattern of ethylene propylene dyne monomer (EPDM) rubber compound

Ethylene Propylene Dyne Monomer (EPDM) rubber is an important and dominant elastomer. In the present experimental work an indigenous EPDM rubber of low, medium and high hardness values have been selected for abrasive wear study in a two-body abrasion tester ‘TR-605′ (Ducom) in dry condition. Needless to be mentioned that this indigenously developed material in the laboratory of NEL, Kolkata has no prior data related to tribological characteristics. Moreover, all rubber materials have its own complex characteristics and unlike metallic materials the overall property prediction of any viscoelastic material is quite difficult. This is the motivation and novelty consideration of conducting the present study. Four experimental factors like hardness of rubber, abrasive grade, load on the job and cycle time have been selected judiciously at three levels each for the laboratory experimentations. Optimum combinations have been obtained through Taguchi’s design of experiment (DOE) technique. The results have been validated through confirmatory trials with the optimum combination of factor levels. The predicted response being 27.92 the obtained response after additional confirmatory trial has been noticed as 28.61. Hence, the accuracy of the prediction is considerably satisfactory. The surface abrasion patterns have been characterized by SEM study (SEM: JEOL, JSM-6360, model 75 82). The abraded surfaces have been coated with a very thin film of palladium (Pd) using an ion sputtering machine (Auto Fine Coater: JEOL, JFC-1600) before SEM studies. Finally, the conclusions have been made highlighting the possible future researches in the related field.

Unlubricated sliding wear of B4C composites spark-plasma sintered with Si aids and of their reference B4C monoliths

Two fully-dense B4C–SiC composites were fabricated by spark-plasma sintering (SPS) from B4C+Si powders, one superhard (i.e., ∼28.7(8) GPa) with abundant SiC by SPS of B4C+20vol%Si at 1400 °C and the other ultrahard (i.e., ∼35.1(4) GPa) with little SiC by SPS of B4C+4.28vol%Si at 1800 °C, and their unlubricated sliding wear was investigated and compared with those of the reference B4C monoliths. It was found that the two B4C–SiC composites underwent mild tribo-oxidative wear with preferential removal of the oxide tribolayer, with the one SPS-ed at 1400 °C from B4C+20vol%Si being, despite its lower hardness and greater proneness to form oxide tribolayer, only slightly less wear resistant than the one SPS-ed at 1800 °C from B4C+4.28vol%Si (i.e., ∼1.0(5)·107vs 1.37(8)·107 (N⋅m)/mm3). The reference B4C monolith SPS-ed at 1400 °C is comparatively two orders of magnitude less wear resistant (i.e., ∼1.70(6)·105 (N⋅m)/mm3), attributable to its undergoing severe purely mechanical wear by microfracture-dominated three-body abrasion due to its very poor sintering (i.e., high porosity of ∼33.5 %), poor grain cohesion, and low hardness (i.e., ∼3.1(5) GPa). The reference B4C monolith SPS-ed at 1800 °C, while equally or less hard (i.e., ∼28.4(9) GPa) and slightly porous (i.e., ∼5.3 %), is somewhat more wear resistant (∼1.8(3)·107 (N⋅m)/mm3) than the B4C–SiC composites, attributable to its undergoing only mild purely mechanical wear by plasticity-dominated two-body abrasion without porosity-induced grain pull-out, but it requires SPS temperatures well above 1400 °C. Finally, relevant implications for the ceramics and hard-materials communities with interests in tribological applications are discussed.

Tribo-chemical wear of various 3d-transition metals against DLC: Influence of tribo-oxidation and low-shear transferred layer

Diamond-like carbon (DLC) is a promising solid lubricant owing to its excellent anti-friction and wear-resistance characteristics. However, the high hardness of DLC causes two-body abrasion to its counterpart, which generally are ferrous and brass metals having a relatively low hardness, resulting in severe wear of counterpart. Therefore, it is required to solve the wear-imbalance issue, leading to noise and vibration in tribo-system. In this study, we aimed to investigate the wear behavior of counterparts sliding against DLC. We used four-3d-transition metals (Ti, Fe, Ni, and Cu) as the counterpart of DLC, based on the chemical properties for carbon and oxygen, i.e., the activation energy of oxidation and work of separation with carbon. Our finding is suggested that the wear of transition metals was governed by oxidative wear rather than mechanical wear (e.g., adhesive wear and abrasive wear). Moreover, their oxidative wear was prevented by carbon-containing tribofilm, which is transferred from DLC continuously. It revealed that severe oxidational wear was caused in copper and iron, because of their chemical properties.

Tribological mechanisms of slurry abrasive wear

Abrasive wear mechanisms—including two-body and three-body abrasion—dominate the performance and lifespan of tribological systems in many engineering fields, even of those operating in lubricated conditions. Bearing steel (100Cr6) pins and discs in a flat-on-flat contact were utilized in experiments together with 5 and 13 µm Al2O3-based slurries as interfacial media to shed light on the acting mechanisms. The results indicate that a speed-induced hydrodynamic effect occurred and significantly altered the systems’ frictional behavior in tests that were performed using the 5 µm slurry. Further experiments revealed that a speed-dependent hydrodynamic effect can lead to a 14% increase in film thickness and a decrease in friction of around 2/3, accompanied by a transition from two-body abrasion to three-body abrasion and a change in wear mechanism from microcutting and microploughing to fatigue wear. Surprisingly, no correlation could be found between the total amount of wear and the operating state of the system during the experiment; however, the wear distribution over pin and disc was observed to change significantly. This paper studies the influence of the hydrodynamic effect on the tribological mechanism of lubricated abrasive wear and also highlights the importance to not only consider a tribological systems’ global amount of wear.

Evaluation of additive friction stir deposition of AISI 316L for repairing surface material loss in AISI 4340

Additive technologies provide a means for repair of various failure modes associated with material degradation occurring during use in aggressive environments. Possible repair strategies for AISI 4340 steel using AISI 316L deposited by additive friction stir deposition (AFSD) were evaluated under this research by metallography, microhardness, and wear and mechanical testing. Two repair geometries were investigated: groove-filling and surface cladding. The former represents repair of localized grinding to eliminate cracks, while the latter represents material replacement over a larger area, for example, to repair general corrosion or wear. The 316L deposited by AFSD exhibited a refined microstructure with decreased grain size and plastic strain, ~ 12% lower strength, and 5–12% lower hardness than the as-received feedstock. Wear testing by both two-body abrasion and erosion by particle impingement indicated that the wear resistance of the 316L cladding was as good as, or better than, the substrate 4340 material; however, there was some evidence that the resistance to intergranular corrosion was compromised due to the formation of carbides or sigma phase. In both repair geometries, the microstructure of the substrate beneath the deposited material exhibited heat affected zones where the substrate appeared to have austenized to a depth of ~ 4 mm during the deposition process, and transformed to martensite or bainite during cooling. This report constitutes an initial evaluation of a novel approach to the repair of structural steel components damaged by microcracking, wear, or corrosion, with potentially broad applicability to the marine, aerospace, and heavy duty off-road industries.

Wear properties of nanoclay modified basalt fibre composites under dry adhesive sliding, two-body abrasive, and slurry pot erosive

This paper reports the effect of 1.0 wt%, 3.0 wt% and 5.0 wt% nanoclay loadings on specific wear rate properties of basalt fiber reinforced polymer (BFRP) composites. The specific wear rate properties of the BFRP composites were analyzed at three different wear conditions, i.e., dry adhesive sliding, two-body abrasion, and slurry pot erosion in which the composites slide against smooth steel, rough silicon carbide, and medium-coarse sand mixture, respectively. The operating parameters for the wear tests were set at 30 N load, 300 rpm speed, and 10 km distance. The results demonstrated that the addition of nanoclay effectively enhanced the adhesive and erosive wear properties of BFRP composites. In adhesive wear properties, BFRP containing up to 5.0 wt% (EP/BF/5NC) marked 31.73% improvement when compared to the pure system, whereas, under erosive wear condition, the wear rate reduced by up to 51.12% when 1.0 wt% of nanoclay was added to EP/BF. As the nanoclay content increases, the wear rate exhibited improvement as indicated by reduction of erosive wear resistance. In contrast, nanoclay incorporation deteriorated the abrasive wear properties of BFRP. The abrasive wear rates reduced as nanoclay content increased, for example, the incorporation of nanoclay up to 5.0 wt% deteriorated about 101.94% when compared to pure EP/BF. The morphology of worn surfaces was evaluated using scanning electron microscopy (SEM) to study the wear behavior of the nano clay modified BFRP composites. It concluded that nanoclay incorporation exhibited significant influence on wear properties of the polymer composites depending on the wear environment condition.

Microstructure and Two-Body Abrasive Wear Behavior of Fe-B Surfacing Alloys with Different Chromium and Vanadium Contents

Microstructure and Two-Body Abrasive Wear Behavior of Fe-B Surfacing Alloys with Different Chromium and Vanadium Contents

Investigation of abrasive behavior between pad asperity and oxide thin film in chemical mechanical planarization

In this paper, tribological effects on the material removal rate (MRR) are investigated using two types of slurry abrasives (i.e., ceria and silica) and three types of pads. From a micro to macro viewpoint, the physico-chemical interaction between the pad-wafer interface and abrasive was studied based on multi-asperity contact. First, the relative contact pressure in high or low proportions among all asperities was calculated using a contact mechanics model. The results indicate that for the commercial slurry used in the semiconductor industry, relatively high contact pressure due to the asperities can be transferred to the ceria abrasives, and only a low contact pressure can be supported by these silica abrasives. Furthermore, it was confirmed that the two different slurry abrasives showed opposite behaviors according to the real contact area of the pad asperities. That is, as the pad texture changed from ‘Desired pad’ to ‘Smoothed pad’, the MRR of the ceria increased by 47%, while the MRR of the silica decreased 59%. Lastly, the Stribeck curve, which is suitable for the CMP process, was re-analyzed to clarify the abrasion mechanism under the pad asperity scale. The results showed that two-body abrasion may be maintained for the ceria CMP, and transition is possible from two-body to three-body abrasion at the silica CMP as the contact area increases. The present paper is expected to clarify the tribological mechanism of the oxide CMP and can provide further insight into optimizing and selecting consumables such as conditioner, pad, and slurry.

Abrasive Wear of High-Carbon Low-Alloyed Austenite Steel: Microhardness, Microstructure and X-ray Characteristics of Worn Surface.

A high-carbon, high-silicon steel (1.21 wt% C, 2.56 wt% Mn, 1.59 wt% Si) was subjected to quenching from 900 and 1000 °C, resulting in microstructures containing 60 and 94% of retained austenite, respectively. Subsequent abrasive wear tests of quenched samples were performed using two-body abrasion and three-body abrasion testing machines. Investigations on worn surface and subsurface were carried out using SEM, XRD, and microhardness measurement. It was found that the highest microhardness of worn surface (about 1400 HV0.05) was achieved on samples quenched from 900 °C after three-body abrasion. Microhardness of samples after two-body abrasion was noticeably smaller. with a maximum of about 1200 HV0.05. This difference correlates with microstructure investigations along with XRD results. Three-body abrasion has produced a significantly deeper deformed layer; corresponding diffractograms show bigger values of the full width at half maximum parameter (FWHM) for both α and γ alone standing peaks. The obtained results are discussed in the light of possible differences in abrasive wear conditions and differing stability of retained austenite after quenching from different temperatures. It is shown that a structure of metastable austenite may be used as a detector for wear conditions, as the sensitivity of such austenite to phase transformation strongly depends on wear conditions, and even small changes in the latter lead to significant differences in the properties of the worn surface.

Micro fillers effect on two body abrasive wear behavior of Polyamide 66, Polyamide 6 blend based composites

The effect of hybrid micro fillers on two body abrasive wear of PA66/PA6 blend based composites was investigated. Three composites: Blend (PA66/PA6) (80/20 wt%), Blend/10 wt% PTFE and Blend/10 wt% PTFE/5 wt% MoS2 were considered for the investigation. These micro composites were prepared by using melt mix method using twin screw extrusion technique. The two-body abrasion wear behavior of these micro composites was investigated using 180 grit SiC abrasion paper in a multipass condition as per ASTM G99 standard under the influence of variable abrasion load at a constant velocity of 0.5 m/s. It is found from the experimentation that the volumetric wear loss is totally dependent on abrading load. Further, it is found that Blend/PTFE composites exhibited good abrasion wear behaviour due to excellent Ratner-Lancaster (σε) factor. Micro ploughing and micro cutting were noticed during the morphological study through SEM images. Among the micro composites studied, Blend/10 wt% PTFE exhibited better abrasive wear resistance compared to other composites.

Ultra-low wear B4C-SiC-MoB2 composites fabricated at lower temperature from B4C with MoSi2 additives

Seeking to fabricate B4C composites that are even more superhard (>30 GPa) at lower cost, B4C was transient liquid-phase assisted spark-plasma-sintered, somewhat counterintuitively, at lower temperature (<1750 °C) and with greater MoSi2 aid content (>15 vol.%) than ever before. It was found that just 20 vol.% MoSi2 aid enables the full densification of B4C at 1700 °C, thereby avoiding the deleterious transformation β-MoB2→α-MoB2, having consumed the entire MoSi2 to form MoB2 and SiC. This maximizes the hardness (∼33 GPa) of these novel triplex-particulate B4C-SiC-MoB2 composites without penalizing their toughness (∼4.1 MPa⋅m0.5). Also importantly, the dry sliding-wear of these novel composites was investigated for the first time, showing that they undergo only mild wear (specific wear rate of ∼10−8 mm³/(N⋅m)) by plasticity-dominated two-body abrasion. Moreover, it was demonstrated that they are much more wear resistant than porous B4C monolithics fabricated under both the same and more demanding conditions, and at least as equally wear resistant as fully-dense B4C monolithics and composites fabricated under more demanding conditions.

Tribological behaviors of Mo2BC ceramics against various counterpart materials

In this study, the tribological behaviors of Mo2BC ceramics against four different counterpart materials were studied. It was established that the tribological properties of Mo2BC were sensitive to the counterpart material. For the Mo2BC/SiC and Mo2BC/Al2O3 tribo-pairs, a layer of tribofilm, mainly consisting of MoO3, was generated owing to the tribo-oxidation reaction. However, the tribofilm did not provide lubrication under ambient conditions. Tribo-oxidation and adhesion wear were the main wear mechanisms. For the Mo2BC/Si3N4 tribo-pair, only minor MoO3 tribo-oxides were generated, and the tribo-pair showed better tribological properties; the friction coefficient was as low as 0.42. The dominant wear mechanism was two-body abrasion. The Mo2BC/GCr15 steel tribo-pair showed a high friction coefficient, owing to the adhesion effect of Fe.