Abstract:The wear of PTFE filled with layered silicates (LS) was investigated depending on the concentration and chemical nature of the fillers. The influence of these factors on the tribotechnical characteristics and the structure of the surface layers of composites is shown. Using SEM methods, it has been established that the introduction of LS contributes to the formation of a protective layer on the friction surface consisting of worn PTFE particles and a filler. The thickness of the layer does not depend on the co… Show more
“…In addition, PTFE itself is a good lubricant, and there are three forms of PTFE falling off from the composite surface: one part falls off from the contact area and directly forms wear debris; The other part is transferred to the metal friction ring surface to form a transfer film; Another part does not break away from the contact surface or form a transfer film, but flows like a fluid along the sliding friction direction, which can reduce the friction coefficient. 50 Figure 6.Friction coefficient and volumetric wear rate of GF/MoS 2 /PTFE composites at different pressures.…”
Section: Resultsmentioning
confidence: 99%
“…In addition, PTFE itself is a good lubricant, and there are three forms of PTFE falling off from the composite surface: one part falls off from the contact area and directly forms wear debris; The other part is transferred to the metal friction ring surface to form a transfer film; Another part does not break away from the contact surface or form a transfer film, but flows like a fluid along the sliding friction direction, which can reduce the friction coefficient. 50 Surface morphology analysis of glass fiber/ molybdenum disulfide/ polytetrafluoroethylene composites Figures 7 and 8 show, respectively, the SEM images of the GF/MoS 2 /PTFE composites before and after wear for various molding pressures. Figure 7 shows that the surface of the specimens produced without abrasion studies is smooth, devoid of obvious wear indicators such pits, furrows, and surface peeling, and the filling material is more evenly distributed throughout the matrix at lower molding pressure.…”
Section: Effect Of Different Molding Pressure Processes On the Tribol...mentioning
Both glass fiber (GF) and molybdenum disulfide (MoS2) can enhance the comprehensive properties of PTFE (polytetrafluoroethylene)-based composites, however the properties of the composites are significantly influenced by the molding pressure utilized. In this study, GF/MoS2/PTFE composites were produced under varied molding pressures (50–70 MPa), and the composites’ mechanical and tribological properties were evaluated. The results showed that the tribological parameters (such as friction coefficient and volumetric wear rate) and mechanical parameters (such as density, hardness, tensile strength, and elongation at break) varied depending on the molding pressure. When the molding pressure was 50 MPa, the GF/MoS2/PTFE composites displayed their finest mechanical properties. The composite had the best wear resistance with the lowest wear rate of only of 2.135 × 10−6 mm3/Nm at a molding pressure of 60 MPa and the lowest friction coefficient of 0.166 at a molding pressure of 70 MPa. The increased molding pressure that was employed to make the samples, as predicted by SEM analysis, would lead to greater residual stresses inside the specimens, which would ultimately result in cracking and peeling. In the friction test, specimens with a lower forming pressure are more likely to have surface furrows that are deeper and wider, as well as to shed their filler. Due to the increased molding pressure, the depth of furrows and filler shedding on the composite surface are also more apparent.
“…In addition, PTFE itself is a good lubricant, and there are three forms of PTFE falling off from the composite surface: one part falls off from the contact area and directly forms wear debris; The other part is transferred to the metal friction ring surface to form a transfer film; Another part does not break away from the contact surface or form a transfer film, but flows like a fluid along the sliding friction direction, which can reduce the friction coefficient. 50 Figure 6.Friction coefficient and volumetric wear rate of GF/MoS 2 /PTFE composites at different pressures.…”
Section: Resultsmentioning
confidence: 99%
“…In addition, PTFE itself is a good lubricant, and there are three forms of PTFE falling off from the composite surface: one part falls off from the contact area and directly forms wear debris; The other part is transferred to the metal friction ring surface to form a transfer film; Another part does not break away from the contact surface or form a transfer film, but flows like a fluid along the sliding friction direction, which can reduce the friction coefficient. 50 Surface morphology analysis of glass fiber/ molybdenum disulfide/ polytetrafluoroethylene composites Figures 7 and 8 show, respectively, the SEM images of the GF/MoS 2 /PTFE composites before and after wear for various molding pressures. Figure 7 shows that the surface of the specimens produced without abrasion studies is smooth, devoid of obvious wear indicators such pits, furrows, and surface peeling, and the filling material is more evenly distributed throughout the matrix at lower molding pressure.…”
Section: Effect Of Different Molding Pressure Processes On the Tribol...mentioning
Both glass fiber (GF) and molybdenum disulfide (MoS2) can enhance the comprehensive properties of PTFE (polytetrafluoroethylene)-based composites, however the properties of the composites are significantly influenced by the molding pressure utilized. In this study, GF/MoS2/PTFE composites were produced under varied molding pressures (50–70 MPa), and the composites’ mechanical and tribological properties were evaluated. The results showed that the tribological parameters (such as friction coefficient and volumetric wear rate) and mechanical parameters (such as density, hardness, tensile strength, and elongation at break) varied depending on the molding pressure. When the molding pressure was 50 MPa, the GF/MoS2/PTFE composites displayed their finest mechanical properties. The composite had the best wear resistance with the lowest wear rate of only of 2.135 × 10−6 mm3/Nm at a molding pressure of 60 MPa and the lowest friction coefficient of 0.166 at a molding pressure of 70 MPa. The increased molding pressure that was employed to make the samples, as predicted by SEM analysis, would lead to greater residual stresses inside the specimens, which would ultimately result in cracking and peeling. In the friction test, specimens with a lower forming pressure are more likely to have surface furrows that are deeper and wider, as well as to shed their filler. Due to the increased molding pressure, the depth of furrows and filler shedding on the composite surface are also more apparent.
“…Based on the previous works conducted by such authors as Okhlopkova A.A., Sleptsova S.A. et al, and judging by the socalled "critical concentrations" that determine the maximum change in the tribological properties of a polymer composite materials, the following concentrations of filler content are selected: 2 mass% of SP and 1.5 mass% of SP + 0.5 mass% of MS [13,17]. A reason for the use of magnesium spinel as a functional additive lay in the ability of nanoparticles to selforganize, or rather that due to their activity nanodispersed particles in the mass of the polymer matrix tend to form clusters, which contributed to the reinforcement of the material leading to an increase in strength characteristics [17].…”
Section: Methodsmentioning
confidence: 99%
“…This surface layer is apparently formed mainly by wear particles appearing in large quantities at the beginning of abrasion, and falling onto the friction surface. It means that the products of wear repeatedly fall onto the friction surface, and then they are subjected to mechanochemical influence, as well as processes of dispersion, defragmentation, activation and oxidation [13]. For instance, in the work of Beliy et al it was shown that the process of friction of PCMs was accompanied by changes in the surface and near-surface layers of the composite, which led to formation of a new layer with modified characteristics, differing in physical and chemical, physical and mechanical properties from the properties of the PCM itself [18,21].…”
Section: Worn Surface Analysismentioning
confidence: 99%
“…Analysis of the results of researches conducted in the field of development of tribotechnical PCMs based on polytetrafluoroethylene (PTFE) shows that patterns of wear of PCM containing layered silicates [4,5,[10][11][12] have not been studied thoroughly. The works by Sleptsova, Kirillina and Vasiliev reflect studies of the properties of composites based on PTFE and layered silicates [13][14][15]. It was shown that the improvement of wear resistance could reach up to 1000 times compared to the original polymer.…”
The tribotechnical characteristics of polymer composites based on PTFE and layer silicates (serpentinite) were studied, depending on the test duration time. It was indicated that adding a serpentinite and magnesium spinel increased the wear resistance of the composite by up to 480 times compared to the original PTFE. It was found that particles of fillers and PTFE promote formation of a secondary structure on the friction surface, helping reduce the material wear process. The method of infrared (IR) spectroscopy and EDS showed that tribochemical reactions take place on the friction surface of composites.
Wear caused by friction is one of the main causes of most mechanical component failures. The application of powders as anti-wear lubricating materials has achieved great advances, which are of great significance in reducing friction and wear. This review focuses on the applications of phyllosilicates mineral powders as anti-wear lubricating materials in lubricating oil. The tribological behaviors of phyllosilicates mineral powders and the combination of phyllosilicates mineral powders with other materials as lubricant additives are provided. Moreover, the fundamental mechanism are systematically reviewed and concluded based on tribology data and surface, and interface analysis. Finally, current unsolved issues and suggestions for future research on phyllosilicates mineral powders as lubricant additives are proposed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
