The Experts below are selected from a list of 147057 Experts worldwide ranked by ideXlab platform
Satish V. Kailas - One of the best experts on this subject based on the ideXlab platform.
-
Friction and Transfer Layer formation in polymer–steel tribo-system: Role of surface texture and roughness parameters
Wear, 2011Co-Authors: Pradeep L. Menezes, Kishore, Satish V. Kailas, Michael R. LovellAbstract:In the present investigation, various kinds of surface textures were attained on the steel plates. Roughness of the textures was varied using various grinding or polishing methods. The surface textures were characterized in terms of roughness parameters using an optical profilometer. Then experiments were conducted using an inclined pin-on-plate sliding apparatus to identify the role of surface texture and its roughness parameters on coefficient of friction and Transfer Layer formation. In the experiments, a soft polymer (polypropylene) was used for the pin and hardened steel was used for the plate. Experiments were conducted at a sliding velocity of 2 minis in ambient conditions under both dry and lubricated conditions. The normal load was varied from 1 to 120 N during the tests. The morphologies of the worn surfaces of the pins and the formation of a Transfer Layer on the steel plate surfaces were observed using a scanning electron microscope. Based on the experimental results, it was observed that the Transfer Layer formation and the coefficient of friction along with its two components, namely adhesion and plowing, were controlled by the surface texture of the harder mating surfaces and were less dependent of surface roughness (R(a)) of the harder mating surfaces. The effect of surface texture on the friction was attributed to the variation of the plowing component of friction for different surfaces. Among the various surface roughness parameters studied, the mean slope of the profile, Delta(a), was found to most accurately characterize variations in the friction and wear behavior. (C) 2011 Elsevier B.V. All rights reserved.
-
The role of surface texture on friction and Transfer Layer formation during repeated sliding of Al–4Mg against steel
Wear, 2011Co-Authors: Pradeep L. Menezes, Kishore, Satish V. Kailas, Michael R. LovellAbstract:In the present investigation, various kinds of textures, namely, unidirectional, 8-ground, and random were attained on the die surfaces. Roughness of the textures was varied using different grits of emery papers or polishing powders. Then pins made of Al-4Mg alloys were slid against steel plates at various numbers of cycles, namely, 1, 3, 5, 10 and 20 using pin-on-plate reciprocating sliding tester. Tests were conducted at a sliding velocity of 2 minis in ambient conditions under both dry and lubricated conditions. A constant normal load of 35 N was applied in the tests. The morphologies of the worn surfaces of the pins and the formation of Transfer Layer on the counter surfaces were observed using a scanning electron microscope. Surface roughness parameters of the plates were measured using an optical profilometer. In the experiments, it was observed that the coefficient of friction and formation of the Transfer Layer depend on the die surface textures under both dry and lubricated conditions. More specifically, the coefficient of friction decreases for unidirectional and 8-ground surfaces while for random surfaces it increases with number of cycles. However, the coefficient of friction is highest for the sliding perpendicular to the unidirectional textures and least for the random textures under both dry and lubricated conditions. The difference in friction values between these two surfaces decreases with increasing number of cycles. The variation in the coefficient of friction under both dry and lubrication conditions is attributed to the change in texture of the surfaces during sliding. (C) 2011 Elsevier B.V. All rights reserved
-
Influence of Inclination Angle and Machining Direction on Friction and Transfer Layer Formation
Journal of Tribology-transactions of The Asme, 2010Co-Authors: Pradeep L. Menezes, Kishore, Satish V. Kailas, Michael R. LovellAbstract:In the present investigation, unidirectional grinding marks were created on a set of steel plates. Sliding experiments were then conducted with the prepared steel plates using Al-Mg alloy pins and an inclined pin-on-plate sliding tester. The goals of the experiments were to ascertain the influence of inclination angle and grinding mark direction on friction and Transfer Layer formation during sliding contact. The inclination angle of the plate was held at 0.2 deg, 0.6 deg, 1 deg, 1.4 deg, 1.8 deg, 2.2 deg, and 2.6 deg in the tests. The pins were slid both perpendicular and parallel to the grinding marks direction. The experiments were conducted under both dry and lubricated conditions on each plate in an ambient environment. Results showed that the coefficient of friction and the formation of Transfer Layer depend on the grinding marks direction and inclination angle of the hard surfaces. For a given inclination angle, under both dry and lubricated conditions, the coefficient of friction and Transfer Layer formation were found to be greater when the pins slid perpendicular to the unidirectional grinding marks than when the pins slid parallel to the grinding marks. In addition, a stick-slip phenomenon was observed under lubricated conditions at the highest inclination angle for sliding perpendicular to the grinding marks direction. This phenomenon could be attributed to the extent of plane strain conditions taking place at the asperity level during sliding. DOI: 10.1115/1.4002604]
-
Studies on Friction and Transfer Layer Formation When Pure Magnesium Pins Slid at Various Numbers of Cycles on Steel Plates of Different Surface Texture
STLE ASME 2010 International Joint Tribology Conference, 2010Co-Authors: Pradeep L. Menezes, Kishore, Satish V. Kailas, Michael R. LovellAbstract:In the present investigation, various kinds of textures (undirectional, 8-ground, and random,) were attained on a set of steel plate surfaces. The roughness of the textures was varied using different grits of emery papers or polishing powders. Pins made of pure magnesium were then slid against the steel plates at various numbers of cycles (1, 2, 6, 10 and 20) using an inclined pin-on-plate sliding apparatus. In the experiments, it was observed that the coefficient of friction and the formation of a Transfer Layer depended on the die surface textures under both dry and lubricated conditions. The coefficient of friction increased with number of cycles under dry conditions for all of the textures studied. Under lubricated conditions, however, the coefficient of friction decreased for unidirectional and 8-ground surfaces and increased for random surfaces with the number of cycles. A stick-slip phenomenon was observed under both dry and lubricated conditions. Occurrence of the stick slip behavior depended on the surface texture, the load and the number of cycles. The variation in the coefficient of friction under both dry and lubrication conditions was attributed to changes in the texture of the surfaces during sliding.Copyright © 2010 by ASME
-
Influence of tilt angle of plate on friction and Transfer Layer - a study of aluminium pin sliding against steel plate
Tribology International, 2009Co-Authors: Pradeep L. Menezes, Kishore, Satish V. Kailas, BobjibAbstract:In the present investigation, unidirectional grinding marks were attained on the steel plates. Then aluminium (Al) pins were slid at 0.2°, 0.6°, 1.0°, 1.4°, 1.8°, 2.2° and 2.6° tilt angles of the plate with the grinding marks perpendicular and parallel to the sliding direction under both dry and lubricated conditions using a pin-on-plate inclined sliding tester to understand the influence of tilt angle and grinding marks direction of the plate on coefficient of friction and Transfer Layer formation. It was observed that the Transfer Layer formation and the coefficient of friction depend primarily on the grinding marks direction of the harder mating surface. Stick-slip phenomenon was observed only under lubricated conditions. For the case of pins slid perpendicular to the unidirectional grinding marks stick-slip phenomenon was observed for tilt angles exceeding 0.6°, the amplitude of which increases with increasing tilt angles. However, for the case of the pins slid parallel to the unidirectional grinding marks the stick-slip phenomena was observed for angles exceeding 2.2°, the amplitude of which also increases with increasing tilt angle. The presence of stick-slip phenomena under lubricated conditions could be attributed to the molecular deformation of the lubricant component confined between asperities.
Pradeep L. Menezes - One of the best experts on this subject based on the ideXlab platform.
-
Influence of environmental friendly multiphase lubricants on the friction and Transfer Layer formation during sliding against textured surfaces
Journal of Cleaner Production, 2019Co-Authors: Arpith Siddaiah, Ashish K. Kasar, Arjun Manoj, Pradeep L. MenezesAbstract:Abstract Both surface texture and multiphase lubricants (additives in base oil) influence the friction and wear performance during sliding. However, the synergy of their interaction is still unknown. In the present investigation, an effort is made to understand the influence of environmental friendly multiphase lubricants on the friction and Transfer Layer formation during sliding against various surface textures. In this study, unidirectional surface textures were created and sliding tests were conducted against various grinding angles of the unidirectional texture. The sliding tests were conducted in multiphase lubricants consisting of canola oil (biolubricant) and nano-additives (graphene) at various concentrations. The results showed that the coefficient of friction (COF) and Transfer Layer formation was influenced by the grinding angle. However, it was found that this influence can be minimized by using an optimum concentration of graphene in canola oil. A minimum COF of 0.05 ± 0.01 could be achieved for various grinding angles by utilizing a specific concentration of graphene. It was found that a high concentration of Gr (3 wt%) was required when sliding at 0° and a low concentration of Gr (1 wt%) was required when sliding at 45° to achieve the minimum COF. This was attributed to the variations in asperity and Gr additive interaction when sliding at different grinding angles. The present study details the observed friction and Transfer Layer formation results and analyzes the mechanism of multiphase lubrication during sliding at various grinding angles. An asperity interaction model for sliding against various grinding angles and in a multiphase lubricant with varying additive concentrations has also been presented.
-
Friction and Transfer Layer formation in polymer–steel tribo-system: Role of surface texture and roughness parameters
Wear, 2011Co-Authors: Pradeep L. Menezes, Kishore, Satish V. Kailas, Michael R. LovellAbstract:In the present investigation, various kinds of surface textures were attained on the steel plates. Roughness of the textures was varied using various grinding or polishing methods. The surface textures were characterized in terms of roughness parameters using an optical profilometer. Then experiments were conducted using an inclined pin-on-plate sliding apparatus to identify the role of surface texture and its roughness parameters on coefficient of friction and Transfer Layer formation. In the experiments, a soft polymer (polypropylene) was used for the pin and hardened steel was used for the plate. Experiments were conducted at a sliding velocity of 2 minis in ambient conditions under both dry and lubricated conditions. The normal load was varied from 1 to 120 N during the tests. The morphologies of the worn surfaces of the pins and the formation of a Transfer Layer on the steel plate surfaces were observed using a scanning electron microscope. Based on the experimental results, it was observed that the Transfer Layer formation and the coefficient of friction along with its two components, namely adhesion and plowing, were controlled by the surface texture of the harder mating surfaces and were less dependent of surface roughness (R(a)) of the harder mating surfaces. The effect of surface texture on the friction was attributed to the variation of the plowing component of friction for different surfaces. Among the various surface roughness parameters studied, the mean slope of the profile, Delta(a), was found to most accurately characterize variations in the friction and wear behavior. (C) 2011 Elsevier B.V. All rights reserved.
-
The role of surface texture on friction and Transfer Layer formation during repeated sliding of Al–4Mg against steel
Wear, 2011Co-Authors: Pradeep L. Menezes, Kishore, Satish V. Kailas, Michael R. LovellAbstract:In the present investigation, various kinds of textures, namely, unidirectional, 8-ground, and random were attained on the die surfaces. Roughness of the textures was varied using different grits of emery papers or polishing powders. Then pins made of Al-4Mg alloys were slid against steel plates at various numbers of cycles, namely, 1, 3, 5, 10 and 20 using pin-on-plate reciprocating sliding tester. Tests were conducted at a sliding velocity of 2 minis in ambient conditions under both dry and lubricated conditions. A constant normal load of 35 N was applied in the tests. The morphologies of the worn surfaces of the pins and the formation of Transfer Layer on the counter surfaces were observed using a scanning electron microscope. Surface roughness parameters of the plates were measured using an optical profilometer. In the experiments, it was observed that the coefficient of friction and formation of the Transfer Layer depend on the die surface textures under both dry and lubricated conditions. More specifically, the coefficient of friction decreases for unidirectional and 8-ground surfaces while for random surfaces it increases with number of cycles. However, the coefficient of friction is highest for the sliding perpendicular to the unidirectional textures and least for the random textures under both dry and lubricated conditions. The difference in friction values between these two surfaces decreases with increasing number of cycles. The variation in the coefficient of friction under both dry and lubrication conditions is attributed to the change in texture of the surfaces during sliding. (C) 2011 Elsevier B.V. All rights reserved
-
Influence of Inclination Angle and Machining Direction on Friction and Transfer Layer Formation
Journal of Tribology-transactions of The Asme, 2010Co-Authors: Pradeep L. Menezes, Kishore, Satish V. Kailas, Michael R. LovellAbstract:In the present investigation, unidirectional grinding marks were created on a set of steel plates. Sliding experiments were then conducted with the prepared steel plates using Al-Mg alloy pins and an inclined pin-on-plate sliding tester. The goals of the experiments were to ascertain the influence of inclination angle and grinding mark direction on friction and Transfer Layer formation during sliding contact. The inclination angle of the plate was held at 0.2 deg, 0.6 deg, 1 deg, 1.4 deg, 1.8 deg, 2.2 deg, and 2.6 deg in the tests. The pins were slid both perpendicular and parallel to the grinding marks direction. The experiments were conducted under both dry and lubricated conditions on each plate in an ambient environment. Results showed that the coefficient of friction and the formation of Transfer Layer depend on the grinding marks direction and inclination angle of the hard surfaces. For a given inclination angle, under both dry and lubricated conditions, the coefficient of friction and Transfer Layer formation were found to be greater when the pins slid perpendicular to the unidirectional grinding marks than when the pins slid parallel to the grinding marks. In addition, a stick-slip phenomenon was observed under lubricated conditions at the highest inclination angle for sliding perpendicular to the grinding marks direction. This phenomenon could be attributed to the extent of plane strain conditions taking place at the asperity level during sliding. DOI: 10.1115/1.4002604]
-
Studies on Friction and Transfer Layer Formation When Pure Magnesium Pins Slid at Various Numbers of Cycles on Steel Plates of Different Surface Texture
STLE ASME 2010 International Joint Tribology Conference, 2010Co-Authors: Pradeep L. Menezes, Kishore, Satish V. Kailas, Michael R. LovellAbstract:In the present investigation, various kinds of textures (undirectional, 8-ground, and random,) were attained on a set of steel plate surfaces. The roughness of the textures was varied using different grits of emery papers or polishing powders. Pins made of pure magnesium were then slid against the steel plates at various numbers of cycles (1, 2, 6, 10 and 20) using an inclined pin-on-plate sliding apparatus. In the experiments, it was observed that the coefficient of friction and the formation of a Transfer Layer depended on the die surface textures under both dry and lubricated conditions. The coefficient of friction increased with number of cycles under dry conditions for all of the textures studied. Under lubricated conditions, however, the coefficient of friction decreased for unidirectional and 8-ground surfaces and increased for random surfaces with the number of cycles. A stick-slip phenomenon was observed under both dry and lubricated conditions. Occurrence of the stick slip behavior depended on the surface texture, the load and the number of cycles. The variation in the coefficient of friction under both dry and lubrication conditions was attributed to changes in the texture of the surfaces during sliding.Copyright © 2010 by ASME
Kishore - One of the best experts on this subject based on the ideXlab platform.
-
The role of surface texture on friction and Transfer Layer formation during repeated sliding of Al–4Mg against steel
Wear, 2011Co-Authors: Pradeep L. Menezes, Kishore, Satish V. Kailas, Michael R. LovellAbstract:In the present investigation, various kinds of textures, namely, unidirectional, 8-ground, and random were attained on the die surfaces. Roughness of the textures was varied using different grits of emery papers or polishing powders. Then pins made of Al-4Mg alloys were slid against steel plates at various numbers of cycles, namely, 1, 3, 5, 10 and 20 using pin-on-plate reciprocating sliding tester. Tests were conducted at a sliding velocity of 2 minis in ambient conditions under both dry and lubricated conditions. A constant normal load of 35 N was applied in the tests. The morphologies of the worn surfaces of the pins and the formation of Transfer Layer on the counter surfaces were observed using a scanning electron microscope. Surface roughness parameters of the plates were measured using an optical profilometer. In the experiments, it was observed that the coefficient of friction and formation of the Transfer Layer depend on the die surface textures under both dry and lubricated conditions. More specifically, the coefficient of friction decreases for unidirectional and 8-ground surfaces while for random surfaces it increases with number of cycles. However, the coefficient of friction is highest for the sliding perpendicular to the unidirectional textures and least for the random textures under both dry and lubricated conditions. The difference in friction values between these two surfaces decreases with increasing number of cycles. The variation in the coefficient of friction under both dry and lubrication conditions is attributed to the change in texture of the surfaces during sliding. (C) 2011 Elsevier B.V. All rights reserved
-
Friction and Transfer Layer formation in polymer–steel tribo-system: Role of surface texture and roughness parameters
Wear, 2011Co-Authors: Pradeep L. Menezes, Kishore, Satish V. Kailas, Michael R. LovellAbstract:In the present investigation, various kinds of surface textures were attained on the steel plates. Roughness of the textures was varied using various grinding or polishing methods. The surface textures were characterized in terms of roughness parameters using an optical profilometer. Then experiments were conducted using an inclined pin-on-plate sliding apparatus to identify the role of surface texture and its roughness parameters on coefficient of friction and Transfer Layer formation. In the experiments, a soft polymer (polypropylene) was used for the pin and hardened steel was used for the plate. Experiments were conducted at a sliding velocity of 2 minis in ambient conditions under both dry and lubricated conditions. The normal load was varied from 1 to 120 N during the tests. The morphologies of the worn surfaces of the pins and the formation of a Transfer Layer on the steel plate surfaces were observed using a scanning electron microscope. Based on the experimental results, it was observed that the Transfer Layer formation and the coefficient of friction along with its two components, namely adhesion and plowing, were controlled by the surface texture of the harder mating surfaces and were less dependent of surface roughness (R(a)) of the harder mating surfaces. The effect of surface texture on the friction was attributed to the variation of the plowing component of friction for different surfaces. Among the various surface roughness parameters studied, the mean slope of the profile, Delta(a), was found to most accurately characterize variations in the friction and wear behavior. (C) 2011 Elsevier B.V. All rights reserved.
-
Influence of Inclination Angle and Machining Direction on Friction and Transfer Layer Formation
Journal of Tribology-transactions of The Asme, 2010Co-Authors: Pradeep L. Menezes, Kishore, Satish V. Kailas, Michael R. LovellAbstract:In the present investigation, unidirectional grinding marks were created on a set of steel plates. Sliding experiments were then conducted with the prepared steel plates using Al-Mg alloy pins and an inclined pin-on-plate sliding tester. The goals of the experiments were to ascertain the influence of inclination angle and grinding mark direction on friction and Transfer Layer formation during sliding contact. The inclination angle of the plate was held at 0.2 deg, 0.6 deg, 1 deg, 1.4 deg, 1.8 deg, 2.2 deg, and 2.6 deg in the tests. The pins were slid both perpendicular and parallel to the grinding marks direction. The experiments were conducted under both dry and lubricated conditions on each plate in an ambient environment. Results showed that the coefficient of friction and the formation of Transfer Layer depend on the grinding marks direction and inclination angle of the hard surfaces. For a given inclination angle, under both dry and lubricated conditions, the coefficient of friction and Transfer Layer formation were found to be greater when the pins slid perpendicular to the unidirectional grinding marks than when the pins slid parallel to the grinding marks. In addition, a stick-slip phenomenon was observed under lubricated conditions at the highest inclination angle for sliding perpendicular to the grinding marks direction. This phenomenon could be attributed to the extent of plane strain conditions taking place at the asperity level during sliding. DOI: 10.1115/1.4002604]
-
Studies on Friction and Transfer Layer Formation When Pure Magnesium Pins Slid at Various Numbers of Cycles on Steel Plates of Different Surface Texture
STLE ASME 2010 International Joint Tribology Conference, 2010Co-Authors: Pradeep L. Menezes, Kishore, Satish V. Kailas, Michael R. LovellAbstract:In the present investigation, various kinds of textures (undirectional, 8-ground, and random,) were attained on a set of steel plate surfaces. The roughness of the textures was varied using different grits of emery papers or polishing powders. Pins made of pure magnesium were then slid against the steel plates at various numbers of cycles (1, 2, 6, 10 and 20) using an inclined pin-on-plate sliding apparatus. In the experiments, it was observed that the coefficient of friction and the formation of a Transfer Layer depended on the die surface textures under both dry and lubricated conditions. The coefficient of friction increased with number of cycles under dry conditions for all of the textures studied. Under lubricated conditions, however, the coefficient of friction decreased for unidirectional and 8-ground surfaces and increased for random surfaces with the number of cycles. A stick-slip phenomenon was observed under both dry and lubricated conditions. Occurrence of the stick slip behavior depended on the surface texture, the load and the number of cycles. The variation in the coefficient of friction under both dry and lubrication conditions was attributed to changes in the texture of the surfaces during sliding.Copyright © 2010 by ASME
-
Influence of tilt angle of plate on friction and Transfer Layer - a study of aluminium pin sliding against steel plate
Tribology International, 2009Co-Authors: Pradeep L. Menezes, Kishore, Satish V. Kailas, BobjibAbstract:In the present investigation, unidirectional grinding marks were attained on the steel plates. Then aluminium (Al) pins were slid at 0.2°, 0.6°, 1.0°, 1.4°, 1.8°, 2.2° and 2.6° tilt angles of the plate with the grinding marks perpendicular and parallel to the sliding direction under both dry and lubricated conditions using a pin-on-plate inclined sliding tester to understand the influence of tilt angle and grinding marks direction of the plate on coefficient of friction and Transfer Layer formation. It was observed that the Transfer Layer formation and the coefficient of friction depend primarily on the grinding marks direction of the harder mating surface. Stick-slip phenomenon was observed only under lubricated conditions. For the case of pins slid perpendicular to the unidirectional grinding marks stick-slip phenomenon was observed for tilt angles exceeding 0.6°, the amplitude of which increases with increasing tilt angles. However, for the case of the pins slid parallel to the unidirectional grinding marks the stick-slip phenomena was observed for angles exceeding 2.2°, the amplitude of which also increases with increasing tilt angle. The presence of stick-slip phenomena under lubricated conditions could be attributed to the molecular deformation of the lubricant component confined between asperities.
Michael R. Lovell - One of the best experts on this subject based on the ideXlab platform.
-
The role of surface texture on friction and Transfer Layer formation during repeated sliding of Al–4Mg against steel
Wear, 2011Co-Authors: Pradeep L. Menezes, Kishore, Satish V. Kailas, Michael R. LovellAbstract:In the present investigation, various kinds of textures, namely, unidirectional, 8-ground, and random were attained on the die surfaces. Roughness of the textures was varied using different grits of emery papers or polishing powders. Then pins made of Al-4Mg alloys were slid against steel plates at various numbers of cycles, namely, 1, 3, 5, 10 and 20 using pin-on-plate reciprocating sliding tester. Tests were conducted at a sliding velocity of 2 minis in ambient conditions under both dry and lubricated conditions. A constant normal load of 35 N was applied in the tests. The morphologies of the worn surfaces of the pins and the formation of Transfer Layer on the counter surfaces were observed using a scanning electron microscope. Surface roughness parameters of the plates were measured using an optical profilometer. In the experiments, it was observed that the coefficient of friction and formation of the Transfer Layer depend on the die surface textures under both dry and lubricated conditions. More specifically, the coefficient of friction decreases for unidirectional and 8-ground surfaces while for random surfaces it increases with number of cycles. However, the coefficient of friction is highest for the sliding perpendicular to the unidirectional textures and least for the random textures under both dry and lubricated conditions. The difference in friction values between these two surfaces decreases with increasing number of cycles. The variation in the coefficient of friction under both dry and lubrication conditions is attributed to the change in texture of the surfaces during sliding. (C) 2011 Elsevier B.V. All rights reserved
-
Friction and Transfer Layer formation in polymer–steel tribo-system: Role of surface texture and roughness parameters
Wear, 2011Co-Authors: Pradeep L. Menezes, Kishore, Satish V. Kailas, Michael R. LovellAbstract:In the present investigation, various kinds of surface textures were attained on the steel plates. Roughness of the textures was varied using various grinding or polishing methods. The surface textures were characterized in terms of roughness parameters using an optical profilometer. Then experiments were conducted using an inclined pin-on-plate sliding apparatus to identify the role of surface texture and its roughness parameters on coefficient of friction and Transfer Layer formation. In the experiments, a soft polymer (polypropylene) was used for the pin and hardened steel was used for the plate. Experiments were conducted at a sliding velocity of 2 minis in ambient conditions under both dry and lubricated conditions. The normal load was varied from 1 to 120 N during the tests. The morphologies of the worn surfaces of the pins and the formation of a Transfer Layer on the steel plate surfaces were observed using a scanning electron microscope. Based on the experimental results, it was observed that the Transfer Layer formation and the coefficient of friction along with its two components, namely adhesion and plowing, were controlled by the surface texture of the harder mating surfaces and were less dependent of surface roughness (R(a)) of the harder mating surfaces. The effect of surface texture on the friction was attributed to the variation of the plowing component of friction for different surfaces. Among the various surface roughness parameters studied, the mean slope of the profile, Delta(a), was found to most accurately characterize variations in the friction and wear behavior. (C) 2011 Elsevier B.V. All rights reserved.
-
Influence of Inclination Angle and Machining Direction on Friction and Transfer Layer Formation
Journal of Tribology-transactions of The Asme, 2010Co-Authors: Pradeep L. Menezes, Kishore, Satish V. Kailas, Michael R. LovellAbstract:In the present investigation, unidirectional grinding marks were created on a set of steel plates. Sliding experiments were then conducted with the prepared steel plates using Al-Mg alloy pins and an inclined pin-on-plate sliding tester. The goals of the experiments were to ascertain the influence of inclination angle and grinding mark direction on friction and Transfer Layer formation during sliding contact. The inclination angle of the plate was held at 0.2 deg, 0.6 deg, 1 deg, 1.4 deg, 1.8 deg, 2.2 deg, and 2.6 deg in the tests. The pins were slid both perpendicular and parallel to the grinding marks direction. The experiments were conducted under both dry and lubricated conditions on each plate in an ambient environment. Results showed that the coefficient of friction and the formation of Transfer Layer depend on the grinding marks direction and inclination angle of the hard surfaces. For a given inclination angle, under both dry and lubricated conditions, the coefficient of friction and Transfer Layer formation were found to be greater when the pins slid perpendicular to the unidirectional grinding marks than when the pins slid parallel to the grinding marks. In addition, a stick-slip phenomenon was observed under lubricated conditions at the highest inclination angle for sliding perpendicular to the grinding marks direction. This phenomenon could be attributed to the extent of plane strain conditions taking place at the asperity level during sliding. DOI: 10.1115/1.4002604]
-
Studies on Friction and Transfer Layer Formation When Pure Magnesium Pins Slid at Various Numbers of Cycles on Steel Plates of Different Surface Texture
STLE ASME 2010 International Joint Tribology Conference, 2010Co-Authors: Pradeep L. Menezes, Kishore, Satish V. Kailas, Michael R. LovellAbstract:In the present investigation, various kinds of textures (undirectional, 8-ground, and random,) were attained on a set of steel plate surfaces. The roughness of the textures was varied using different grits of emery papers or polishing powders. Pins made of pure magnesium were then slid against the steel plates at various numbers of cycles (1, 2, 6, 10 and 20) using an inclined pin-on-plate sliding apparatus. In the experiments, it was observed that the coefficient of friction and the formation of a Transfer Layer depended on the die surface textures under both dry and lubricated conditions. The coefficient of friction increased with number of cycles under dry conditions for all of the textures studied. Under lubricated conditions, however, the coefficient of friction decreased for unidirectional and 8-ground surfaces and increased for random surfaces with the number of cycles. A stick-slip phenomenon was observed under both dry and lubricated conditions. Occurrence of the stick slip behavior depended on the surface texture, the load and the number of cycles. The variation in the coefficient of friction under both dry and lubrication conditions was attributed to changes in the texture of the surfaces during sliding.Copyright © 2010 by ASME
-
Response of materials as a function of grinding angle on friction and Transfer Layer formation
The International Journal of Advanced Manufacturing Technology, 2009Co-Authors: Pradeep L. Menezes, Kishore, Satish V. Kailas, Michael R. LovellAbstract:Surface texture influences friction and Transfer Layer formation during sliding contact. In the present investigation, basic studies were conducted using an inclined pin-on-plate sliding apparatus to understand the effect of grinding mark directionality on the coefficient of friction and Transfer Layer formation. In the experiments, 080 M40 steel plates were ground to attain different surface roughness with unidirectional grinding marks. Pins consisting of soft materials (pure Al, pure Mg, and Al–4Mg alloy) were then slid against the prepared steel plates. The grinding angle (angle between direction of sliding and grinding marks) was varied between 0° and 90° in the tests. The experiments were conducted under both dry and lubricated conditions in an ambient environment. It was observed that the Transfer Layer formation and the coefficient of friction depend primarily on the directionality of the plate grinding marks. For the case of pure Mg pins, a stick-slip friction phenomenon was observed for all grinding angles under dry conditions and for grinding angles over 25° under lubricated conditions. In the case of Al pins, the stick-slip phenomenon was observed only under lubricated conditions for angles exceeding 25°. The stick-slip phenomena did not occur in any of the conditions studied with Al–4Mg alloy pins. Based on the results, it was concluded that the magnitudes of the friction and the stick-slip motion amplitude (for Al and Mg pins) were primarily controlled by changes in the level of plowing friction.
Zhiyong Fan - One of the best experts on this subject based on the ideXlab platform.
-
high efficiency and stable perovskite solar cell using zno rgo qds as an electron Transfer Layer
Advanced Materials Interfaces, 2016Co-Authors: Mohammad Mahdi Tavakoli, Rouhollah Tavakoli, Zahra Nourbakhsh, Aashir Waleed, Umar Siddique Virk, Zhiyong FanAbstract:Fabrication of organohalide perovskite materials on the top of ZnO nanoparticles (NPs) has some beneficial advantages such as room temperature processing; however, the perovskite is not stable on ZnO NPs Layer during the annealing process. In fact, there are only a few reports about the fabrication of perovskite solar cells on ZnO NPs Layer. Herein, the decomposition mechanism of CH3NH3PbI3 perovskite materials on ZnO is reported, and it is found that the perovskite film on the top of the ZnO Layer is converted into PbI2 during the annealing process due to the existence of hydroxide groups on the surface of the ZnO NPs. Depending on the annealing temperature, the reaction rate and the quality of the perovskite film can be changed. In order to tackle this problem, a quasi core shell structure of ZnO/reduced graphene oxide (rGO) quantum dots is synthesized and is employed as an electron Transfer Layer. In this regard, rGO not only passivates the surface of the ZnO NPs to prevent the reaction, but also extracts the charge carriers quickly from the perovskite Layer to reduce the carrier recombination. Our results show that perovskite solar cell on ZnO/rGO Layer exhibits a stable power conversion efficiency as high as 15.2% and 11.2% on fluorine-doped tin oxide (FTO) glass and polyethylene terephthalate (PET) substrates, respectively, under AM1.5G illumination.
-
High Efficiency and Stable Perovskite Solar Cell Using ZnO/rGO QDs as an Electron Transfer Layer
Advanced Materials Interfaces, 2016Co-Authors: Mohammad Mahdi Tavakoli, Rouhollah Tavakoli, Zahra Nourbakhsh, Aashir Waleed, Umar Siddique Virk, Zhiyong FanAbstract:Fabrication of organohalide perovskite materials on the top of ZnO nanoparticles (NPs) has some beneficial advantages such as room temperature processing; however, the perovskite is not stable on ZnO NPs Layer during the annealing process. In fact, there are only a few reports about the fabrication of perovskite solar cells on ZnO NPs Layer. Herein, the decomposition mechanism of CH3NH3PbI3 perovskite materials on ZnO is reported, and it is found that the perovskite film on the top of the ZnO Layer is converted into PbI2 during the annealing process due to the existence of hydroxide groups on the surface of the ZnO NPs. Depending on the annealing temperature, the reaction rate and the quality of the perovskite film can be changed. In order to tackle this problem, a quasi core shell structure of ZnO/reduced graphene oxide (rGO) quantum dots is synthesized and is employed as an electron Transfer Layer. In this regard, rGO not only passivates the surface of the ZnO NPs to prevent the reaction, but also extracts the charge carriers quickly from the perovskite Layer to reduce the carrier recombination. Our results show that perovskite solar cell on ZnO/rGO Layer exhibits a stable power conversion efficiency as high as 15.2% and 11.2% on fluorine-doped tin oxide (FTO) glass and polyethylene terephthalate (PET) substrates, respectively, under AM1.5G illumination.
