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Reactive Pulsed Laser Deposition of Clustered-Type MoSx (x ~ 2, 3, and 4) Films and Their Solid Lubricant Properties at Low Temperature
摘要： We studied the tribological properties of amorphous molybdenum sulfide (MoSx) thin-film coatings during sliding friction in an oxidizing environment at a low temperature (?100 °C). To obtain films with different sulfur contents (x ~ 2, 3, and 4), we used reactive pulsed laser deposition, where laser ablation of the Mo target was performed in H2S at various pressures. The lowest coefficient of friction (0.08) was observed during tribo-testing of the MoS3 coating. This coating had good ductility and low wear; the wear of a steel counterbody was minimal. The MoS2 coating had the best wear resistance, due to the tribo-film adhering well to the coating in the wear track. Tribo-modification of the MoS2 coating, however, caused a higher coefficient of friction (0.16) and the most intensive wear of the counterbody. The MoS4 coating had inferior tribological properties. This study explored the mechanisms of possible tribo-chemical changes and structural rearrangements in MoSx coatings upon contact with a counterbody when exposed to oxygen and water. The properties of the tribo-film and the efficiency of its transfer onto the coating and/or the counterbody largely depended on local atomic packing of the nanoclusters that formed the structure of the amorphous MoSx films.
关键词： wear,molybdenum sulfides,solid lubricants,nanoclusters,reactive pulsed laser deposition,low temperature,coefficient of friction
更新于2025-09-23 15:19:57
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Laser hardening of copper-iron pseudoalloy
摘要： The purpose of the study is to improve the performance characteristics of powder pseudo-alloy materials using surface heat treatment. Such materials have unique properties, for example, self-lubrication under dry friction conditions, high thermal conductivity coefficient, and high electro-erosion resistance. The disadvantage of powder pseudo-alloys is their relatively low strength. The paper considers the method of surface hardening by high-energy treatment - laser radiation. The paper describes the method of experimental research, describes the method of obtaining powder material, its chemical composition, shows the equipment used. The results of studies of the microstructure and microhardness of the surface layer of steel-copper powder pseudo-alloy after laser heat treatment (LHT) of a continuous-wave fiber laser with a maximum power of 1 kW are given, LHT modes are indicated, the influence of LHT parameters on the characteristics of the hardened layer is evaluated. It is revealed that the partial melting region in which melting occurs in the volumes of the fusible component (copper) in the initial structure and contacting segments of steel matrix is formed in the material in addition to the total melting zone. Then the quenching zone from the solid state follows, in which the maximal hardness up to 1000 HV is attained for best samples in the volume of martensite, which is formed in perlite colonies of the initial steel–copper material.
关键词： Steel–copper pseudoalloy,Microhardness,Abrasive wear,Laser heat treatment,Powder metallurgy,Microstructure
更新于2025-09-23 15:19:57
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Corrosion wear and electrochemical corrosion behaviors of laser cladded amorphous FeSiB coating in 3.5% NaCl solution
摘要： An amorphous FeSiB composite coating was fabricated on S355 structural steel using a laser cladding. The corrosion wear and electrochemical corrosion behaviors of FeSiB coating in 3.5% NaCl solution were investigated using a wear tester and electrochemical workstation. The results show that the FeSiB coating with the hardness of 601 HV is primarily composed of amorphous and crystal phases of α–Fe(Si) and Fe2B. The average coefficients of friction (COFs) of FeSiB coating at the wear loads of 3, 5 and 7 N loads are 0.888, 0.751, and 0.564, respectively, which deceases with the increase of wear loads; and the corresponding wear rates are 7.60, 8.02 and 10.04 μm3?N–1?m–1, respectively. The corrosion potentials of FeSiB coating and substrate are –0.718 and –1.042 V, respectively, exhibiting that the corrosion potential of FeSiB coating shifts positively, its corrosion resistance was higher than that of substrate.
关键词： electrochemical corrosion,amorphous FeSiB composite coating,coefficient of friction (COF),wear mechanism,laser cladding (LC)
更新于2025-09-23 15:19:57
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Wear resistance and microstructures of nanocrystals reinforced laser melt deposited composite coating
摘要： The Stellite SF12-TiC-Mo-Sn laser melt deposited (LMD) composite coating was produced on a TA1 titanium alloy. Such composite coating was researched using scanning electron microscope (SEM) and a high-resolution transmission electron microscope (HRTEM). It was con?rmed that Ti3Sn nanocrystals appeared at an intersplat region, which was very compatible to the d-space of the Ti3Sn at an orientation of (101). The Ti3Sn particles were surrounded by the amorphous phases. Under the action of such composite coating, the micro-hardness distribution of the substrate surface is in a range of 1350–1500 HV0.2, and the wear volume loss is 1/13 of a TA1 alloy.
关键词： composites,sliding wear,lasers,titanium
更新于2025-09-19 17:15:36
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Effect of pad wear on tool influence function in robotic polishing of large optics
摘要： Robotic polishing can greatly improve the manufacturing efficiency of precision optics, and its tool influence function (TIF) needs to be modeled precisely for deterministic fabrication. When polishing large optics, the TIFs are significantly affected by the wear of the polishing pad, which in turn will change the material removal rate. In this paper, the generating mechanism of the pad wear is analyzed, so as to quantitatively predict the wear amount of the polishing pad under different processing parameters; consequently, the TIF error caused by pad wear can be compensated. The experimental results demonstrate that the proposed model can reliably predict the polishing pad shape and the corresponding TIF after different wearing time; henceforth, the resulting form quality and convergence rate of robotic polishing can be significantly improved.
关键词： Pad wear,Polishing,Robot,Optics fabrication,Tool influence function
更新于2025-09-19 17:15:36
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Microstructure refinement and properties of 1.0C-1.5Cr steel in a duplex treatment combining double quenching and laser surface quenching
摘要： The 1.0C-1.5Cr steel was subjected to conventional quenching and laser surface quenching treatment. A process combing double quenching and laser surface quenching was proposed for enhancing surface hardness and obtaining finer microstructure. The cementite dissolution and grain growth behavior in the austenitizing process of single quenching, double quenching, and laser surface quenching were studied. The results indicated that compared with single quenching, mean diameter of undissolved cementite particles (UCP) was much finer in double quenching, and the final prior austenite grain size (PAGS) could be decreased by nearly 40% to about 4.5 μm. Both grain and cementite particles near the surface will coarsen after laser surface treatment. Compared with single quenching, the PAGS within hardened layer can be decreased by at least 11% through double quenching, and the mean diameter of UCP at the bottom of hardened layer can be decreased by about 20%. Compared with conventional quenching, surface hardness was enhanced by about 20% through laser surface quenching, contributing to the wear resistance. However, the hard and brittle surface layer tends to be crack source during the impact process, leading to the deterioration of final impact toughness. Under the identical laser parameters, the impact absorbed energy is similar in both single and double quenching, which is about 25% of that before laser surface quenching. The impact absorbed energy can be increased from 22J to 28J by preheating at 160 C during the laser surface quenching.
关键词： Impact toughness,Grain size,Cementite,Laser surface quenching,Double quenching,Wear
更新于2025-09-19 17:13:59
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[IEEE 2019 International Conference on Engineering, Science, and Industrial Applications (ICESI) - Tokyo, Japan (2019.8.22-2019.8.24)] 2019 International Conference on Engineering, Science, and Industrial Applications (ICESI) - Wear Resistance Behaviour of Laser Additive Manufacture Materials: An Overview
摘要： Laser additive manufacturing technology is an exciting technology which is based on powder metallurgy and laser technologies that has come to revolutionize the way important product are designed and produced. This manufacturing technology has a number of advantages over the traditional manufacturing processes which include: ability to reduce weight of product and with improved functionality, ability to manufacture part as a composite material and with high complexity in a single manufacturing process. Some of additive manufacturing process can also be used to repair high valued part. Apart these advantages, additive manufacturing technologies have been shown to have a high impact on the resulting properties of the manufactured materials which include the wear resistance behaviour. This paper presents an overview of the wear resistance behaviour of additive manufacture materials. The various classes of additive manufacturing technology are analyzed and presented. This study revealed that the wear resistance property of materials processed using additive manufacturing technologies can be improved by adjusting the processing parameters. Also the rapid cooling that is associated with this manufacturing process has a great influence in improving the wear resistance performance of the processed materials.
关键词： wear resistance,Laser additive manufacturing,processing parameters,rapid cooling,additive manufacture materials
更新于2025-09-19 17:13:59
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The Increasing of the Operational Stability of Wood-Working tools by the laser cementation
摘要： The paper describes the technology of laser cementation of woodworking tools, which allows to increase the operational stability no less than twice. The tool wear resistance is increased due to carbon saturation of the surface to 1.8-2.0% and the formation of martensite and residual austenite on the surface of the structural composition. The tests results of wear resistance and determination of the period of resistance of the treated tool are given. The modes of laser cementation for the studied grades of tool steels are offered.
关键词： wear resistance,woodworking tools,laser cementation,hardening,tool steel
更新于2025-09-19 17:13:59
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On the Role of a ZDDP in the Tribological Performance of Femtosecond Laser-Induced Periodic Surface Structures on Titanium Alloy against Different Counterbody Materials
摘要： Laser-induced periodic surface structures (LIPSS, ripples) with ~500–700 nm period were produced on titanium alloy (Ti6Al4V) surfaces upon scan processing in air by a Ti:sapphire femtosecond laser. The tribological performance of the surfaces were quali?ed in linear reciprocating sliding tribological tests against balls made of di?erent materials using di?erent oil-based lubricants. The corresponding wear tracks were characterized by optical and scanning electron microscopy and confocal pro?lometry. Extending our previous work, we studied the admixture of the additive 2-ethylhexyl-zinc-dithiophosphate to a base oil containing only anti-oxidants and temperature stabilizers. The presence of this additive along with the variation of the chemical composition of the counterbodies allows us to explore the synergy of the additive with the laser-oxidized nanostructures.
关键词： laser-induced periodic surface structures (LIPSS),friction,lubricant additives,wear
更新于2025-09-19 17:13:59
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Fiber Laser || Laser Surface Modification — A Focus on the Wear Degradation of Titanium Alloy
摘要： Over the years, engineering materials are being developed due to the need for better service performance. Wear, a common phenomenon in applications requiring surface interaction, leads to catastrophic failure of materials in the industry. Hence, preventing this form of degradation requires the selection of an appropriate surface modification technique. Laser surface modification techniques have been established by researchers to improve mechanical and tribological properties of materials. In this chapter, adequate knowledge about laser surface cladding and its processing parameters coupled with the oxidation, wear and corrosion performances of laser-modified titanium has been reviewed.
关键词： Titanium,Laser surface cladding,Wear,Surface modification technique
更新于2025-09-19 17:13:59