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C H Shek - One of the best experts on this subject based on the ideXlab platform.
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evolution of 3d nanoporosity and morphology in selectively dealloying ternary au55cu25si20 metallic Glass Ribbon with enhanced alcohol electro oxidation performance
Nanoscale, 2018Co-Authors: Yi Xu, Junye Cheng, Guangcun Shan, Tamaki Shibayama, Seiichi Watanabe, Masato Ohnuma, C H ShekAbstract:Current fabrication methods of nanoporous gold (NPG) mainly rely on dealloying Ag–Au binary crystalline precursors, typically Ag65Au35, with the “dealloying threshold” or “parting limit” above 55 at%. Here we report a simple chemical dealloying process, through selective dissolution of one element from a Au55Cu25Si20 metallic Glass Ribbon with low ‘parting limit’, and a novel peculiar three-dimensional ‘cone shaped protrusion’ nanoporous structure which has never been reported before. In this structure, a metastable gold silicide formed in the initial dealloying stage was decomposed into gold nanoparticles and amorphous SiOx in the later coarsening stage. Our finding provides insights into the underlying relationship between ‘parting limit’ and atomic level structure of metallic Glass. Comprehensive discussions on the porosity evolution stages as well as the correlation between the porous ‘cone shaped protrusion’ development and potential energy landscape are made in this report. The fabricated 3D NPG also exhibited excellent electro-oxidation catalytic ability attributed to the high density of low-coordinated atomic sites provided by the gold particle inside of ‘cone shaped protrusion’.
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gold rich ligament nanostructure by dealloying au based metallic Glass Ribbon for surface enhanced raman scattering
Scientific Reports, 2017Co-Authors: Bokai Chao, Yi Xu, Hsinchia Ho, C H Shek, Chunhway HsuehAbstract:A new method to fabricate an Au-rich interconnected ligament substrate by dealloying the Au-based metallic Glass Ribbon for surface-enhanced Raman scattering (SERS) applications was investigated in this study. Specifically, three substrates, Au film, Au-based metallic Glass Ribbon, and dealloyed Au-based metallic Glass Ribbon, were studied. The dealloyed surface showed ligament nanostructure with protruding micro-islands. Based on the field emission scanning electron microscopy, reflection and scattering measurements, the dealloyed Au-based metallic Glass provided a large surface area, multiple reflections, and numerous fine interstices to produce hot spots for SERS enhancements. The SERS signal of analyte, p-aminothiophenol, in the micro-island region of dealloyed Au-based metallic Glass was about 2 orders of magnitude larger than the flat Au film. Our work provides a new method to fabricate the inexpensive and high SERS enhancements substrates.
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electroplastic forming in a fe based metallic Glass Ribbon
Journal of Alloys and Compounds, 2016Co-Authors: Chia Hsiang Hsueh, C H ShekAbstract:Abstract Electric current has been applied to lower the temperature and loading required for metalworking of extremely strong or brittle alloys. However, limited studies have been conducted on the electrically-assisted forming of metallic Glasses. Our previous study revealed the feasibility of electroplastically deforming a Fe 78 B 13 Si 9 metallic Glass Ribbon. Yet the drawback is that pre-stressing was required prior to electropulsing and large elastic recovery limited the dimensional accuracy of the forming process. In the present work we demonstrate a setup in which metallic Glass Ribbons were subjected to punching, with electropulsing applied simultaneously in various combinations of frequency and punching speed. Process temperature was measured to be significantly below the Glass transition temperature and the process only takes 20–30 s. Lower load was required to punch the Ribbon with electrical pulses applied. All the Ribbons were fully deformed without spring back after the punch was retracted. X-ray diffraction revealed that all Ribbon were essentially amorphous, with only some rare cases suffering from embrittlement. It is concluded that electric current provided a directional force acting as an aid to overcome the activation barrier of shear transformation zones; however, as a side effect joule heating also accelerated beta relaxation causing the embrittlement. This study revealed a novel way of shaping metallic Glasses with the potential of industrial scale application.
J A Verduzco - One of the best experts on this subject based on the ideXlab platform.
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Corrosion resistance of bonding zone of AISI 316L–304 stainless steels joined with iron based Glass Ribbon interlayer: microstructural effects
Corrosion Engineering Science and Technology, 2020Co-Authors: J A Verduzco, V H Verduzco, V H Lopez, L Dzib-pérez, J. González-sánchez, J SolisAbstract:The effect of holding time on the microstructure and corrosion resistance of the junction zone of AISI 316L bonded to AISI 304 stainless steels (SSs) at 960°C using an Fe based alloy filler was investigated. Samples of austenitic SSs were joined in a sandwich-like arrangement using non-commercial Fe60Ni12Cr8P13B7 metallic Glass Ribbon. Microstructural analysis revealed significant dissolution of the amorphous Ribbon in both SSs for short holding times, exhibiting a narrow interlayer with very fine precipitates. Larger holding times induced widening of the interlayer and coarsening of γ precipitates in the iron based alloy and significant variation of the interlayer chemical composition. Microstructural dissimilarity of the bonding zone promoted selective dissolution coupled with crevice corrosion of the joints in 3·5 wt-% sodium chloride solution. In general, at the joining temperature of 960°C, the bonding Ribbon and the AISI 316L SS presented higher corrosion resistance as the holding time increased up ...
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corrosion resistance on the interlayer of aisi 316l aisi 304 stainless steels joined with an iron based metallic Glass Ribbon at 1000 c by induction heating
Advanced Materials Research, 2014Co-Authors: J A Verduzco, V H Verduzco, Jorge A Gonzalez, Carlos Ernesto Borja, Jose Guadalupe Quezada, I A FigueroaAbstract:This work presents a study of the corrosion resistance as a function of the holding time on the interface generated during the process of brazing an AISI 304 to AISI 316L stainless steels by using a non-commercial Fe60Ni12Cr8P13B7 metallic Glass alloy Ribbon by induction heating at 1000 °C into a chamber with an Ar controlled atmosphere. Samples of the austenitic stainless steels were joined in a sandwich-like arrangement using the Fe-based metallic Glass Ribbon. Corrosion experiments carried out in distilled water and 3.5 wt. % sodium chloride solution revealed that the corrosion resistance was higher for samples tested in the distilled water than the latest medium for all dwell joining times, since in the former medium the samples passivated. It was also found that the highest corrosion resistance was achieved for samples joined for a dwelling time of 4 minutes.
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Corrosion Resistance on the Interlayer of AISI 316L/AISI 304 Stainless Steels Joined with an Iron Based Metallic Glass Ribbon at 1000 °C by Induction Heating
Advanced Materials Research, 2014Co-Authors: J A Verduzco, V H Verduzco, Jorge A Gonzalez, Carlos Ernesto Borja, Jose Guadalupe Quezada, I A FigueroaAbstract:This work presents a study of the corrosion resistance as a function of the holding time on the interface generated during the process of brazing an AISI 304 to AISI 316L stainless steels by using a non-commercial Fe60Ni12Cr8P13B7 metallic Glass alloy Ribbon by induction heating at 1000 °C into a chamber with an Ar controlled atmosphere. Samples of the austenitic stainless steels were joined in a sandwich-like arrangement using the Fe-based metallic Glass Ribbon. Corrosion experiments carried out in distilled water and 3.5 wt. % sodium chloride solution revealed that the corrosion resistance was higher for samples tested in the distilled water than the latest medium for all dwell joining times, since in the former medium the samples passivated. It was also found that the highest corrosion resistance was achieved for samples joined for a dwelling time of 4 minutes.
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corrosion resistance of bonding zone of aisi 316l 304 stainless steels joined with iron based Glass Ribbon interlayer microstructural effects
Corrosion Engineering Science and Technology, 2012Co-Authors: J A Verduzco, V H Verduzco, L Dzibperez, J Gonzalezsanchez, V H Lopez, J SolisAbstract:The effect of holding time on the microstructure and corrosion resistance of the junction zone of AISI 316L bonded to AISI 304 stainless steels (SSs) at 960°C using an Fe based alloy filler was investigated. Samples of austenitic SSs were joined in a sandwich-like arrangement using non-commercial Fe60Ni12Cr8P13B7 metallic Glass Ribbon. Microstructural analysis revealed significant dissolution of the amorphous Ribbon in both SSs for short holding times, exhibiting a narrow interlayer with very fine precipitates. Larger holding times induced widening of the interlayer and coarsening of γ precipitates in the iron based alloy and significant variation of the interlayer chemical composition. Microstructural dissimilarity of the bonding zone promoted selective dissolution coupled with crevice corrosion of the joints in 3·5 wt-% sodium chloride solution. In general, at the joining temperature of 960°C, the bonding Ribbon and the AISI 316L SS presented higher corrosion resistance as the holding time increased up ...
A. Nijhuis - One of the best experts on this subject based on the ideXlab platform.
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magnetic measurement of interstrand contact resistance and persistent current magnetization of nb3sn rutherford cables with cores of mgo tape and woven s Glass Ribbon
ADVANCES IN CRYOGENIC ENGINEERING: Transactions of the International Cryogenic Materials Conference - ICMC Volume 58, 2012Co-Authors: E. W. Collings, M. D. Sumption, M. A. Susner, D. R. Dietderich, A. NijhuisAbstract:Rutherford cables exhibit two classes of parasitic magnetization both of which can distort the bore-field of an accelerator magnet: (1) a static magnetization ("hysteretic") resulting from intrastrand persistent currents, and (2) a dynamic magnetization produced by interstrand coupling currents passing through interstrand contact resistances (ICR) during field ramping. Interstrand coupling can be controlled by a core placed between the layers of the cable. Stainless steel Ribbon (with its associated native oxide coating) is a frequently used core. Recently, however, MgO-paper tapes and woven s-Glass Ribbons have been suggested as alternative core materials in the interests of improved flexibility and compatibility with the cabling process. Interstrand contact resistances can be extracted from the results of AC loss measurement. Accordingly pickup-coil magnetization measurements of AC loss have been carried out on a group of cables with paper and Ribbon cores. This paper reports on the resulting ICR results which it compares to those from uncored and stainless-steel-cored cables; it concludes by comparing the LHC-ramp-rate induced coupling magnetization of a typical cored Nb3Sn Rutherford cable with its transport-current-moderated persistent-current magnetizations at low and high fields.Rutherford cables exhibit two classes of parasitic magnetization both of which can distort the bore-field of an accelerator magnet: (1) a static magnetization ("hysteretic") resulting from intrastrand persistent currents, and (2) a dynamic magnetization produced by interstrand coupling currents passing through interstrand contact resistances (ICR) during field ramping. Interstrand coupling can be controlled by a core placed between the layers of the cable. Stainless steel Ribbon (with its associated native oxide coating) is a frequently used core. Recently, however, MgO-paper tapes and woven s-Glass Ribbons have been suggested as alternative core materials in the interests of improved flexibility and compatibility with the cabling process. Interstrand contact resistances can be extracted from the results of AC loss measurement. Accordingly pickup-coil magnetization measurements of AC loss have been carried out on a group of cables with paper and Ribbon cores. This paper reports on the resulting ICR result...
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Coupling Loss, Interstrand Contact Resistance, and Magnetization of Nb $_{3}$ Sn Rutherford Cables With Cores of MgO Tape and S-Glass Ribbon
IEEE Transactions on Applied Superconductivity, 2011Co-Authors: E. W. Collings, M. D. Sumption, M. A. Susner, D. R. Dietderich, A. NijhuisAbstract:Multistrand cables may exhibit two classes of parasitic magnetization both of which can distort the bore-field of an accelerator magnet: (1) a static magnetization (“hysteretic”) resulting from intrastrand persistent currents, and (2) a dynamic magnetization produced by interstrand coupling currents generated during field ramping. The latter, which are moderated by the interstrand contact resistances (ICR), can be controlled by the presence of an insulating core inserted between the layers of the cable. Stainless steel Ribbon (with its associated native oxide coating) is a frequently used core. Recently, however, MgO-paper tapes and woven s-Glass Ribbons have been suggested by LBNL (Lawrence Berkeley National Laboratory) as alternative core materials in the interests of improved flexibility and compatibility with the cabling process. This paper reports on the results of calorimetric AC loss (hence ICR) measurements on a set of four such cables and presents the results within the context of previously measured cored and uncored Nb3Sn cables. Also considered is a typical ramp-rate-induced coupling magnetization and its relationship to persistent-current magnetizations over the operating range of an accelerator magnet.
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coupling loss interstrand contact resistance and magnetization of nb _ 3 sn rutherford cables with cores of mgo tape and s Glass Ribbon
IEEE Transactions on Applied Superconductivity, 2011Co-Authors: E. W. Collings, M. D. Sumption, M. A. Susner, D. R. Dietderich, A. NijhuisAbstract:Multistrand cables may exhibit two classes of parasitic magnetization both of which can distort the bore-field of an accelerator magnet: (1) a static magnetization (“hysteretic”) resulting from intrastrand persistent currents, and (2) a dynamic magnetization produced by interstrand coupling currents generated during field ramping. The latter, which are moderated by the interstrand contact resistances (ICR), can be controlled by the presence of an insulating core inserted between the layers of the cable. Stainless steel Ribbon (with its associated native oxide coating) is a frequently used core. Recently, however, MgO-paper tapes and woven s-Glass Ribbons have been suggested by LBNL (Lawrence Berkeley National Laboratory) as alternative core materials in the interests of improved flexibility and compatibility with the cabling process. This paper reports on the results of calorimetric AC loss (hence ICR) measurements on a set of four such cables and presents the results within the context of previously measured cored and uncored Nb3Sn cables. Also considered is a typical ramp-rate-induced coupling magnetization and its relationship to persistent-current magnetizations over the operating range of an accelerator magnet.
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Coupling Loss, Interstrand Contact Resistance, and Magnetization of Nb$_{3}$ Sn Rutherford Cables With Cores of MgO Tape and S-Glass Ribbon
IEEE Transactions on Applied Superconductivity, 2011Co-Authors: E. W. Collings, M. D. Sumption, M. A. Susner, D. R. Dietderich, A. NijhuisAbstract:Multistrand cables may exhibit two classes of parasitic magnetization both of which can distort the bore-field of an accelerator magnet: (1) a static magnetization (“hysteretic”) resulting from intrastrand persistent currents, and (2) a dynamic magnetization produced by interstrand coupling currents generated during field ramping. The latter, which are moderated by the interstrand contact resistances (ICR), can be controlled by the presence of an insulating core inserted between the layers of the cable. Stainless steel Ribbon (with its associated native oxide coating) is a frequently used core. Recently, however, MgO-paper tapes and woven s-Glass Ribbons have been suggested by LBNL (Lawrence Berkeley National Laboratory) as alternative core materials in the interests of improved flexibility and compatibility with the cabling process. This paper reports on the results of calorimetric AC loss (hence ICR) measurements on a set of four such cables and presents the results within the context of previously measured cored and uncored Nb3Sn cables. Also considered is a typical ramp-rate-induced coupling magnetization and its relationship to persistent-current magnetizations over the operating range of an accelerator magnet.
K N Subramanian - One of the best experts on this subject based on the ideXlab platform.
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Thermal expansion studies on a metallic-Glass Ribbon-reinforced Glass-ceramic-matrix composite
Journal of Materials Science, 1994Co-Authors: Rajendra U. Vaidya, Krishan Kumar Chawla, K N SubramanianAbstract:The thermal-expansion behaviour of a metallic-Glass Ribbon-reinforced Glass-ceramic-matrix composite was studied. The coefficient of thermal expansion of such composites measured in the longitudinal direction was correlated with the volume fraction, the length and the width of the Ribbon reinforcements. The experimentally measured values of the thermal-expansion coefficients were found to be in good agreement with a modified Schapery's equation. Formation of an oxide layer on the Ribbon surface and other related phenomena occurring at elevated temperatures were also found to affect the thermal expansion of such composites, and these factors were accommodated into Schapery's equation by incorporating an empirical constant.
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thermal expansion studies on a metallic Glass Ribbon reinforced Glass ceramic matrix composite
Journal of Materials Science, 1994Co-Authors: R U Vaidya, Krishan Kumar Chawla, K N SubramanianAbstract:The thermal-expansion behaviour of a metallic-Glass Ribbon-reinforced Glass-ceramic-matrix composite was studied. The coefficient of thermal expansion of such composites measured in the longitudinal direction was correlated with the volume fraction, the length and the width of the Ribbon reinforcements. The experimentally measured values of the thermal-expansion coefficients were found to be in good agreement with a modified Schapery's equation.
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Interfacial effects in a metallic-Glass Ribbon reinforced Glass-ceramic matrix composite
Journal of Materials Science, 1992Co-Authors: Rajendra U. Vaidya, C. Norris, K N SubramanianAbstract:The effect of temperature on the interfacial effects in a metallic-Glass Ribbon reinforced Glass-ceramic matrix composite was investigated. The metallic-Glass Ribbon present in this composite was found to be significantly affected at elevated temperatures, owing to the diffusion of lead and zinc from the matrix. The presence of the matrix in the vicinity of the Ribbon enhanced the formation of an oxide layer on the Ribbon surface. The oxide layer decreased the interfacial bond strength between the Ribbon and the matrix, affecting the failure mode of such composites at elevated temperatures.
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Discontinuous metallic-Glass Ribbon reinforced Glass-ceramic matrix composites
Journal of Materials Science, 1991Co-Authors: Rajendra U. Vaidya, K N SubramanianAbstract:Discontinuous metallic-Glass Ribbons of varying lengths and widths were used to reinforce a brittle Glass-ceramic matrix. The fracture strength and toughness of such composites as a function of Ribbon volume fraction and geometry were measured by three-point bending. The mechanical properties were found to be relatively isotropic in the plane of compaction (without significant loss of strengthening achieved with unidirectional reinforcement). The higher composite strength exhibited in a direction perpendicular to the plane of compaction was attributed to the higher percentage of Ribbons oriented with their short transverse faces perpendicular to the opening crack front.
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FABRICATION OF METALLIC-Glass Ribbon REINFORCED Glass-CERAMIC MATRIX COMPOSITES
Materials and Manufacturing Processes, 1991Co-Authors: R U Vaidya, K N SubramanianAbstract:Metallic-Glass Ribbon reinforced Glass-ceramic matrix composites were fabricated by conventional wet pressing and sintering techniques. Some of the important aspects of composite fabrication are discussed. Variables such as binder content, compaction pressure and specimen size, and their interdependency on one another are discussed. The optimum processing conditions required to obtain the best specimens are described. The sintering temperature was also found to be very important. The sintering temperature not only controls the softening characteristics of the parent Glass, but also affects the specimen distortion. Proper selection of the sintering temperature can ensure minimum distortion in the specimens, while at the same time retain the ease and efficiency of fabrication.
V H Verduzco - One of the best experts on this subject based on the ideXlab platform.
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Corrosion resistance of bonding zone of AISI 316L–304 stainless steels joined with iron based Glass Ribbon interlayer: microstructural effects
Corrosion Engineering Science and Technology, 2020Co-Authors: J A Verduzco, V H Verduzco, V H Lopez, L Dzib-pérez, J. González-sánchez, J SolisAbstract:The effect of holding time on the microstructure and corrosion resistance of the junction zone of AISI 316L bonded to AISI 304 stainless steels (SSs) at 960°C using an Fe based alloy filler was investigated. Samples of austenitic SSs were joined in a sandwich-like arrangement using non-commercial Fe60Ni12Cr8P13B7 metallic Glass Ribbon. Microstructural analysis revealed significant dissolution of the amorphous Ribbon in both SSs for short holding times, exhibiting a narrow interlayer with very fine precipitates. Larger holding times induced widening of the interlayer and coarsening of γ precipitates in the iron based alloy and significant variation of the interlayer chemical composition. Microstructural dissimilarity of the bonding zone promoted selective dissolution coupled with crevice corrosion of the joints in 3·5 wt-% sodium chloride solution. In general, at the joining temperature of 960°C, the bonding Ribbon and the AISI 316L SS presented higher corrosion resistance as the holding time increased up ...
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corrosion resistance on the interlayer of aisi 316l aisi 304 stainless steels joined with an iron based metallic Glass Ribbon at 1000 c by induction heating
Advanced Materials Research, 2014Co-Authors: J A Verduzco, V H Verduzco, Jorge A Gonzalez, Carlos Ernesto Borja, Jose Guadalupe Quezada, I A FigueroaAbstract:This work presents a study of the corrosion resistance as a function of the holding time on the interface generated during the process of brazing an AISI 304 to AISI 316L stainless steels by using a non-commercial Fe60Ni12Cr8P13B7 metallic Glass alloy Ribbon by induction heating at 1000 °C into a chamber with an Ar controlled atmosphere. Samples of the austenitic stainless steels were joined in a sandwich-like arrangement using the Fe-based metallic Glass Ribbon. Corrosion experiments carried out in distilled water and 3.5 wt. % sodium chloride solution revealed that the corrosion resistance was higher for samples tested in the distilled water than the latest medium for all dwell joining times, since in the former medium the samples passivated. It was also found that the highest corrosion resistance was achieved for samples joined for a dwelling time of 4 minutes.
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Corrosion Resistance on the Interlayer of AISI 316L/AISI 304 Stainless Steels Joined with an Iron Based Metallic Glass Ribbon at 1000 °C by Induction Heating
Advanced Materials Research, 2014Co-Authors: J A Verduzco, V H Verduzco, Jorge A Gonzalez, Carlos Ernesto Borja, Jose Guadalupe Quezada, I A FigueroaAbstract:This work presents a study of the corrosion resistance as a function of the holding time on the interface generated during the process of brazing an AISI 304 to AISI 316L stainless steels by using a non-commercial Fe60Ni12Cr8P13B7 metallic Glass alloy Ribbon by induction heating at 1000 °C into a chamber with an Ar controlled atmosphere. Samples of the austenitic stainless steels were joined in a sandwich-like arrangement using the Fe-based metallic Glass Ribbon. Corrosion experiments carried out in distilled water and 3.5 wt. % sodium chloride solution revealed that the corrosion resistance was higher for samples tested in the distilled water than the latest medium for all dwell joining times, since in the former medium the samples passivated. It was also found that the highest corrosion resistance was achieved for samples joined for a dwelling time of 4 minutes.
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corrosion resistance of bonding zone of aisi 316l 304 stainless steels joined with iron based Glass Ribbon interlayer microstructural effects
Corrosion Engineering Science and Technology, 2012Co-Authors: J A Verduzco, V H Verduzco, L Dzibperez, J Gonzalezsanchez, V H Lopez, J SolisAbstract:The effect of holding time on the microstructure and corrosion resistance of the junction zone of AISI 316L bonded to AISI 304 stainless steels (SSs) at 960°C using an Fe based alloy filler was investigated. Samples of austenitic SSs were joined in a sandwich-like arrangement using non-commercial Fe60Ni12Cr8P13B7 metallic Glass Ribbon. Microstructural analysis revealed significant dissolution of the amorphous Ribbon in both SSs for short holding times, exhibiting a narrow interlayer with very fine precipitates. Larger holding times induced widening of the interlayer and coarsening of γ precipitates in the iron based alloy and significant variation of the interlayer chemical composition. Microstructural dissimilarity of the bonding zone promoted selective dissolution coupled with crevice corrosion of the joints in 3·5 wt-% sodium chloride solution. In general, at the joining temperature of 960°C, the bonding Ribbon and the AISI 316L SS presented higher corrosion resistance as the holding time increased up ...