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This paper aims to study the micro-structure evolution of friction layers to optimize the friction and wear behaviors of TiAl-based material. It further enlarges the scope of using TiAl alloys and increase in the service life of TiAl alloy-made mechanical components, especially under some extreme conditions.

To study the structure evolution of friction layers, the HT-1000 tribometer is used to study the friction and wear properties of as-prepared samples. With the assistance of field emission scanning electron microscopy and an electron probe micro-analyzer, the stratified structures in cross-sections and a surface morphology of the wear scars are well characterized. A ST400 surface profiler helps in better understanding of the three-dimensional texture profiles of wear scars. X-ray diffractometer (XRD) is also used to analyze phases in the as-prepared samples.

An analysis method on the micro-structure evolution can provide better views to understand the influence of friction layers on the tribological behavior, at different wear stages. It finds that the micro-structure evolution of friction layers has an immediate effect on the friction coefficients and wear rates of TiAl-based material. It also proves to be a useful tool for evaluating the behaviors in friction and wear of TiAl-based material.

The findings of this paper provide better assistance to explore the effect of friction layers on the friction and wear behaviors of TiAl-based materials. The results help in deep understanding of the micro-structure evolution of friction layers. It also increases the service life of TiAl-based mechanical components.

Random point-contact between the space bearing retainer and the rolling elements may cause wear of the space bearing retainer. The paper aims to clarify the friction and wear behaviors of polyimide bearing retainer under point-contact condition.

Space bearing retainers were cut into flat specimens and the tribological behaviors of the specimens were studied under point-contact condition using a friction and wear testing machine. Different sliding velocities and normal loads were used to simulate the running state of space bearing retainer. The wear behaviors of the space bearing retainer were analyzed by SEM and white light interferometer.

The friction coefficient of the polyimide composites decreased with increase in sliding velocity from 1  to 5 mm/s. Moreover, with increase in sliding velocity and normal load, the wear rate of the polyimide composites decreased and increased, respectively. Moreover, the wear behaviors of the polyimide composites were mainly determined by the combined actions of ploughing friction and adhesive friction. The lubricating properties of transfer film and wear debris were limited under point-contact condition.

The paper includes implications for the understanding of the wear mechanism of the polyimide composites space bearing retainer under point-contact condition and then to optimize space bearing retainer materials further.

Under point-contact condition, wear debris can hardly participate in the friction process because of limited contact area. Consequently, the wear debris has limited impact on the wear process to decrease the friction and wear.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-01-2020-0017/

The main aim of this paper was to study the self-lubricating behavior and failure mechanism of silver-rich solid film for in-depth analyzing of the friction and wear property of TiAl-10 wt. per cent Ag self-lubricating composite.

The friction and wear property of TiAl-10 wt. per cent Ag self-lubricating composite sliding against Si3N4 ball was tested under the testing conditions of ball-on-disk wear system. Field emission scanning electron microscopy and electron probe microanalyzer were used to analyze the surface morphology of silver-rich solid film. The main element contents were tested by energy dispersive spectroscopy. Silver phase on wear scar could be well identified using X-ray photo-electron spectroscopy. The theory calculation of shearing stress on wear scar was executed to discuss the local failure mechanism of silver-rich solid film. The lubricating role of silver was also discussed to analyze the anti-friction and anti-wear behavior of silver-rich solid film.

The friction coefficients and wear rates of TASC gradually reduced at 0-65 min, and approached to small values (0.31 in friction coefficient and 3.10×104 mm3N-1m-1 in wear rate) at 65-75 min. The excellent friction and wear behavior of TASC was mainly attributed to the lubricating property of silver-rich film at 65-75 min. At 12→20 N, surface shearing stress increased up to 146.31 MPa, and exceeded more than the shearing strength (125 MPa) of silver-rich film, which caused the propagating of fatigue crack and the destroying of silver-rich film, leading to high friction and severe wear.

It is important that the self-lubricating behavior and local failure of solid film is explored for further understanding the friction and wear property of TiAl alloys.

The main goal of the present study is to investigate the friction and wear behaviors of aluminum matrix composites with an A360 matrix reinforced with SiC, B₄C and SiC/B₄C particles.

Un‐reinforced aluminum casting alloy, Al/SiC, Al/B₄C and Al/SiC/B₄C aluminum composites were prepared for the present study. Friction and wear tests of aluminum and its composites versus AISI316L stainless steel were carried out for dry sliding condition using by a pin‐on‐disc arrangement. Tests were realized at the sliding speed of 0.5, 1.0 and 1.5 ms⁻¹ and under the loads of 10, 20 and 30 N. The microstructures of the present composites were examined by scanning electron microscopy and energy dispersive spectroscopy analysis.

The coefficient of friction of the composites is approximately 25‐30 percent lower than that of the un‐reinforced aluminum. The specific wear rate of the aluminum and its composites decreases with the increase in load and increases with the increment of sliding speed. Un‐reinforced aluminum has specific wear rate value of 1.73×10⁻¹³ which is the highest specific wear rate, while Al+17%SiC has specific wear rate value of 2.25×10⁻¹³ m² N⁻¹ which is the lowest specific wear rate among the tested materials. The average specific wear rates for Al+17%B₄C, Al+17%SiC/B₄C and Al+17%SiC composites are obtained about 49, 79 and 160 percent lower than aluminum wear rate under the same test conditions, respectively.

In the present study, composites were prepared by pressured infiltration technique. The employed composites are important in industry due to their higher wear resistance, light in weight and less thermal distortion comparing to conventional composites. Also, wear behavior of Al/B₄C, Al/SiC/B₄C and Al/SiC composites produced by pressured infiltration technique were not studied very much earlier, therefore more explanation about these composites were proposed.

The purpose of the present paper aims to, study the coefficient of friction and wear behavior of nickel based super alloys used in manufacturing of gas and steam turbine blades. In present paper, parametric study focuses on normal load, dry sliding velocity and contact temperature influence on coefficient of friction and wear of a nickel based super alloy material.

Experimental investigation is carried out to know the effect of varying load at constant sliding velocity and varying sliding velocity at constant load on coefficient of friction and wear behavior of nickel based super alloy material. The experiments are carried out on a nickel based super alloy material using pin on disk apparatus by load ranging from 30 N to 90 N and sliding velocity from 1.34 m/s to 2.67 m/s. The contact temperature between pin and disk is measured using K-type thermocouple for all test conditions to know effect of contact temperature on coefficient of friction and wear behavior of nickel based super alloy material. Analytical calculations are carried out to find wear rate and wear coefficient of the test specimen and are compared with experimental results for validation of experimental setup. Regression equations are generated from experimental results to estimate coefficient of friction and wear in the range of test conditions.

From the experimental results, it is observed that by increasing the normal load or sliding velocity, the contact temperature between the pin and disk increases, the coefficient of friction decreases and wear increases. Analysis of variance (ANOVA) is used to study the influence of individual parameters like normal load, dry sliding speed and sliding distance on the coefficient of friction and wear of nickel based super alloy material.

This is the first time to study effect of contact temperature on the coefficient of friction and wear behavior of nickel-based super alloy used for gas and steam turbine blades. Separate regression equations have been developed to determine the coefficient of friction and wear for the entire range of speed of gas turbine blades made of nickel based super alloy. The regression equations are also validated against experimental results.

This paper aims to investigate the correlation between wear behavior and microstructure evolution in friction-induced deformation layers (FDL) of 30CrMnSi steel, especially the role of strain-hardening induced by plastic deformation in FDL, which accordingly alters the wear behavior.

Dry sliding friction and wear behaviors of the 30CrMnSi steel against quenched and tempered GCr15 steel were studied using a pin-on-disc tester. The microstructure, hardness and plastic deformation of FDL were investigated.

It was found that the evolution of microstructure and strain-hardening induced by plastic deformation were occurred in the subsurface. When the microstructure, hardness and depth of the plastic deformation layer (PDL) reached a relatively steady state, the friction process transformed into stable-state stage. The wear loss and depth of the PDL was in dynamic equilibrium at stable wear stage.

In this paper, the correlation among the microstructure evolution, the strain-hardening and wear behavior were systemically analyzed. This paper could provide a theoretical reference for optimizing the microstructure and strain hardening properties of tribo-pairs materials.

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 is to investigate the effect of round pits arrangement patterns on tribological properties of journal bearing. In this paper, the tribological behaviors of journal bearing with different arrangement patterns under lubrication condition were studied based on M-2000 friction and wear tester.

The friction and wear of journal bearing contact surface were simulated by ANSYS. The wear mechanism of bearing contact surfaces was investigated by the means of energy dispersive spectrum analysis on the surface morphology and friction and wear status of the journal bearing specimens by Scanning Electron Microscopy (SEM) and Energy Dispersive Spectrometer (EDS). Besides, the wearing capacity of the textured bearing was predicted by using the GM (1,1) and Grey–Markov model.

As the loads increase, the friction coefficient of journal bearing specimens decrease first and then increase slowly. The higher rotation speed, the lower friction coefficient and the faster temperature build-up. The main friction method of the bearing sample is three-body friction. The existence of texture can effectively reduce friction and wear. In many arrangement patterns, the best is 4# bearing with round pits cross-arrangement pattern. Its texturing diameters are 60 µm and 125 µm, and the spacing and depth are 200 µm and 25 µm, respectively. In addition, the Grey–Markov model prediction result is more accurate and fit the experimental value better.

The friction and wear mechanism is helpful for scientific research and engineers to understand the tribological behaviors and engineering applications of textured bearing. The wear capacity of textured bearing is predicted by using the Grey–Markov model, which provides technical help and theoretical guidance for the service life and reliability of textured bearing.

The serious friction and wear problem occurs on the mechanical seal’s faces during the start-up stage of the high-speed turbopump for a liquid rocket engine. This paper aims to propose a kind of thick metal alloy coatings on the surface of the seal’s rotor so as reduce the friction and wear.

With the pin-disk (the graphite pin and the disk with the metal coating) tribology-tester, the tribological behaviors of four metal coatings are investigated. The special friction coefficients under the dry friction, boundary friction and different temperatures of water-lubricated conditions were obtained.

The test results show that the thick metal coating has a good performance of the wear resistance and friction reduction; and the friction coefficients of a Sn-Sb-Cu coating under the dry friction and water-lubricated conditions are 0.377 and 0.043, respectively, and the corresponding mass wear volumes are only 2.74 and 0.81 mg, respectively.

The thick metal coating scheme for the mechanical seal’s faces might lend itself to the harsh working conditions of the low-viscosity liquid rocket engine.

The purpose of this paper is to characterize carbide coatings obtained by thermo reactive diffusion (TRD) method on AISI 52100 and 440C bearing steels, which are extensively used in industry, and to study wear behaviour of coated steels at elevated temperatures.

For coatings of vanadium and titanium carbides, TRD treatment is performed on AISI 52100 and 440C steels using pack method at 950°C for 3 h. Carbide coatings are characterized using X‐ray diffraction (XRD). The Daimler‐Benz Rockwell‐C adhesion test and micro‐Knoop indenter is used to assess the adhesion and hardness of the carbide layers, respectively. Ball‐on‐disc arrangement is used for determination of tribological properties of carbide‐coated steels. Friction and wear tests are carried out against Si₃N₄ ball at elevated temperatures up to 600°C under 5 N load, for sliding speed of 0.3 m/s.

The presence of carbides formed on AISI 52100 (Ti₆C_3.75 and VC_0.88 phases) and on AISI 440C (Ti₆C_3.75, VC_0.88 and minor Cr₂₃C₆ and Cr₇C₃ phases) is confirmed by XRD analysis. Hardness values of titanium and vanadium carbides on the 52100 and 440C steels are about 2,175‐2,464 and 2,128‐2,433 HK_0.05, respectively. Friction experiments show that this type of coating is more effective than the substrates in regards to achieving lower friction up to 300°C. Above this temperature, the effect of substrate is more dominant on the friction coefficient. Scanning electron microscopy and energy‐dispersive X‐ray analysis results show the presence of the compact oxide layers at elevated temperatures as a result of increased sintering and oxidation of the wear debris.

This paper deals with only characterization of vanadium and titanium carbide coatings and high temperature wear properties of the coated steels.

Carbide coatings obtained by TRD method are satisfactory in terms of high temperature tribological applications in comparison with those produced vapor deposition processes, which are expensive and complicated equipment.

There is no literature about high temperature wear and friction behaviour of TRD carbide‐coated 52100 and 440C steels. In this study, there are new results on high temperature wear of TRD carbide‐coated steels.