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Novel laser textured surface designs for improved zirconia implants performance
摘要： The development of new surface designs to enhance the integration process between surgically placed implants and biological tissues remains a challenge for the scientific community. In this way and trying to overcome this issue, in this work, laser technology was explored to produce novel textures on the surface of green zirconia compacts produced by cold pressing technique. Two strategies regarding line design (8 and 16 lines design) and different laser parameters (laser power and number of laser passages) were explored to assess their influence on geometry and depth of created textures. The produced textures were evaluated with Scanning Electron Microscopy (SEM) and it was observed that well-defined textured surfaces with regular geometric features (cavities or pillars) were obtained by laser combining different strategies lines design and parameters. The potential of proposed textures was also evaluated regarding surface wettability, friction performance (static and dynamic coefficient of friction evolution) against bone, aging resistance and flexural strength. Results demonstrated that all the produced textures display a super hydrophilic or hydrophilic behavior. Regarding the friction behavior, it was experimentally observed a high initial static coefficient of friction (COF) for all produced textures. Concerning the aging resistance, all the textured surfaces revealed a low monoclinic content, less than 25% after 5?h of hydrothermal aging. The flexural strength results showed that the mechanical resistance of zirconia was not significantly compromised with the laser action. Based on the obtained results, it is possible to prove that the processing route used for manufacturing the new and different surface designs (cold pressing technique followed by laser texturing) showed to be particularly effective for the production of zirconia implants with customized surface designs according to the properties required in a specific application. These new surface designs besides to enhance the surface wettability and also to improve the fixation at the initial moment of the implantation, do not significantly compromise the resistance to aging and the mechanical performance of zirconia. Hence, a positive impact on the long-term performance of the zirconia implants may be expected with the proposed novel laser textured surface designs.
关键词： Flexural strength,Aging resistance,Zirconia,Surface wettability,Coefficient of friction,Laser surface texturing
更新于2025-09-12 10:27:22
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[IEEE 2019 IEEE 4th Optoelectronics Global Conference (OGC) - Shenzhen, China (2019.9.3-2019.9.6)] 2019 IEEE 4th Optoelectronics Global Conference (OGC) - The Optimization Control of Model-Based Friction Compensation and Experimental Test for the Laser Communication System
摘要： Axis mechanical system can influence the accuracy of the terminal motion control system. Friction can cause the steady state error and making the system response slow. Communication terminal will benefit from the friction compensation in the servo system. The performance of the servo system using the LuGre friction model for compensation is better than the same system without friction compensation. The high performance requirements for the terminal control system can be achieved. This paper describes the nonlinear friction mathematical model, the estimation of the model parameters and reports and analyzes friction compensation experiment. For an actual terminal motor drive system, the nonlinear friction characteristics of the terminal control system based on the friction compensation is presented. The effectiveness of this control technique is discussed and investigated.
关键词： control system,communication terminal,friction compensation,LuGre model
更新于2025-09-12 10:27:22
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Laser dimple texturing – applications, process, challenges, and recent developments: a review
摘要： Laser dimple texturing has been a surge in the surface to surface contact applications like the cutting tool/workpiece interaction, piston-cylinder assembly, bearings, prosthetic hip & knee joints, blanking punch- die assembly, etc. to control the friction and wear between the interactions. In this article, the first part presented about a broad literature review on an effect of dimple texture in various industrial applications like bio-implant components and cutting tools. In the second part, detailed information has discussed on a process of laser dimple texturing and influence of laser process parameters such as laser wavelength, laser energy, number of pulses, pulse duration and focal distance on dimple geometry. The third part describes a comprehensive literature review on challenges/limitations of laser dimple texturing process like heat affected zone, tensile residual stresses, bulges around the dimple, etc. Finally, in the fourth part, proper attention has given on recent developments like laser shock peen texturing, laser texturing under water and post-processing techniques to overcome the limitations of laser surface texturing process.
关键词： Friction,Hip & knee joints,Wear,Cutting tool,Laser peen texturing,Heat affected zone,Laser dimple texture
更新于2025-09-12 10:27:22
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Mechanical and tribological performance of fiber laser cladded h-BN + SS316 composite on SS316 surface
摘要： Laser cladding is a unique process for adding one material to the surface of another base material by utilizing high energy and coherent laser beam. For the present investigation, h-BN (hexagonal boron nitride) + SS316 composite coating was applied on SS316 substrate surface by fiber laser cladding operations. Under the influence of various input process parameters, the surface morphology, microstructure, X-ray diffraction, clad layer thickness, micro-hardness, and tribological behaviour of the composite coating were examined. The result showed good metallurgical bonding between the clad powder and substrate surface. Surface morphology did not show any pores and cracks on the clad surface. From FESEM analysis, the clad surface was found to be smooth and free from any crack propagation during laser processing. X-ray diffraction analysis showed formation of Fe3N, Cr2N, CrB, B2C5N2, γ- (Ni, Fe), h-BN phases which are responsible for enhancing mechanical and tribological properties of the clad layer. During the study, the micro-hardness of the clad layer was found to increase with an increase in % v/v of h-BN by 2-2.5 times compared (525 HV0.3) to parent material (220 HV0.3). Further, dry sliding wear test was carried out with Pin-On-Disc, showed that the coefficient of friction value decreased significantly from 0.560 (parent surface) to 0.251 (clad surface).
关键词： solid lubricant,micro-hardness,fiber laser cladding,coefficient of friction,h-BN,microstructure
更新于2025-09-11 14:15:04
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Experimental and Numerical Investigation of Surface Texturing 316L Stainless Steel by Laser Shock Processing
摘要： Surface texturing is considered as a promising method to reduce friction coefficient and improve wear resistance of frictional pairs. In this study, laser peen texturing (LPT) based on laser shock process is proposed to fabricate dimple array on 316L stainless steel. LTP experiments are carried out to investigate the geometrical characteristics of the micro-dimple. It is shown that LPT is capable of fabricating micro-dimples with good repeatability. Numerical simulation based on finite element method is conducted to further study the process of LPT. It is found that the dimple depth obtained from numerical simulation shows a good agreement with that measured from experiments. Moreover, by means of stress analysis, it is shown that residual compressive stress exists in the specimen, which is supposed to be helpful to improve the triboligical performance of frictional pairs.
关键词： friction reduction,wear resistance,316L stainless steel,surface texturing,laser shock processing
更新于2025-09-11 14:15:04
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Influence of Femtosecond Laser Surface Nanotexturing on the Friction Behavior of Silicon Sliding Against PTFE
摘要： The aim of the present work was to investigate the influence of laser-induced periodic surface structures (LIPSS) produced by femtosecond laser on the friction behavior of silicon sliding on polytetrafluoroethylene (PTFE) in unlubricated conditions. Tribological tests were performed on polished and textured samples in air using a ball-on-flat nanotribometer, in order to evaluate the friction coefficient of polished and textured silicon samples, parallel and perpendicularly to the LIPSS orientation. In the polished specimens, the friction coefficient decreases with testing time at 5 mN, while it increases slightly at 25 mN. It also decreases with increasing applied load. For the textured specimens, the friction coefficient tends to decrease with testing time in both sliding directions studied. In the parallel sliding direction, the friction coefficient decreases with increasing load, attaining values similar to those measured for the polished specimen, while it is independent of the applied load in the perpendicular sliding direction, exhibiting values lower than in the two other cases. These results can be explained by variations in the main contributions to friction and in the wear mechanisms. The influence of the temperature increase at the interface and the consequent changes in the crystalline phases of PTFE are also considered.
关键词： silicon,laser surface texturing,friction,LIPSS,PTFE,laser-induced periodic surface structures
更新于2025-09-11 14:15:04
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Characteristics of Diamond-Like Carbon Films Fabricated by Using a Filtered Vacuum Arc System for Dye-Sensitized Solar Cells
摘要： Dye-sensitized solar cells (DSSC) based on diamond-like carbon (DLC) anti-re?ection coating (ARC) thin ?lms are investigated. The DLC ?lm was proposed to improve the cell performance of DSSC devices. In this work, the DLC ?lms were fabricated by using the FVA (?ltered vacuum arc) method, the structural, optical, and physical properties of the fabricated DLC ?lms with various ?lm thicknesses were experimentally investigated. All DLC ?lms showed smoother and more uniform surfaces with increasing ?lm thickness. Furthermore, the values of rms surface roughness, friction coe?cient, the refractive index, and the absorption coe?cient increased with increasing ?lm thickness, the hardness and the elastic modulus of the DLC ?lms were improved. These results are associated with the increased sp3 contents in the amorphous carbon ?lm due to the e?ects of the energetic ion bombardment during ?lm deposition.
关键词： DLC,Filtered vacuum arc (FVA),Hardness,Anti-re?ection,Friction coe?cient,Power conversion e?ciency
更新于2025-09-11 14:15:04
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Plasmon-Polariton Properties in Metallic Nanosphere Chains
摘要： The propagation of collective wave type plasmonic excitations along in?nite chains of metallic nanospheres has been analyzed, including near-, medium- and far-?eld contributions to the plasmon dipole interaction with all retardation effects taken into account. It is proven that there exist weakly-damped self-modes of plasmon-polaritons in the chain for which the propagation range is limited by relatively small Ohmic losses only. In this regime, the Lorentz friction irradiation losses on each nanosphere in the chain are ideally compensated by the energy income from the rest of the chain. The completely undamped collective waves were identi?ed in the case of the presence of persistent external excitation of some fragment of the chain. The obtained characteristics of these excitations ?t the experimental observations well.
关键词： radiative undamped propagation,Lorentz friction,plasmon-polariton,metallic nano-chain,plasmons
更新于2025-09-10 09:29:36
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Preparation of ZnO nanoparticle-reinforced polyamide 6 composite by <i>in situ</i> -coproduced method and their properties
摘要： Polyamide 6/ZnO nanocomposites (noted as PA6/ZnO) were prepared by an in situ co-producing method, during which Zn2(OH)2CO3 decomposed into nano-ZnO in the process of the opening-ring polymerization of caprolactam at high temperature. Transmission electron microscopy, X-ray diffraction, thermogravimetric analysis, and differential scanning calorimetry were used to analyze the size and dispersive properties of nano-ZnO, the crystallization and melting properties, the thermal properties, and crystal structure of PA6/ZnO composite, respectively. The results showed that the nano-ZnO derived from Zn2(OH)2CO3 via in situ polymerization of PA6-ZnO was uniformly dispersed in PA6 matrix. However, the overall nano-ZnO crystallization rate and crystal size in the PA6 matrix were hindered by the bulky PA6 molecular chains. The mechanical properties were evaluated using universal tensile and impact testing instruments. The results revealed that PA6/ZnO composite with 0.2% nano-ZnO content possessed excellent tensile strength, enhanced by 75% in comparison with the pure PA6. The nano-ZnO had little influence on the impact strength of PA6.
关键词： friction property,mechanical performance,nanocomposites,polyamide 6,nano-ZnO,polyamides,composite
更新于2025-09-09 09:28:46
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[ASME ASME 2018 37th International Conference on Ocean, Offshore and Arctic Engineering - Madrid, Spain (Sunday 17 June 2018)] Volume 5: Pipelines, Risers, and Subsea Systems - Development and Testing of a Friction-Based Post-Installable Fiber-Optic Monitoring System for Subsea Applications
摘要： This paper continues to document the design, development, and test of a friction-based (non-adhesive) post-installable fiber-optic strain sensing system for oil and gas applications – especially those that require deployment on existing subsea structures. (Ref: OMAE2017-61494 Development and Testing of a Friction-Based Post-Installable Sensor for Subsea Fiber-Optic Monitoring Systems [1]). The prototype fiber-optic monitoring system collects a wide range of real-time data, which can be used to determine structural loading, fatigue, temperature, pressure, and flow assurance on operational platforms. The primary challenge of a post-installed instrumentation monitoring system is to ensure secure coupling between the sensors and the structure of interest for reliable measurements. Friction-based coupling devices have the potential to overcome installation challenges caused by marine growth and soil contamination on subsea structures, flowlines, or risers. This particular design solution is compatible with structures that are suspended in the water column and those that are resting on the seabed. In addition, the system can be installed by commercial divers in shallow depths or by remotely operated vehicles in deep-water applications. Operational limitations of the initial design concept were identified in the previous series of tests (2016-2017), and several innovative enhancements have been implemented which resulted in significant improvements in sensor system coupling and strain measurement correlation with traditional strain measuring devices. This paper provides a summary of the notable prototype design changes, full-scale test article buildup, and detailed performance data recorded during tension and compression loading that simulated representative offshore conditions. The test results were positive and demonstrated the effectiveness of the design enhancements. Compromises made during mounting of the sensing elements resulted in better performance in tension than compression. These effects are well understood and are fully discussed, and do not influence the viability of the design changes. This study is part of a continuing collaboration between the Houston-based NASA-Johnson Space Center and Astro Technology, Inc. within a study called Clear Gulf. The primary objective of the Clear Gulf study is to develop advanced instrumentation technologies that will improve operational safety and reduce the risk of hydrocarbon spillage. NASA provided unique insights, expansive test facilities, and technical expertise to advance these technologies that would benefit the environment, the public, and commercial industries.
关键词： structural loading,subsea,fiber-optic,flow assurance,monitoring system,temperature,pressure,friction-based,fatigue,post-installable
更新于2025-09-09 09:28:46