Editorial

4 pages, 177 KiB

Open AccessEditorial

Coating Technology Makes Comprehensive Surface Protection Possible

by Chi Ma

Coatings 2023, 13(3), 658; https://doi.org/10.3390/coatings13030658 - 21 Mar 2023

Cited by 4 | Viewed by 1450

The tribology and wear protection of coatings has been an active and rapidly developing area for research and industries in recent years, with innovative coating materials, structures, and fabrication technologies [...] Full article

(This article belongs to the Special Issue Tribological Properties and Wear Protection of Coatings and Alloys)

Research

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17 pages, 5526 KiB

Open AccessArticle

Frictional Study on 30CrNi2MoVA Steel Based on Experiments and Finite Element Simulation: Wear Prediction

by Ao Wei, Yiyi Li, Lianghai Feng, Yongjun Feng and Zhiwen Xie

Coatings 2024, 14(3), 265; https://doi.org/10.3390/coatings14030265 - 22 Feb 2024

Viewed by 707

Abstract

30CrNi2MoVA steel demonstrates excellent performance, meeting the requirements of a crucial material for high-load structural parts. However, after experiencing high loads and thermal cycling, the material undergoes wear on its contact surfaces, resulting in a certain wear depth that determines its service life. [...] Read more.

30CrNi2MoVA steel demonstrates excellent performance, meeting the requirements of a crucial material for high-load structural parts. However, after experiencing high loads and thermal cycling, the material undergoes wear on its contact surfaces, resulting in a certain wear depth that determines its service life. Therefore, accurately predicting and evaluating the wear performance and wear depth of this material is of paramount importance. This study employs a combined approach of experimental and simulation methods. Initially, friction and wear tests were conducted to investigate the wear behavior of the 30CrNi2MoVA steel. The experimental results reveal a significant influence of thermal cycling temperature on the material’s wear resistance, with wear mechanisms primarily attributed to adhesive wear and abrasive wear. Subsequently, a ball-on-disc wear model was established. Based on experimental data, the modified Archard model was implemented as a user subroutine in finite element software (ABAQUS version 2020) to assess the material’s wear volume. The simulation results demonstrate a close agreement with the experimental wear depths. Furthermore, a fitting formula was developed to correlate the wear depth of the material with the number of wear cycles, enabling accurate wear depth prediction. This study provides theoretical support for enhancing the performance and extending the service life of 30CrNi2MoVA steel. Full article

(This article belongs to the Special Issue Tribological Properties and Wear Protection of Coatings and Alloys)

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11 pages, 4812 KiB

Open AccessArticle

Effect of Cu Addition on Properties of an Al-La Alloy

by Shuanqiang Wang, Guanghui Meng and Menghua Song

Coatings 2023, 13(9), 1505; https://doi.org/10.3390/coatings13091505 - 25 Aug 2023

Viewed by 1039

Abstract

The effect of copper content on the microstructure and properties of an aluminum copper alloy containing lanthanum was studied by adding 0.5 wt% lanthanum and different contents of copper to the 2A12 alloy. We used a universal testing machine, Brinell hardness tester, and [...] Read more.

The effect of copper content on the microstructure and properties of an aluminum copper alloy containing lanthanum was studied by adding 0.5 wt% lanthanum and different contents of copper to the 2A12 alloy. We used a universal testing machine, Brinell hardness tester, and friction and wear testing machine to test the mechanical properties of the alloy. The microstructure and phase composition of the alloy were analyzed using scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction. The results show that, after adding La and Cu, the alloy grain is refined, and the fracture mode changes from dissociation fracture to quasi dissociation fracture. A new phase containing La accumulates at the grain boundary. If the amount of Cu added is too large, the tendency for hot cracking increases, which can easily lead to the formation of voids or even cracks. The tensile strength and hardness of the cast alloy significantly increase with the increase in Cu addition. In the range of adding 2 wt% to 5 wt% Cu, the tensile strength and hardness of the cast alloy increases by approximately 12% and 17.84%, respectively, compared with the original alloy. With the increase in Cu addition, the elongation of the alloy first increases and then decreases, reaching its maximum value when Cu addition is 3 wt%. Adding Cu is beneficial for improving the wear resistance of the alloy. When the addition of Cu is 3 wt%, the alloy has the best wear resistance and minimum wear amount. This is due to the enrichment of La and Cu at the grain boundaries, forming new La phases or other phases with higher hardness, which changes the properties of the alloy. It shows that the content of Cu in the 2A12 alloy can be increased to 7-8% with the increasing of additional rare-earth elements, and a new Al-Cu (7 wt% to 8 wt%)-Mg (1.2 wt% to 1.8 wt%)-Mn (0.3 wt% to 0.9 wt%)-La (0.5 wt%) alloy, in which tensile strength, hardness, and elongation of the alloy are increased by 8.1%, 16%, and 79.1%, respectively, can be formed. In addition, the wear resistance of Al-La alloys also improves significantly with the addition of copper content. The coefficient of friction is reduced by 68% compared with no copper addition. Full article

(This article belongs to the Special Issue Tribological Properties and Wear Protection of Coatings and Alloys)

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12 pages, 5397 KiB

Open AccessArticle

Investigation of the Effect of Additional Zirconium Diboride (ZrB₂) in Spherical Graphite Cast Iron on Mechanical Properties

by Rifat Yakut and Ramazan Ortakaya

Coatings 2023, 13(8), 1385; https://doi.org/10.3390/coatings13081385 - 07 Aug 2023

Cited by 2 | Viewed by 681

Abstract

Steering gearbox bodies, which are produced from spheroidal graphite cast iron, experience wear and gaps over time since they operate under load. It is important to strengthen steering gearbox bodies to avoid this. In this study, a steering gearbox body was produced from [...] Read more.

Steering gearbox bodies, which are produced from spheroidal graphite cast iron, experience wear and gaps over time since they operate under load. It is important to strengthen steering gearbox bodies to avoid this. In this study, a steering gearbox body was produced from a spheroidal graphite cast iron material with zirconium diboride at varying rates (0%, 0.227%, 0.455%, and 1.364%). Samples of the material were prepared according to established standards for hardness, compressive strength, and wear resistance tests. The mechanical properties of test samples with and without zirconium diboride (hardness, compressive strength, and wear resistance) were compared. Sample C showed the highest hardness measurement of 243 HB after adding 0.455% zirconium diboride. As the rate of addition increased, the values obtained from the hardness measurement test also increased. Sample C had the highest compressive value of 1438 MPa, with a 0.455% addition rate. It was found that the compressive strength values also increased as the addition rate increased. Wear tests were conducted to analyse wear volume, wear rate, and friction coefficients. A scanning electron microscope (SEM) device was utilised to identify wear mechanisms on the worn surfaces of the samples. Per the results of this study, wear volume values were found to increase with the load value. Full article

(This article belongs to the Special Issue Tribological Properties and Wear Protection of Coatings and Alloys)

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14 pages, 6406 KiB

Open AccessArticle

Wear Mechanism of TC4 Titanium Alloy with TiN Coating against Self-Lubricating Fabric

by Song Zhao, Haoran Zhang, Xiaowen Qi, Yu Dong and Yan Zhang

Coatings 2023, 13(7), 1209; https://doi.org/10.3390/coatings13071209 - 06 Jul 2023

Cited by 2 | Viewed by 1292

Abstract

Vapor deposition technology can improve the surface wear resistance of titanium alloys, and prepare lightweight and corrosion-resistant self-lubricating spherical plain bearings made of titanium alloys. However, titanium alloys with hard films can be worn by soft self-lubricating fabrics. This paper focuses on the [...] Read more.

Vapor deposition technology can improve the surface wear resistance of titanium alloys, and prepare lightweight and corrosion-resistant self-lubricating spherical plain bearings made of titanium alloys. However, titanium alloys with hard films can be worn by soft self-lubricating fabrics. This paper focuses on the wear problem of TiN coating on the surfaces of self-lubricating spherical plain bearings based on titanium alloys. Ring-to-plate wear tests were carried out to study the tribological properties of TiN coating on TC4 titanium alloy against self-lubricating fabric under different working conditions (load: 500–2000 N and speed: 100–500 r/min), along with the investigation of the wear mechanism of TiN coating, and the evaluation of applicable working conditions of GE15 type self-lubricating spherical plain bearings through swing tests. The results have revealed that TiN coatings can maintain a certain friction distance without wear. Increasing friction speed and load can make TiN coatings more prone to wear. A thick transfer film can protect the TiN coating from wear. The main wear mechanism is attributed to fatigue wear induced by the repeated formation and peeling of transfer films. The GE15 bearing has achieved a self-lubricating fabric wear of approximately 0.04 mm when the swinging for 500 m (25,000 times) is under a specific condition of 27 kN and 0.2 Hz without damaging the inner ring of the bearing. The bearing is suitable for swing conditions with applied loads below 27 kN. This study provides a fundamental understanding of designing self-lubricating spherical plain bearings made of titanium alloys. Full article

(This article belongs to the Special Issue Tribological Properties and Wear Protection of Coatings and Alloys)

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16 pages, 7977 KiB

Open AccessArticle

High Temperature Tribological Behavior of Electroless Plating Ni-P-Si₃N₄-WS₂ Composite Coatings

by Xiaohua Zheng, Yindi Huang, Chenbin Cai, Haijun Huang and Fanger Yang

Coatings 2023, 13(4), 723; https://doi.org/10.3390/coatings13040723 - 02 Apr 2023

Viewed by 1460

Abstract

Electroless nickel composite coatings have the potential for high-temperature tribological applications, and a combination of high wear resistance and low friction factor is one of the desirable solutions but still a tricky problem. The addition of self-lubricating WS₂ and hard Si₃ [...] Read more.

Electroless nickel composite coatings have the potential for high-temperature tribological applications, and a combination of high wear resistance and low friction factor is one of the desirable solutions but still a tricky problem. The addition of self-lubricating WS₂ and hard Si₃N₄ nanoparticles to the Ni-P coatings is expected to obtain good high-temperature tribological performance. In this work, Ni-P-Si₃N₄-WS₂ composite coatings with various contents of WS₂ nanoparticles were prepared using electroless plating and subsequently annealed at 400 °C in an inert atmosphere. The tribological properties of the coatings were evaluated using a ball-on-disc wear instrument at operating temperatures from 25 to 600 °C. The microstructure, chemical composition, and surface morphology of the coatings were characterized by X-ray diffractometry (XRD), energy disperse spectroscopy (EDS), and scanning electron microscopy (SEM). Upon increasing the WS₂ dosage in the bath, the WS₂ content in the coating increased and the micro-hardness of the as-plated coating increased from 539 to 717 HV. After heat treatment, the coating underwent a crystallization process, and the hardness increased from 878 to 1094 HV. The main wear mechanism of the coating changed from adhesive wear in the as-plated state to abrasive wear in the annealed state. The annealed Ni-P-Si₃N₄-WS₂ coating with a WS₂ dosage of 2.5 g/L in the bath exhibited excellent mechanical properties, with a hardness of 10.9 GPa, a friction coefficient of ~0.51, and a wear rate of 8.4 × 10⁻¹⁵ m³N⁻¹⋅m⁻¹ at room temperature, and maintained optimal performance at high temperatures. At operating temperatures of 200, 400, and 600 °C, the form of wear was adhesive wear for coatings with a WS₂ dosage <1.5 g/L and abrasive wear for coatings with a WS₂ dosage ≥1.5 g/L. The synergism of WS₂ and Si₃N₄ particles refined the grains of the Ni-P matrix in as-plated coatings and obviously reduced the friction coefficient of friction pairs in annealed coatings at all operating temperatures. Full article

(This article belongs to the Special Issue Tribological Properties and Wear Protection of Coatings and Alloys)

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19 pages, 19661 KiB

Open AccessArticle

Investigation on Sliding Tribological Properties of Laser Cladding Alloy Coating for Subway Wheels

by Qian Xiao, Bo Zhang and Wenbin Yang

Coatings 2022, 12(10), 1561; https://doi.org/10.3390/coatings12101561 - 16 Oct 2022

Cited by 2 | Viewed by 1406

Abstract

The wheel pair is a key component of the subway. Routes of subway conditions are more complex, while frequent starting and braking are more likely to cause wheel damage. To improve the sliding tribological properties of subway wheels, this article focused on laser-cladding [...] Read more.

The wheel pair is a key component of the subway. Routes of subway conditions are more complex, while frequent starting and braking are more likely to cause wheel damage. To improve the sliding tribological properties of subway wheels, this article focused on laser-cladding technology to repair the wheel. Ni-based and Fe-based alloy coatings were prepared. The microstructure of the coatings was studied by SEM, EDS, XRD, and 3D optical morphology. The mechanical properties of the coating were studied by the Vickers microhardness tester and MFT-EC4000 reciprocating electrochemical friction and wear tester. There are mainly γ(Ni, Fe), Cr₇C₃, Cr₂₃C_6, and other phases in the Ni-based coating, and there are mainly γ-Fe, (Fe, Ni), (Fe-Cr-Ni) solid solution and other phases in the Fe-based coating. The hardness of the Ni-based coating is 250 HV_0.7, which is essentially the same as the hardness of the substrate. The hardness of the Fe-based coating reaches a maximum of 715HV_0.7. The hardness of the Fe-based coating is 2.86 times higher than the hardness of the substrate. The Fe-based coating is strengthened by the solid solution due to the existence of the solid-solution phase. The Ni-based coating in high-temperature performance is general. Its hardness and friction performance were also ordinary. The results of the study can provide theoretical and technical guidance for the application of laser-cladding technology on subway wheels. Full article

(This article belongs to the Special Issue Tribological Properties and Wear Protection of Coatings and Alloys)

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Review

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32 pages, 18782 KiB

Open AccessReview

Effects of Rare Earths on Microstructure and Wear Resistance in Metal Additive Manufacturing: A Review

by Dingding Xiang, Di Wang, Tingfang Zheng and Yu Chen

Coatings 2024, 14(1), 139; https://doi.org/10.3390/coatings14010139 - 20 Jan 2024

Cited by 2 | Viewed by 989

Abstract

Rare earth elements (REEs) doping technology can effectively control the microstructure and improve the quality and performance of materials. This paper summarizes the research progress of REEs in metal additive manufacturing (MAM) in recent years and briefly introduces the effects of REEs on [...] Read more.

Rare earth elements (REEs) doping technology can effectively control the microstructure and improve the quality and performance of materials. This paper summarizes the research progress of REEs in metal additive manufacturing (MAM) in recent years and briefly introduces the effects of REEs on the molten pool fluidity, purified structure, and interfacial bonding between the molten cladding layer and substrate. It focuses on the mechanism of the role of REEs in the refinement and homogenization of microstructures, including grain growth, columnar to equiaxed transition (CET), and elemental segregation. The reasons for the influence of REEs on the homogenization of the structure and elemental segregation are analyzed. The effects of REE type, content, and dimension on hardness and wear resistance are investigated. Finally, tribological applications of REEs in biological and high-temperature environments are summarized, and the impact of REEs-modified alloys is summarized and prospected. Full article

(This article belongs to the Special Issue Tribological Properties and Wear Protection of Coatings and Alloys)

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25 pages, 50606 KiB

Open AccessReview

Quality Evaluation System of Monolayer Brazed Diamond Tools: A Brief Review

by Jinfang Wang, Yamei Mao, Meng Zhang, Nengyong Ye, Sheng Dai and Liu Zhu

Coatings 2023, 13(3), 565; https://doi.org/10.3390/coatings13030565 - 06 Mar 2023

Cited by 5 | Viewed by 1596

Abstract

In this article, the studies undertaken on brazed diamond tools were reviewed. The influences of the brazing alloys with different active elements on the brazing quality of brazed diamond tools are emphatically discussed. The differences in the micromorphology, friction and wear properties, and [...] Read more.

In this article, the studies undertaken on brazed diamond tools were reviewed. The influences of the brazing alloys with different active elements on the brazing quality of brazed diamond tools are emphatically discussed. The differences in the micromorphology, friction and wear properties, and mechanical properties of brazed diamonds caused by three different brazing alloys are described in detail. The quality evaluation of brazed diamond tools is discussed from several aspects, such as the difference in microstructure of the diamond/brazing alloy interface, the friction and wear of brazed diamond tools, and the strength and residual stress of the brazing interface. Finally, relevant open questions related to the brazed diamond tools’ performance are outlined, and the future has been prospected. Full article

(This article belongs to the Special Issue Tribological Properties and Wear Protection of Coatings and Alloys)

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