Advanced engineering coatings offer a promising solution to enhance the longevity and performance of medical biomaterials in orthopaedic implants.This study hypothesises that diamond-like carbon(DLC)coatings exhibit d...Advanced engineering coatings offer a promising solution to enhance the longevity and performance of medical biomaterials in orthopaedic implants.This study hypothesises that diamond-like carbon(DLC)coatings exhibit distinct frictional performance based on substrate and counterface material.Three different DLC coatings were tested using a pin-on-plate test in four material combinations.Virgin and DLC-coated CoCrMo and Ti6Al4V pins were tested under sliding against UHMWPE and glass plates with simulated body fluid lubrication.Results revealed that coating composition significantly impacts frictional performance,with silicon-and oxygen-doped coatings showing great potential to minimise friction.Surprisingly,reducing contact pressure had either a neutral or somewhat negative effect.Future investigations will focus on long-term testing and lubrication analyses of these material combinations.展开更多
Real-time external alteration of the internal properties of lubricants is highly desirable in all mechanical systems. However, fabricating a suitable and effective smart lubricant is a long-lasting experimental proces...Real-time external alteration of the internal properties of lubricants is highly desirable in all mechanical systems. However, fabricating a suitable and effective smart lubricant is a long-lasting experimental process. In this study, the film thickness and frictional response of ionic liquid-lubricated non-conformal contacts to an electric field excitation under elastohydrodynamic conditions were examined. Film thickness was evaluated using a "ball-on-disc" optical tribometer with an electric circuit. Friction tests were carried on a mini traction machine (MTM) tribometer with a "ball-on-disc" rotation module and an electric circuit for contact area excitation. The results demonstrate that there is a difference in the behaviour of the ionic liquid during electric field excitation at the evaluated film thicknesses. The results of evaluated film thicknesses demonstrate that there is a difference in the behaviour of the ionic liquid during electric field excitation. Therefore, the ionic liquids could be a new basis for the smart lubrication of mechanical components. Moreover, the proposed experimental approach can be used to identify electrosensitive fluids.展开更多
In railway network,friction is an important factor to consider in terms of the service behaviors of wheel-rail system.The objective of this study was to investigate the effect of a solid friction modifier(FM)in a rail...In railway network,friction is an important factor to consider in terms of the service behaviors of wheel-rail system.The objective of this study was to investigate the effect of a solid friction modifier(FM)in a railway environment.This was achieved by studying the friction,wear,and rolling contact fatigue(RCF)damage on the wheel-rail materials at different slip ratios.The results showed that when a solid FM was applied,the friction coefficient decreased.After the solid FM was separated from the wheel-rail interface,the friction coefficient gradually increased to its original level.With the application of the solid FM,the wear rates of the wheel-rail decreased.In addition,the thickness and hardness of the plastic deformation layers of the wheel-rail materials were reduced.The worn surfaces of the wheel-rail were dominated by pits and RCF cracks.Without the FM,RCF cracks ranged from 84 to 120μm,and subsurface cracks were generated.However,with the FM,RCF cracks ranged from 17 to 97μm and no subsurface cracks were generated.These findings indicate possible methods of improving the performance of railway rolling stock by managing friction,and reducing wear and permanent RCF damage affecting both the wheels and rails.展开更多
Hip joint replacements represent the most effective way of treatment for patients suffering from joint diseases.Despite the rapid improvement of implant materials over the last few decades,limited longevity associated...Hip joint replacements represent the most effective way of treatment for patients suffering from joint diseases.Despite the rapid improvement of implant materials over the last few decades,limited longevity associated with wear-related complications persists as the main drawback.Therefore,improved tribological perfor-mance is required in order to extend the service life of replacements.The effect of surface texturing of ultra-high molecular weight polyethylene(UHMWPE)acetabular cup was investigated in the present study.Unique tilling method was utilized for manufacturing the dimples with controlled diameter and depths on the contact surface of the cup.The experiments with four commercial femoral components and two model lubricants were realized.The main attention was paid to a coefficient of friction considering the differences between the original and the dimpled cups.Results showed remarkable lowering of friction,in general.Focusing on the simulated human synovial fluid,friction was reduced by 40%(alumina ceramic),38.8%(zirconia toughened ceramic),25.5%(metal),and 9.9%(oxinium).In addition,the dimples helped to keep the friction stable without fluctuations.To conclude,the paper brings a new insight into frictional behaviour of the hip replacements during running-in phase which is essential for overall implant lifespan.It is believed that proper surface texturing may rapidly improve the life quality of millions of patients and may lead to considerable financial savings.展开更多
The biochemical reaction during the formation of lubricant film the in case of a cobalt-chromium ball on an ultrahigh-molecular weight polyethylene cup was studied.Three types of model synovial fluids and hyaluronic a...The biochemical reaction during the formation of lubricant film the in case of a cobalt-chromium ball on an ultrahigh-molecular weight polyethylene cup was studied.Three types of model synovial fluids and hyaluronic acid(HA)at physiologic concentrations were used in the experiment.The coefficient of friction was measured using a pendulum hip simulator,and Raman spectroscopy was used to perceive chemical reactions between the synovial fluid and implant material.Raman spectra evidenced that the three model fluids and HA chemisorbed onto the cobalt-chromium surface.Anα-helix structure of the model fluid components was detected on the surface of the prosthesis.展开更多
基金This research was carried out under a project funded by the Czech Science Foundation,Grant No.22‐02154S and No.25‐15390SM.Marian greatly acknowledges the financial support from the Vicerrectoria Academica(VRA)of the Pontificia Universidad Catolica de Chile within the Programa de Insercion Academica(PIA).
文摘Advanced engineering coatings offer a promising solution to enhance the longevity and performance of medical biomaterials in orthopaedic implants.This study hypothesises that diamond-like carbon(DLC)coatings exhibit distinct frictional performance based on substrate and counterface material.Three different DLC coatings were tested using a pin-on-plate test in four material combinations.Virgin and DLC-coated CoCrMo and Ti6Al4V pins were tested under sliding against UHMWPE and glass plates with simulated body fluid lubrication.Results revealed that coating composition significantly impacts frictional performance,with silicon-and oxygen-doped coatings showing great potential to minimise friction.Surprisingly,reducing contact pressure had either a neutral or somewhat negative effect.Future investigations will focus on long-term testing and lubrication analyses of these material combinations.
基金This research was carried out under the CEITEC 2020 project (LQ1601) with financial support from the Ministry of Education, Youth and Sports of the Czech Republic under the National Sustainability Programme II and the project FSI-S-17-4415 with financial support from the Ministry of Education, Youth and Sports of the Czech Republic. Aleksandar VENCL acknowledges the projects TR 34028 and TR 35021, financially supported by the Republic of Serbia, Ministry of Education, Science and Technological Development.
文摘Real-time external alteration of the internal properties of lubricants is highly desirable in all mechanical systems. However, fabricating a suitable and effective smart lubricant is a long-lasting experimental process. In this study, the film thickness and frictional response of ionic liquid-lubricated non-conformal contacts to an electric field excitation under elastohydrodynamic conditions were examined. Film thickness was evaluated using a "ball-on-disc" optical tribometer with an electric circuit. Friction tests were carried on a mini traction machine (MTM) tribometer with a "ball-on-disc" rotation module and an electric circuit for contact area excitation. The results demonstrate that there is a difference in the behaviour of the ionic liquid during electric field excitation at the evaluated film thicknesses. The results of evaluated film thicknesses demonstrate that there is a difference in the behaviour of the ionic liquid during electric field excitation. Therefore, the ionic liquids could be a new basis for the smart lubrication of mechanical components. Moreover, the proposed experimental approach can be used to identify electrosensitive fluids.
基金This study was supported by the National Key R&D Program Intergovernmental Key Items for International Scientific and Technological Innovation Cooperation(No.2018YFE0109400)Sichuan Science and Technology Program(No.2020YFH0057)+1 种基金Fundamental Research Funds for the Central Universities(No.2682020CX29)The study was also carried out under the Project 8JCH1042 with financial support from the Ministry of Education,Youth and Sports of the Czech Republic.
文摘In railway network,friction is an important factor to consider in terms of the service behaviors of wheel-rail system.The objective of this study was to investigate the effect of a solid friction modifier(FM)in a railway environment.This was achieved by studying the friction,wear,and rolling contact fatigue(RCF)damage on the wheel-rail materials at different slip ratios.The results showed that when a solid FM was applied,the friction coefficient decreased.After the solid FM was separated from the wheel-rail interface,the friction coefficient gradually increased to its original level.With the application of the solid FM,the wear rates of the wheel-rail decreased.In addition,the thickness and hardness of the plastic deformation layers of the wheel-rail materials were reduced.The worn surfaces of the wheel-rail were dominated by pits and RCF cracks.Without the FM,RCF cracks ranged from 84 to 120μm,and subsurface cracks were generated.However,with the FM,RCF cracks ranged from 17 to 97μm and no subsurface cracks were generated.These findings indicate possible methods of improving the performance of railway rolling stock by managing friction,and reducing wear and permanent RCF damage affecting both the wheels and rails.
基金The research was.carried out under the project JSPS/OF280,PE17046with financial support from the Japan Society for the Promotion of Science.This research was also supported by the project FSI-S-17-4415with financial support from the Ministry of Education,Youth and Sports of the Czech Republic(MEYS).
文摘Hip joint replacements represent the most effective way of treatment for patients suffering from joint diseases.Despite the rapid improvement of implant materials over the last few decades,limited longevity associated with wear-related complications persists as the main drawback.Therefore,improved tribological perfor-mance is required in order to extend the service life of replacements.The effect of surface texturing of ultra-high molecular weight polyethylene(UHMWPE)acetabular cup was investigated in the present study.Unique tilling method was utilized for manufacturing the dimples with controlled diameter and depths on the contact surface of the cup.The experiments with four commercial femoral components and two model lubricants were realized.The main attention was paid to a coefficient of friction considering the differences between the original and the dimpled cups.Results showed remarkable lowering of friction,in general.Focusing on the simulated human synovial fluid,friction was reduced by 40%(alumina ceramic),38.8%(zirconia toughened ceramic),25.5%(metal),and 9.9%(oxinium).In addition,the dimples helped to keep the friction stable without fluctuations.To conclude,the paper brings a new insight into frictional behaviour of the hip replacements during running-in phase which is essential for overall implant lifespan.It is believed that proper surface texturing may rapidly improve the life quality of millions of patients and may lead to considerable financial savings.
文摘The biochemical reaction during the formation of lubricant film the in case of a cobalt-chromium ball on an ultrahigh-molecular weight polyethylene cup was studied.Three types of model synovial fluids and hyaluronic acid(HA)at physiologic concentrations were used in the experiment.The coefficient of friction was measured using a pendulum hip simulator,and Raman spectroscopy was used to perceive chemical reactions between the synovial fluid and implant material.Raman spectra evidenced that the three model fluids and HA chemisorbed onto the cobalt-chromium surface.Anα-helix structure of the model fluid components was detected on the surface of the prosthesis.
