The Experts below are selected from a list of 42 Experts worldwide ranked by ideXlab platform
Koji Kato - One of the best experts on this subject based on the ideXlab platform.
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The Effect of Sliding History on the Steady State Friction Coefficient between CNX Coatings under N2 Lubrication
Life Cycle Tribology, 2005Co-Authors: Koshi Adachi, T. Wakabayashi, Koji KatoAbstract:In order to clarify the effect of reducing Friction with N 2 gas supply by blowing, Friction tests were carried out with ball/disk combinations of Si3N4/Si3N4, Si3N4/CNx, CNx/Si3N4 and CNx/CNx in air, O 2 gas stream and N 2 gas stream. As a result, steady state Friction coefficient reduced by N 2 gas supply in contact combinations of Si3N4/Si3N4, Si3N4/CNx, and CNx/CNx by the amount of 50%, 50% and 77% respectively. In the cases of Si3N4/CNx and CNx/CNx sliding, sliding history before the N 2 gas supply much affected the steady state Friction coefficient in N 2 gas stream. The initial 50 Cycles sliding in O 2 gas stream before N 2 gas supply by blowing to the sliding interface of CNx/CNx reduced the Friction coefficient to 0.005 from about 0.1 that was obtained in the same system in N 2 gas stream from the 1st Friction Cycle. In the running-in process, Friction coefficient increased in the initial stage, and decreased to relatively low and constant value. Such change in air and O 2 gas stream were ten times faster than that in N 2 gas stream. It was concluded that an optimum sliding Cycles in air or O 2 gas stream before N 2 gas supply could be necessary not only to obtain low Friction in N 2 gas stream but also to decrease total wear.
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Humidity effect on the critical number of Friction Cycles for wear particle generation in carbon nitride coatings
Wear, 2002Co-Authors: Dong F Wang, Koji KatoAbstract:Abstract Wear particle generation in carbon nitride coatings by a spherical diamond counterpart in repeated sliding contacts has been studied with an emphasis on the effect of relative humidity varying from 0.4 to 80%. An environmental scanning electron microscope (E-SEM), in which a pin-on-disk type apparatus was installed, has in situ provided direct evidence that when and where the wear particle generation do occur. The in situ examination of non-conductive carbon nitride coatings are therefore available free from surface charging with controllable relative humidity and a sliding speed of 50 mm/s varying normal load from 10 to 250 mN. Based on the in situ examination, the shape transition maps for generated wear particles have been obtained for carbon nitride coatings in various relative humidity. The results show that the critical number of Friction Cycles ( N c ) for detecting a cluster of wear particles is observed to be generally increasing with an increase in relative humidity. It also appears that the increase in relative humidity results in a decrease in peak-to-valley (P-V) values of contact tracks during the first Friction Cycle, which is essentially induced by a combined plastic deformation behavior of carbon nitride coated silicon surface. This further implies that the effective surface property such as hardness has been possibly changed by introducing water vapor into the contact interface between the carbon nitride coating and the spherical diamond counterpart, if assuming the contact pressure has a constant value.
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Microwear mechanisms of coatings
Surface and Coatings Technology, 1995Co-Authors: Koji KatoAbstract:Abstract Microwear mechanisms of coatings are studied by focusing attention on mechanical wear. Wear rates and wear modes of chemically vapour-deposited TiN and Al2O3 coatings in abrasive sliding are observed experimentally with a scanning electron microscope which has a videotape recording system and a tribosystem. It is shown that the wear rate changes by factors of 3–5 orders of magnitude depending on load and Friction Cycle. Wear modes of ploughing, powder formation, flake formation and coating delamination are observed and their transitions are related to the change of load and Friction Cycle. For the prediction of possible wear modes, a new local yield map is proposed by taking into account the stress analysis at the contact region with the finite element method.
Witold Piekoszewski - One of the best experts on this subject based on the ideXlab platform.
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The surface texture and its influence on the tribological characteristics of a Friction pair: metal-polymer
Archives of Civil and Mechanical Engineering, 2017Co-Authors: Magdalena Niemczewska-wójcik, Witold PiekoszewskiAbstract:The selection of a manufacturing process (finishing) related to material properties seems to be of vital importance. On the condition that manufacturing and machining parameters are chosen correctly, they may optimize the functional properties of components, ensuring reduction of wear and longer life of a Friction pair. The subjects of research were metal surfaces used in conjunction with polymer surfaces. These both materials are used in medicine. From the precision machining process, three different kinds of plate surface textures (defined by Ra parameter: Ra(A) < Ra(B) < Ra(C)) were obtained. The tribological research was performed with a tribotester in the Ringer’s solution, which helped determine the following tribological characteristics of a Friction pair: Friction coefficient and the wear intensity of a polymeric pin. Two devices were employed to analyze surface texture: a scanning electron microscopy and a white light interference microscopy. It was noticed that there was a certain correlation between the machined surface established in the manufacturing process, tribological characteristics, and the worn surface created during a Friction Cycle. The lowest Friction coefficient as well as the smallest value of wear intensity were obtained for Friction pair: pin-on-plate A. The results should be verified during the following stage - tribological tests on a simulator.
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The surface texture and its influence on the tribological characteristics of a Friction pair: metal–polymer
Archives of Civil and Mechanical Engineering, 2017Co-Authors: Magdalena Niemczewska-wójcik, Witold PiekoszewskiAbstract:Abstract The selection of a manufacturing process (finishing) related to material properties seems to be of vital importance. On the condition that manufacturing and machining parameters are chosen correctly, they may optimize the functional properties of components, ensuring reduction of wear and longer life of a Friction pair. The subjects of research were metal surfaces used in conjunction with polymer surfaces. These both materials are used in medicine. From the precision machining process, three different kinds of plate surface textures (defined by Ra parameter: Ra (A) Ra (B) Ra (C)) were obtained. The tribological research was performed with a tribotester in the Ringer's solution, which helped determine the following tribological characteristics of a Friction pair: Friction coefficient and the wear intensity of a polymeric pin. Two devices were employed to analyze surface texture: a scanning electron microscopy and a white light interference microscopy. It was noticed that there was a certain correlation between the machined surface established in the manufacturing process, tribological characteristics, and the worn surface created during a Friction Cycle. The lowest Friction coefficient as well as the smallest value of wear intensity were obtained for Friction pair: pin-on-plate A. The results should be verified during the following stage – tribological tests on a simulator.
Magdalena Niemczewska-wójcik - One of the best experts on this subject based on the ideXlab platform.
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The surface texture and its influence on the tribological characteristics of a Friction pair: metal-polymer
Archives of Civil and Mechanical Engineering, 2017Co-Authors: Magdalena Niemczewska-wójcik, Witold PiekoszewskiAbstract:The selection of a manufacturing process (finishing) related to material properties seems to be of vital importance. On the condition that manufacturing and machining parameters are chosen correctly, they may optimize the functional properties of components, ensuring reduction of wear and longer life of a Friction pair. The subjects of research were metal surfaces used in conjunction with polymer surfaces. These both materials are used in medicine. From the precision machining process, three different kinds of plate surface textures (defined by Ra parameter: Ra(A) < Ra(B) < Ra(C)) were obtained. The tribological research was performed with a tribotester in the Ringer’s solution, which helped determine the following tribological characteristics of a Friction pair: Friction coefficient and the wear intensity of a polymeric pin. Two devices were employed to analyze surface texture: a scanning electron microscopy and a white light interference microscopy. It was noticed that there was a certain correlation between the machined surface established in the manufacturing process, tribological characteristics, and the worn surface created during a Friction Cycle. The lowest Friction coefficient as well as the smallest value of wear intensity were obtained for Friction pair: pin-on-plate A. The results should be verified during the following stage - tribological tests on a simulator.
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The surface texture and its influence on the tribological characteristics of a Friction pair: metal–polymer
Archives of Civil and Mechanical Engineering, 2017Co-Authors: Magdalena Niemczewska-wójcik, Witold PiekoszewskiAbstract:Abstract The selection of a manufacturing process (finishing) related to material properties seems to be of vital importance. On the condition that manufacturing and machining parameters are chosen correctly, they may optimize the functional properties of components, ensuring reduction of wear and longer life of a Friction pair. The subjects of research were metal surfaces used in conjunction with polymer surfaces. These both materials are used in medicine. From the precision machining process, three different kinds of plate surface textures (defined by Ra parameter: Ra (A) Ra (B) Ra (C)) were obtained. The tribological research was performed with a tribotester in the Ringer's solution, which helped determine the following tribological characteristics of a Friction pair: Friction coefficient and the wear intensity of a polymeric pin. Two devices were employed to analyze surface texture: a scanning electron microscopy and a white light interference microscopy. It was noticed that there was a certain correlation between the machined surface established in the manufacturing process, tribological characteristics, and the worn surface created during a Friction Cycle. The lowest Friction coefficient as well as the smallest value of wear intensity were obtained for Friction pair: pin-on-plate A. The results should be verified during the following stage – tribological tests on a simulator.
Henry Vandewalle - One of the best experts on this subject based on the ideXlab platform.
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Friction-Loaded Cycle Ergometers: Past, Present and Future
Cogent Engineering, 2015Co-Authors: Henry Vandewalle, Driss TarakAbstract:The first Friction-Cycle ergometers of the end of the nineteenth century and the beginning of the 20th century are presented before the description of more recent ergometers such as Fleisch ergometer (1954), ErgomécaTM (1985), sinus-balance ergometer, and weight-basket loaded ergometer. The limits of each ergometer are debated. The interest of Friction-loaded ergometers was renewed with the proposal of different protocols enabling the assessment of maximal power during short all-out sprints on a Cycle ergometer. These protocols are succinctly presented: corrected peak power protocol, force-speed test during repeated all-out sprints against different loads, torque–velocity relationship during a single all-out sprint. The different calibration procedures (static, dynamic, and physiological calibrations) of Friction-loaded ergometers are described before the presentation of their results in the literature. Some improvements for the future Friction-loaded ergometers are presented at the end of the paper.
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Friction-loaded Cycle ergometers: Past, present and future
Cogent Engineering, 2015Co-Authors: Henry Vandewalle, Tarak DrissAbstract:AbstractThe first Friction-Cycle ergometers of the end of the nineteenth century and the beginning of the 20th century are presented before the description of more recent ergometers such as Fleisch ergometer (1954), ErgomecaTM (1985), sinus-balance ergometer, and weight-basket loaded ergometer. The limits of each ergometer are debated. The interest of Friction-loaded ergometers was renewed with the proposal of different protocols enabling the assessment of maximal power during short all-out sprints on a Cycle ergometer. These protocols are succinctly presented: corrected peak power protocol, force-speed test during repeated all-out sprints against different loads, torque–velocity relationship during a single all-out sprint. The different calibration procedures (static, dynamic, and physiological calibrations) of Friction-loaded ergometers are described before the presentation of their results in the literature. Some improvements for the future Friction-loaded ergometers are presented at the end of the paper.
Tarak Driss - One of the best experts on this subject based on the ideXlab platform.
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Friction-loaded Cycle ergometers: Past, present and future
Cogent Engineering, 2015Co-Authors: Henry Vandewalle, Tarak DrissAbstract:AbstractThe first Friction-Cycle ergometers of the end of the nineteenth century and the beginning of the 20th century are presented before the description of more recent ergometers such as Fleisch ergometer (1954), ErgomecaTM (1985), sinus-balance ergometer, and weight-basket loaded ergometer. The limits of each ergometer are debated. The interest of Friction-loaded ergometers was renewed with the proposal of different protocols enabling the assessment of maximal power during short all-out sprints on a Cycle ergometer. These protocols are succinctly presented: corrected peak power protocol, force-speed test during repeated all-out sprints against different loads, torque–velocity relationship during a single all-out sprint. The different calibration procedures (static, dynamic, and physiological calibrations) of Friction-loaded ergometers are described before the presentation of their results in the literature. Some improvements for the future Friction-loaded ergometers are presented at the end of the paper.
