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Poly‐ether‐ether‐ketone (PEEK), a specialty polymer, does not have any tribo‐utility as a bearing material in a virgin form since it exhibits quite a high coefficient of friction (μ) and stick‐slip behavior. The present paper seeks to deal with the adhesive wear behavior of series of PEEK composites based on inclusion of short fibers of glass (GF) and carbon (CF) and solid lubricants such as Polytetrafluoroethylene and graphite. The studies are focused to examine the role of these ingredients on enhancing PV limit, which is an indication of utility of a tribo‐polymer in severe operating conditions.

The Adhesive wear studies were performed on a pin on disc machine fabricated for high speed, load and temperature conditions. A composite pin slid over a disc of mild steel under two selected sliding speeds (2 and 3 m/s) for an hour. The load was varied in each experiment till the pin showed failure. The performance assessment was done based on multiple parameters such as magnitude of μ and its fluctuations with time, specific wear rate, PV limit, compatibility with the counterface, etc. PV limit was judged by observing either sudden increase in μ or wear rate (or both), deformation of the pin or change in the color of the disc.

It was observed that the neat PEEK exhibited very high and fluctuating μ with very low P‐V limit value (150 Nm/s) and high wear rate (2 × 10⁻¹⁴ m³/Nm). Inclusion of 30 percent CF benefited the strength properties but not the tribo‐performance appreciably. Composite D with a combination of GF (25 percent) and solid lubricants (30 percent) excelled in performance with a wide margin. The highest PV limit along with the lowest μ and lowest wear rate and counterface friendliness proved it to be most promising bearing material for the selected harsh operating conditions.

The composite D, which worked better than the commercial composite in almost all the selected operating conditions, indicates its commercial potential as a bearing grade material for high PV conditions.

Synergism between reinforcement and solid lubricants in right amount led to excellent friction and wear performance which was very well analysed based on worn surface topography.

The purpose of this study is to present a novel approach for the evaluation of tribological properties of brake friction materials (BFM).

In this study, a BFM was newly formulated with 16 different ingredients and produced using an industrial hot compression molding process. Experimentation was carried out on the brake tester, which was developed for this purpose according to SAE J661 standards. The braking applications, sliding speed and braking pressure were considered as performance parameters, whereas coefficient of friction (CoF) and wear rate as output parameters. The influence of the performance parameters on the output was studied using response surface plots. Analysis of variance and regression analysis was accomplished for post-experimental evaluation of results. Multi-criteria decision-making (MCDM) and multi-objective genetic algorithm (MOGA) were applied for estimating the most critical performance parameter combination to evaluate the BFM.

The present experimental model was significant and effectively used to predict the performance. MCDM generates the optimal values for the parameters braking applications, braking pressure (Bar) and sliding speed (rpm) as 1000, 30 and 915, whereas MOGA as 1008, 10.503 and 462.8202, respectively.

An efficient model for performance evaluation of the BFM considering maximum CoF and minimum wear rate was experimentally presented and statistically verified. Also, the two multi-objective optimization methodologies were implemented and compared. A comparison between the results of MCDM and MOGA reveals that MOGA yields 30% better results than MCDM.

This paper aims to investigate the tribological performance, i.e. abrasion resistance, friction coefficient and wear rates, of self-lubricated water conditioned polyamide6/boric oxide composites.

Polyamide6 and polyamide6/boric oxide self-lubricated composites were immersed in water for 15 days to analyze the effect of water conditioning on friction, wear and abrasion resistance. Tribological testing on pin-on-disc tribometer and abrasion resistance testing on TABER abrader were performed to see the friction coefficient and wear rates of materials. The scanning electron microscopy (SEM) characterizations were performed to analyze the wear tracks.

Tribological testing results revealed the loss in abrasive resistance, but there was an improvement in frictional coefficient and wear rates with steel after water absorption. The SEM images clearly show less depth of wear tracks in water-conditioned materials than dry ones. Water conditioning was found supportive in the formation of smooth lubricating transfer film on steel disc during the tribological testing.

The tribological behaviour of polymer composites is different in dry and in high humidity or water conditions. Experiments were performed to investigate B₂O₃ solid lubricant filler effectiveness on tribological behaviour of water-conditioned polyamide composites. Bonding between polyamide6 and water molecules plus the formation of orthoboric acid was found advantageous in decreasing the friction coefficient and wear rates of composites.

The purpose of this paper is to study the potential of alumina (Al₂O₃) in nanometer size in automotive brake friction materials.

Four brake linings containing alumina differing in particle size (355 µm and 80 nm) and various amount (5 and 10 Wt.%) were designed and produced. The hardness, density and porosity of the samples were measured. All samples were tested on a full-scale brake dynamometer with gray cast iron disc to determine the tribological properties. Detailed examinations on the worn surface were analyzed using a scanning electron microscopy.

It was concluded that all performance parameters were beneficially affected because of nano alumina.

This paper emphasizes the importance of nano-composites in the automotive industry and helps industrial firms and academicians working on wear of materials.

The use of laser sintering (LS) in the medical sector has increased dramatically in recent years. With the move towards direct use of these parts in clinical applications, there is a greater need to understand the effects of standard processes on the part properties. The purpose of this study is to determine the effect that steam sterilisation has on the mechanical properties of LS polyamide 12 parts.

The research presented here focusses on the effect of a single steam sterilisation cycle on the mechanical properties of polyamide 12 parts manufactured using LS. The influence of water content on the properties was investigated, with additional drying steps trialled to establish the potential to reverse any changes observed and to determine their root cause.

The results show that steam sterilisation has a significant effect on the mechanical properties of LS polyamide 12 parts, with a 39% reduction in elastic modulus, a 13% decrease in ultimate tensile strength and a 64% increase in the elongation at break. These properties were also all found to correlate with the water content, suggesting that this was the cause of the difference. The original properties of the parts were able to be recovered after oven drying.

These results show that with an additional drying step, LS polyamide 12 parts can be steam sterilised with no effect on the mechanical properties.

This is believed to be the first investigation into the effects of steam sterilisation in isolation on LS polyamide 12 parts, the first instance of drying parts to recover mechanical properties and the first instance of multiple water content measurements being directly linked to the mechanical properties.

This paper aims to develop a stable gel-type lubricant emulating commercial conditions. This encompassed rheological and tribological assessments, alongside field trials on the Medellín tram system.

The gel-type lubricant with graphite and aluminum powder is synthesized. Rheological tests, viscosity measurements and linear viscoelastic regime assessments are conducted. Subsequently, tribological analyses encompassing four-ball and twin disc methods are executed. Finally, real-world testing is performed on the Medellín tram system.

An achieved lubricant met the stipulated criteria, yielding innovative insights into the interaction of graphite and aluminum powder additives under varying tests.

Novel findings are unveiled regarding the interaction of graphite and aluminum powder additives in tribological, rheological and real-world trials. In addition, the wear behavior of polymers is observed, along with the potential utilization of such additives in tramway systems.

The present study aims to find out the best polymer/polymer pair in electrical insulating applications. Moreover, the effects of different polymer counterpart and applied load on the friction and wear behaviour of PA 46 + 30%GFR and unfilled PA 66 thermoplastic polymers are to be studied.

Friction and wear tests vs PA 46 + 30%GFR and PPS + 30%GFR polymer composites were carried out on a pin‐on‐disc arrangement and at a dry sliding conditions. Tribological tests were performed at room temperature under 20, 40 and 60 N loads and at 0.5 m/s sliding speed.

The results showed that, the coefficient of friction decreases with the increasing of load (up to 40 N) for PA 46 + 30%GFR composite and polyamide (PA) 66 polymer used in this study. However, above 40 N applied load the coefficient of friction increases. The specific wear rate for PA 46 + 30%GFR and PA 66 against PPS + 30%GFR polymer composite counterpart are about in the order of 10⁻¹³ m²/N while the specific wear rate for PA 46 + 30%GFR and PA 66 against PA 46 + 30%GFR polymer composite counterpart are in the order of 10⁻¹⁴ m²/N. For PA 46 + 30%GFR composite and unfilled PA 66 polymers tested the specific wear rate values increased with the increment of load. The highest specific wear rate is for unfilled PA 66 against PPS + 30%GFR with a value of 2.81 × 10⁻¹³ m²/N followed by PA 66 against PA 46 + 30%GFR with a value of 2.26 × 10⁻¹³ m²/N. The lowest wear rate is PA 46 + 30%GFR polymer composite against PA 46 + 30%GFR polymer composite counterpart with a value of 3.19 × 10⁻¹⁴ m²/N. The average specific wear rates for unfilled PA 66 against PA 46 + 30%GFR is 80 times higher than PA 46 + 30%GFR wear rate while specific wear rates for unfilled PA 66 against PPS + 30%GFR is 100 times higher than that of PA 46 + 30%GFR wear rate. From point view of tribological performance, PA 46 + 30%GFR is a more suitable engineering thermoplastic composite materials for electrical contact breaker applications.

In the present work, tribological tests were performed only at room temperature under three different loads and a sliding speed. This is the limitation of the work.

This work is easily used for industrial polyamides to check their tribological behaviours.

This is an original and experimental study and it will be useful both for academicians and for industrial sides.

The purpose of this paper, brake friction material samples with six different contents were produced using three different fiber types consisting of variable proportions of huntite mineral and basalt, glass and steel fibers. The friction properties and formation of the transfer film in these friction materials were investigated.

Friction materials were produced using a hot molding method from materials containing 10%–15% huntite in varying proportions, consisting of basalt, glass and steel fibers. The densities and hardness values of the samples were measured. Friction tests were performed using a brake pad friction material tester to determine tribological properties. After the friction tests, microscopic examination of the sample surfaces was performed using scanning electron microscope (SEM) and three-dimensional (3D) surface profilometer devices.

Huntite mineral content and fiber type affected the friction coefficient. With an increase in the amount of huntite, the friction coefficient increased in the friction material samples formed with glass and steel fibers. The fiber type and amount of huntite also affected the transfer film formation. The surface roughness values of all the friction materials decreased with an increase in the amount of huntite. The surface roughness values of the samples with glass fibers were higher than those of other samples.

The importance of using huntite minerals and different fiber types in automotive brake friction materials is emphasized. This will help industrial companies and academics study the tribological properties of friction materials.

This study aims to discuss the impact of using bio-polymer (kraft lignin) in the formulation of passenger vehicle disc brake pads (as a substitute for cashew nutshell liquid [CNSL]-based friction dust) and investigate the characteristics of the pads.

Within the scope of this investigation, three different brake pads were generated by altering the biopolymer-lignin content in conjunction with the friction dust from CNSL without modifying the other components. The brake pads were created in accordance with industry-standard practices. Industrial standards were used to evaluate the newly created brake pad’s thermal, physical and mechanical qualities. The tribological properties of the materials were determined using a full-scale inertia brake dynamometer. The scanning electron microscope examined the worn surfaces in conjunction with elemental mapping.

The test findings suggest that the brake pads filled with biopolymer-lignin and CNSL-based friction dust (as a partial replacement 50%) exhibited excellent thermal, physical, mechanical characteristics, as well as steady friction and low wear rate.

A bio-polymer (kraft lignin) in friction composites has the potential to produce eco-friendly brake pads and improve the tribological performance of its copper free-composition, which might be used to replace CNSL-based friction dust in friction composites by addressing the issues raised in this work.

The purpose of the study was to find the best performance polymer material to be used in railway car bogies.

Wear tests and optical and scanning electron microscopy were used.

The friction coefficients of ultra-high-molecular-weight polyethylene (UHMWPE) and Nylon 6 polymers, as opposed to AISI 4140 steel, reduced with the increment of applied loads. With the increment of sliding speed, the friction coefficient increased in both UHMWPE and Nylon 6 polymers. The specific wear rate of the UHMWPE polymer was determined to be about 10-14 m2/N, whereas the rate of Nylon 6 was determined to be 10-13 m2/N.

The aim of the study was to find the best performance polymer material to be used in railway car bogies.

The friction and wear performance of UHMWPE and Nylon 6 engineering polymers were studied and compared to their AISI 4140 steel counterparts. It is an original work and it is not published in any media.