The Experts below are selected from a list of 138 Experts worldwide ranked by ideXlab platform
Jibin Pu - One of the best experts on this subject based on the ideXlab platform.
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the Tribological performance of selected solid lubricant films in sand dust environments
Wear, 2011Co-Authors: Jianwei Qi, Yunfeng Wang, Liping Wang, Jibin PuAbstract:Solid lubricant films have received considerable research attention in the last decades owing to their remarkable improved Tribological characteristics. In this paper, the abrasive wear behaviour of five types of solid lubricant films (magnetron-sputtered diamond-like carbon, magnetron-sputtered molybdenum disulfide, bonded molybdenum disulfide, bonded polytetrafluoroethylene and bonded graphite) in sand-dust environment has been investigated using a reciprocating pin-on-disc test rig. The effects of applied load, amount of sand and particle size on the Tribological performance of these films were systemically studied. Experimental results show that magnetron-sputtered films give excellent anti-friction and wear-resistance performances under sand-dust environments compared to bonded solid lubricant films. The significant differences of surface roughness, hardness, microstructure and intrinsic lubricating property directly lead to the different Tribological performances and worn morphology. The formed composite transfer layer plays a vital role in reducing friction and wear due to its anti-friction and shielding action of the film surface from the hard metal asperities. Two main abrasive wear mechanisms (three-body rolling wear and two-body grooving wear) occur simultaneously in the Tribological Process under sand-dust environments. A transfer layer-hardening composite wear modeling was established to further explain the anti-wear mechanisms and friction-reducing capacity of these solid lubricant films under sand-dust environments.
Braham Prakash - One of the best experts on this subject based on the ideXlab platform.
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high temperature friction and wear behaviour of different tool steels during sliding against al si coated high strength steel
Tribology International, 2008Co-Authors: Jens Hardell, Braham PrakashAbstract:Abstract The recent years have witnessed an increasing usage of high-strength steels as structural reinforcements and in energy-absorbing systems in automobile applications due to their favourable high-strength-to-weight ratios. Owing to poor formability, complex-shaped high-strength steel components are invariably produced through hot-metal forming. The high-strength steel sheets are in some instances used with an Al–Si-coating with a view to prevent scaling of components during hot-metal forming. However, friction and wear characteristics of Al–Si-coated high-strength steel during interaction with different tool steels have not yet been investigated. With this in view, friction and wear behaviours of different tool steels sliding against Al–Si-coated high-strength steel at elevated temperatures have been investigated by using a high-temperature version of the Optimol SRV reciprocating friction and wear tester at temperatures of 40, 400 and 800 °C. In these studies both temperature ramp tests with continuously increasing temperature from 40 to 800 °C and constant temperature tests at 40, 400 and 800 °C, have been conducted. The results have shown that both the friction and wear of tool steel/Al–Si-coated high-strength steel pairs are temperature dependent. Friction decreased with increasing temperature whereas wear of the tool steel increased with temperature. On the other hand, the Al–Si-coated high-strength steel showed significantly lower wear rates at 800 °C as compared to those at 40 and 400 °C. The Al–Si-coated surface undergoes some interesting morphological changes when exposed to elevated temperatures and these changes may affect the friction and wear characteristics. The mechanisms of these changes and their influence on the Tribological Process are unclear and further studies are necessary to fully explain these mechanisms.
Chiangsan Chen - One of the best experts on this subject based on the ideXlab platform.
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Tribological Process induced conformational transformation of protein may change the friction of cartilage
Materials Letters, 2007Co-Authors: Chihhung Chang, Hsuwei Fang, Hueiting Huang, Manching Hsieh, Chiangsan ChenAbstract:In-vitro testing procedures have been successfully developed to investigate the effects of Tribological Process induced transformation of protein-based lubricant on the friction change of articular cartilages. Serum and albumin solutions were the biological lubricants used in this study. The results indicated that the lubricating ability for cartilages deteriorates after the biological lubricants were articulated between polyethylene and stainless steel materials. In addition, the secondary structure change of the albumin molecule has been characterized after the molecules were articulated by the artificial joint materials. We have provided evidence that the conformational change of protein lubricants leads to the friction increase of articular cartilage.
Hsuwei Fang - One of the best experts on this subject based on the ideXlab platform.
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Investigation of the friction induced conformational change of protein and wear of UHMWPE by a wear Process with microfabricated surfaces
Materials Science and Engineering: C, 2009Co-Authors: Hsuwei Fang, Hueiting Huang, Yu-chih Su, Wei-bor TsaiAbstract:Abstract An accelerated wear testing procedure was developed to carry out an articulation Process between UHWMPE and microfabricated surfaces with controlled asperities. By such a design, the effect of lubricant on wear of UHMWPE can be scaled-up and measured within a short duration of the test. The most abundant composition of the synovial fluid–human serum albumin was employed as a lubricant. Analysis of the albumin protein structure by a circular dichroism (CD) spectroscopy was proceeded to detect the conformational change during a Tribological Process. We observed that the thinner and fibril-like wear particles were found in biological lubricants than the particle generated in water. Our results also indicated that the content of α-helix structure of albumin was decreased after the Tribological Process. The denatured albumin solution resulted in the decrease of UHMWPE wear rate. It may be due to the decrease of the contact angle of unfolding albumin protein on articulating surfaces. It implies a larger coverage of the lubricating molecules on the UHMWPE surface. The relevance of the Tribological Process induced conformational change and wear of UHWMPE were discussed in this study.
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Tribological Process induced conformational transformation of protein may change the friction of cartilage
Materials Letters, 2007Co-Authors: Chihhung Chang, Hsuwei Fang, Hueiting Huang, Manching Hsieh, Chiangsan ChenAbstract:In-vitro testing procedures have been successfully developed to investigate the effects of Tribological Process induced transformation of protein-based lubricant on the friction change of articular cartilages. Serum and albumin solutions were the biological lubricants used in this study. The results indicated that the lubricating ability for cartilages deteriorates after the biological lubricants were articulated between polyethylene and stainless steel materials. In addition, the secondary structure change of the albumin molecule has been characterized after the molecules were articulated by the artificial joint materials. We have provided evidence that the conformational change of protein lubricants leads to the friction increase of articular cartilage.
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Frictional characteristics of the Tribological unfolding albumin for polyethylene and cartilage
Chemical Physics Letters, 2006Co-Authors: Charng-bin Yang, Chihhung Chang, Hsuwei Fang, Manching Hsieh, Hueiting HuangAbstract:Studies were carried out to investigate the effect of Tribological Process induced conformational change of human serum albumin on the frictional characteristics. Albumin acts as the interfacial molecule in the boundary lubrication regime. The results indicate that a decrease of α-helical content and an unfolding of the secondary structure of albumin are possibly induced by the frictional heat of UHMWPE-steel articulation Process. The conformational change of albumin differentiates the frictional characteristics for polyethylene and cartilages. A model describing the frictional features of the conformational change of albumin on the hydrophilic cartilage and the hydrophobic UHMWPE was proposed.
Jianwei Qi - One of the best experts on this subject based on the ideXlab platform.
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the Tribological performance of selected solid lubricant films in sand dust environments
Wear, 2011Co-Authors: Jianwei Qi, Yunfeng Wang, Liping Wang, Jibin PuAbstract:Solid lubricant films have received considerable research attention in the last decades owing to their remarkable improved Tribological characteristics. In this paper, the abrasive wear behaviour of five types of solid lubricant films (magnetron-sputtered diamond-like carbon, magnetron-sputtered molybdenum disulfide, bonded molybdenum disulfide, bonded polytetrafluoroethylene and bonded graphite) in sand-dust environment has been investigated using a reciprocating pin-on-disc test rig. The effects of applied load, amount of sand and particle size on the Tribological performance of these films were systemically studied. Experimental results show that magnetron-sputtered films give excellent anti-friction and wear-resistance performances under sand-dust environments compared to bonded solid lubricant films. The significant differences of surface roughness, hardness, microstructure and intrinsic lubricating property directly lead to the different Tribological performances and worn morphology. The formed composite transfer layer plays a vital role in reducing friction and wear due to its anti-friction and shielding action of the film surface from the hard metal asperities. Two main abrasive wear mechanisms (three-body rolling wear and two-body grooving wear) occur simultaneously in the Tribological Process under sand-dust environments. A transfer layer-hardening composite wear modeling was established to further explain the anti-wear mechanisms and friction-reducing capacity of these solid lubricant films under sand-dust environments.
