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18 pages, 12315 KiB

Open AccessArticle

Influence of Graphene Type and Content on Friction and Wear of Silicon Carbide/Graphene Nanocomposites in Aqueous Environment

by Bernadette Schlüter, Christian Schröder, Wenli Zhang, Rolf Mülhaupt, Ulrich Degenhardt, Richard Sedlák, Ján Dusza, Katalin Balázsi, Csaba Balázsi and Andreas Kailer

Materials 2022, 15(21), 7755; https://doi.org/10.3390/ma15217755 - 03 Nov 2022

Viewed by 1397

Abstract

Two different types of graphene materials were used as functional nanofillers for the mechanical and tribological improvement of silicon carbide/graphene nanocomposites. On the one hand is thermally reduced graphite oxide (TRGO) reduced at three different temperatures, and on the other hand is graphene [...] Read more.

Two different types of graphene materials were used as functional nanofillers for the mechanical and tribological improvement of silicon carbide/graphene nanocomposites. On the one hand is thermally reduced graphite oxide (TRGO) reduced at three different temperatures, and on the other hand is graphene made of three different organic precursors, which were directly coated on silicon carbide (SiC) platelets (GSiC). Additionally, benchmark materials were also used as carbon fillers. The SiC/graphene nanocomposites with 2 wt% filler content were manufactured by pressureless sintering (PLS). Some composites were produced with higher graphene contents of 4% and 8% and sintered by spark plasma sintering (SPS). Microstructural analyses were conducted using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Underwater lubrication, the SP sintered TRGO and GSiC materials with high graphene content have shown the most promising tribological performance. Furthermore, the reduced size of the homogeneously distributed nanoparticles promotes the formation of surface states, which improve the friction and wear properties. Full article

(This article belongs to the Special Issue Tribology: Friction and Wear of Engineering Materials (Second Volume))

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21 pages, 3643 KiB

Open AccessArticle

Mixtures of Lubricants and Ecological Refrigerants under Starved Lubrication Conditions

by Kasper Górny, Arkadiusz Stachowiak, Przemysław Tyczewski and Wiesław Zwierzycki

Materials 2022, 15(21), 7747; https://doi.org/10.3390/ma15217747 - 03 Nov 2022

Cited by 1 | Viewed by 1124

Abstract

The presented results show that the presence of refrigerant significantly deteriorates the lubricating properties of compressor oil under starved lubrication conditions (with a small amount of oil). The change can be 40–120% compared to the properties of the oil alone. Additionally, in the [...] Read more.

The presented results show that the presence of refrigerant significantly deteriorates the lubricating properties of compressor oil under starved lubrication conditions (with a small amount of oil). The change can be 40–120% compared to the properties of the oil alone. Additionally, in the group of oils that are substitutes (operational alternatives) compatible with a given refrigerant, the effect of the refrigerant on the lubricating properties varies. The differences can be as much as 25%. In order to evaluate and properly select compressor oils for the refrigerant, the lubricating properties should be tested in a mixture with the refrigerant under conditions similar to actual operation. Such an evaluation of lubricating properties is made possible by the author’s method of testing the wear of the block-on-ring friction node. The obtained rankings of lubricating properties for oils (due to the wear volume) can provide good guidelines for the suitable selection of a lubricant for refrigeration compressors (especially for new, environmentally friendly refrigerants, such as R452A). The research was carried out for mixtures of zeotropic refrigerants (R404A, R452A) with polyester oils (POE) and natural refrigerant (R600a) with mineral oils (MO). In each group of refrigerants, different mechanisms of oil–refrigerant mixture formation occur. Each refrigerant was tested with three different compressor oils recommended for each other for alternative uses in refrigeration systems. Full article

(This article belongs to the Special Issue Tribology: Friction and Wear of Engineering Materials (Second Volume))

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17 pages, 6179 KiB

Open AccessArticle

Effect of the Sliding Element Surface Topography on the Oil Film Thickness in EHD Lubrication in Non-Conformal Contact

by Lidia Galda, Jaroslaw Sep and Slawomir Swirad

Materials 2022, 15(21), 7549; https://doi.org/10.3390/ma15217549 - 27 Oct 2022

Cited by 1 | Viewed by 1160

Abstract

Under hard operating conditions such as high load, low speed and a lack of a sufficient quantity of lubricant, the sliding pairs could suffer serious damage. One of the methods that improves the tribological performance of sliding elements in hard operating conditions is [...] Read more.

Under hard operating conditions such as high load, low speed and a lack of a sufficient quantity of lubricant, the sliding pairs could suffer serious damage. One of the methods that improves the tribological performance of sliding elements in hard operating conditions is the appropriate surface creation that keeps lubricating substance in cavities. This article presents the results obtained in experimental investigations of the oil film thickness in lubricated non-conformal contact with a different surface topography of the sliding element. The tests were conducted on a ball-on-disc instrument equipped with colorimetric interferometry. Balls of diameter equaled to 19.05 mm were produced from 100 Cr6 steel. To provide hard operating conditions, the glass disc rotated at small speeds in the range of 0.1–0.2 m/s. The tests were carried out at loads of 20 N and 30 N. As a result, in most cases, the highest minimum and average oil film thickness values were obtained when the surface of steel balls was characterized by high negative asymmetry with mainly shallow cavities and some valleys of great depth compared to the height of the peaks. The modified sliding surface that had better performance comprised a comparatively small number of peaks and the curvature of the peaks were large. Full article

(This article belongs to the Special Issue Tribology: Friction and Wear of Engineering Materials (Second Volume))

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15 pages, 4963 KiB

Open AccessEditor’s ChoiceArticle

Effects of Operating Conditions and Pit Area Ratio on the Coefficient of Friction of Textured Assemblies in Lubricated Reciprocating Sliding

by Slawomir Wos, Waldemar Koszela, Andrzej Dzierwa and Pawel Pawlus

Materials 2022, 15(20), 7199; https://doi.org/10.3390/ma15207199 - 15 Oct 2022

Cited by 3 | Viewed by 1128

Abstract

The experiment was carried out in a reciprocating lubricated conformal sliding contact between steel discs of the same hardness. The effects of disc surface texturing on the friction coefficient at various operating conditions (temperature, normal load, and frequency of oscillations) were studied. Under [...] Read more.

The experiment was carried out in a reciprocating lubricated conformal sliding contact between steel discs of the same hardness. The effects of disc surface texturing on the friction coefficient at various operating conditions (temperature, normal load, and frequency of oscillations) were studied. Under various conditions, surface texturing caused friction reductions of sliding pairs. The largest reduction was 4.6 times at a lower temperature and 2.5 times at a higher temperature. The effect of the pit area ratio on the friction reduction was visible at a higher temperature. The highest dimple density of 25% corresponded to a lower coefficient of friction than the smallest density of 9%. The sliding pair with a dimple density of 17% led to large variation of the friction force. At lower temperatures, the coefficients of friction were lower compared to tests at higher temperatures. Full article

(This article belongs to the Special Issue Tribology: Friction and Wear of Engineering Materials (Second Volume))

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16 pages, 5351 KiB

Open AccessEditor’s ChoiceArticle

Sliding Friction and Wear Characteristics of Wire Rope Contact with Sheave under Long-Distance Transmission Conditions

by Xiangdong Chang, Yuxing Peng, Zhencai Zhu, Hao Lu, Wei Tang and Xing Zhang

Materials 2022, 15(20), 7092; https://doi.org/10.3390/ma15207092 - 12 Oct 2022

Cited by 1 | Viewed by 2657

Abstract

Wire rope has different degrees of surface wear under long-distance transmission conditions, which leads to performance degradation and greatly threatens its safety and reliability in service. In this paper, friction and wear tests between the transmission wire rope and sheave under different sliding [...] Read more.

Wire rope has different degrees of surface wear under long-distance transmission conditions, which leads to performance degradation and greatly threatens its safety and reliability in service. In this paper, friction and wear tests between the transmission wire rope and sheave under different sliding velocities (from 0.8 m/s to 1.6 m/s) were carried out using a homemade test rig. The material of the steel wires was low carbon steel, and pulley material was ASTM A36 steel plate. The sliding friction coefficient (COF), friction temperature rise, wear characteristic parameters and wear mechanisms of the wire rope were analyzed. Additionally, the effect of different wear on the fracture behavior of the wire rope was investigated by a breaking tensile test. The results show that the average COF in the relatively stable stage decreased from approximately 0.58 to 0.51 with the increase of sliding velocity. The temperature rise of the wire rope increased rapidly with an increase of sliding velocity, from approximately 52.7 °C to 116.2 °C. The maximum wear width was the smallest when the sliding velocity was 1.2 m/s (approximately 1.5 mm). The surface wear was characterized by spalling, furrowing and plastic deformation, which are strongly affected by the sliding velocity. The wear mechanisms of the wire rope were mainly adhesive wear and abrasive wear. Surface wear changes the fracture morphology of the wire rope and accelerates its fracture speed. Full article

(This article belongs to the Special Issue Tribology: Friction and Wear of Engineering Materials (Second Volume))

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17 pages, 5745 KiB

Open AccessArticle

Investigation and Modelling of the Weight Wear of Friction Pads of a Railway Disc Brake

by Wojciech Sawczuk, Agnieszka Merkisz-Guranowska, Dariusz Ulbrich, Jakub Kowalczyk and Armando-Miguel Rilo Cañás

Materials 2022, 15(18), 6312; https://doi.org/10.3390/ma15186312 - 12 Sep 2022

Cited by 7 | Viewed by 2078

Abstract

This paper presents the results of tests on the railway disc brake with regard to the weight wear of friction pads. The tests were carried out at a certified brake test bench where the friction-mechanical characteristics of the railway brake were determined. The [...] Read more.

This paper presents the results of tests on the railway disc brake with regard to the weight wear of friction pads. The tests were carried out at a certified brake test bench where the friction-mechanical characteristics of the railway brake were determined. The test stand was additionally equipped with a thermal imaging camera to observe the contact between the brake pads and the brake disc. The scientific goal of the test is to evaluate the relationship between the weight wear of friction pads and the quantities characterizing the braking process. The quantities characterizing the braking process included pad-to-disc contact area, friction pad thickness, pad-to-disc pressure, and braking speed. A regression model to estimate the friction pad wear on the basis of a single braking with the given input quantities was determined. The greatest influence on the increase in weight wear of friction pads has the braking velocity, which was confirmed by the value of the correlation coefficient of the regression model at value 0.81. The pressure of the friction pad to the disc and the friction pad thickness do not have a significant effect on the weight wear described by the regression model, and the obtained correlation coefficient for these parameters was lower than the value of 0.2. Full article

(This article belongs to the Special Issue Tribology: Friction and Wear of Engineering Materials (Second Volume))

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17 pages, 7827 KiB

Open AccessArticle

The Microstructure Transformations and Wear Properties of Nanostructured Bainite Steel with Different Si Content

by Lihua Fu, Meng Zhou, Yanlin Wang, Yuanan Gao, Yongzhen Zhang, Sanming Du, Yi Zhang and Yanshan Mao

Materials 2022, 15(18), 6252; https://doi.org/10.3390/ma15186252 - 08 Sep 2022

Viewed by 1292

Abstract

Nanostructured bainite (NB) bearing steel has excellent strength and ductility combinations, which can improve the fatigue life and wear resistance of bearing steel in harsh conditions. However, the phase transformations and the correlation between the microstructure and wear properties of NB bearing steel [...] Read more.

Nanostructured bainite (NB) bearing steel has excellent strength and ductility combinations, which can improve the fatigue life and wear resistance of bearing steel in harsh conditions. However, the phase transformations and the correlation between the microstructure and wear properties of NB bearing steel are still unclear. In this study, bearing steels with different Si contents (GCr15SiMo and GCr15Si1Mo) were prepared to have nano-bainitic structures, and their microstructure transformations and wear mechanisms were investigated. The results show that the Si element can inhibit the precipitation of carbides and can then promote the block-like retained austenite formation and refine the bainitic ferrite lamellar structure. The impact energy of GCr15Si1Mo is larger than that of GCr15SiMo because the nanostructured bainite and retained austenite are the main toughness phase in these steels. The wear results indicate that the steels which possess appropriate strength and toughness are helpful for improving wear resistance properties. Finally, the wear resistance performance of the GCr15Si1Mo austempered at 210 °C and GCr15SiMo austempered at 230 °C was good in this work. Full article

(This article belongs to the Special Issue Tribology: Friction and Wear of Engineering Materials (Second Volume))

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16 pages, 6677 KiB

Open AccessArticle

Development and Verification Experiment of In-Situ Friction Experiment Device for Simulating UV Irradiation in Space

by Aobo Wei, Qian Liu, Guozheng Ma, Wenbo Yu, Jiadong Shi, Yunfan Liu, Cuihong Han, Zhen Li, Haidou Wang and Guolu Li

Materials 2022, 15(6), 2063; https://doi.org/10.3390/ma15062063 - 11 Mar 2022

Cited by 5 | Viewed by 1689

Abstract

In order to explore the influence of space ultraviolet radiation on spacecraft lubricating materials, an in-situ friction experimental device simulating space ultraviolet radiation was developed in the laboratory, and the experimental verification was carried out. This paper firstly introduced the design index, structure [...] Read more.

In order to explore the influence of space ultraviolet radiation on spacecraft lubricating materials, an in-situ friction experimental device simulating space ultraviolet radiation was developed in the laboratory, and the experimental verification was carried out. This paper firstly introduced the design index, structure and working principle of the space ultraviolet irradiation simulation device, and then calibrated and tested the parameters of the whole device, and also conducted a virtual operation of the device’s operation effect by simulation software, and the results showed that it met the design index. Finally, the validation tested of the ultraviolet irradiated in-situ friction experimental device were described in detail. By using the device to irradiate the samples, it was found that the in-situ ultraviolet irradiation device could achieve the expected irradiation effect, and the irradiation would lead to changes in the surface structure and properties of the PTFE material, while also achieving the need for in-situ spatial friction property testing of the material, providing favorable conditions for future testing. Full article

(This article belongs to the Special Issue Tribology: Friction and Wear of Engineering Materials (Second Volume))

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15 pages, 6268 KiB

Open AccessArticle

Frictional Losses of Polyamides Mounted on Tensioning Guides in Contact with Chains

by Radu Gabriel Velicu, Mihai Tiberiu Lates and Cornel Catalin Gavrila

Materials 2022, 15(4), 1345; https://doi.org/10.3390/ma15041345 - 11 Feb 2022

Cited by 1 | Viewed by 1460

Abstract

The development of polyamides has increased in recent years due to scientific research and the aim of the industry to find materials characterized by good frictional behavior at high temperatures, high loads and high speeds. The wide areas of application of polyamides in [...] Read more.

The development of polyamides has increased in recent years due to scientific research and the aim of the industry to find materials characterized by good frictional behavior at high temperatures, high loads and high speeds. The wide areas of application of polyamides in the mechanical contacts with relative motions offered new development opportunities for polyamides (PA), such as PA66, PA46 and PTFE mixed PA46. One of the applications of these polyamides in mechanical contacts with relative motions is the contact between the timing chains and the active part of the tensioning guides. For a comparison with a previous study of friction of PA66, PA46 and PTFE mixed PA46, performed on a pin-on-disk tribometer, this study is based on performing tests on the same materials, on the tensioning guide of a silent chain used as a timing chain in combustion engines, with lubricating conditions much closer to the application field. The diagrams comparatively present the variation of the percentage of frictional losses for PTFE mixed PA46, PA46 and PA66 polyamides mounted on tensioning guides in contact with chains. The results clearly show that the PTFE mixed PA46 polyamide has smaller frictional losses than the PA46 and the PA66 polyamides, but the influence of speed and tensioning is also important. A comparison with the previous study is also useful for making a decision on using a polyamide for the guide of a timing chain. Full article

(This article belongs to the Special Issue Tribology: Friction and Wear of Engineering Materials (Second Volume))

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14 pages, 4173 KiB

Open AccessArticle

Hexagonal Nano and Micro Boron Nitride: Properties and Lubrication Applications

by Szymon Senyk, Arkadiusz Chodkiewicz, Krzysztof Gocman, Barbara Szczęśniak and Tadeusz Kałdoński

Materials 2022, 15(3), 955; https://doi.org/10.3390/ma15030955 - 26 Jan 2022

Cited by 10 | Viewed by 4394

Abstract

The article presents a discussion on the use of hexagonal boron nitride as an additive to lubricants. Based on the analysis of the research, factors determining its application were identified. These include particle size distribution, their morphology, specific surface area, and porosity. Next, [...] Read more.

The article presents a discussion on the use of hexagonal boron nitride as an additive to lubricants. Based on the analysis of the research, factors determining its application were identified. These include particle size distribution, their morphology, specific surface area, and porosity. Next, the research identifying these properties for the four types of h-BN was described. Based on the results, the possible mechanisms of the influence of individual h-BN types were described. It was also found that the use of h-BN nanoparticles as lubricants seems to be promising. Full article

(This article belongs to the Special Issue Tribology: Friction and Wear of Engineering Materials (Second Volume))

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10 pages, 3265 KiB

Open AccessArticle

Influence of Anodizing Stages on the Preload Force of Implant–Abutment Screws and Their Benefits Regarding the Concept of Immediate Implant Placement—An In Vitro Study

by Florian Rathe, Paul Weigl, Jan Wasiak, Christoph Ratka and Holger Zipprich

Materials 2022, 15(3), 776; https://doi.org/10.3390/ma15030776 - 20 Jan 2022

Cited by 1 | Viewed by 1344

Abstract

The tightening torque applied to a screw in a provisional restoration immediately after implant placement in a fresh extraction socket is often too low to gain sufficient preload force. Therefore, abutment screw loosening is a common complication. The aim of this study was [...] Read more.

The tightening torque applied to a screw in a provisional restoration immediately after implant placement in a fresh extraction socket is often too low to gain sufficient preload force. Therefore, abutment screw loosening is a common complication. The aim of this study was to investigate whether it is possible to increase the preload force of a given tightening torque by anodizing parts of the implant–abutment complex. In test group 1 (TG1), only the abutment screw was anodized, in four different stages, whereas in test group 2 (TG2), the abutment and the threaded sleeve were anodized in four anodizing stages (TG2a–TG2d). The control group (CG) consisted of non-anodized components. The results were tested for normal distribution, and the components were subsequently parametrically analyzed using a linear model. Both test groups showed higher preload forces compared to the non-anodized control group. The CG obtained an average preload force of 390 N at a tightening torque of 35 Ncm. Comparable values were already obtained at a tightening torque of 20 to 30 Ncm in TG1c/D and TG2b/d. It can be concluded that anodization of abutment screws and components is an effective measure to increase the preload force of the abutment screws by a given tightening torque. Full article

(This article belongs to the Special Issue Tribology: Friction and Wear of Engineering Materials (Second Volume))

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15 pages, 9458 KiB

Open AccessArticle

The Effect of Ball Burnishing on Dry Fretting

by Slawomir Swirad and Pawel Pawlus

Materials 2021, 14(22), 7073; https://doi.org/10.3390/ma14227073 - 21 Nov 2021

Cited by 11 | Viewed by 1454

Abstract

Experiments were conducted under a dry gross fretting regime. Steel discs were put in contact with ceramic balls. Before tribological tests, discs were subjected to ball burnishing with different pressures. Due to ball burnishing, a decrease in surface amplitude and an increase in [...] Read more.

Experiments were conducted under a dry gross fretting regime. Steel discs were put in contact with ceramic balls. Before tribological tests, discs were subjected to ball burnishing with different pressures. Due to ball burnishing, a decrease in surface amplitude and an increase in microhardness occurred. Ball burnishing caused decreases in the friction force and volumetric wear of up to 45% in comparison to sliding pairs containing milled discs. The friction force and volumetric wear were higher for a higher roughness of disc. Full article

(This article belongs to the Special Issue Tribology: Friction and Wear of Engineering Materials (Second Volume))

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17 pages, 3243 KiB

Open AccessArticle

Analysis of the Accuracy of Mass Difference-Based Measurement of Dry Clutch Friction Material Wear

by Matija Hoić, Alen Miklik, Milan Kostelac, Joško Deur and Andreas Tissot

Materials 2021, 14(18), 5356; https://doi.org/10.3390/ma14185356 - 16 Sep 2021

Cited by 2 | Viewed by 1922

Abstract

The paper demonstrates that the dry clutch friction plate wear rate, measured based on the plate mass difference method, exhibits a transient behavior after each change of friction interface temperature level. The effect is hypothesized to be caused by a temperature-dependent change in [...] Read more.

The paper demonstrates that the dry clutch friction plate wear rate, measured based on the plate mass difference method, exhibits a transient behavior after each change of friction interface temperature level. The effect is hypothesized to be caused by a temperature-dependent change in the moisture content/mass level in the friction material. To test this hypothesis, a series of synchronized characterization experiments have been conducted by using two friction plates, one for wear tests and the other for drying in an oven under the same temperature conditions. Based on the analysis of test results, a moisture content compensation procedure, which reduces the transient wear rate from being 100% to being 50% higher compared to stabilized wear rate, is proposed and verified. The gained insights are used to set recommendations on the organization of routine wear characterization experiments aimed at avoiding the effect of moisture content influence on the accuracy of wear measurement. The main recommendations are to minimize the number of temperature target level changes through proper design of the experiment, insert a run-in test after every long test pause, and execute a pre-heat, blind wear test at the beginning of each test day. Full article

(This article belongs to the Special Issue Tribology: Friction and Wear of Engineering Materials (Second Volume))

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23 pages, 3009 KiB

Open AccessArticle

Application of Multidimensional Statistical Analysis in Tribotechnical Diagnostics of Hydraulic Fluids in Woodworking Equipment

by Michaela Hnilicová, Ján Turis and Richard Hnilica

Materials 2021, 14(16), 4628; https://doi.org/10.3390/ma14164628 - 17 Aug 2021

Cited by 3 | Viewed by 1336

Abstract

The article dealt with the assessment of the quality of hydraulic oil and determination of the mode of wear of the friction surfaces of Baljer & Zembrod manipulating lines through the information traces in the oils by applying tribotechnical diagnostics. We presented the [...] Read more.

The article dealt with the assessment of the quality of hydraulic oil and determination of the mode of wear of the friction surfaces of Baljer & Zembrod manipulating lines through the information traces in the oils by applying tribotechnical diagnostics. We presented the assessment of the level of degradation of the oils. In addition, we presented the mode of wear of the friction surfaces washed in oil through evaluation of the qualitative and quantitative characteristics of the particles found in the oil. In detail, we focused on the application of suitable multivariate statistical methods on the data matrix. The article also presents predictive models that can sort oils into groups based on the assessment of quality of the oil and the state of the friction couples. The models can be used in research and in solving practical tasks in tribotechnical diagnostics of hydraulic fluids in woodworking equipment. Our results showed that the manipulation lines were greatly thermically stressed due to inadequate oil and machine maintenance. By correlative integration of all methods used, we could determine the real mode of the wear of the tribologic nodes of the machine. The experiment enabled the early detection of an undesirable process in the tribological node and implementation of corrective measures before the machine would break down. Full article

(This article belongs to the Special Issue Tribology: Friction and Wear of Engineering Materials (Second Volume))

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15 pages, 24328 KiB

Open AccessArticle

Assessment of Padding Elements Wear of Belt Conveyors Working in Combination of Rubber–Quartz–Metal Condition

by Dawid Romek, Dariusz Ulbrich, Jaroslaw Selech, Jakub Kowalczyk and Roksana Wlad

Materials 2021, 14(15), 4323; https://doi.org/10.3390/ma14154323 - 02 Aug 2021

Cited by 5 | Viewed by 1889

Abstract

Elements of belt conveyors, like other machine parts, are subject to wear processes. The conveyors transporting the spoil in the quartz sand mine are exposed to accelerated wear due to the effect of quartz on metal elements. Intensive wear of metal parts leads [...] Read more.

Elements of belt conveyors, like other machine parts, are subject to wear processes. The conveyors transporting the spoil in the quartz sand mine are exposed to accelerated wear due to the effect of quartz on metal elements. Intensive wear of metal parts leads to downtime and the need to replace damage parts which generates additional costs. Therefore, it is important to perform surface treatment of metal elements, which will allow to extend the operation time of belt conveyors by reducing wear. The main objective of the article is to determine the impact of the pad welding process of the surface layer of metal elements on the abrasive wear of elements working in the metal–quartz sand–rubber conditions used in belt conveyors. In this research study, three different types of electrodes were used for pad welding the surface. The wear results obtained on the test stand were compared to wear of the basic element without surface treatment. The average wear value of the samples padded with electrode 3 was about 25% lower than the samples without surface treatment. The main mechanism of sample wear was the abrasion process due to the interaction between the steel surface and hard sand particles. The results presented in the article are important not only for belt conveyor elements but also for other machine parts where it is desirable to reduce abrasive wear. Full article

(This article belongs to the Special Issue Tribology: Friction and Wear of Engineering Materials (Second Volume))

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16 pages, 1571 KiB

Open AccessArticle

Theoretical Prediction Method for Erosion Damage of Horizontal Pipe by Suspended Particles in Liquid–Solid Flows

by Guoqiang Liu, Wenzhe Zhang, Liang Zhang and Jiarui Cheng

Materials 2021, 14(15), 4099; https://doi.org/10.3390/ma14154099 - 23 Jul 2021

Cited by 4 | Viewed by 1429

Abstract

In order to study the erosion of a pipe wall via a liquid–solid suspension flow, a two-phase flow model combined with an erosion forecasting model for multiparticle impact on horizontal pipe wall surfaces was established in this work on the basis of low-cycle [...] Read more.

In order to study the erosion of a pipe wall via a liquid–solid suspension flow, a two-phase flow model combined with an erosion forecasting model for multiparticle impact on horizontal pipe wall surfaces was established in this work on the basis of low-cycle fatigue theory. In the model establishment process, the effects of particle motion and material damage were considered, and a simplified method for predicting horizontal wall erosion was obtained. The calculated results showed that the particles impact the wall at a small angle of most liquid flow velocities, causing cutting erosion damage of the wall. The settling velocity and fluctuating velocity of the particles together determine the radial velocity of the particles, which affects the impact angle of the particles. The cutting erosion caused by the small-angle impact of the particles in the pipe is more likely to cause rapid loss of the wall material. Therefore, the pipe wall is usually evenly thinned. Full article

(This article belongs to the Special Issue Tribology: Friction and Wear of Engineering Materials (Second Volume))

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10 pages, 2816 KiB

Open AccessArticle

Wear Resistance of the Glass-Fiber Reinforced Polymer Composite with the Addition of Quartz Filler

by Wojciech Zurowski, Jarosław Zepchło, Aneta Krzyzak, Edwin Gevorkyan, Mirosław Rucki, Elżbieta Siek and Anita Białkowska

Materials 2021, 14(14), 3825; https://doi.org/10.3390/ma14143825 - 08 Jul 2021

Cited by 5 | Viewed by 1580

Abstract

The paper presents the results of investigations on the glass fiber reinforced composite for the floor panels with quartz powder additions of different percentages in terms of wear resistance, friction coefficient, hardness, and strength. The wear resistance was assessed using the specific wear [...] Read more.

The paper presents the results of investigations on the glass fiber reinforced composite for the floor panels with quartz powder additions of different percentages in terms of wear resistance, friction coefficient, hardness, and strength. The wear resistance was assessed using the specific wear work parameter determined by the novel tribotester with friction band. It was found that an increase in quartz powder addition to the tested polymer composite does not enhance its mechanical increasingly properties. From the wear tests it can be concluded that only the composite with four layers of glass fibers and 6 wt.% of the quartz powder exhibited improvement of the wear resistance, but its shear strength was lower than that of the two layer specimens with similar powder proportions. On the other hand, the highest friction coefficient’s, which is microhardness HV₀₅, shear strength and impact strength were attained for the composite with two layers of glass fibers and 3 wt.% of the quartz powder. Among four layer samples, very close results were obtained for the samples with 10% of powder and insignificantly lower strength were observed for the samples with no powder added. The results revealed that there is no clear trend for the effect of silica filler percentage on the composite performance, which indicates the need for individual purpose-dependent decision making in the design of the glass fiber reinforced composites with quartz powder filler. Full article

(This article belongs to the Special Issue Tribology: Friction and Wear of Engineering Materials (Second Volume))

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17 pages, 3415 KiB

Open AccessArticle

Tribological Behavior of Carbon-Based Nanomaterial-Reinforced Nickel Metal Matrix Composites

by Amit Patil, Ganesh Walunj, Furkan Ozdemir, Rajeev Kumar Gupta and Tushar Borkar

Materials 2021, 14(13), 3536; https://doi.org/10.3390/ma14133536 - 24 Jun 2021

Cited by 7 | Viewed by 2421

Abstract

Carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs) with exceptional mechanical, thermal, chemical, and electrical properties are enticing reinforcements for fabricating lightweight, high-strength, and wear-resistant metal matrix composites with superior mechanical and tribological performance. Nickel–carbon nanotube composite (Ni-CNT) and nickel–graphene nanoplatelet composite (Ni-GNP) were [...] Read more.

Carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs) with exceptional mechanical, thermal, chemical, and electrical properties are enticing reinforcements for fabricating lightweight, high-strength, and wear-resistant metal matrix composites with superior mechanical and tribological performance. Nickel–carbon nanotube composite (Ni-CNT) and nickel–graphene nanoplatelet composite (Ni-GNP) were fabricated via mechanical milling followed by the spark plasma sintering (SPS) technique. The Ni-CNT/GNP composites with varying reinforcement concentrations (0.5, 2, and 5 wt%) were ball milled for twelve hours to explore the effect of reinforcement concentration and its dispersion in the nickel microstructure. The effect of varying CNT/GNP concentration on the microhardness and the tribological behavior was investigated and compared with SPS processed monolithic nickel. Ball-on-disc tribological tests were performed to determine the effect of different structural morphologies of CNTs and GNPs on the wear performance and coefficient of friction of these composites. Experimental results indicate considerable grain refinement and improvement in the microhardness of these composites after the addition of CNTs/GNPs in the nickel matrix. In addition, the CNTs and GNPs were effective in forming a lubricant layer, enhancing the wear resistance and lowering the coefficient of friction during the sliding wear test, in contrast to the pure nickel counterpart. Pure nickel demonstrated the highest CoF of ~0.9, Ni-0.5CNT and Ni-0.5GNP exhibited a CoF of ~0.8, whereas the lowest CoF of ~0.2 was observed for Ni-2CNT and Ni-5GNP composites. It was also observed that the uncertainty of wear resistance and CoF in both the CNT/GNP-reinforced composites increased when loaded with higher reinforcement concentrations. The wear surface was analyzed using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) analysis to elucidate the wear mechanism in these composites. Full article

(This article belongs to the Special Issue Tribology: Friction and Wear of Engineering Materials (Second Volume))

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23 pages, 4425 KiB

Open AccessArticle

The Effect of TiN and DLC Anti-Wear Coatings on the Tribofilm Formation and Frictional Heat Phenomena in Coated Metals vs. WC-Co

by Magdalena Łępicka, Yurii Tsybrii, Daniel Kiejko and Karol Golak

Materials 2021, 14(12), 3342; https://doi.org/10.3390/ma14123342 - 17 Jun 2021

Cited by 5 | Viewed by 1938

Abstract

The aim of this work was to study the effect of anti-wear coatings on the selected frictional phenomena, i.a., frictional heating and tribofilm formation, of model tribological pairs. For this purpose, three popular metallic substrate materials were selected: AISI 316L and AISI 440B [...] Read more.

The aim of this work was to study the effect of anti-wear coatings on the selected frictional phenomena, i.a., frictional heating and tribofilm formation, of model tribological pairs. For this purpose, three popular metallic substrate materials were selected: AISI 316L and AISI 440B stainless steels, as well as Ti6Al4V two-phase titanium alloy. The substrates were tested in the dry sliding conditions in three states: uncoated, as well as titanium nitride (TiN) or diamond-like-carbon (DLC) coated. According to the results provided, under applied frictional conditions TiN coating, even if it is worn off the sample surface, contributes to excessive frictional heating of a tribological pair by altering the tribofilm formation. The analysis also showed that in some tribological pairs, rapid temperature alteration of a counter sample can be used to approximate the sliding distance after which the TiN coating becomes worn off. On the contrary, in all pairs tested, the DLC film became locally damaged, but it sustained its antifriction properties, contributing to low coefficients of friction (COFs) and the lowest frictional temperatures observed. Full article

(This article belongs to the Special Issue Tribology: Friction and Wear of Engineering Materials (Second Volume))

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16 pages, 11196 KiB

Open AccessArticle

Effect of Martensite Volume Fraction on Oxidative and Adhesive Wear

by Yunbo Zhang and Abdeljalil Jourani

Materials 2021, 14(11), 2964; https://doi.org/10.3390/ma14112964 - 31 May 2021

Cited by 4 | Viewed by 2206

Abstract

It is generally known that microstructure can considerably affect the tribological behavior of non-lubricated rubbing. However, there is still a lack of awareness about the effect of microstructure on oxidative wear. The present study focused on the effect of martensite volume fraction (MVF) [...] Read more.

It is generally known that microstructure can considerably affect the tribological behavior of non-lubricated rubbing. However, there is still a lack of awareness about the effect of microstructure on oxidative wear. The present study focused on the effect of martensite volume fraction (MVF) on oxidative wear by using 25CD4 dual-phase steel. Dry friction tests were performed on a ball-on-flat tribometer with a normal load of 15 N and a mean sliding velocity of 0.013 m/s. Friction coefficient and wear rate increase with the increasing MVF. SEM observation and EDXS analyses of the wear scars showed that the oxidation increases with decreasing MVF. For lower MVF, the main wear mechanism is mild oxidative wear. For higher MVF, severe adhesion is predominant as a wear mechanism. The size of the debris decreases with decreasing MVF. Full article

(This article belongs to the Special Issue Tribology: Friction and Wear of Engineering Materials (Second Volume))

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13 pages, 16361 KiB

Open AccessArticle

Effect of FSP on Tribological Properties of Grade B89 Tin Babbitt

by Marcin Madej, Beata Leszczyńska-Madej, Joanna Hrabia-Wiśnios and Aleksandra Węglowska

Materials 2021, 14(10), 2627; https://doi.org/10.3390/ma14102627 - 17 May 2021

Cited by 5 | Viewed by 1563

Abstract

The article presents the results of tests of the tribological properties of a bearing alloy on a tin matrix (B89) after surface modification by means of friction stir processing (FSP) with a Whorl tool. The samples were processed using two tool speeds of [...] Read more.

The article presents the results of tests of the tribological properties of a bearing alloy on a tin matrix (B89) after surface modification by means of friction stir processing (FSP) with a Whorl tool. The samples were processed using two tool speeds of 280 and 580 RPM and a constant linear speed of 355 mm/min. The obtained results proved the significant influence of FSP on both the morphology of the precipitates and the investigated properties. Changes in the nature and course of friction were also observed, including the participation of individual wear mechanisms in the studied test conditions. The use of the 560 RPM tool rotation speed reduces the friction coefficient and the weight loss by about 30%. The flexural strength was also increased from 123 to 307 MPa. Full article

(This article belongs to the Special Issue Tribology: Friction and Wear of Engineering Materials (Second Volume))

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Review

Jump to: Research

30 pages, 10001 KiB

Open AccessReview

Surface Texturing of Cylinder Liners: A Review

by Pawel Pawlus, Waldemar Koszela and Rafal Reizer

Materials 2022, 15(23), 8629; https://doi.org/10.3390/ma15238629 - 03 Dec 2022

Cited by 5 | Viewed by 1627

Abstract

The effect of cylinder liners on engine performance is substantial. Typically, the cylinder surfaces were plateau honed. However, recently additional dimples or grooves were created on them. This work discusses the tribological impacts of textured cylinder liner surfaces based on a review of [...] Read more.

The effect of cylinder liners on engine performance is substantial. Typically, the cylinder surfaces were plateau honed. However, recently additional dimples or grooves were created on them. This work discusses the tribological impacts of textured cylinder liner surfaces based on a review of the literature. The results of the experimental research obtained using test rigs and fired engines were critically reviewed. In addition, the results of the modeling are shown. Circular oil pockets and grooves perpendicular to the sliding direction of piston rings of small depths were typically used. Surface texturing of the cylinder liners governs lubrication between the cylinder liner and the piston ring by an increase in oil film thickness near the reversal points leading to reductions in friction force and wear and in the fired engine to a decrease in fuel consumption and to an increase in power or torque. The correct texturing pattern ensures a decrease in the oil consumption, blow-by, and emissions of the internal combustion engine compared to plateau-honed surfaces. Considerations of future challenges are also addressed. The volume of lubricant reservoir in surface topography, called oil capacity, should be a substantial parameter characterizing textured surfaces. Full article

(This article belongs to the Special Issue Tribology: Friction and Wear of Engineering Materials (Second Volume))

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18 pages, 11571 KiB

Open AccessReview

A Brief Review on Factors Affecting the Tribological Interaction between Human Skin and Different Textile Materials

by Brian D’Souza, Ashish K. Kasar, Jaycob Jones, Andre Skeete, Lane Rader, Pankaj Kumar and Pradeep L. Menezes

Materials 2022, 15(6), 2184; https://doi.org/10.3390/ma15062184 - 16 Mar 2022

Cited by 9 | Viewed by 3105

Abstract

The application of tribology is not just limited to mechanical components of engineering systems. As a matter of fact, the understanding of friction and wear can be applied to everyday life. One of the important fields is skin tribology, as human skin interacts [...] Read more.

The application of tribology is not just limited to mechanical components of engineering systems. As a matter of fact, the understanding of friction and wear can be applied to everyday life. One of the important fields is skin tribology, as human skin interacts with various surfaces of different materials. This paper focuses on the friction behavior of the skin when in contact with the fabric and other materials in relative motion. The excessive friction at the fabric-skin interface may lead to discomfort, blistering, chafing, and pressure ulcers especially in athletes who experience higher friction due to rapid movement for an extended period. Other than understanding the fabric properties, it is equally important to understand the structure and properties of the skin to evaluate its function and interaction with the different fabric materials. The identification of the contributing factors of skin friction can help to design suitable fabric materials. An overview of skin functions and the factors that affect the friction on the skin–textile material interface are presented in this review article. Full article

(This article belongs to the Special Issue Tribology: Friction and Wear of Engineering Materials (Second Volume))

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27 pages, 8211 KiB

Open AccessReview

Solid Lubrication at High-Temperatures—A Review

by Rahul Kumar, Irina Hussainova, Ramin Rahmani and Maksim Antonov

Materials 2022, 15(5), 1695; https://doi.org/10.3390/ma15051695 - 24 Feb 2022

Cited by 61 | Viewed by 6741

Abstract

Understanding the complex nature of wear behavior of materials at high-temperature is of fundamental importance for several engineering applications, including metal processing (cutting, forming, forging), internal combustion engines, etc. At high temperatures (up to 1000 °C), the material removal is majorly governed by [...] Read more.

Understanding the complex nature of wear behavior of materials at high-temperature is of fundamental importance for several engineering applications, including metal processing (cutting, forming, forging), internal combustion engines, etc. At high temperatures (up to 1000 °C), the material removal is majorly governed by the changes in surface reactivity and wear mechanisms. The use of lubricants to minimize friction, wear and flash temperature to prevent seizing is a common approach in engine tribology. However, the degradation of conventional liquid-based lubricants at temperatures beyond 300 °C, in addition to its harmful effects on human and environmental health, is deeply concerning. Solid lubricants are a group of compounds exploiting the benefit of wear diminishing mechanisms over a wide range of operating temperatures. The materials incorporated with solid lubricants are herein called ‘self-lubricating’ materials. Moreover, the possibility to omit the use of conventional liquid-based lubricants is perceived. The objective of the present paper is to review the current state-of-the-art in solid-lubricating materials operating under dry wear conditions. By opening with a brief summary of the understanding of solid lubrication at a high temperature, the article initially describes the recent developments in the field. The mechanisms of formation and the nature of tribo-films (or layers) during high-temperature wear are discussed in detail. The trends and ways of further development of the solid-lubricating materials and their future evolutions are identified. Full article

(This article belongs to the Special Issue Tribology: Friction and Wear of Engineering Materials (Second Volume))

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26 pages, 5225 KiB

Open AccessReview

Tribological Properties of High-Entropy Alloys under Dry Conditions for a Wide Temperature Range—A Review

by Ashish K. Kasar, Kelsey Scalaro and Pradeep L. Menezes

Materials 2021, 14(19), 5814; https://doi.org/10.3390/ma14195814 - 05 Oct 2021

Cited by 31 | Viewed by 3199

Abstract

High-entropy alloys (HEAs) are composed of multiple elements with equimolar or near equimolar composition that have superior mechanical and tribological properties. In this article, we present a review on the tribological performance of HEAs. The tribological properties of different HEAs systems have been [...] Read more.

High-entropy alloys (HEAs) are composed of multiple elements with equimolar or near equimolar composition that have superior mechanical and tribological properties. In this article, we present a review on the tribological performance of HEAs. The tribological properties of different HEAs systems have been evaluated, and it has been found that the wear rate strongly depends on the crystal structure of the phases. The most common structures are face-centered cubic (FCC), body-centered cubic (BCC), and dual-phase (FCC + BCC) alloys due to the high entropy of mixing instead of forming intermetallic phases. In general, HEAs with a BCC structure showed superior hardness and wear properties compared to FCC and FCC + BCC alloys. The lesser wear rate of HEAs with a BCC structure is attributed to the reductions in ductility, resulting in strong but brittle alloys. In addition to the crystal structure, the effect of temperature on the tribological performance of the HEAs is also discussed, which highlights their potential applications for high temperatures. Moreover, various other factors such as grain size, formation of an oxide layer, and wear mechanisms are discussed. Full article

(This article belongs to the Special Issue Tribology: Friction and Wear of Engineering Materials (Second Volume))

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