The Experts below are selected from a list of 4281 Experts worldwide ranked by ideXlab platform
Johanna Rosen - One of the best experts on this subject based on the ideXlab platform.
-
macroparticle generation in dc arc discharge from a wc cathode
Journal of Applied Physics, 2017Co-Authors: Igor Zhirkov, Szilard Kolozsvari, Peter Polcik, Johanna RosenAbstract:We have studied macroparticle generation from a tungsten carbide cathode used in a dc vacuum arc discharge. Despite a relatively high decomposition/melting point (∼3100 K), there is an intensive generation of visible particles with sizes in the range 20–35 μm. Visual observations during the discharge and scanning electron microscopy of the cathode surface and of collected Macroparticles indicate a new mechanism for particle formation and acceleration. Based on the W-C phase diagram, there is an intensive sublimation of carbon from the melt resulting from the cathode spot. The sublimation supports the formation of a sphere, which is accelerated upon an explosion initiated by Joule heating at the critical contact area between the sphere and the cathode body. The explosive nature of the particle acceleration is confirmed by surface features resembling the remains of a splash on the droplet surface.
-
generation of super size Macroparticles in a direct current vacuum arc discharge from a mo cu cathode
Applied Physics Letters, 2016Co-Authors: Igor Zhirkov, Andrejs Petruhins, Szilard Kolozsvari, Peter Polcik, Johanna RosenAbstract:An inherent property of cathodic arc is the generation of Macroparticles, of a typical size ranging from submicrometer up to a few tens of μm. In this work, we have studied macroparticle generation from a Mo0.78Cu0.22 cathode used in a dc vacuum arc discharge, and we present evidence for super-size Macroparticles of up to 0.7 mm in diameter. All analyzed particles are found to be rich in Mo (≥98 at. %). The particle generation is studied by visual observation of the cathode surface during arcing, by analysis of composition and geometrical features of the used cathode surface, and by examination of the generated Macroparticles with respect to shape and composition. A mechanism for super-size macroparticle generation is suggested based on observed segregated layers of Mo and Cu identified in the topmost part of the cathode surface, likely due to the discrepancy in melting and evaporation temperatures of Mo and Cu. The results are of importance for increasing the fundamental understanding of macroparticle ge...
-
vacuum arc plasma generation and thin film deposition from a tib2 cathode
Applied Physics Letters, 2015Co-Authors: Igor Zhirkov, Andrejs Petruhins, Lars-Åke Näslund, Szilard Kolozsvari, Peter Polcik, Johanna RosenAbstract:We have studied the utilization of TiB2 cathodes for thin film deposition in a DC vacuum arc system. We present a route for attaining a stable, reproducible, and fully ionized plasma flux of Ti and B by removal of the external magnetic field, which leads to dissipation of the vacuum arc discharge and an increased active surface area of the cathode. Applying a magnetic field resulted in instability and cracking, consistent with the previous reports. Plasma analysis shows average energies of 115 and 26 eV, average ion charge states of 2.1 and 1.1 for Ti and B, respectively, and a plasma ion composition of approximately 50% Ti and 50% B. This is consistent with measured resulting film composition from X-ray photoelectron spectroscopy, suggesting a negligible contribution of neutrals and Macroparticles to the film growth. Also, despite the observations of macroparticle generation, the film surface is very smooth. These results are of importance for the utilization of cathodic arc as a method for synthesis of ...
Igor Zhirkov - One of the best experts on this subject based on the ideXlab platform.
-
macroparticle generation in dc arc discharge from a wc cathode
Journal of Applied Physics, 2017Co-Authors: Igor Zhirkov, Szilard Kolozsvari, Peter Polcik, Johanna RosenAbstract:We have studied macroparticle generation from a tungsten carbide cathode used in a dc vacuum arc discharge. Despite a relatively high decomposition/melting point (∼3100 K), there is an intensive generation of visible particles with sizes in the range 20–35 μm. Visual observations during the discharge and scanning electron microscopy of the cathode surface and of collected Macroparticles indicate a new mechanism for particle formation and acceleration. Based on the W-C phase diagram, there is an intensive sublimation of carbon from the melt resulting from the cathode spot. The sublimation supports the formation of a sphere, which is accelerated upon an explosion initiated by Joule heating at the critical contact area between the sphere and the cathode body. The explosive nature of the particle acceleration is confirmed by surface features resembling the remains of a splash on the droplet surface.
-
generation of super size Macroparticles in a direct current vacuum arc discharge from a mo cu cathode
Applied Physics Letters, 2016Co-Authors: Igor Zhirkov, Andrejs Petruhins, Szilard Kolozsvari, Peter Polcik, Johanna RosenAbstract:An inherent property of cathodic arc is the generation of Macroparticles, of a typical size ranging from submicrometer up to a few tens of μm. In this work, we have studied macroparticle generation from a Mo0.78Cu0.22 cathode used in a dc vacuum arc discharge, and we present evidence for super-size Macroparticles of up to 0.7 mm in diameter. All analyzed particles are found to be rich in Mo (≥98 at. %). The particle generation is studied by visual observation of the cathode surface during arcing, by analysis of composition and geometrical features of the used cathode surface, and by examination of the generated Macroparticles with respect to shape and composition. A mechanism for super-size macroparticle generation is suggested based on observed segregated layers of Mo and Cu identified in the topmost part of the cathode surface, likely due to the discrepancy in melting and evaporation temperatures of Mo and Cu. The results are of importance for increasing the fundamental understanding of macroparticle ge...
-
vacuum arc plasma generation and thin film deposition from a tib2 cathode
Applied Physics Letters, 2015Co-Authors: Igor Zhirkov, Andrejs Petruhins, Lars-Åke Näslund, Szilard Kolozsvari, Peter Polcik, Johanna RosenAbstract:We have studied the utilization of TiB2 cathodes for thin film deposition in a DC vacuum arc system. We present a route for attaining a stable, reproducible, and fully ionized plasma flux of Ti and B by removal of the external magnetic field, which leads to dissipation of the vacuum arc discharge and an increased active surface area of the cathode. Applying a magnetic field resulted in instability and cracking, consistent with the previous reports. Plasma analysis shows average energies of 115 and 26 eV, average ion charge states of 2.1 and 1.1 for Ti and B, respectively, and a plasma ion composition of approximately 50% Ti and 50% B. This is consistent with measured resulting film composition from X-ray photoelectron spectroscopy, suggesting a negligible contribution of neutrals and Macroparticles to the film growth. Also, despite the observations of macroparticle generation, the film surface is very smooth. These results are of importance for the utilization of cathodic arc as a method for synthesis of ...
Slobodan Mitrovic - One of the best experts on this subject based on the ideXlab platform.
-
microstructural characterization and artificial aging of compo casted hybrid a356 sicp grp composites with graphite Macroparticles
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2014Co-Authors: Ilija Bobic, Aleksandar Vencl, Biljana Bobic, Jovana Ružic, Miroslav Babic, Slobodan MitrovicAbstract:Abstract Hybrid A356/SiCp/Grp composites were produced via compo-casting using the A356 aluminum alloy as the composite matrix, with silicon carbide microparticles (SiCp) and graphite Macroparticles (Grp) as reinforcements. The effect of the thixocasting process on the microstructure of a modified A356 alloy (with 0.03 mass% of strontium) was considered. The microstructures of the thixocast A356 alloy and the synthesized composite materials were examined by means of optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS) and X-ray diffraction (XRD). The fracture surfaces of the composite matrix and the composites were also analyzed. The thixocast A356 alloy and the composites were subjected to artificial aging after a solution heat treatment. Aging kinetics was followed by hardness measurements. Differential scanning calorimetry (DSC) was applied to reveal the presence of phases formed during artificial aging. The composites reached maximum hardness faster than the thixocast A356 alloy. The time required to attain peak hardness decreases with the increase in the content of particulate reinforcements.
Szilard Kolozsvari - One of the best experts on this subject based on the ideXlab platform.
-
macroparticle generation in dc arc discharge from a wc cathode
Journal of Applied Physics, 2017Co-Authors: Igor Zhirkov, Szilard Kolozsvari, Peter Polcik, Johanna RosenAbstract:We have studied macroparticle generation from a tungsten carbide cathode used in a dc vacuum arc discharge. Despite a relatively high decomposition/melting point (∼3100 K), there is an intensive generation of visible particles with sizes in the range 20–35 μm. Visual observations during the discharge and scanning electron microscopy of the cathode surface and of collected Macroparticles indicate a new mechanism for particle formation and acceleration. Based on the W-C phase diagram, there is an intensive sublimation of carbon from the melt resulting from the cathode spot. The sublimation supports the formation of a sphere, which is accelerated upon an explosion initiated by Joule heating at the critical contact area between the sphere and the cathode body. The explosive nature of the particle acceleration is confirmed by surface features resembling the remains of a splash on the droplet surface.
-
generation of super size Macroparticles in a direct current vacuum arc discharge from a mo cu cathode
Applied Physics Letters, 2016Co-Authors: Igor Zhirkov, Andrejs Petruhins, Szilard Kolozsvari, Peter Polcik, Johanna RosenAbstract:An inherent property of cathodic arc is the generation of Macroparticles, of a typical size ranging from submicrometer up to a few tens of μm. In this work, we have studied macroparticle generation from a Mo0.78Cu0.22 cathode used in a dc vacuum arc discharge, and we present evidence for super-size Macroparticles of up to 0.7 mm in diameter. All analyzed particles are found to be rich in Mo (≥98 at. %). The particle generation is studied by visual observation of the cathode surface during arcing, by analysis of composition and geometrical features of the used cathode surface, and by examination of the generated Macroparticles with respect to shape and composition. A mechanism for super-size macroparticle generation is suggested based on observed segregated layers of Mo and Cu identified in the topmost part of the cathode surface, likely due to the discrepancy in melting and evaporation temperatures of Mo and Cu. The results are of importance for increasing the fundamental understanding of macroparticle ge...
-
vacuum arc plasma generation and thin film deposition from a tib2 cathode
Applied Physics Letters, 2015Co-Authors: Igor Zhirkov, Andrejs Petruhins, Lars-Åke Näslund, Szilard Kolozsvari, Peter Polcik, Johanna RosenAbstract:We have studied the utilization of TiB2 cathodes for thin film deposition in a DC vacuum arc system. We present a route for attaining a stable, reproducible, and fully ionized plasma flux of Ti and B by removal of the external magnetic field, which leads to dissipation of the vacuum arc discharge and an increased active surface area of the cathode. Applying a magnetic field resulted in instability and cracking, consistent with the previous reports. Plasma analysis shows average energies of 115 and 26 eV, average ion charge states of 2.1 and 1.1 for Ti and B, respectively, and a plasma ion composition of approximately 50% Ti and 50% B. This is consistent with measured resulting film composition from X-ray photoelectron spectroscopy, suggesting a negligible contribution of neutrals and Macroparticles to the film growth. Also, despite the observations of macroparticle generation, the film surface is very smooth. These results are of importance for the utilization of cathodic arc as a method for synthesis of ...
Peter Polcik - One of the best experts on this subject based on the ideXlab platform.
-
macroparticle generation in dc arc discharge from a wc cathode
Journal of Applied Physics, 2017Co-Authors: Igor Zhirkov, Szilard Kolozsvari, Peter Polcik, Johanna RosenAbstract:We have studied macroparticle generation from a tungsten carbide cathode used in a dc vacuum arc discharge. Despite a relatively high decomposition/melting point (∼3100 K), there is an intensive generation of visible particles with sizes in the range 20–35 μm. Visual observations during the discharge and scanning electron microscopy of the cathode surface and of collected Macroparticles indicate a new mechanism for particle formation and acceleration. Based on the W-C phase diagram, there is an intensive sublimation of carbon from the melt resulting from the cathode spot. The sublimation supports the formation of a sphere, which is accelerated upon an explosion initiated by Joule heating at the critical contact area between the sphere and the cathode body. The explosive nature of the particle acceleration is confirmed by surface features resembling the remains of a splash on the droplet surface.
-
generation of super size Macroparticles in a direct current vacuum arc discharge from a mo cu cathode
Applied Physics Letters, 2016Co-Authors: Igor Zhirkov, Andrejs Petruhins, Szilard Kolozsvari, Peter Polcik, Johanna RosenAbstract:An inherent property of cathodic arc is the generation of Macroparticles, of a typical size ranging from submicrometer up to a few tens of μm. In this work, we have studied macroparticle generation from a Mo0.78Cu0.22 cathode used in a dc vacuum arc discharge, and we present evidence for super-size Macroparticles of up to 0.7 mm in diameter. All analyzed particles are found to be rich in Mo (≥98 at. %). The particle generation is studied by visual observation of the cathode surface during arcing, by analysis of composition and geometrical features of the used cathode surface, and by examination of the generated Macroparticles with respect to shape and composition. A mechanism for super-size macroparticle generation is suggested based on observed segregated layers of Mo and Cu identified in the topmost part of the cathode surface, likely due to the discrepancy in melting and evaporation temperatures of Mo and Cu. The results are of importance for increasing the fundamental understanding of macroparticle ge...
-
vacuum arc plasma generation and thin film deposition from a tib2 cathode
Applied Physics Letters, 2015Co-Authors: Igor Zhirkov, Andrejs Petruhins, Lars-Åke Näslund, Szilard Kolozsvari, Peter Polcik, Johanna RosenAbstract:We have studied the utilization of TiB2 cathodes for thin film deposition in a DC vacuum arc system. We present a route for attaining a stable, reproducible, and fully ionized plasma flux of Ti and B by removal of the external magnetic field, which leads to dissipation of the vacuum arc discharge and an increased active surface area of the cathode. Applying a magnetic field resulted in instability and cracking, consistent with the previous reports. Plasma analysis shows average energies of 115 and 26 eV, average ion charge states of 2.1 and 1.1 for Ti and B, respectively, and a plasma ion composition of approximately 50% Ti and 50% B. This is consistent with measured resulting film composition from X-ray photoelectron spectroscopy, suggesting a negligible contribution of neutrals and Macroparticles to the film growth. Also, despite the observations of macroparticle generation, the film surface is very smooth. These results are of importance for the utilization of cathodic arc as a method for synthesis of ...
