The Experts below are selected from a list of 240 Experts worldwide ranked by ideXlab platform
Petr Vašina - One of the best experts on this subject based on the ideXlab platform.
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Automatic and robust deposition process control to grow hard ncTiC/a-C:H coatings using industrial magnetron sputtering devices and tribological analysis of the titanium-carbon coatings
2015Co-Authors: Radek Žemlička, Milan Jilek, Petr Vogl, Vilma Buršíková, Pavel Souček, Petr VašinaAbstract:nc-TiC/a-C:H coatings consist of TiC crystallites embedded in an amorphous hydrogenated carbon matrix. Depending mainly on the chemical composition, the properties of these coatings can be tailored from hard coatings, with hardness of greater than 35 GPa to tribological coatings, with coefficients of friction lower than 0.1. In our research, we employed industrial PVD device of Platit equipped with a central titanium rotating cylindrical cathode. Titanium was sputtered in a mixture of argon and Acetylene. At critical Acetylene supply, a sudden drop in the cathode voltage was observed. This sudden change in the plasma parameters was mirrored in chemical composition and mechanical properties of the deposited coatings. Close to critical Acetylene supply, the highest coating hardness of 35 GPa was obtained. The critical acatylene supply shifts as the target get eroded. In our work, we suggest the fully automatic, robust and reliable procedure to deposit hard nc-TiC/a-C:H coatings using the occurrence of the sudden plasma parameters change at critical Acetylene supply to set the optimal deposition conditions. Further, the tribological analysis of the series of the titaniumcarbon coatings with different amount of amorphous carbon was carried out. We discovered, that the coefficient of friction strongly depends on humidity of the environment and we found, that the changes of the CoF during the tribological measurements are caused by the changes of the surface roughness.
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automatic and robust deposition process control to grow hard nctic a c h coatings using industrial magnetron sputtering devices and tribological analysis of the titanium carbon coatings
E-MRS 2015 Spring meeting: Symposium EE Protective coatings and thin films, 2015Co-Authors: Radek Žemlička, Milan Jilek, Petr Vogl, Vilma Buršíková, Pavel Souček, Petr VašinaAbstract:nc-TiC/a-C:H coatings consist of TiC crystallites embedded in an amorphous hydrogenated carbon matrix. Depending mainly on the chemical composition, the properties of these coatings can be tailored from hard coatings, with hardness of greater than 35 GPa to tribological coatings, with coefficients of friction lower than 0.1. In our research, we employed industrial PVD device of Platit equipped with a central titanium rotating cylindrical cathode. Titanium was sputtered in a mixture of argon and Acetylene. At critical Acetylene supply, a sudden drop in the cathode voltage was observed. This sudden change in the plasma parameters was mirrored in chemical composition and mechanical properties of the deposited coatings. Close to critical Acetylene supply, the highest coating hardness of 35 GPa was obtained. The critical acatylene supply shifts as the target get eroded. In our work, we suggest the fully automatic, robust and reliable procedure to deposit hard nc-TiC/a-C:H coatings using the occurrence of the sudden plasma parameters change at critical Acetylene supply to set the optimal deposition conditions. Further, the tribological analysis of the series of the titaniumcarbon coatings with different amount of amorphous carbon was carried out. We discovered, that the coefficient of friction strongly depends on humidity of the environment and we found, that the changes of the CoF during the tribological measurements are caused by the changes of the surface roughness.
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Automatic and robust deposition process control to grow hard nc-TiC/a-C:H coatings using industrial magnetron sputtering devices
2014Co-Authors: Radek Žemlička, Milan Jilek, Petr Vogl, Vilma Buršíková, Pavel Souček, Petr VašinaAbstract:nc-TiC/a-C:H coatings consist of TiC crystallites embedded in an amorphous hydrogenated carbon matrix. Depending mainly on the chemical composition (ratio of Ti/C), the properties of these coatings can be tailored from hard coatings to tribological coatings, with low coefficients of friction and wear. However none of the major industrial coating centers offer this coating in their portfolio, probably because of the lack of the reliable deposition technology. In our research, we employed industrial PVD device of Platit equipped with a central titanium rotating cylindrical cathode. Titanium was sputtered in a mixture of argon and Acetylene. When the Acetylene supply was gradually increased, deposition process characteristics such as the cathode voltage and the total pressure in the deposition chamber underwent a sudden change. At critical Acetylene supply, a sudden drop in the cathode voltage was observed, while before and after the drop, the cathode voltage evolved slowly. This sudden change in the plasma parameters was mirrored in chemical composition and mechanical properties of the deposited coatings. Close to critical Acetylene supply, the highest coating hardness of 35 GPa was obtained. The critical acatylene supply shifts as the target gets eroded. In our work, we suggest the fully automatic, robust and reliable procedure to deposit hard nc-TiC/a-C:H coatings using the occurrence of the sudden plasma parameters change at critical Acetylene supply to set the optimal deposition conditions. The procedure automatically controls the Acetylene supply as a function of the cathode voltage and the pressure evolution. The process control was tested for different states of the target erosion and different chamber configurations.
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automatic and robust deposition process control to grow hard nc tic a c h coatings using industrial magnetron sputtering devices
2014Co-Authors: Radek Žemlička, Milan Jilek, Petr Vogl, Vilma Buršíková, Pavel Souček, Petr VašinaAbstract:nc-TiC/a-C:H coatings consist of TiC crystallites embedded in an amorphous hydrogenated carbon matrix. Depending mainly on the chemical composition (ratio of Ti/C), the properties of these coatings can be tailored from hard coatings to tribological coatings, with low coefficients of friction and wear. However none of the major industrial coating centers offer this coating in their portfolio, probably because of the lack of the reliable deposition technology. In our research, we employed industrial PVD device of Platit equipped with a central titanium rotating cylindrical cathode. Titanium was sputtered in a mixture of argon and Acetylene. When the Acetylene supply was gradually increased, deposition process characteristics such as the cathode voltage and the total pressure in the deposition chamber underwent a sudden change. At critical Acetylene supply, a sudden drop in the cathode voltage was observed, while before and after the drop, the cathode voltage evolved slowly. This sudden change in the plasma parameters was mirrored in chemical composition and mechanical properties of the deposited coatings. Close to critical Acetylene supply, the highest coating hardness of 35 GPa was obtained. The critical acatylene supply shifts as the target gets eroded. In our work, we suggest the fully automatic, robust and reliable procedure to deposit hard nc-TiC/a-C:H coatings using the occurrence of the sudden plasma parameters change at critical Acetylene supply to set the optimal deposition conditions. The procedure automatically controls the Acetylene supply as a function of the cathode voltage and the pressure evolution. The process control was tested for different states of the target erosion and different chamber configurations.
Marek Chmielewski - One of the best experts on this subject based on the ideXlab platform.
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Direct, Catalytic Synthesis of Carbapenams via Cycloaddition/Rearrangement Cascade Reaction: Unexpected Acetylenes’ Structure Effect
Journal of Organic Chemistry, 2010Co-Authors: Adam Mames, Sebastian Stecko, Bartłomiej Furman, Paulina Mikolajczyk, Magdalena Soluch, Marek ChmielewskiAbstract:Reactions of Acetylenes derived from glyceraldehyde and propargyl aldehyde show remarkable reactivity in Kinugasa cycloaddition/rearrangement cascade process catalyzed by Cu(I) ion. Reactions proceed by formation of a rigid dinuclear copper(I) complex in which each copper ion is coordinated to one or both oxygen atoms in the Acetylene molecule and to both triple bonds. It has been demonstrated that one oxygen atom can be replaced by the phenyl ring, which is able to coordinate the copper ion by the aromatic sextet. Kinugasa reactions that proceed in a high yield can also be performed in the presence of a catalytic amount of the copper salt to provide products in an acceptable yield without a decrease of diastereoselectivity.
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direct catalytic synthesis of carbapenams via cycloaddition rearrangement cascade reaction unexpected Acetylenes structure effect
Journal of Organic Chemistry, 2010Co-Authors: Adam Mames, Sebastian Stecko, Paulina Mikolajczyk, Magdalena Soluch, Bartlomiej Furman, Marek ChmielewskiAbstract:Reactions of Acetylenes derived from glyceraldehyde and propargyl aldehyde show remarkable reactivity in Kinugasa cycloaddition/rearrangement cascade process catalyzed by Cu(I) ion. Reactions proceed by formation of a rigid dinuclear copper(I) complex in which each copper ion is coordinated to one or both oxygen atoms in the Acetylene molecule and to both triple bonds. It has been demonstrated that one oxygen atom can be replaced by the phenyl ring, which is able to coordinate the copper ion by the aromatic sextet. Kinugasa reactions that proceed in a high yield can also be performed in the presence of a catalytic amount of the copper salt to provide products in an acceptable yield without a decrease of diastereoselectivity.
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Asymmetric Kinugasa reaction of cyclic nitrones and nonracemic Acetylenes.
Journal of Organic Chemistry, 2009Co-Authors: Sebastian Stecko, Adam Mames, Bartłomiej Furman, Marek ChmielewskiAbstract:Kinugasa reactions between chiral Acetylenes and five-membered nitrones, achiral and bearing a stereogenic center in both enantiomeric forms, proceed in moderate to good yield with high diastereoselectivity affording mostly one dominant product. The first step of the reaction is controlled by the configuration of the nitrone, whereas the protonation of intermediate enolate in the second step depends mainly on the configuration of the bridgehead carbon atom formed in the first step. In the case of the mismatched pair, the configuration at the C-6 center of the carbapenam skeleton may also be affected by the configuration of the stereogenic center in the Acetylene portion.
Radek Žemlička - One of the best experts on this subject based on the ideXlab platform.
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Automatic and robust deposition process control to grow hard ncTiC/a-C:H coatings using industrial magnetron sputtering devices and tribological analysis of the titanium-carbon coatings
2015Co-Authors: Radek Žemlička, Milan Jilek, Petr Vogl, Vilma Buršíková, Pavel Souček, Petr VašinaAbstract:nc-TiC/a-C:H coatings consist of TiC crystallites embedded in an amorphous hydrogenated carbon matrix. Depending mainly on the chemical composition, the properties of these coatings can be tailored from hard coatings, with hardness of greater than 35 GPa to tribological coatings, with coefficients of friction lower than 0.1. In our research, we employed industrial PVD device of Platit equipped with a central titanium rotating cylindrical cathode. Titanium was sputtered in a mixture of argon and Acetylene. At critical Acetylene supply, a sudden drop in the cathode voltage was observed. This sudden change in the plasma parameters was mirrored in chemical composition and mechanical properties of the deposited coatings. Close to critical Acetylene supply, the highest coating hardness of 35 GPa was obtained. The critical acatylene supply shifts as the target get eroded. In our work, we suggest the fully automatic, robust and reliable procedure to deposit hard nc-TiC/a-C:H coatings using the occurrence of the sudden plasma parameters change at critical Acetylene supply to set the optimal deposition conditions. Further, the tribological analysis of the series of the titaniumcarbon coatings with different amount of amorphous carbon was carried out. We discovered, that the coefficient of friction strongly depends on humidity of the environment and we found, that the changes of the CoF during the tribological measurements are caused by the changes of the surface roughness.
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automatic and robust deposition process control to grow hard nctic a c h coatings using industrial magnetron sputtering devices and tribological analysis of the titanium carbon coatings
E-MRS 2015 Spring meeting: Symposium EE Protective coatings and thin films, 2015Co-Authors: Radek Žemlička, Milan Jilek, Petr Vogl, Vilma Buršíková, Pavel Souček, Petr VašinaAbstract:nc-TiC/a-C:H coatings consist of TiC crystallites embedded in an amorphous hydrogenated carbon matrix. Depending mainly on the chemical composition, the properties of these coatings can be tailored from hard coatings, with hardness of greater than 35 GPa to tribological coatings, with coefficients of friction lower than 0.1. In our research, we employed industrial PVD device of Platit equipped with a central titanium rotating cylindrical cathode. Titanium was sputtered in a mixture of argon and Acetylene. At critical Acetylene supply, a sudden drop in the cathode voltage was observed. This sudden change in the plasma parameters was mirrored in chemical composition and mechanical properties of the deposited coatings. Close to critical Acetylene supply, the highest coating hardness of 35 GPa was obtained. The critical acatylene supply shifts as the target get eroded. In our work, we suggest the fully automatic, robust and reliable procedure to deposit hard nc-TiC/a-C:H coatings using the occurrence of the sudden plasma parameters change at critical Acetylene supply to set the optimal deposition conditions. Further, the tribological analysis of the series of the titaniumcarbon coatings with different amount of amorphous carbon was carried out. We discovered, that the coefficient of friction strongly depends on humidity of the environment and we found, that the changes of the CoF during the tribological measurements are caused by the changes of the surface roughness.
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Automatic and robust deposition process control to grow hard nc-TiC/a-C:H coatings using industrial magnetron sputtering devices
2014Co-Authors: Radek Žemlička, Milan Jilek, Petr Vogl, Vilma Buršíková, Pavel Souček, Petr VašinaAbstract:nc-TiC/a-C:H coatings consist of TiC crystallites embedded in an amorphous hydrogenated carbon matrix. Depending mainly on the chemical composition (ratio of Ti/C), the properties of these coatings can be tailored from hard coatings to tribological coatings, with low coefficients of friction and wear. However none of the major industrial coating centers offer this coating in their portfolio, probably because of the lack of the reliable deposition technology. In our research, we employed industrial PVD device of Platit equipped with a central titanium rotating cylindrical cathode. Titanium was sputtered in a mixture of argon and Acetylene. When the Acetylene supply was gradually increased, deposition process characteristics such as the cathode voltage and the total pressure in the deposition chamber underwent a sudden change. At critical Acetylene supply, a sudden drop in the cathode voltage was observed, while before and after the drop, the cathode voltage evolved slowly. This sudden change in the plasma parameters was mirrored in chemical composition and mechanical properties of the deposited coatings. Close to critical Acetylene supply, the highest coating hardness of 35 GPa was obtained. The critical acatylene supply shifts as the target gets eroded. In our work, we suggest the fully automatic, robust and reliable procedure to deposit hard nc-TiC/a-C:H coatings using the occurrence of the sudden plasma parameters change at critical Acetylene supply to set the optimal deposition conditions. The procedure automatically controls the Acetylene supply as a function of the cathode voltage and the pressure evolution. The process control was tested for different states of the target erosion and different chamber configurations.
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automatic and robust deposition process control to grow hard nc tic a c h coatings using industrial magnetron sputtering devices
2014Co-Authors: Radek Žemlička, Milan Jilek, Petr Vogl, Vilma Buršíková, Pavel Souček, Petr VašinaAbstract:nc-TiC/a-C:H coatings consist of TiC crystallites embedded in an amorphous hydrogenated carbon matrix. Depending mainly on the chemical composition (ratio of Ti/C), the properties of these coatings can be tailored from hard coatings to tribological coatings, with low coefficients of friction and wear. However none of the major industrial coating centers offer this coating in their portfolio, probably because of the lack of the reliable deposition technology. In our research, we employed industrial PVD device of Platit equipped with a central titanium rotating cylindrical cathode. Titanium was sputtered in a mixture of argon and Acetylene. When the Acetylene supply was gradually increased, deposition process characteristics such as the cathode voltage and the total pressure in the deposition chamber underwent a sudden change. At critical Acetylene supply, a sudden drop in the cathode voltage was observed, while before and after the drop, the cathode voltage evolved slowly. This sudden change in the plasma parameters was mirrored in chemical composition and mechanical properties of the deposited coatings. Close to critical Acetylene supply, the highest coating hardness of 35 GPa was obtained. The critical acatylene supply shifts as the target gets eroded. In our work, we suggest the fully automatic, robust and reliable procedure to deposit hard nc-TiC/a-C:H coatings using the occurrence of the sudden plasma parameters change at critical Acetylene supply to set the optimal deposition conditions. The procedure automatically controls the Acetylene supply as a function of the cathode voltage and the pressure evolution. The process control was tested for different states of the target erosion and different chamber configurations.
Adam Mames - One of the best experts on this subject based on the ideXlab platform.
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Direct, Catalytic Synthesis of Carbapenams via Cycloaddition/Rearrangement Cascade Reaction: Unexpected Acetylenes’ Structure Effect
Journal of Organic Chemistry, 2010Co-Authors: Adam Mames, Sebastian Stecko, Bartłomiej Furman, Paulina Mikolajczyk, Magdalena Soluch, Marek ChmielewskiAbstract:Reactions of Acetylenes derived from glyceraldehyde and propargyl aldehyde show remarkable reactivity in Kinugasa cycloaddition/rearrangement cascade process catalyzed by Cu(I) ion. Reactions proceed by formation of a rigid dinuclear copper(I) complex in which each copper ion is coordinated to one or both oxygen atoms in the Acetylene molecule and to both triple bonds. It has been demonstrated that one oxygen atom can be replaced by the phenyl ring, which is able to coordinate the copper ion by the aromatic sextet. Kinugasa reactions that proceed in a high yield can also be performed in the presence of a catalytic amount of the copper salt to provide products in an acceptable yield without a decrease of diastereoselectivity.
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direct catalytic synthesis of carbapenams via cycloaddition rearrangement cascade reaction unexpected Acetylenes structure effect
Journal of Organic Chemistry, 2010Co-Authors: Adam Mames, Sebastian Stecko, Paulina Mikolajczyk, Magdalena Soluch, Bartlomiej Furman, Marek ChmielewskiAbstract:Reactions of Acetylenes derived from glyceraldehyde and propargyl aldehyde show remarkable reactivity in Kinugasa cycloaddition/rearrangement cascade process catalyzed by Cu(I) ion. Reactions proceed by formation of a rigid dinuclear copper(I) complex in which each copper ion is coordinated to one or both oxygen atoms in the Acetylene molecule and to both triple bonds. It has been demonstrated that one oxygen atom can be replaced by the phenyl ring, which is able to coordinate the copper ion by the aromatic sextet. Kinugasa reactions that proceed in a high yield can also be performed in the presence of a catalytic amount of the copper salt to provide products in an acceptable yield without a decrease of diastereoselectivity.
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Asymmetric Kinugasa reaction of cyclic nitrones and nonracemic Acetylenes.
Journal of Organic Chemistry, 2009Co-Authors: Sebastian Stecko, Adam Mames, Bartłomiej Furman, Marek ChmielewskiAbstract:Kinugasa reactions between chiral Acetylenes and five-membered nitrones, achiral and bearing a stereogenic center in both enantiomeric forms, proceed in moderate to good yield with high diastereoselectivity affording mostly one dominant product. The first step of the reaction is controlled by the configuration of the nitrone, whereas the protonation of intermediate enolate in the second step depends mainly on the configuration of the bridgehead carbon atom formed in the first step. In the case of the mismatched pair, the configuration at the C-6 center of the carbapenam skeleton may also be affected by the configuration of the stereogenic center in the Acetylene portion.
Banglin Chen - One of the best experts on this subject based on the ideXlab platform.
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microporous metal organic frameworks for Acetylene storage and separation
CrystEngComm, 2011Co-Authors: Zhangjing Zhang, Shengchang Xiang, Banglin ChenAbstract:Acetylene is an important starting material in the petrochemical and electronic industry for various industrial and consumer products, and a promising alternative energy source for future Acetylene fuel cell vehicles. Porous metal–organic frameworks have been demonstrated as very practical useful materials for Acetylene storage and separation which might provide the solid resolution for the safe storage and transportation of Acetylene. Because of the explosive nature of Acetylene, strong interactions of the pore surfaces with Acetylene are very important to realize high Acetylene storage MOFs at room temperature and low pressure, which can be fulfilled by the immobilization of open metal sites. Microporous MOFs having high adsorption affinity and matchable pore size with Acetylene molecules have been realized to exhibit high selective C2H2/CO2, C2H2/CH4 and C2H2/C2H4 separation.
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exceptionally high Acetylene uptake in a microporous metal organic framework with open metal sites
Journal of the American Chemical Society, 2009Co-Authors: Shengchang Xiang, Wei Zhou, Jose M Gallegos, Yun Liu, Banglin ChenAbstract:Six prototype microporous metal−organic frameworks (MOFs) HKUST-1, MOF-505, MOF-508, MIL-53, MOF-5, and ZIF-8 with variable structures and porosities were examined for their Acetylene storage, highlighting HKUST-1 as the highest Acetylene storage material ever reported with an uptake of 201 cm3/g at 295 K and 1 atm. To locate the Acetylene binding sites within HKUST-1, neutron powder diffraction studies on Acetylene loaded HKUST-1 were carried out and have conclusively established the significant contribution of open Cu2+ sites for Acetylene storage by their strong preferred interactions with Acetylene molecules. The binding properties of Acetylene gas at different sites were further investigated by first-principles calculations.
