The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
S Aravindan - One of the best experts on this subject based on the ideXlab platform.
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tribological performance of Microwave sintered copper tic graphite hybrid composites
Tribology International, 2011Co-Authors: K Rajkumar, S AravindanAbstract:Abstract Copper matrix composites are finding many applications due to their inherent properties such as good electrical and thermal conductivity and corrosion resistance. New series of copper–TiC (5–15 vol%)–graphite (5–10 vol%) hybrid composites are fabricated through a novel Microwave Processing technique. Pin-on-disc is used to evaluate their tribological properties under testing parameters of normal loads 12–48 N and sliding speed of 1.25–2.51 m/s. The formation of mixed smooth layer with higher graphite hybrid composites improves the wear resistance and reduces the friction coefficient. Morphology of worn out surfaces and wear debris were analyzed to understand the wear mechanisms.
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fabrication of copper tic graphite hybrid metal matrix composites through Microwave Processing
The International Journal of Advanced Manufacturing Technology, 2010Co-Authors: Reddy G Chandrakanth, K Rajkumar, S AravindanAbstract:The significant requirements such as wear resistance and better tribological properties in addition to good electrical conductivity necessitate the development of copper-based advanced metal matrix composites for electrical sliding contact applications. Though the addition of graphite to copper matrix induces self-lubricating property, the strength of the composite reduces. The improvement in the strength of the composite can be achieved by reinforcing harder ceramic particles such as SiC, TiC, and Al2O3. In this paper, the development of hybrid composite of copper metal matrix reinforced with TiC and graphite particles through Microwave Processing was investigated. The effects of TiC (5, 10, and 15 vol.%) and graphite (5 and 10 vol.%) reinforcements on physical and mechanical properties of Microwave-sintered copper–TiC–graphite hybrid composites are discussed in detail. Micrographs show the uniform distribution of reinforcements in copper matrix. Microwave-sintered composites exhibited higher relative density, sintered density, and hardness compared with conventionally sintered ones.
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Microwave sintering of copper graphite composites
Journal of Materials Processing Technology, 2009Co-Authors: K Rajkumar, S AravindanAbstract:Abstract Microwave Processing is a distinctive and alternative technique when compared with the available processes such as material synthesis, sintering, and Processing utilizing the conventional heating sources. Owing to Microwave–material molecular interaction, Microwave heating is of internal and faster. This results in improved quality of the product with time and energy savings. Metal at its bulk form reflects Microwaves; however in its powder form, it couples with Microwaves. This work emphasizes on the development of copper–graphite metal matrix composite for electrical sliding contact applications through Microwave hybrid heating (2.45 GHz, 3.2 kW). The fabricated composites were tested for their mechanical properties such as porosity, relative density and hardness. Microstructural aspects were studied through SEM.
Oliver C Kappe - One of the best experts on this subject based on the ideXlab platform.
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rapid nickel catalyzed suzuki miyaura cross couplings of aryl carbamates and sulfamates utilizing Microwave heating
Journal of Organic Chemistry, 2011Co-Authors: Mostafa Baghbanzadeh, Christian Pilger, Oliver C KappeAbstract:High-speed and scalable nickel-catalyzed cross-coupling of arylboronic acids with aryl carbamates and sulfamates is achieved by using sealed-vessel Microwave Processing.
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on the energy efficiency of Microwave assisted organic reactions
Chemsuschem, 2008Co-Authors: Tahseen Razzaq, Oliver C KappeAbstract:The energy consumed for four different organic transformations carried out under Microwave and conventional heating under otherwise identical reaction conditions was measured with the aid of a Wattmeter. In the case of open-vessel reflux Processing, Microwave dielectric heating required significantly more energy than conventional techniques using oil baths or heating mantles. This is a consequence of the comparably low energy efficiency of the magnetron in converting electrical to Microwave energy. Significant savings in energy were experienced by taking advantage of sealed-vessel Microwave Processing at high temperatures. When comparing a conventionally heated reflux experiment with a Microwave-heated experiment using a superheated solvent in a sealed vessel, reaction times were reduced significantly from hours to minutes. The energy savings in these instances are, however, largely connected to the reduced reaction time and are not an inherent feature of Microwave heating.
K Rajkumar - One of the best experts on this subject based on the ideXlab platform.
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tribological performance of Microwave sintered copper tic graphite hybrid composites
Tribology International, 2011Co-Authors: K Rajkumar, S AravindanAbstract:Abstract Copper matrix composites are finding many applications due to their inherent properties such as good electrical and thermal conductivity and corrosion resistance. New series of copper–TiC (5–15 vol%)–graphite (5–10 vol%) hybrid composites are fabricated through a novel Microwave Processing technique. Pin-on-disc is used to evaluate their tribological properties under testing parameters of normal loads 12–48 N and sliding speed of 1.25–2.51 m/s. The formation of mixed smooth layer with higher graphite hybrid composites improves the wear resistance and reduces the friction coefficient. Morphology of worn out surfaces and wear debris were analyzed to understand the wear mechanisms.
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fabrication of copper tic graphite hybrid metal matrix composites through Microwave Processing
The International Journal of Advanced Manufacturing Technology, 2010Co-Authors: Reddy G Chandrakanth, K Rajkumar, S AravindanAbstract:The significant requirements such as wear resistance and better tribological properties in addition to good electrical conductivity necessitate the development of copper-based advanced metal matrix composites for electrical sliding contact applications. Though the addition of graphite to copper matrix induces self-lubricating property, the strength of the composite reduces. The improvement in the strength of the composite can be achieved by reinforcing harder ceramic particles such as SiC, TiC, and Al2O3. In this paper, the development of hybrid composite of copper metal matrix reinforced with TiC and graphite particles through Microwave Processing was investigated. The effects of TiC (5, 10, and 15 vol.%) and graphite (5 and 10 vol.%) reinforcements on physical and mechanical properties of Microwave-sintered copper–TiC–graphite hybrid composites are discussed in detail. Micrographs show the uniform distribution of reinforcements in copper matrix. Microwave-sintered composites exhibited higher relative density, sintered density, and hardness compared with conventionally sintered ones.
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Microwave sintering of copper graphite composites
Journal of Materials Processing Technology, 2009Co-Authors: K Rajkumar, S AravindanAbstract:Abstract Microwave Processing is a distinctive and alternative technique when compared with the available processes such as material synthesis, sintering, and Processing utilizing the conventional heating sources. Owing to Microwave–material molecular interaction, Microwave heating is of internal and faster. This results in improved quality of the product with time and energy savings. Metal at its bulk form reflects Microwaves; however in its powder form, it couples with Microwaves. This work emphasizes on the development of copper–graphite metal matrix composite for electrical sliding contact applications through Microwave hybrid heating (2.45 GHz, 3.2 kW). The fabricated composites were tested for their mechanical properties such as porosity, relative density and hardness. Microstructural aspects were studied through SEM.
Tiensheng Chao - One of the best experts on this subject based on the ideXlab platform.
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Susceptor Coupling for the Uniformity and Dopant Activation Efficiency in Implanted Si Under Fixed-Frequency Microwave Anneal
2016Co-Authors: Yaojen Lee, Fukuo Hsueh, Michael I Current, Tiensheng ChaoAbstract:Abstract—Microwave annealing of dopants in Si has been re-ported to produce highly activated junctions at temperatures far below those needed for comparable results using conventional thermal processes. However, during conventional fixed-frequency Microwave heating, standing wave patterns can be established in the Microwave Processing chamber, resulting in nodes and antinodes over the Processing area, resulting in thermal variations over the process wafer. In this letter, the effects of Si or quartz susceptor wafers on dopant activation and sheet resistance unifor-mity during fixed-frequency Microwave anneal are studied. The composition, number, and spacing of susceptor wafers were varied in a systematic fashion in these experiments. Index Terms—Coupling effect, low temperature, Microwave an-neal, phosphorus, quartz
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susceptor coupling for the uniformity and dopant activation efficiency in implanted si under fixed frequency Microwave anneal
IEEE Electron Device Letters, 2012Co-Authors: Yaojen Lee, Fukuo Hsueh, Michael I Current, Tiensheng ChaoAbstract:Microwave annealing of dopants in Si has been reported to produce highly activated junctions at temperatures far below those needed for comparable results using conventional thermal processes. However, during conventional fixed-frequency Microwave heating, standing wave patterns can be established in the Microwave Processing chamber, resulting in nodes and antinodes over the Processing area, resulting in thermal variations over the process wafer. In this letter, the effects of Si or quartz susceptor wafers on dopant activation and sheet resistance uniformity during fixed-frequency Microwave anneal are studied. The composition, number, and spacing of susceptor wafers were varied in a systematic fashion in these experiments.
S K Seshadri - One of the best experts on this subject based on the ideXlab platform.
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in situ composite coating of titania hydroxyapatite on commercially pure titanium by Microwave Processing
Surface & Coatings Technology, 2010Co-Authors: A Siddharthan, T Sampath S Kumar, S K SeshadriAbstract:Abstract Microwave (MW) Processing has been studied as an alternative method of hydroxyapatite (HA) based composite coatings on commercially pure titanium (CPTi) to enhance the bioactivity for orthopaedic and dental implant applications. The coating was formed by Processing CPTi metal packed in HA and at 800 W Microwave power for 22 min. The composition of the coating was found to be TiO 2 (rutile) as major phase along with HA as minor phase. The MW absorption of non-stoichiometric TiO 2 layer, which was grown during the initial hybrid heating, resulted in sintering of apatite particles interfacing them. The non-stoichiometric nature of TiO 2 was evident from the observed mid-gap bands in ultraviolet–visible diffusive reflectance (UV–VIS-DR) spectrum. The lamellar α structure of the substrate suggests that the Processing temperature was above β transus of CPTi (1155 K). The oxygen stabilized α phase whose thickness increased with Microwave Processing time, was likely to be the reason for the increase in Young's Modulus and hardness of the substrate. The coating induced apatite precipitation in bioactivity test. The osteoblast cell adhesion test demonstrated cell spreading which is considered favourable for cell proliferation and differentiation. Thus, in situ composite coating of titania and HA on CPTi was obtained by a simple one-step process.