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S V Vosel - One of the best experts on this subject based on the ideXlab platform.
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evaluation of surface tension and tolman length as a function of droplet radius from experimental Nucleation rate and supersaturation ratio metal vapor homogeneous Nucleation
Journal of Chemical Physics, 2006Co-Authors: A. A. Onischuk, V. V. Karasev, Peter A. Purtov, A. M. Baklanov, S V VoselAbstract:Zinc and silver vapor homogeneous Nucleations are studied experimentally at the temperature from 600 to 725 and 870K, respectively, in a laminar flow diffusion chamber with Ar as a carrier gas at atmospheric pressure. The size, shape, and concentration of aerosol particles outcoming the diffusion chamber are analyzed by a transmission electron microscope and an automatic diffusion battery. The wall deposit is studied by a scanning electron microscope (SEM). Using SEM data the Nucleation rate for both Zn and Ag is estimated as 1010cm−3s−1. The dependence of critical supersaturation on temperature for Zn and Ag measured in this paper as well as Li, Na, Cs, Ag, Mg, and Hg measured elsewhere is analyzed. To this aim the classical Nucleation theory is extended by the dependence of surface tension on the nucleus radius. The preexponent in the formula for the vapor Nucleation rate is derived using the formula for the work of formation of noncritical embryo [obtained by Nishioka and Kusaka [J. Chem. Phys. 96, 5370 (1992)] and later by Debenedetti and Reiss [J. Chem. Phys. 108, 5498 (1998)]] and Reiss replacement factor. Using this preexponent and the Gibbs formula for the work of formation of critical nucleus the dependence of surface tension on the radius RS of the surface of tension is evaluated from the Nucleation data for above-mentioned metals. For the alkali metals and Ag the surface tension was determined to be a strong function of RS. For the bivalent metals (Zn, Hg, and Mg) the surface tension was independent of radius in the experimental range. A new formula for the Tolman length δ as a function of surface tension and radius RS is derived by integration of Gibbs-Tolman-Koenig equation assuming that δ is a monotonic function of radius. The formula derived is more correct than the Tolman formula and convenient for the elaboration of experimental data. Using this formula the values of δ are determined as a function of RS from the experimental Nucleation data. It is determined that all the metals considered are characterized by strong dependence of δ on radius; for the bivalent metals δ changes sign.Zinc and silver vapor homogeneous Nucleations are studied experimentally at the temperature from 600 to 725 and 870K, respectively, in a laminar flow diffusion chamber with Ar as a carrier gas at atmospheric pressure. The size, shape, and concentration of aerosol particles outcoming the diffusion chamber are analyzed by a transmission electron microscope and an automatic diffusion battery. The wall deposit is studied by a scanning electron microscope (SEM). Using SEM data the Nucleation rate for both Zn and Ag is estimated as 1010cm−3s−1. The dependence of critical supersaturation on temperature for Zn and Ag measured in this paper as well as Li, Na, Cs, Ag, Mg, and Hg measured elsewhere is analyzed. To this aim the classical Nucleation theory is extended by the dependence of surface tension on the nucleus radius. The preexponent in the formula for the vapor Nucleation rate is derived using the formula for the work of formation of noncritical embryo [obtained by Nishioka and Kusaka [J. Chem. Phys. 96, 537...
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evaluation of surface tension and tolman length as a function of droplet radius from experimental Nucleation rate and supersaturation ratio metal vapor homogeneous Nucleation
Journal of Chemical Physics, 2006Co-Authors: A. A. Onischuk, V. V. Karasev, Peter A. Purtov, A. M. Baklanov, S V VoselAbstract:Zinc and silver vapor homogeneous Nucleations are studied experimentally at the temperature from 600 to 725 and 870K, respectively, in a laminar flow diffusion chamber with Ar as a carrier gas at atmospheric pressure. The size, shape, and concentration of aerosol particles outcoming the diffusion chamber are analyzed by a transmission electron microscope and an automatic diffusion battery. The wall deposit is studied by a scanning electron microscope (SEM). Using SEM data the Nucleation rate for both Zn and Ag is estimated as 1010cm−3s−1. The dependence of critical supersaturation on temperature for Zn and Ag measured in this paper as well as Li, Na, Cs, Ag, Mg, and Hg measured elsewhere is analyzed. To this aim the classical Nucleation theory is extended by the dependence of surface tension on the nucleus radius. The preexponent in the formula for the vapor Nucleation rate is derived using the formula for the work of formation of noncritical embryo [obtained by Nishioka and Kusaka [J. Chem. Phys. 96, 537...
Taejoon Park - One of the best experts on this subject based on the ideXlab platform.
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Isothermal crystallization kinetics of (Cu 60 Zr 25 Ti 15 ) 99.3 Nb 0.7 bulk metallic glass
Scientific reports, 2020Co-Authors: Soumen Mandal, Dong-eun Lee, Taejoon ParkAbstract:This paper reports the crystallization kinetics of (Cu60Zr25Ti15)99.3Nb0.7 bulk metallic glass under isothermal conditions. Differential scanning calorimetry (DSC) has been employed for isothermal annealing at ten different temperatures prior to the onset of crystallization (To) temperature. X-ray diffraction and transmission electron microscopy have been used to confirm the amorphous structure of the as cast sample. Crystallized volume fractions (x) are calculated from the exothermic peaks of DSC scans. Crystallized volume fractions (x) against time show sigmoidal type of curves as well as the curves become steeper at higher annealing temperatures. Continuous heating transformation diagram has been simulated to understand the stability of the bulk metallic glass. Crystallization kinetics parameters are calculated using Arrhenius and Johnson-Mehl-Avrami equations. Activation energy (Ea) and Avrami exponential factor (n) have exhibited strong correlation with crystallized volume fraction (x). The average activation energy for isothermal crystallization is found to be 330 ± 30 kJ/mol by Arrhenius equation. Nucleation activation energy (ENucleation) is found to be higher than that of growth activation energy (Egrowth). The Avrami exponential factor (n) indicates about the diffusion controlled mechanism of the Nucleation and three-dimensional growth.
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Crystallization kinetics of Cu_60Zr_25Ti_15 and (Cu_60Zr_25Ti_15)_95Ni_5 bulk metallic glasses by differential scanning calorimetry (DSC)
Journal of Thermal Analysis and Calorimetry, 2020Co-Authors: Soumen Mandal, Dong-eun Lee, Taejoon ParkAbstract:Amorphous structures of the as-cast bulk metallic glass samples (BMGs) of Cu_60Zr_25Ti_15 and (Cu_60Zr_25Ti_15)_95Ni_5 alloys are confirmed by X-ray diffraction. Isothermal crystallization kinetics of these BMGs are investigated using differential scanning calorimetry. For both the alloys, the apparent activation energy ( E _a) shows a strong dependency on crystallization volume fraction ( x ). Isothermal crystallization kinetic parameters are calculated by Arrhenius and Johnson–Mehl–Avrami equations. Avrami exponential factor ( n ) is also found to show clear correlation with the crystallization volume fraction ( x ). It is found that the crystallization process is easier in Cu_60Zr_25Ti_15 BMG than in (Cu_60Zr_25Ti_15)_95Ni_5 BMG as the E _a decreases constantly for the former alloy though in the case of second alloy, the E _a is almost unchanged up to x = 60%. For both the alloys, Nucleation activation energy ( E _Nucleation) is found to be higher than that of growth activation energy ( E _growth). This indicates that the growth of crystals during isothermal crystallization in these glasses is easier than Nucleation, and the minor addition of Ni causes the higher thermal stability against crystallization in isothermal condition.
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Crystallization kinetics of Cu_60Zr_25Ti_15 and (Cu_60Zr_25Ti_15)_95Ni_5 bulk metallic glasses by differential scanning calorimetry (DSC)
Journal of Thermal Analysis and Calorimetry, 2020Co-Authors: Soumen Mandal, Taejoon ParkAbstract:Amorphous structures of the as-cast bulk metallic glass samples (BMGs) of Cu_60Zr_25Ti_15 and (Cu_60Zr_25Ti_15)_95Ni_5 alloys are confirmed by X-ray diffraction. Isothermal crystallization kinetics of these BMGs are investigated using differential scanning calorimetry. For both the alloys, the apparent activation energy ( E _a) shows a strong dependency on crystallization volume fraction ( x ). Isothermal crystallization kinetic parameters are calculated by Arrhenius and Johnson–Mehl–Avrami equations. Avrami exponential factor ( n ) is also found to show clear correlation with the crystallization volume fraction ( x ). It is found that the crystallization process is easier in Cu_60Zr_25Ti_15 BMG than in (Cu_60Zr_25Ti_15)_95Ni_5 BMG as the E _a decreases constantly for the former alloy though in the case of second alloy, the E _a is almost unchanged up to x = 60%. For both the alloys, Nucleation activation energy ( E _Nucleation) is found to be higher than that of growth activation energy ( E _growth). This indicates that the growth of crystals during isothermal crystallization in these glasses is easier than Nucleation, and the minor addition of Ni causes the higher thermal stability against crystallization in isothermal condition.
A. A. Onischuk - One of the best experts on this subject based on the ideXlab platform.
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evaluation of surface tension and tolman length as a function of droplet radius from experimental Nucleation rate and supersaturation ratio metal vapor homogeneous Nucleation
Journal of Chemical Physics, 2006Co-Authors: A. A. Onischuk, V. V. Karasev, Peter A. Purtov, A. M. Baklanov, S V VoselAbstract:Zinc and silver vapor homogeneous Nucleations are studied experimentally at the temperature from 600 to 725 and 870K, respectively, in a laminar flow diffusion chamber with Ar as a carrier gas at atmospheric pressure. The size, shape, and concentration of aerosol particles outcoming the diffusion chamber are analyzed by a transmission electron microscope and an automatic diffusion battery. The wall deposit is studied by a scanning electron microscope (SEM). Using SEM data the Nucleation rate for both Zn and Ag is estimated as 1010cm−3s−1. The dependence of critical supersaturation on temperature for Zn and Ag measured in this paper as well as Li, Na, Cs, Ag, Mg, and Hg measured elsewhere is analyzed. To this aim the classical Nucleation theory is extended by the dependence of surface tension on the nucleus radius. The preexponent in the formula for the vapor Nucleation rate is derived using the formula for the work of formation of noncritical embryo [obtained by Nishioka and Kusaka [J. Chem. Phys. 96, 5370 (1992)] and later by Debenedetti and Reiss [J. Chem. Phys. 108, 5498 (1998)]] and Reiss replacement factor. Using this preexponent and the Gibbs formula for the work of formation of critical nucleus the dependence of surface tension on the radius RS of the surface of tension is evaluated from the Nucleation data for above-mentioned metals. For the alkali metals and Ag the surface tension was determined to be a strong function of RS. For the bivalent metals (Zn, Hg, and Mg) the surface tension was independent of radius in the experimental range. A new formula for the Tolman length δ as a function of surface tension and radius RS is derived by integration of Gibbs-Tolman-Koenig equation assuming that δ is a monotonic function of radius. The formula derived is more correct than the Tolman formula and convenient for the elaboration of experimental data. Using this formula the values of δ are determined as a function of RS from the experimental Nucleation data. It is determined that all the metals considered are characterized by strong dependence of δ on radius; for the bivalent metals δ changes sign.Zinc and silver vapor homogeneous Nucleations are studied experimentally at the temperature from 600 to 725 and 870K, respectively, in a laminar flow diffusion chamber with Ar as a carrier gas at atmospheric pressure. The size, shape, and concentration of aerosol particles outcoming the diffusion chamber are analyzed by a transmission electron microscope and an automatic diffusion battery. The wall deposit is studied by a scanning electron microscope (SEM). Using SEM data the Nucleation rate for both Zn and Ag is estimated as 1010cm−3s−1. The dependence of critical supersaturation on temperature for Zn and Ag measured in this paper as well as Li, Na, Cs, Ag, Mg, and Hg measured elsewhere is analyzed. To this aim the classical Nucleation theory is extended by the dependence of surface tension on the nucleus radius. The preexponent in the formula for the vapor Nucleation rate is derived using the formula for the work of formation of noncritical embryo [obtained by Nishioka and Kusaka [J. Chem. Phys. 96, 537...
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evaluation of surface tension and tolman length as a function of droplet radius from experimental Nucleation rate and supersaturation ratio metal vapor homogeneous Nucleation
Journal of Chemical Physics, 2006Co-Authors: A. A. Onischuk, V. V. Karasev, Peter A. Purtov, A. M. Baklanov, S V VoselAbstract:Zinc and silver vapor homogeneous Nucleations are studied experimentally at the temperature from 600 to 725 and 870K, respectively, in a laminar flow diffusion chamber with Ar as a carrier gas at atmospheric pressure. The size, shape, and concentration of aerosol particles outcoming the diffusion chamber are analyzed by a transmission electron microscope and an automatic diffusion battery. The wall deposit is studied by a scanning electron microscope (SEM). Using SEM data the Nucleation rate for both Zn and Ag is estimated as 1010cm−3s−1. The dependence of critical supersaturation on temperature for Zn and Ag measured in this paper as well as Li, Na, Cs, Ag, Mg, and Hg measured elsewhere is analyzed. To this aim the classical Nucleation theory is extended by the dependence of surface tension on the nucleus radius. The preexponent in the formula for the vapor Nucleation rate is derived using the formula for the work of formation of noncritical embryo [obtained by Nishioka and Kusaka [J. Chem. Phys. 96, 537...
Soumen Mandal - One of the best experts on this subject based on the ideXlab platform.
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Isothermal crystallization kinetics of (Cu 60 Zr 25 Ti 15 ) 99.3 Nb 0.7 bulk metallic glass
Scientific reports, 2020Co-Authors: Soumen Mandal, Dong-eun Lee, Taejoon ParkAbstract:This paper reports the crystallization kinetics of (Cu60Zr25Ti15)99.3Nb0.7 bulk metallic glass under isothermal conditions. Differential scanning calorimetry (DSC) has been employed for isothermal annealing at ten different temperatures prior to the onset of crystallization (To) temperature. X-ray diffraction and transmission electron microscopy have been used to confirm the amorphous structure of the as cast sample. Crystallized volume fractions (x) are calculated from the exothermic peaks of DSC scans. Crystallized volume fractions (x) against time show sigmoidal type of curves as well as the curves become steeper at higher annealing temperatures. Continuous heating transformation diagram has been simulated to understand the stability of the bulk metallic glass. Crystallization kinetics parameters are calculated using Arrhenius and Johnson-Mehl-Avrami equations. Activation energy (Ea) and Avrami exponential factor (n) have exhibited strong correlation with crystallized volume fraction (x). The average activation energy for isothermal crystallization is found to be 330 ± 30 kJ/mol by Arrhenius equation. Nucleation activation energy (ENucleation) is found to be higher than that of growth activation energy (Egrowth). The Avrami exponential factor (n) indicates about the diffusion controlled mechanism of the Nucleation and three-dimensional growth.
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Crystallization kinetics of Cu_60Zr_25Ti_15 and (Cu_60Zr_25Ti_15)_95Ni_5 bulk metallic glasses by differential scanning calorimetry (DSC)
Journal of Thermal Analysis and Calorimetry, 2020Co-Authors: Soumen Mandal, Dong-eun Lee, Taejoon ParkAbstract:Amorphous structures of the as-cast bulk metallic glass samples (BMGs) of Cu_60Zr_25Ti_15 and (Cu_60Zr_25Ti_15)_95Ni_5 alloys are confirmed by X-ray diffraction. Isothermal crystallization kinetics of these BMGs are investigated using differential scanning calorimetry. For both the alloys, the apparent activation energy ( E _a) shows a strong dependency on crystallization volume fraction ( x ). Isothermal crystallization kinetic parameters are calculated by Arrhenius and Johnson–Mehl–Avrami equations. Avrami exponential factor ( n ) is also found to show clear correlation with the crystallization volume fraction ( x ). It is found that the crystallization process is easier in Cu_60Zr_25Ti_15 BMG than in (Cu_60Zr_25Ti_15)_95Ni_5 BMG as the E _a decreases constantly for the former alloy though in the case of second alloy, the E _a is almost unchanged up to x = 60%. For both the alloys, Nucleation activation energy ( E _Nucleation) is found to be higher than that of growth activation energy ( E _growth). This indicates that the growth of crystals during isothermal crystallization in these glasses is easier than Nucleation, and the minor addition of Ni causes the higher thermal stability against crystallization in isothermal condition.
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Crystallization kinetics of Cu_60Zr_25Ti_15 and (Cu_60Zr_25Ti_15)_95Ni_5 bulk metallic glasses by differential scanning calorimetry (DSC)
Journal of Thermal Analysis and Calorimetry, 2020Co-Authors: Soumen Mandal, Taejoon ParkAbstract:Amorphous structures of the as-cast bulk metallic glass samples (BMGs) of Cu_60Zr_25Ti_15 and (Cu_60Zr_25Ti_15)_95Ni_5 alloys are confirmed by X-ray diffraction. Isothermal crystallization kinetics of these BMGs are investigated using differential scanning calorimetry. For both the alloys, the apparent activation energy ( E _a) shows a strong dependency on crystallization volume fraction ( x ). Isothermal crystallization kinetic parameters are calculated by Arrhenius and Johnson–Mehl–Avrami equations. Avrami exponential factor ( n ) is also found to show clear correlation with the crystallization volume fraction ( x ). It is found that the crystallization process is easier in Cu_60Zr_25Ti_15 BMG than in (Cu_60Zr_25Ti_15)_95Ni_5 BMG as the E _a decreases constantly for the former alloy though in the case of second alloy, the E _a is almost unchanged up to x = 60%. For both the alloys, Nucleation activation energy ( E _Nucleation) is found to be higher than that of growth activation energy ( E _growth). This indicates that the growth of crystals during isothermal crystallization in these glasses is easier than Nucleation, and the minor addition of Ni causes the higher thermal stability against crystallization in isothermal condition.
Peter A. Purtov - One of the best experts on this subject based on the ideXlab platform.
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evaluation of surface tension and tolman length as a function of droplet radius from experimental Nucleation rate and supersaturation ratio metal vapor homogeneous Nucleation
Journal of Chemical Physics, 2006Co-Authors: A. A. Onischuk, V. V. Karasev, Peter A. Purtov, A. M. Baklanov, S V VoselAbstract:Zinc and silver vapor homogeneous Nucleations are studied experimentally at the temperature from 600 to 725 and 870K, respectively, in a laminar flow diffusion chamber with Ar as a carrier gas at atmospheric pressure. The size, shape, and concentration of aerosol particles outcoming the diffusion chamber are analyzed by a transmission electron microscope and an automatic diffusion battery. The wall deposit is studied by a scanning electron microscope (SEM). Using SEM data the Nucleation rate for both Zn and Ag is estimated as 1010cm−3s−1. The dependence of critical supersaturation on temperature for Zn and Ag measured in this paper as well as Li, Na, Cs, Ag, Mg, and Hg measured elsewhere is analyzed. To this aim the classical Nucleation theory is extended by the dependence of surface tension on the nucleus radius. The preexponent in the formula for the vapor Nucleation rate is derived using the formula for the work of formation of noncritical embryo [obtained by Nishioka and Kusaka [J. Chem. Phys. 96, 5370 (1992)] and later by Debenedetti and Reiss [J. Chem. Phys. 108, 5498 (1998)]] and Reiss replacement factor. Using this preexponent and the Gibbs formula for the work of formation of critical nucleus the dependence of surface tension on the radius RS of the surface of tension is evaluated from the Nucleation data for above-mentioned metals. For the alkali metals and Ag the surface tension was determined to be a strong function of RS. For the bivalent metals (Zn, Hg, and Mg) the surface tension was independent of radius in the experimental range. A new formula for the Tolman length δ as a function of surface tension and radius RS is derived by integration of Gibbs-Tolman-Koenig equation assuming that δ is a monotonic function of radius. The formula derived is more correct than the Tolman formula and convenient for the elaboration of experimental data. Using this formula the values of δ are determined as a function of RS from the experimental Nucleation data. It is determined that all the metals considered are characterized by strong dependence of δ on radius; for the bivalent metals δ changes sign.Zinc and silver vapor homogeneous Nucleations are studied experimentally at the temperature from 600 to 725 and 870K, respectively, in a laminar flow diffusion chamber with Ar as a carrier gas at atmospheric pressure. The size, shape, and concentration of aerosol particles outcoming the diffusion chamber are analyzed by a transmission electron microscope and an automatic diffusion battery. The wall deposit is studied by a scanning electron microscope (SEM). Using SEM data the Nucleation rate for both Zn and Ag is estimated as 1010cm−3s−1. The dependence of critical supersaturation on temperature for Zn and Ag measured in this paper as well as Li, Na, Cs, Ag, Mg, and Hg measured elsewhere is analyzed. To this aim the classical Nucleation theory is extended by the dependence of surface tension on the nucleus radius. The preexponent in the formula for the vapor Nucleation rate is derived using the formula for the work of formation of noncritical embryo [obtained by Nishioka and Kusaka [J. Chem. Phys. 96, 537...
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evaluation of surface tension and tolman length as a function of droplet radius from experimental Nucleation rate and supersaturation ratio metal vapor homogeneous Nucleation
Journal of Chemical Physics, 2006Co-Authors: A. A. Onischuk, V. V. Karasev, Peter A. Purtov, A. M. Baklanov, S V VoselAbstract:Zinc and silver vapor homogeneous Nucleations are studied experimentally at the temperature from 600 to 725 and 870K, respectively, in a laminar flow diffusion chamber with Ar as a carrier gas at atmospheric pressure. The size, shape, and concentration of aerosol particles outcoming the diffusion chamber are analyzed by a transmission electron microscope and an automatic diffusion battery. The wall deposit is studied by a scanning electron microscope (SEM). Using SEM data the Nucleation rate for both Zn and Ag is estimated as 1010cm−3s−1. The dependence of critical supersaturation on temperature for Zn and Ag measured in this paper as well as Li, Na, Cs, Ag, Mg, and Hg measured elsewhere is analyzed. To this aim the classical Nucleation theory is extended by the dependence of surface tension on the nucleus radius. The preexponent in the formula for the vapor Nucleation rate is derived using the formula for the work of formation of noncritical embryo [obtained by Nishioka and Kusaka [J. Chem. Phys. 96, 537...
