bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Ga2O3 Nanoparticles Dispersion on Microstructure and Thermoelectric Properties of p-Type BiSbTe Based Alloys
Authors: Kim E.-B. , Koo J.-M. , Hong S.-J. 
Published: July 2017

AbstractIn this study, p-type Bi0.5Sb1.5Te3based nanocomposites with addition of different weight percentages of Ga2O3nanoparticles are fabricated by mechanical milling and spark plasma sintering. The fracture surfaces of all Bi0.5Sb1.5Te3nanocomposites exhibited similar grain distribution on the entire fracture surface. The Vickers hardness is improved for the Bi0.5Sb1.5Te3nanocomposites with 6 wt% added Ga2O3due to exhibiting fine microstructure, and dispersion strengthening mechanism. The Seebeck coefficient of Bi0.5Sb1.5Te3nanocomposites are significantly improved owing to the decrease in carrier concentration. The electrical conductivity is decreased rapidly upon the addition of Ga2O3nanoparticle due to increasing carrier scattering at newly formed interfaces. The peak power factor of 3.24 W/mK2is achieved for the base Bi0.5Sb1.5Te3sintered bulk. The Bi0.5Sb1.5Te3nanocomposites show low power factor than base sample due to low electrical conductivity.
Effect of Surfactant Addition on Bi2Te3 Nanostructures Synthesized by Hydrothermal Method
Authors: Dharmaiah Peyala , Lee C.H. , Madavali B. , Hong Soon-Jik 
Published: July 2017

AbstractIn the present work, we have prepared Bi2Te3nanostructures with different morphologies such as nano-spherical, nanoplates and nanoflakes obtained using various surfactant additions (EG, PVP, and EDTA) by a hydrothermal method. The shape of the nanoparticles can be controlled by addition of surfactants. The samples were characterized by x-ray diffraction (XRD) and scanning electron microscopy (SEM). It is found that the minority BiOCl phase disappears after maintained pH at 10 with EG as surfactant. SEM bulk microstructure reveals that the sample consists of fine and coarse grains. Temperature dependence of thermoelectric properties of the nanostructured bulk sample was investigated in the range of 300-450K. The presence of nanograins in the bulk sample exhibits a reduction of thermal conductivity and less effect on electrical conductivity. As a result, a figure of merit of the sintered bulk sample reached 0.2 at 400 K. A maximum micro Vickers hardness of 102 Hv was obtained for the nanostructured sample, which was higher than the other reported results.
Increasing the Surface Hardness of Cast Iron by Electrodeposition of Borides in Molten Salts
Authors: Al-Azzawi A.H. , Sytchev J. , Baumli P. 
Published: July 2017

AbstractIn this paper the electrodeposition of boron on the surface of cast iron as a coating is applied to increase the hardness and protect the substrate against abrasive wear. The boron containing coating was synthesized by electrodeposition process from a NaCl-KCl (1:1 mol)-10 w%NaF-10w% KBF4molten salt. The effect of electrolysis parameters (temperature and time) on the hardness is presented; the current density varied in the range −37 – −4.5 mA/cm2, allowing perfect coverage of and respect for dimensions. The electrochemical process was carried out at different temperatures (750°C-900°C) and for different periods of time (5-10 hours). Depending on the current density and duration of electrolysis, the deposits consist of FeB or Fe2B. Microhardness measurements across the boride layer indicated very high hardness values (between 1600 and 2100 HV0.05). The structure of the boride layer is linked to its boron content and thermal history: as-deposited coatings present very small grain sizes and can be considered as nearly amorphous.
Enhancement of Life Time of the Dimensionally Stable Anode for Copper Electroplating Applications
Authors: Son Seong Ho , Park Sung Cheol , Lee Man Seung 
Published: July 2017

Abstract
In order to enhance the long-term stability of DSA for copper electroplating process, in the present study, noble metal oxides with excellent electrochemical properties was used and optimum condition was determined the ratio of noble metal oxides, surface pre-treatment of titanium substrate and heat treatment. The effect of the surface pretreatment of titanium substrate and ratio of noble metal oxides were estimated by accelerated test at the highly current density conditions. The lifetime of DSA increase six-fold higher as the oxide thickness of Ta 7 : Ir 3 composition ratio. Under the optimal condition, surface pretreatment led to dramatic increase in the lifetime of DSA.
Crystallization behavior of Zr62Al8Ni13Cu17 Metallic Glass
Authors: Jo Mi Sun , Lee Jin Kyu 
Published: July 2017

AbstractThe crystallization behavior has been studied in Zr62Al8Ni13Cu17metallic glass alloy. The Zr62Al8Ni13Cu17metallic glass crystallized through two steps. The fcc Zr2Ni phase transformed from the amorphous matrix during first crystallization and then the Zr2Ni and residual amorphous matrix transformed into a mixture of tetragonal Zr2Cu and hexagonal Zr6Al2Ni phases. Johnson-Mehl-Avrami analysis of isothermal transformation data suggested that the formation of crystalline phase is primary crystallization by diffusion-controlled growth.
Whisker-Like Formations in Sn-3.0Ag-Pb Alloys
Authors: Koncz-Horváth D. , Gergely G. , Gácsi Z. 
Published: July 2017

AbstractIn this study, different types of whisker-like formations of Sn-3.0Ag based alloy were presented. In the experimental process the amount of Pb element was changed between 1000 and 2000 ppm, and the furnace atmosphere and cooling rate were also modified. The novelty of this work was that whisker-like formations in macro scale size were experienced after an exothermic reaction. The whiskers of larger sizes than general provided opportunities to investigate the microstructure and the concentration nearby the whiskers. In addition, the whisker-like formations from Sn-Ag based bulk material did not only consist of pure tin but tin and silver phases. The whisker-like growth appeared in several forms including hillock, spire and nodule shaped formations in accordance with parameters. It was observed that the compound phases were clustered in many cases mainly at hillocks.
Impact Characteristic According to the Structure of Crash Box at the Vehicle
Authors: Min B.S. , Cho J.U. 
Published: July 2017

AbstractThe crash box between a bumper and a car body in automobiles can reduce impacts for car bodies with a bumper at a low-speed collision by preventing the shocks. Also, this crash box is the part playing a very important role for the safety of vehicle and the reduction of repair cost, and many studies have been investigated for the performance. In this study, aluminum foam was inserted in an aluminum crash box to analyze the relationships of deformation, stress and internal energy. The compression characteristics are compared with six cases. In addition, the load due to displacement at experiment for a case is verified by modeling with finite elements and performing the structural analysis. As these study results for investigating characteristics of the crash box, it is thought that the effective designs of crash box to enhance the durability for collision are made possible.
Reaction Kinetics and Morphological Study of TiNb2O7 Synthesized by Solid-State Reaction
Authors: Choi S.H. , Ali B. , Choi K.S. , Hyun S.K. , Sim J.J. , Choi W.J. , Joo W. , Lim J.H. , Lee T.H. , Kim T.S. , Park K.T. 
Published: July 2017

AbstractAlthough TiNb2O7is regarded as a material with high application potential in lithium-ion batteries (LIBs) and solid-oxide fuel cells (SOFCs), it has been difficult to find suitable cost-effective conditions for synthesizing it on a commercial scale. In this study, TiNb2O7compounds were synthesized by a solid state synthesis process. For stoichiometrically precise synthesis of the TiNb2O7phase, the starting materials, TiO2and Nb2O5were taken in a 1:1 molar ratio. Activation energy and reaction kinetics of the system were investigated at various synthesis temperatures (800,1000,1200, and 1400°C) and for various holding durations (1,5,10, and 20 h). Furthermore, change in the product morphology and particle size distribution were also evaluated as a function of synthesis temperature and duration. Additionally, quantitative phase analysis was conducted using the Rietveld refinement method. It was found that increases in the synthesis temperature and holding time lead to increase in the mean particle size from 1 to 4.5 μm. The reaction rate constant for the synthesis reaction was also calculated.
Synthesis and Characterization of Antimony Telluride for Thermoelectric and Optoelectronic Applications
Authors: Zybała R. , Mars K. , Mikuła A. , Bogusławski J. , Soboń G. , Sotor J. , Schmidt M. , Kaszyca K. , Chmielewski M. , Ciupiński L. , Pietrzak K. 
Published: July 2017

AbstractAntimony telluride (Sb2Te3) is an intermetallic compound crystallizing in a hexagonal lattice withR-3mspace group. It creates a c lose packed structure of anABCABCtype. As intrinsic semiconductor characterized by excellent electrical properties, Sb2Te3is widely used as a low-temperature thermoelectric material. At the same time, due to unusual properties (strictly connected with the structure), antimony telluride exhibits nonlinear optical properties, including saturable absorption. Nanostructurization, elemental doping and possibilities of synthesis Sb2Te3in various forms (polycrystalline, single crystal or thin film) are the most promising methods for improving thermoelectric properties of Sb2Te3. Applications of Sb2Te3in optical devices (e.g. nonlinear modulator, in particular saturable absorbers for ultrafast lasers) are also interesting. The antimony telluride in form of bulk polycrystals and layers for thermoelectric and optoelectronic applications respectively were used. For optical applications thin layers of the material were formed and studied. Synthesis and structural characterization of Sb2Te3were also presented here. The anisotropy (packed structure) and its influence on thermoelectric properties have been performed. Furthermore, preparation and characterization of Sb2Te3thin films for optical uses have been also made.
Effect of Hafnium and Zirconium to Glass Forming Ability, Thermal Stability, Plasticity Deformation and Crystallization of Ni-Free Pentabasic Ti-Based Bulk Metallic Glasses
Authors: Oak J.J. , Kim Y.H. , Bae K.C. , Park Y.H. 
Published: July 2017

AbstractThe newly designed Ti-based bulk metallic glass (BMG) in which case of fracture behavior was observed 1990MPa to compressive strength with a wide plastic deformation around 7% after process of elastic deformation. This phenomenon can be compared with those of Ti-based alloys and other Ti-based BMGs and indicates high potential to be applied in use. It was evaluated the Ti-based BMG for thermal stability that the reduced glass parameters, ΔTx,Trgand γ, are 79K, 0.50 and 0.38, respectively. In addition, it reveals high activation energies for crystallization in which are estimated toEx1= 291.77 ±9.71 kJ/mol,Ex2= 588.77 ±28.88 kJ/mol andEx3= 330.26 ±3.61 kJ/mol on kissinger plotting in this study.
Effect of Fe Content on the Microstructure and Mechanical Properties of Ti-Al-Mo-V-Cr-Fe Alloys
Authors: Bae K.C. , Oak J.J. , Kim Y.H. , Park Y.H. 
Published: July 2017

AbstractTo investigate the effect of Fe content on the correlation between the microstructure and mechanical properties in near-b titanium alloys, the Ti-5Al-5Mo-5V-1Cr-xFe alloy system has been characterized in this study. As the Fe content increased, the number of nucleation sites and the volume fraction of theαphase decreased. We observed a significant difference in the shape and size of theαphase in the matrix before and after Fe addition. In addition, these morphological deformations were accompanied by a change in the shape of theαphase, which became increasingly discontinuous, and changed into globular-typeαphase in the matrix. These phenomena affected the microstructure and mechanical properties of Ti alloys. Specimen #2 exhibited a high ultimate tensile strength (1071 MPa), which decreased with further addition of Fe.
Synthesis and Characterization of Si Oxide Coated Nano Ceria by Hydrolysis, and Hydrothermal Treatment at Low Temperature
Authors: Kong M. , Kim H.W. 
Published: July 2017

AbstractThe purpose of this work was to the application of Si oxide coatings. This study deals with the preparation of ceria (CeO2) nanoparticles coating with SiO2by water glass and hydrolysis reaction. First, the low temperature hydro-reactions were carried out at 30~100°C. Second, Silicon oxide-coated Nano compounds were obtained by the catalyzing synthesis. CeO2Nano-powders have been successfully synthesized by means of the hydrothermal method, in a low temperature range of 100~200°C. In order to investigate the structure and morphology of the Nano-powders, scanning electron microscopy (SEM) and X-ray diffraction (XRD) were employed. The XRD results revealed the amorphous nature of silica nanoparticles. To analyze the quantity and properties of the compounds coated with Si oxide, transmission electron microscopy (TEM) in conjunction with electron dispersive spectroscopy was used. Finally, it is suggested that the simple growth process is more favorable mechanism than the solution/aggregation process.
Effect of Ultrasonication Dispersion Technique on Sintering Properties of CNT Reinforced Al-Zn-Mg-Cu Powder
Authors: Rudianto H. , Edtmaier C. , Dlouhy I. , Soukal F. 
Published: July 2017

Abstract
CNT has been researched significantly due to its properties especially mechanical and conductivity properties. Due to strong affinity between particles, dispersion has been remained a problem for its applications. Ultrasonication technique was used to disperse CNT on aluminum powder. Ultrasonication has successfully dispersed CNT on aluminum powder in ethanol. Low energy ball milling for 1h under argon gas with 5:1 ball to powder ratio was used to optimize dispersion of CNT on aluminum. CNT concentration in this research is ranged from 0.1 up to 3wt%. Premix Al-5.5Zn-2.5Mg-0.5Cu powder was used as matrix for this research. Sintering at 580°C for 1h under argon gas was carried to produce high density materials. Pores are still remained on material and it is possibility that pores were caused by agglomeration of CNT. Dispersion high content of CNT is still remained obstacle on this research. Aluminum carbide, Al4C3 is recognized as a ‘bridge between aluminum and CNT for stress transfer was investigated in this research. Raman Spectroscopy, XRD and SEM-EDS were carried out to characterize materials.
Transient Liquid Phase Behavior of Sn-Coated Cu Particles and Chip Bonding using Paste Containing the Particles
Authors: Hwang Jun Ho , Lee Jong-Hyun 
Published: July 2017

AbstractSn-coated Cu particles were prepared as a filler material for transient liquid phase (TLP) bonding. The thickness of Sn coating was controlled by controlling the number of plating cycles. The Sn-coated Cu particles best suited for TLP bonding were fabricated by Sn plating thrice, and the particles showed a pronounced endothermic peak at 232°C. The heating of the particles for just 10 s at 250°C destroyed the initial core-shell structure and encouraged the formation of Cu-Sn intermetallic compounds. Further, die bonding was also successfully performed at 250°C under a slight bonding pressure of around 0.1 MPa using a paste containing the particles. The bonding time of 30 s facilitated the bonding of Sn-coated Cu particles to the Au surface and also increased the probability of network formation between particles.
Investigation of the Microstructure and Thermoelectric Properties of P-Type BiSbTe Alloys by Usage of Different Revolutions Per Minute (RPM) During Mechanical Milling
Authors: Yoon S.-M. , Madavali B. , Yoon Y.-N. , Hong S.-J. 
Published: July 2017

AbstractIn this work, p-type Bi0.5Sb1.5Te3alloys were fabricated by high-energy ball milling (MA) and spark plasma sintering. Different revolutions per minute (RPM)s were used in the MA process, and their effect on microstructure, and thermoelectric properties of p-type Bi0.5Sb1.5Te3were systematically investigated. The crystal structure of milled powders and sintered samples were characterized using X-ray diffraction. All the powders exhibited the same morphology albeit with slight differences find at 1100 RPM conditions. A slight grain size refinement was observed on the fracture surfaces from 500 to 1100 RPM specimens. The temperature dependence of Seebeck coefficient, electrical conductivity, and power factors were measured as a function of temperature with different RPM conditions. The power factor shows almost same (~3.5 W/mK2at RT) for all samples due to unchanged Seebeck and electrical conductivity values. The peak ZT of 1.07 at 375K is obtained for 1100 RPM specimen due to low thermal conductivity.
Effect of Acid Dissolution Conditions on Recovery of Valuable Metals from Used Plasma Display Panel Scrap
Authors: Kim Chan-Mi , Dharmaiah Peyala , Kim Hyo-Seob , Koo Jar-Myung , Yoon Jae-Sik , Hong Hyun-Seon , Hong Soon-Jik 
Published: July 2017

AbstractThe objective of this particular study was to recover valuable metals from waste plasma display panels using high energy ball milling with subsequent acid dissolution. Dissolution of milled (PDP) powder was studied in HCl, HNO3, and H2SO4acidic solutions. The effects of dissolution acid, temperature, time, and PDP scrap powder to acid ratio on the leaching process were investigated and the most favorable conditions were found: (1) valuable metals (In, Ag, Mg) were recovered from PDP powder in a mixture of concentrated hydrochloric acid (HCl:H2O = 50:50); (2) the optimal dissolution temperature and time for the valuable metals were found to be 60°C and 30 min, respectively; (3) the ideal PDP scrap powder to acid solution ratio was found to be 1:10. The proposed method was applied to the recovery of magnesium, silver, and indium with satisfactory results.
Improved Mechanical Properties of Al-Si Alloys by Adding an Extrusion Process to Conventional Processing Method
Authors: Han J.Y. , Femi O.E. , Kilicaslan F. , Jeong C.U. , Baeg C.H. , Hong S.J. , Koo J.M. 
Published: July 2017

AbstractIn this study, the mechanical properties of Al-Si alloys was improved by selecting higher Si content and avoiding distortion in Al-Si matrix by adding an extrusion process such that the fabrication processes casting and extrusion were in sequence. Cast billets were extruded at ratios 4:1 and 10:1 to obtained two extruded bars with different processing parameters. The as-extruded samples were characterized and investigated for microstructure and mechanical properties. Optical Microscope was used to examined phase morphologies and microstructures of the extruded Al-Si bars. Mechanical properties were conducted on each sample to study the effectiveness of the additional extrusion process in high Si content Al-Si alloys. The result shows that by increasing the extrusion ratio, the size of the primary Si particle reduces leading to a higher density, better tensile and yield strength compared to the cast billet.
Optimization of Roll Bonding by Hot Rolling in Experimental and Industrial Use
Authors: Szabó G. 
Published: July 2017

AbstractIn this study the major topic were the bonding properties of the layer-clad aluminum sheets. The bonding was performed between AlMn1Si0.8 and AlSi10 alloys using hot rolling (a VON ROLL experimental duo mill). The experimental temperatures were 460, 480 and 500°C. The goodness of bonding was tested by tensile test and T-peel test. T-peel test provided a good description about the quality of bonding. Structure analysis was also performed by light microscopy to detect typical bonding faults. The aim of this investigation is modelling the bonding conformation in experimental conditions. Further aim of this investigation is to produce some typical bonding faults and find the cause of formation. The influence of the rolling temperature and surface roughness on the bonding was also analyzed. Rolling schedule and the role of first pass on the development of perfect bonding were experimentally determined.
Effect of Electroless Ni–P Plating on the Bonding Strength of Bi–Te-Based Thermoelectric Modules
Authors: Kim S.S. , Son I. , Kim K.T. 
Published: July 2017

AbstractIn the present study, electroless Ni–P plating was applied to Bi–Te-based thermoelectric materials as a barrier layer and the effect of the Ni–P plating on the bonding strength of the thermoelectric module was investigated. The bonding strength of the n- and p-type modules increased after being subjected to the electroless Ni–P plating treatment. In the case of the thermoelectric module that was not subjected to electroless Ni–P plating, Sn and Te were interdiffused and formed a brittle Sn–Te-based metallic compound. The shearing mostly occurred on the bonding interface where such an intermetallic compound was formed. On the other hands, it was found from the FE-EPMA analysis of the bonding interface of thermoelectric module subjected to electroless Ni-P plating that the electroless Ni-P plating acted as an anti-diffusion layer, preventing the interdiffusion of Sn and Te. Therefore, by forming such an anti-diffusion layer on the surface of the Bi–Te based thermoelectric element, the bonding strength of the thermoelectric module could be increased.
Microstructure Evolution of Ni-Based ODS Superalloy Powders During Horizontal Rotary Ball Milling
Authors: Lee H.-E. , Kim Y.Su. , Park J.K. , Oh S.-T. 
Published: July 2017

AbstractMicrostructure evolution of Ni-based oxide dispersion-strengthened alloy powders with milling time is investigated. The elemental powders having a nominal composition of Ni-15Cr-4.5Al-4W-2.5Ti-2Mo-2Ta-0.15Zr-1.1Y2O3in wt % were ball-milled by using horizontal rotary ball milling with the change of milling velocity. Microstructure observation revealed that large aggregates were formed in the early stages of ball milling, and further milling to 5 h decreased particle size. The average crystalline size, estimated by the peak broadening of XRD, decreased from 28 nm to 15 nm with increasing milling time from 1 h to 5 h. SEM and EPMA analysis showed that the main elements of Ni and Cr were homogeneously distributed inside the powders after ball milling of 5 h.
Effect of Grinding Fineness of Fly Ash on the Properties of Geopolymer Foam
Authors: Szabó R. , Gombkötő I. , Svéda M. , Mucsi G. 
Published: July 2017

AbstractPresent paper deals with the development of geopolymer foam prepared from ground F class power station fly ash. The effect of the fly ash fineness on the rheology of the geopolymer paste and the foam properties have been investigated. The raw fly ash was ground in a ball mill for various duration, 5, 10, 20, 30, 60 and 120 min. Geopolymer paste was prepared from the raw and ground fly ash with NaOH – sodium silicate mixture as alkaline activator. Geopolymer foam production was made using H2O2as foaming agent. Additionally, the geopolymer material structure was investigated by Fourier transform infrared spectrometer, the foam cell structure was monitored using optical microscopy. The rheological behaviour of the geopolymer paste changed due to the grinding of fly ash (from Bingham plastic to Newtonian liquid). Grinding of fly ash has a significant effect on the physical properties as well as on the cell structure of the geopolymer foam.