Investigation of the coefficient of friction, wear, and surface morphology on a sliding contact area due to the large particle size of solid contaminants in grease

Investigation of the Coefficient of Friction, Wear, and Surface Morphology on a Sliding Contact Area due to the Large Particle Size of Solid Contaminants in Grease

A modified method for predicting the wear coefficient of reciprocating sliding wear was proposed in this study, which is less time-consuming. Based on this method, reciprocating sliding wear tests of three chain alloys (CM490, SS316, and TC4) under different loadings were conducted and the friction coefficient, wear coefficient, and wear morphology were obtained and compared. The results indicated that the time-variant coefficient of friction (CoF) could be used as an indicator for the stable wear state; moreover, it also changes periodically with the wear direction. Statistical analysis of friction coefficient indicated that it follows bimodal distribution or multimodal distribution. The friction and wear behaviors of CM490 and SS316 were different from those of TC4, and a detailed micro-morphological analysis indicated that the discrepancy is caused by the difference in the quantity and size of the wear debris. Furthermore, an upper limit of the contact stress-dependent wear coefficient was also observed, and the variability of the wear coefficient was also analyzed.

Festkörpergleitreibung und verschleiss von eisen, kobalt, kupfer, silber, magnesium und aluminium in einem sauerstoff-stickstoff-gemisch zwischen 760 und 2 × 10 −7 torr

Objectives: This study deals with the optimization of wear properties of Al 6101-alloy foam treated with different temperature zones such as Untreated (UT), Heat Treated (HT), Cryogenic Treated (CT), and Cryogenic Heat Treated (CHT), respectively. The results of this study concerning confirmation tests enable us to validate the proposed optimization findings for the coefficient of friction and specific wear. Methods: The Al 6101 foam samples used in this study are exposed to different heat and cryogenic treatments as well as wear tests using the pin-on-disk apparatus setup with the Taguchi optimization technique. The wear parameters are enhanced further using the Analysis of variance (ANOVA) technique, and this model is processed using the MINITAB software. The Al 6101 foam samples are evaluated using important wear testing parameters like Heat Zone, Load (N), Speed (rpm), and Sliding Distance (m), as well as the output parameters such as coefficient of friction and specific wear (mm3/Nm). Findings: The optimum combination of the coefficient of friction and specific wear, according to the graphic and analytical results of Taguchi’s optimization, is with 40 N load, 400 rpm speed, and 1500 m distance for a cryogenic zone and 40 N load, 400 rpm speed, and 2000 m distance for a cryogenic heat zone, respectively. The interaction of sliding distance, load, and speed, which has probabilities of 17.42, 8.95, and 7.74, respectively, is followed by the coefficient of friction, which has a greater probability percentage of 48.01 for the heat zone. The ANOVA for the specific wear has a higher probability percentage of 48.82 for the load and is followed by the interaction of heat zone, sliding distance, and speed, which have probabilities of 37.59, 6.02, and 2.85, respectively. Novelty: Considering Al 6101 foam, which is mostly a nonferrous material, this experiment once again confirmed that novel cryogenic treatment has a noteworthy improvement in coefficient of friction and specificwear. Additionally, Taguchi’s optimization and ANOVA analysis proved that the Al 6101 closed-cell foam specimen in the CHT zone exhibited optimal results when compared with other heat zones. The results confirmed that the CHT processing improves the wear resistance of the Al 6101 closed-cell foam effectively when examined with other different heat zones. Keywords: Al 6101 ClosedCell Foam; Cryogenic Treatment; Taguchi Technique; Coefficient Of Friction; Specific Wear; Wear Graph; Surface Morphology; L16 Orthogonal Array; ANOVA

Optimization of wear coefficient and coefficient of friction of borosilicate glass ceramics using Taguchi coupled grey fuzzy logic technique

This paper describes the microstructural characteristics and dry sliding spray performance of Al–10 wt. % Cu alloys. In this study Al-10 wt. % Cu alloys are manufactured using the spray atomisation and deposition method. Microstructures of spray deposited alloys were examined by optical microscopy (OM), Scanning electron microscopy (SEM) and Energy dispersive X-ray spectroscopy (EDS). The size of the alloy grains was measured using optical microstructure. The average grain size of the Al–10 wt. percent of the Cu alloy was evaluated to be 5.5 μm. The study of microstructural features showed different variations in wear behaviour and coefficient of friction of alloys. Tribological characterisation was performed for the spray formed by Al-10 wt. Percent Cu alloy specimens developed with optimum parameters for the determination of sliding specific wear levels for the combination of wear parameters like sliding distance, load and velocity. The Al–10 of the Wt. Percent of Cu alloy shows better wear resistance, particularly at higher loads. The coefficient of friction implies a dependency on the applied load. The nature of these alloys is discussed in the light of both the morphology of debris particles and the morphology of damaged surfaces.

The wear and sliding friction response of a hybrid copper metal matrix composite reinforced with 10 wt% of tin (Sn) and soft solid lubricant (1, 5, and 7 wt% of MoS2) fabricated by a powder metallurgy route was investigated. The influence of the percentages of reinforcement, load, sliding speed, and sliding distance on both the wear and friction coefficient were studied. The wear test with an experimental plan of six loads (5–30 N) and five sliding speeds (0.5–2.5 m/s) was conducted on a pin-on-disc machine to record loss in mass due to wear for two total sliding distances of 1,000 and 2,000 m. The results showed that the specific wear rate of the composites increased at room temperature with sliding distance and decreased with load. The wear resistance of the hybrid composite containing 7 wt% MoS2 was superior to that of the other composites. It was also observed that the specific wear rates of the composites decreased with the addition of MoS2. The 7 wt% MoS2 composites exhibited a very low coefficient of friction of 0.35. The hardness of the composite increased as the weight percentage of MoS2 increased. The wear and friction coefficient were mainly influenced by both the percentage of reinforcement and the load applied. Wear morphology was also studied using scanning electron microscopy and energy-dispersive X-ray analysis.

Al alloy 7075 reinforced with Al2O3 particles of three different sizes (63,102, and 165 μm) were fabricated through the stir casting method. Dry sliding wear tests were conducted to evaluate the influence of load, sliding velocity and particle size on the wear loss and coefficient of friction of the composites using a pin-on-disc wear testing rig. Tests were conducted according to L9 Taguchi orthogonal array for three different loads (10, 30, and 50 N) at three different velocities (0.837, 1.674, and 2.512 m/s) for a constant time period of 30 minutes. The results showed that the wear increased with increasing load and sliding velocity whereas the coefficient of friction increased with increasing sliding velocity. On the contrary, the coefficient of friction decreased with increasing load. Composites reinforced with coarse Al2O3 particles exhibit superior wear resistance. It was found that the load was the most dominant factor influencing the wear loss and coefficient of friction followed by sliding velocity and particle size. A Scanning Electron Microscope (SEM) was used to study the morphology of the worn surfaces of the pins.

The combination of the Savage surface energy and the Bowden and Tabor junction formation mechanisms of production of frictional energy is suggested. The physical description of the experiments is sufficiently simplified and represented by a stable state which envelopes the whole field of friction. This leads to a qualitative and satisfactory agreement with the observed results for the values of coefficients of friction between solid surfaces, between solid surfaces with thin liquid or solid soft metal films, for wear, and for the correlation between friction and wear. The coefficient of wear is defined analogously to the coefficient of friction.

For mechanical seal friction vice in dry friction conditions, due to friction wear serious failure, is the slurry pump and other instruments in the operation of the process of the urgent need to solve the problem. In this paper, in order to optimize and enhance the friction and wear problem of mechanical seal end face of slurry pump. Surface treatment of mechanical sealing rings with diamond-like carbon (DLC) coating and surface microtexturing, and at different rotational speeds and normal forces, the surface hardness, wear coefficient and dry friction coefficient of the sealing rings were analyzed by experimental comparison, and the wear morphology was collected by electron microscopy, having analyzed the results of the sets of, the end face structure of the mechanical seal was optimized. Based on Archard wear model simulation calculations, the seal ring wear depth and wear quality were obtained. The results show: under dry friction conditions, the synergistic effect of the DLC coating and the surface micro-texture (MT), the coefficient of friction is reduced by approx. 68% and the quality and depth of wear is minimized. Excessive speeds and normal forces are more prone to wear behavior caused by abrasive wear. Simulation results of surface treatment groups, DLC / MT group maximum wear depth is the smallest; wear quality test and simulation of the maximum error within 15.7%. The results of the study can provide a basis for a phosphoric acid plant slurry pump mechanical seal design.

The friction and wear characteristics for copper slid against ZI-005, a newly-developed, three-dimensional-fabric-reinforced plastic, were examined at room temperature (300 K) and at liquid nitrogen temperature(77 K) to determine its suitability for use in cryogenically-cooled electromagnets. For comparison, the friction and wear characteristics for copper slid against G-10, a conventional two-dimensional-fabric-reinforced plastic,were also measured. The friction coefficient for the copper/G-10 pair increased markedly with sliding distance at 300K, achieving a steady-state value of 0. 75; at 77K the friction coefficient is much lower, ~0. 3, and relatively independent of distance. By contrast, the friction coefficient for copper/ZI-005 is equal to ~0. 5, independent of both sliding distance and temperature. The magnitude of the nondimensional wear coefficients for copper/ZI-005 are equal to ~10−4, independent of temperature, and are approximately 100 times greater than those for copper/G-10(~10−6). The magnitude of these wear coefficients, together with an examination of the composites’ surface morphologies, suggest that the surface interactions for copper/ZI-005 are predominantly abrasive, whereas the interactions for copper/G-10 are generally adhesive. Because of its tendency towards abrasive friction, ZI-005 should provide a much stabler friction behavior when used as an insulator between highly-stressed copper windings.

The effect of contact load and relative displacement on tribo-corrosion interaction of parallel steel wires of main cable in the suspension bridge was investigated in this study. A self-made tribo-corrosion test bench was employed to conduct tribo-corrosion tests of parallel steel wires in 3.5% (wt%) NaCl solution and deionized water under different contact loads and different relative displacements. The friction coefficient and wear coefficient of wires were presented. Electrochemical corrosion behavior (Tafel polarization curves, Nyquist diagram, and equivalent circuit diagram) was characterized by electrochemical analyzer. Wear morphology was observed by scanning electron microscope. Wear volume loss and corrosion-wear interaction were quantitatively demonstrated by high-precision weighing balance. The results show that the electrochemical corrosion ability of the steel wires increases with the increase of the contact load or relative displacement. The increased contact load or relative displacement increases the volume loss of corrosion-wear and pure wear, but decreases the wear coefficient. The wear mechanisms in 3.5% NaCl solution are adhesive wear, abrasive wear, and corrosive wear as compared to adhesive wear and abrasive wear in deionized water under different contact loads. The wear mechanisms of parallel steel wires are slightly different under different relative displacements. But the main wear mechanisms are similar to that under different contact loads. The interaction effects of corrosion and wear produced by the contact load and relative displacement are all the synergistic effects.

This paper aims to present an experimental investigation for optimum tribological behavior (wear depth and coefficient of friction) of electroless Ni-P-Cu coatings based on four process parameters using artificial bee colony algorithm. Experiments are carried out by utilizing the combination of three coating process parameters, namely, nickel sulphate, sodium hypophosphite, and copper sulphate, and the fourth parameter is postdeposition heat treatment temperature. The design of experiment is based on the Taguchi L27 experimental design. After coating, measurement of wear and coefficient of friction of each heat-treated sample is done using a multitribotester apparatus with block-on-roller arrangement. Both friction and wear are found to increase with increase of source of nickel concentration and decrease with increase of source of copper concentration. Artificial bee colony algorithm is successfully employed to optimize the multiresponse objective function for both wear depth and coefficient of friction. It is found that, within the operating range, a lower value of nickel concentration, medium value of hypophosphite concentration, higher value of copper concentration, and higher value of heat treatment temperature are suitable for having minimum wear and coefficient of friction. The surface morphology, phase transformation behavior, and composition of coatings are also studied with the help of scanning electron microscopy, X-ray diffraction analysis, and energy dispersed X-ray analysis, respectively.

Tribological performance of low-temperature plasma carburized AISI 420 martensitic stainless steel

This research analysed blended palm oil and blended virgin coconut oil (VCO) as a new formulated bio lubricant utilizing pin on disc experiment. The primary objective of this project is to investigate the tribological characteristics of wear rate and coefficient of friction, as well as to examine the disc's surface morphology, following the ASTM G99 standard. The study was conducted using parameter speeds ranging from 600 rpm to 900 rpm and loads from 30 N to 60 N. Surface roughness of the disc samples was measured using a Surftest machine. The findings revealed that the lubricant with 15% Virgin Coconut Oil (VCO) content had the lowest coefficient of friction, specifically at 750 rpm and a 45 N load. The base lubricant used in this study is 85W140 GL5 gear oil, which was enhanced with blends containing 15% and 30% of Palm Oil and Virgin Coconut Oil. Additionally, the oil blend with 30% Palm Oil content exhibited the lowest wear rate, observed at 600 rpm with a 45 N load. The results, which highlight the highviscosity index, unsaturated/saturated ratio, and the low wear rate and coefficient of friction of Palm Oil and VCO, suggest that these oils are promising candidates as base fluids for lubricants in future applications. This makes them viable alternativesfor various industrial uses, providing stable and favorable performance characteristics