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1

Optical constants and growth mode of Ni films deposited on evaporated Al, Ag and Cu films  

Microsoft Academic Search

Information about the optical constants and structures of Ni films in Ni\\/Al(AlOxAl), Ni\\/Ag and Ni\\/Cu(CuOxCu) bilayer systems are obtained through an attenuated total reflection (ATR) analysis, scanning electron spectroscopy (SEM) observation and the X-ray diffraction measurements. In particular, the optical constants of the Ni films are evaluated at various stages of growth. It is finally concluded that the Ni films

K. Hanamoto; A Shinya; M Kuwahara; T Okamoto; M Haraguchi; M Fukui; K Koto

1998-01-01

2

Laser ablation deposition of Cu-Ni and Ag-Ni films: Nonconservation of alloy composition and film microstructure  

NASA Astrophysics Data System (ADS)

Laser ablation depositon was used to grow polcrystalline Cu-Ni and Ag-Ni thin films on amorphous substrates at room temperature. X-ray diffraction was employed to determine the phases present and the residual macrostress and to analyze the structure imperfection in terms of crystallite size and microstrain. For confirmation and complementary microstructural data transmission electron microscopy was applied. Analysis of the gross compositon was achieved by electron probe microanalysis and x-ray fluorescence. The films contained substantially less Cu and Ag than the targets, which was caused by preferential scattering of ablated Cu and Ag species upon incidence at the growing films. The Cu-Ni films were entirely composed of a Cu(x) Ni(1-x) solid solution. The Ag-Ni films were composed of a Ag(x) Ni(1-x) solid solution and of pure Ag and pure Ni. The nonequilibrium Ag(x) Ni(1-x) solid solution could contain up to 44 at. % Ag. The residual macrostress in the Cu-Ni films was compressive, whereas it was tensile in the Ag-Ni films. The occurrence of these stresses could be interpreted as due to the combined effects of atomic peening and cooling after depositon and, in the case of the Ag-Ni films, of stress relaxation by particle decomposition of the Ag(x) Ni (1-x) solid solution during film growth. The microstrains in the Ag(x) Ni(1-x) solid solutions were higher than in similarly prepared pure elemental Ag and Ni films. Compositional inhomogeneity of the Ag(x) Ni(1-x) solid solution crystallites contributed in particular to this effect. The strain-free lattice parameters of the solid solutions were found to be in fair agreement with those predicted by Vegard's law.

van Ingen, R. P.; Fastenau, R. H. J.; Mittemeijer, E. J.

1994-08-01

3

Effects of limited cu supply on soldering reactions between SnAgCu and Ni  

NASA Astrophysics Data System (ADS)

The volume difference between the various types of solder joints in electronic devices can be enormous. For example, the volume difference between a 760-m ball grid array solder joint and a 75-m flip-chip solder joint is as high as 1000 times. Such a big difference in volume produces a pronounced solder volume effect. This volume effect on the soldering reactions between the Sn3AgxCu (x=0.4, 0.5, or 0.6 wt.%) solders and Ni was investigated. Three different sizes of solder spheres (300, 500, and 760 m in diameter) were soldered onto Ni soldering pads. Both the Cu concentration and the solder volume had a strong effect on the type of the reaction products formed. In addition, (Cu,Ni)6Sn5 massively spalled from the interface under certain conditions, including smaller joints and those with lower Cu concentration. We attributed the massive spalling of (Cu,Ni)6Sn5 to the decrease of the available Cu in the solders. The results of this study suggest that Cu-rich SnAgCu solders can be used to prevent this massive spalling.

Ho, C. E.; Lin, Y. W.; Yang, S. C.; Kao, C. R.; Jiang, D. S.

2006-05-01

4

Study of interaction between Cu-Sn and Ni-Sn interfacial reactions by Ni-Sn3.5Ag-Cu sandwich structure  

Microsoft Academic Search

The interaction between Cu-Sn and Ni-Sn interfacial reactions in a soldering system has been studied using a Ni-Sn3.5Ag-Cu\\u000a sandwich structure. A layer of Cu-Sn intermetallic compound was observed at the interface of the Ni foil after 30 sec of reflowing.\\u000a Two stages of the Cu-Sn compound growth on the Ni side were observed: (1) in the first minute of reflow,

S. J. Wang; C. Y. Liu

2003-01-01

5

Dissolution Rates and Reliability Effects of Au, Ag, Ni and Cu in Lead Base Solders  

Microsoft Academic Search

The rates at which Au, Ag, Cu, and Ni wires dissolved in 95wt%Pb-5%Sn and 92.5wt% Pb-5%In-2.57%Ag soft solders were measured between 360 and 500C. The rates have an Arrhenius behavior with temperature and for both solders nickel has the lowest dissolution rate while gold has the highest. A model is discussed, using the analysis of Lommel and Chalmers, which allows

Howard Berg; Edward L. Hall

1973-01-01

6

Solar Optical Properties of Thin Films of Ag, Cu, Au, Al, Fe, Cr, and Ni.  

National Technical Information Service (NTIS)

The optical properties of metal-coated window glass have been investigated. Various thicknesses of Ag, Al, Au, Cr, Cu, Fe and Ni were deposited on glass substrates, and the reflectance from the front and back side and the transmittance between 0.4 microme...

B. Karlsson C. G. Ribbing

1977-01-01

7

Laser ablation deposition of Cu-Ni and AgNi films: Nonconservation of alloy composition and film microstructure  

Microsoft Academic Search

Laser ablation deposition was used to grow polycrystalline Cu-Ni and Ag-Ni thin films on amorphous substrates at room temperature. X-ray diffraction was employed to determine the phases present and the residual macrostress and to analyze the structural imperfection in terms of crystallite size and microstrain. For confirmation and complementary microstructural data transmission electron microscopy was applied. Analysis of the gross

R. P. van Ingen; R. H. J. Fastenau; E. J. Mittemeijer

1994-01-01

8

Laser ablation deposition of Cu-Ni and AgNi films: Nonconservation of alloy composition and film microstructure  

Microsoft Academic Search

Laser ablation depositon was used to grow polcrystalline Cu-Ni and Ag-Ni thin films on amorphous substrates at room temperature. X-ray diffraction was employed to determine the phases present and the residual macrostress and to analyze the structure imperfection in terms of crystallite size and microstrain. For confirmation and complementary microstructural data transmission electron microscopy was applied. Analysis of the gross

R. P. van Ingen; R. H. J. Fastenau; E. J. Mittemeijer

1994-01-01

9

Interfacial microstructure between Sn-3Ag-xBi alloy and Cu substrate with or without electrolytic Ni plating  

NASA Astrophysics Data System (ADS)

The microstructure of the interfacial phase of Sn-3Ag-xBi alloy on a Cu substrate with or without electrolytic Ni plating was evaluated. Bismuth additions into Sn-Ag alloys do not affect interfacial phase formations. Without plating, ?-Cu6Sn5/?-Cu3Sn interfacial phases developed as reaction products in the as-soldered condition. The ?-phase Cu6Sn5 with a hexagonal close-packed structure grows about 1-m scallops. The ?-phase Cu3Sn with an orthorhombic structure forms with small 100-nm grains between ?-Cu6Sn5 and Cu. For Ni plating, a Ni3Sn4 layer of monoclinic structure formed as the primary reaction product, and a thin ?-Ni3Sn2 layer of hexagonal close-packed structure forms between the Ni3Sn4 and Ni layer. In the Ni layer, Ni-Sn compound particles of nanosize distribute by Sn diffusion into Ni. On the total thickness of interfacial reaction layers, Sn-3Ag-6Bi joints are thicker by about 0.9 m for the joint without Ni plating and 0.18 m for the joint with Ni plating than Sn-3Ag joints, respectively. The thickening of interfacial reaction layers can affect the mechanical properties of strength and fatigue resistance.

Hwang, Chi-Won; Lee, Jung-Goo; Suganuma, Katsuaki; Mori, Hirotaro

2003-02-01

10

Effect of Ni addition on the Sn0.3Ag0.7Cu solder joints  

Microsoft Academic Search

It is gradually recognized that Sn-Ag-Cu is better alloy system for application prospect in the lead-free solders. In order to cut down the cost and improve properties, researchers have always been searching for proper compositions and adding elements to improve properties actively. This paper has investigated the effect of Ni addition on Sn-0.3Ag-0.7Cu (SAC0307) low-Ag solder joint. The results of

Lingling Wang; Fenglian Sun; Yang Liu; Lifeng Wang

2009-01-01

11

Effect of Ag addition on the thermal characteristics and structural evolution of Ag-Cu-Ni ternary alloy nanoclusters: Atomistic simulation study  

NASA Astrophysics Data System (ADS)

Atomic-scale compositional variation in Ag contents across Ag-Cu-Ni alloy upon being subjected to repeated annealing cycles is shown to result in significant differences in the structure and the thermal stability of ternary alloy nanoclusters. Molecular dynamics (MD) simulations employing quantum Sutton-Chen potentials were used to investigate the effect of Ag addition on the thermal characteristics of Ag-Cu-Ni ternary alloy nanoclusters of 4-nm diameter. The initial configurations were generated using Monte Carlo simulations and comprise surface-segregated structures with the lowest surface energy component, Ag, occupying low coordination sites such as corners, edges, and faces. A compositional oscillation between the Cu and Ni atoms was observed for layers beneath the surface which transitions into a bulk alloy composition at the core. We find that the Cu-Ni binary alloys on being subjected to annealing schedules demonstrated an increase in thermal stability, as indicated by the increase in melting points. The annealed configurations of the Ag-Cu-Ni ternary alloy, on the other hand, showed a nonmonotonic behavior. For Ag compositions less than 20%, we observe an initial increase in melting point followed by a decrease in the third cycle. For higher Ag compositions (>20%), we observe a decrease in melting point with annealing; the rate of decrease is strongly correlated to the Ag composition in the alloy. Cu-Ni nanoclusters having 50% Cu showed a transition from an initial icosahedral to a cuboctahedron-like structure whereas Ag-rich Ag-Cu-Ni ternary alloys showed a transition from icosahedral to an amorphous structure. Compositional analysis based on radial distribution functions and density profiles indicate that these transitions were dependent on the distribution of the alloying elements in the nanocluster. Calculated root-mean-square displacements and diffusion coefficients indicate that the rate of mixing of Ag increases with Ag content in the Ag-Cu-Ni ternary alloy. Ternary alloys show heterogeneous melting during the first heating cycle followed by a bulk-like melting during the subsequent annealing cycles. The simulation results are consistent with available experimental studies.

Subbaraman, Ram; Sankaranarayanan, Subramanian K. R. S.

2011-08-01

12

Effects of Ni addition on microstructure and the shear strength of Sn3.0Ag0.5Cu\\/Cu solders joints  

Microsoft Academic Search

The effects of the fourth Ni element on microstructure and monotonic shear strength of Sn-3.0Ag-0.5Cu lead-free solder were investigated. The addition of the Ni element makes the new (CuxNi1-x)6Sn5 phase, which improves the solder microstructure. The results indicate that the addition of Ni element increases the shear strength of solder joint. When the content of Ni is 0.10 wt.%, the

Lifeng Wang; Xuwei Shen; Fenglian Sun; Yang Liu

2008-01-01

13

Microstructure and Intermetallic Growth at the Sn-Ag-Cu\\/Ni Interface after Thermal-shearing Cycling  

Microsoft Academic Search

In this work, microstructure and intermetallic growth at the Sn-Ag-Cu\\/Ni interface were researched under the thermal-shearing cycling condition varying from 25 degC to 125 degC. The results show that two kinds of intermetallic compounds, identified as (NixCu 1-x)Sn3 and (CuxN1-x)6 Sn5, were found at the interface between Sn-3.5Ag-0.5Cu and Ni after thermal-shearing cycling. The (CuxN1-x)6Sn5 IMC grows up slowly as

Lihua Qi; Jihua Huang; Jiangang Zhang; Ye Wang

2005-01-01

14

Reactions of Sn-4.0Ag-0.5Cu on Cu and Electroless Ni Substrate in Premelting Soldering Process  

NASA Astrophysics Data System (ADS)

Early formation of Cu6Sn5 and (Ni,Cu)6Sn5 during soldering was investigated. Sn4.0Ag0.5Cu solder on Cu and electroless Ni-Au substrate was quenched in ice water after the initial stage of melting, and the solder-substrate interface was analyzed by transmission electron microscopy and energy-dispersive x-ray spectroscopy. At the contacting point, Cu3Sn and Cu6Sn5 were found at the solder-Cu substrate interface, while (Ni,Cu)6Sn5 and Ni2SnP were identified at the solder-electroless Ni interface. The contacting points were confirmed as the sites of heterogeneous nucleation. TEM analysis suggested that the nucleation of both intermetallic compounds can be attributed to diffusion-induced crystallization. Details of the early interfacial reactions are discussed.

Chung, C. Key; Chen, Y. J.; Yang, T. L.; Kao, C. R.

2013-06-01

15

A Comparative Study of Sn3.5Ag and Sn3.8Ag0.7Cu for BGA Spheres on Ni\\/Au Finish  

Microsoft Academic Search

A comparative study was conducted with Sn3.5%Ag and Sn3.8%Ag0.7%Cu solder balls on ball grid array (BGA) packages with Ni\\/Au pad finishing. The study was carried out in different levels. At individual solder joint level, Sn3.5Ag showed no intermetallic brittle failure in cold ball pull test under any stress condition. In contrast, 70-100% of the failure mode of SAC387 was brittle

Poh-Leng Eu; Huey-Jiun Hoh; Joachim Rayos; Peng Su; W. Lindsay; S. Chopin; I. Ahmad

2007-01-01

16

Investigation of interfacial reaction between SnAg eutectic solder and Au\\/Ni\\/Cu\\/Ti thin film metallization  

Microsoft Academic Search

This paper reports the formation of intermetallic compounds in Au\\/Ni\\/Cu\\/Ti under-bump-metallization (UBM) structure reacted\\u000a with Ag-Sn eutectic solder. In this study, UBM is prepared by evaporating Au(500 ?)\\/Ni(1000 ?)\\/Cu(7500 ?) \\/Ti (700 ?) thin\\u000a films on top of Si substrates. It is then reacted with Ag-Sn eutectic solder at 260 C for various times to induce different\\u000a stages of the

J. Y. Park; C. W. Yang; J. S. Ha; C.-U. Kim; E. J. Kwon; S. B. Jung; C. S. Kang

2001-01-01

17

Reaction Mechanism and Mechanical Properties of the Flip-Chip Sn-3.0Ag-0.5Cu Solder Bump with Cu/Ni- xCu/Ti Underbump Metallization After Various Reflows  

NASA Astrophysics Data System (ADS)

Ni underbump metallization (UBM) has been widely used as the diffusion barrier between solder and Cu pads. To retard the fast dissolution rate of Ni UBM, Cu was added into Ni thin films. The Ni-Cu UBM can provide extra Cu to the solders to maintain the Cu6Sn5 intermetallic compound (IMC) at the interface, which can thus significantly decrease the Ni dissolution rate. In this study, the Cu content of the sputtered Cu/Ni- xCu/Ti UBM was varied from 0 wt.% to 20 wt.%. Sn-3Ag-0.5Cu solder was reflowed with Cu/Ni-Cu/Ti UBM one, three, and five times. Reflow and cooling conditions altered the morphology of the IMCs formed at the interface. The amount of (Cu,Ni)6Sn5 increased with increasing Cu content in the Ni-Cu film. The Cu concentration of the intermetallic compound was strongly dependent on the composition of the Ni-Cu films. The results of this study suggest that Cu-rich Ni- xCu UBM can be used to suppress interfacial spalling and improve shear strength and pull strength of solder joints.

Peng, Chung-Nan; Duh, Jenq-Gong

2009-12-01

18

Effect of Ni layer thickness and soldering time on intermetallic compound formation at the interface between molten Sn3.5Ag and Ni\\/Cu substrate  

Microsoft Academic Search

The binary eutectic Sn-3.5wt.%Ag alloy was soldered on the Ni\\/Cu plate at 250C, the thickness of the Ni layer changing from\\u000a 0 through 2 and 4 m to infinity, and soldering time changing from 30 to 120 s at intervals of 30 s. The infinite thickness\\u000a was equivalent to the bare Ni plate. The morphology, composition and phase identification of

Won Kyoung Choi; Hyuck Mo Lee

1999-01-01

19

Embedded-atom-method functions for the fcc metals Cu, Ag, Au, Ni, Pd, Pt, and their alloys  

Microsoft Academic Search

A consistent set of embedding functions and pair interactions for use with the embedded-atom method (M.S. Daw and M. I. Baskes, Phys. Rev. B 29, 6443 (1984)) have been determined empirically to describe the fcc metals Cu, Ag, Au, Ni, Pd, and Pt as well as alloys containing these metals. The functions are determined empirically by fitting to the sublimation

S. M. Foiles; M. I. Baskes; M. S. Daw

1986-01-01

20

Electromigration of Sn37Pb and Sn3Ag1.5Cu\\/Sn3Ag0.5Cu composite flip-chip solder bumps with Ti\\/Ni(V)\\/Cu under bump metallurgy  

Microsoft Academic Search

We examine electromigration fatigue reliability and morphological patterns of Sn37Pb and Sn3Ag1.5Cu\\/Sn3Ag0.5Cu composite solder bumps in a flipchip package assembly with Ti\\/Ni(V)\\/Cu UBM. The flipchip test vehicle was subjected to test conditions of five combinations of applied electric currents and ambient temperatures, namely, 0.4A\\/150C, 0.5A\\/150C, 0.6A\\/125C, 0.6A\\/135C, and 0.6A\\/150C. The electrothermal coupling analysis was employed to investigate the current crowding

Yi-Shao Lai; Kuo-Ming Chen; Chin-Li Kao; Chiu-Wen Lee; Ying-Ta Chiu

2007-01-01

21

Low-energy electron elastic scattering from Mn, Cu, Zn, Ni, Ag, and Cd atoms  

SciTech Connect

Electron elastic total cross sections (TCSs) for ground and excited Mn, Cu, Zn, Ni, Ag, and Cd atoms have been investigated in the electron-impact energy range 0 {<=}E{<=} 1 eV. The near-threshold TCSs for both the ground and excited states of these atoms are found to be characterized by Ramsauer-Townsend minima, shape resonances, and extremely sharp resonances corresponding to the formation of stable bound negative ions. The recently developed Regge-pole methodology where the crucial electron-electron correlations are embedded is employed for the calculations. From close scrutiny of the imaginary parts of the complex angular momenta, we conclude that these atoms form stable weakly bound ground and excited negative ions as Regge resonances through slow electron collisions. The extracted electron binding energies from the elastic TCSs of these atoms are contrasted with the available experimental and theoretical values.

Felfli, Z.; Msezane, A. Z. [Department of Physics and Center for Theoretical Studies of Physical Systems, Clark Atlanta University, Atlanta, Georgia 30314 (United States); Sokolovski, D. [School of Mathematics and Physics, Queen's University of Belfast, Belfast, BT7 1NN (United Kingdom); Department of Chemical Physics, University of the Basque Country, Leioa (Spain)

2011-05-15

22

Interfacial reactions between lead-free SnAgCu solder and Ni(P) surface finish on printed circuit boards  

Microsoft Academic Search

Transmission electron microscopy and scanning electron microscopy were employed to analyze the interfacial microstructure between Sn-Ag-Cu solder alloys and Ni(P)\\/Au metallizations. The intermetallic compound Cu6Sn5, containing a small amount of dissolved Ni, was found to form preferentially on the Ni coating. This compound layer served as a barrier for direct reaction of Sn with the Ni(P) coating. On the Ni(P)

Kejun Zeng; Vesa Vuorinen; Jorma K. Kivilahti

2002-01-01

23

Interfacial intermetallic compound growth and shear strength of low-silver SnAgCuBiNi/Cu lead-free solder joints  

NASA Astrophysics Data System (ADS)

The growth rule of the interfacial intermetallic compound (IMC) and the degradation of shear strength of Sn-0.8Ag-0.5Cu-2.0Bi-0.05Ni (SACBN)/Cu solder joints were investigated in comparison with Sn-3.0Ag-0.5Cu (SAC305)/Cu solder joints aging at 373, 403, and 438 K. The results show that (Cu1- x ,Ni x )6Sn5 phase forms between the SACBN solder and Cu substrate during soldering. The interfacial IMC thickens constantly with the aging time increasing, and the higher the aging temperature, the faster the IMC layer grows. Compared with the SAC305/Cu couple, the SACBN/Cu couple exhibits a lower layer growth coefficient. The activation energies of IMC growth for SACBN/Cu and SAC305/Cu couples are 111.70 and 82.35 kJ/mol, respectively. In general, the shear strength of aged solder joints declines continuously. However, SACBN/Cu solder joints exhibit a better shear strength than SAC305/Cu solder joints.

Wei, Guo-qiang; Wang, Lei; Peng, Xin-qiang; Xue, Ming-yang

2013-09-01

24

Electrical characteristics for Sn-Ag-Cu solder bump with Ti\\/Ni\\/Cu under-bump metallization after temperature cycling tests  

Microsoft Academic Search

Lead-free solder bumps have been widely used in current flip-chip technology (FCT) due to environmental issues. Solder joints after temperature cycling tests were employed to investigate the interfacial reaction between the Ti\\/Ni\\/Cu under-bump metallization and Sn-Ag-Cu solders. The interfacial morphology and quantitative analysis of the intermetallic compounds (IMCs) were obtained by electron probe microanalysis (EPMA) and field emission electron probe

T. I. Shih; Y. C. Lin; J. G. Duh; Tom Hsu

2006-01-01

25

Interfacial segregation in Ag-Au, Au-Pd, and Cu-Ni alloys: I. (100) surfaces  

Microsoft Academic Search

Atomistic simulations of segregation to (100) free surface in Ag-Au, Au-Pd, and Cu-Ni alloy systems have been performed for a wide range of temperatures and compositions within the solid solution region of these alloy phase diagrams. In addition to the surface segregation profiles, surface free energies, enthalpies, and entropies were determined. These simulations were performed within the framework of the

H. Y. Wang; R. Najafabadi; D. J. Srolovitz; R. Lesar

1993-01-01

26

Treatment of Au(II), Ag(I), Cu(II), Ni(II) from Electroplating Wastewater by Laminaria japonica: Biosorption, Desorption and Recycling  

Microsoft Academic Search

The pretreated brown algae Laminaria japonica was used to adsorb and desorb Au2+, Ag+, Cu2+ and Ni2+ ions from electroplating wastewater in this article. The results indicated that the biosorption process of Au2+, Ag+, Cu2+ and Ni2+ ions could be divided into two steps. The first step was physical adsorption and reached equilibrium quickly, in less than 15 min. This

Lin Li; He Yuan; Tian Chunyu; Wang Xian; Wang Liyi

2010-01-01

27

Influence of Pd Concentration on the Interfacial Reaction and Mechanical Reliability of the Ni/Sn-Ag-Cu- xPd System  

NASA Astrophysics Data System (ADS)

The interfacial reaction between Ni and Sn-3Ag-0.5Cu- xPd alloys ( x = 0 wt.% to 1 wt.%) at 250C and the mechanical reliability of the solder joints were investigated in this study. The reaction and the resulting mechanical properties were both strongly dependent on the Pd concentration. When x was low (?0.2 wt.%), the reaction product at the Ni/Sn-Ag-Cu- xPd interface was a layer of (Cu,Ni)6Sn5. An increase of x to 0.3 wt.% produced one additional (Pd,Ni)Sn4 compound that was discontinuously scattered above the (Cu,Ni)6Sn5. When x was relatively high (0.5 wt.% to 1 wt.%), a dual layer of (Pd,Ni)Sn4-(Cu,Ni)6Sn5 developed with the reaction time. The results of the high-speed ball shear (HSBS) test showed that the mechanical strength of the Ni/Sn-3Ag-0.5Cu- xPd joints degraded with increasing x, especially when x reached a high level of ?0.3 wt.%. This degradation corresponded to the growth of (Pd,Ni)Sn4 at the interface, and joints easily failed along the boundaries of solder/(Pd,Ni)Sn4 and (Pd,Ni)Sn4/(Cu,Ni)6Sn5 in the HSBS test. The (Pd,Ni)Sn4-induced joint failure (Pd embrittlement) was alleviated by doping the solder with an appropriate amount of Cu. When the Cu concentration increased to 1 wt.% and the Pd concentration did not exceed 0.5 wt.%, the growth of (Pd,Ni)Sn4 could be thoroughly inhibited, thereby avoiding the occurrence of Pd embrittlement in the solder joints.

Ho, C. E.; Hsu, L. H.; Lin, S. W.; Rahman, M. A.

2012-01-01

28

Effect of Ni-Coated Carbon Nanotubes on the Corrosion Behavior of Sn-Ag-Cu Solder  

NASA Astrophysics Data System (ADS)

In this study, the effect of Ni-coated carbon nanotubes (Ni-CNTs) on the corrosion resistance of 95.8Sn-3.5Ag-0.7Cu (SAC) solder at ambient temperature in 3.5 wt.% NaCl solution was investigated using the potentiodynamic polarization method. The corrosion products were analyzed by field-emission scanning electron microscopy (S4800), energy-dispersive spectroscopy, and x-ray diffraction. The results showed that addition of Ni-CNTs enhanced the corrosion resistance of the SAC solder and that increasing the content of Ni-CNTs made the effect more evident. The mechanism of the corrosion resistance improvement is the formation of a compact corrosion layer of Ni-CNTs that provides an inert physical barrier to the initiation and development of corrosion. Furthermore, in the corrosion microcell produced by the Ni-CNTs dispersed in the SAC solder, the Ni-CNTs act as a third phase (electrode) which contributes to reducing the galvanic corrosion between Sn anode and Ag3Sn cathode. Hence, the corrosion resistance of the composite solders was improved.

Han, Y. D.; Chen, L.; Jing, H. Y.; Nai, S. M. L.; Wei, J.; Xu, L. Y.

2013-10-01

29

Suppressing Sn-Patch Growth in Ti/Ni(V)/Cu Under Bump Metallization with Sn-Ag-Cu Solder After Reflow and Aging  

NASA Astrophysics Data System (ADS)

Sputtered Ti/Ni(V)/Cu under bump metallization (UBM) is widely used in flip chip technology because the metals are nonmagnetic and the consumption of the Ni(V) layer is low. It is noted that V does not react with solders and intermetallic compounds (IMC) during reflow and aging; however, a Sn-patch forms in the Ni(V) layer, and the Sn-patch growth may cause the IMCs to detach from the interface of solder joints. In this study, Sn-3.0Ag-0.5Cu solder was reflowed on Ti/Ni(V)/Cu UBM with different Cu thicknesses at 250C for 60 s, and then aged at 150C for various periods of time. It was revealed that the Sn-patch growth could be controlled by increasing the Cu thickness in the Ti/Ni(V)/Cu UBM. A feasible approach to suppress Sn-patch formation after reflow and aging is discussed.

Wang, Kai-Jheng; Duh, Jenq-Gong

2012-04-01

30

Thermal and Mechanical Stability of Ce-Containing Sn-3.9Ag-0.7Cu Lead-Free Solder on Cu and Electroless Ni-P Metallizations  

NASA Astrophysics Data System (ADS)

Rare earth (RE)-containing solders have been shown to exhibit improvements in both physical and mechanical properties. However, the reactive nature of RE elements with oxygen may degrade the mechanical properties even under room-temperature aging. In this article, we report on the microstructure and mechanical properties of as-processed and thermally aged Ce-containing Sn-3.9Ag-0.7Cu solder reflowed on electroless Ni-P and Cu metallizations. The microstructure of both as-reflowed and thermally aged Ce-containing Sn-3.9Ag-0.7Cu solder joints is more refined compared with conventional Sn-3.9Ag-0.7Cu solder joints. The (Cu,Ni)6Sn5 intermetallic layer formed at the Cu/Ce-containing solder interface is thinner than that of Sn-3.9Ag-0.7Cu solder. The monotonic shear behavior of as-reflowed and thermally aged Sn-3.9Ag-0.7Cu-0.5Ce/Cu and electroless Ni-P lap shear joints was studied, and compared with Sn-3.9Ag-0.7Cu. It was found that both as-reflowed and thermally aged Ce-containing Sn-3.9Ag-0.7Cu exhibit higher strain to failure compared with Sn-3.9Ag-0.7Cu solder joints.

Xie, Huxiao; Chawla, Nikhilesh; Mirpuri, Kabir

2012-12-01

31

Wetting and reaction of Sn2.8Ag0.5Cu1.0Bi solder with Cu and Ni substrates  

Microsoft Academic Search

The wettability of newly developed Sn-2.8Ag-0.5Cu-1.0Bi lead-free solder on Cu and Ni substrates was assessed through the\\u000a wetting balance tests. The wettability assessment parameters such as contact angle (?c) and maximum wetting force (Fw) were documented for three solder bath temperatures with three commercial fluxes, namely, no-clean (NC), nonactivated (R),\\u000a and water-soluble organic acid flux (WS). It was found that

M. J. Rizvi; Y. C. Chan; C. Bailey; H. Lu; M. N. Islam; B. Y. Wu

2005-01-01

32

Electrical characteristics for Sn-Ag-Cu solder bump with Ti\\/Ni\\/Cu under-bump metallization after temperature cycling tests  

Microsoft Academic Search

Lead-free solder bumps have been widely used in current flip-chip technology (FCT) due to environmental issues. Solder joints\\u000a after temperature cycling tests were employed to investigate the interfacial reaction between the Ti\\/Ni\\/Cu under-bump metallization\\u000a and Sn-Ag-Cu solders. The interfacial morphology and quantitative analysis of the intermetallic compounds (IMCs) were obtained\\u000a by electron probe microanalysis (EPMA) and field emission electron probe

T. I. Shih; Y. C. Lin; J. G. Duh; Tom Hsu

2006-01-01

33

Intermetallic compound formation in Sn-Co-Cu, Sn-Ag-Cu and eutectic Sn-Cu solder joints on electroless Ni(P) immersion au surface finish after reflow soldering  

Microsoft Academic Search

The interfacial reactions between Sn-0.4Co-0.7Cu eutectic alloy and immersion Au\\/electroless Ni(P)\\/Cu substrate were investigated after reflow soldering at 260degC for 2 minutes. Common Sn-4.0Ag-0.5Cu and eutectic Sn-0.7Cu solders were used as reference. Two types of intermetallic compounds (IMC) were found in the solder matrix of the Sn-0.4Co-0.7Cu alloy, namely coarser CoSn2 and finer Cu6 Sn5 particles, while only one ternary

Peng Sun; Cristina Andersson; Xicheng Wei; Zhaonian Cheng; Dongkai Shangguan; Johan Liu

2006-01-01

34

Atomic size and chemical effects on the local order of Zr2M ( M=Co , Ni, Cu, and Ag) binary liquids  

NASA Astrophysics Data System (ADS)

First-principles molecular dynamics simulations are performed to investigate the atomic size and chemical effects on the short-range order (SRO) in superheated and undercooled Zr-based metallic liquids, Zr2M ( M=Co , Ni, Cu, and Ag). We demonstrate that the local atomic structures in liquids are quite sensitive to the atomic size ratio and the electronic interactions between component elements. The large negative heats of mixing for Zr-M do not favor icosahedral SRO in these binary liquids, contrary to the common belief. Full icosahedral structure units are few in the superheated liquids, although the number of icosahedral clusters increases upon undercooling. Comparing Zr2Co , Zr2Ni , and Zr2Cu , all of which have very similar atomic size ratios, we find that the degree of local icosahedral order increases with decreasing interaction strength between the d electrons in Zr-Co, Zr-Ni, and Zr-Cu. A comparison of Zr2Cu and Zr2Ag alloys shows that the degree of icosahedral order increases much more in Zr2Ag than in Zr2Cu with decreasing temperature. The difference in atomic sizes of Cu and Ag may account for the subtle discrepancy in the evolution of short-range ordering in undercooled Zr2Cu and Zr2Ag liquids.

Huang, Li; Wang, C. Z.; Hao, S. G.; Kramer, M. J.; Ho, K. M.

2010-01-01

35

Effect of Ni-Coated Carbon Nanotubes on Interfacial Reaction and Shear Strength of Sn-Ag-Cu Solder Joints  

NASA Astrophysics Data System (ADS)

In this study, varying weight percentages of Ni-coated carbon nanotubes (Ni-CNTs) were incorporated into Sn-Ag-Cu (SAC) solder matrix, to form composite solder. Up to 0.05% of Ni-CNTs were successfully incorporated. The interfacial microstructure and shear strength of solders on Ni/Au-finished Cu substrates were investigated after aging at 150C for up to 42 days. Results revealed that, after soldering and aging for various lengths of time, the interfacial intermetallic compound (IMC) thickness of the unreinforced solder joint was observed to grow more significantly than that of the composite solder joints. Furthermore, the composite solder joints also showed lower diffusion coefficients (2.5 10-15 cm2/s to 3.2 10-15 cm2/s) compared with that of the SAC solder joints (4.9 10-15 cm2/s). Shear test results revealed that as-soldered and aged composite solder joints had better ultimate shear strength than their monolithic counterparts and the shear strength of all aged solder joints decreased with increasing aging time.

Han, Y. D.; Jing, H. Y.; Nai, S. M. L.; Xu, L. Y.; Tan, C. M.; Wei, J.

2012-09-01

36

On the correlation between phonon spectra and surface segregation features in Ag-Cu-Ni ternary nanoalloys  

NASA Astrophysics Data System (ADS)

Atomic scale characterization of chemical ordering, compositional distribution and microstructure is of tremendous importance for applications such as catalysis which is primarily dominated by processes occurring at surface and is strongly influenced by the subsurface layers. Phonon spectra obtained from molecular dynamics simulations of single metals as well as their bimetallic and ternary alloy nanoclusters can be used to obtain new insights into the atomic scale distribution in the nanoclusters, their microstructure and dynamical properties. Monte-Carlo (MC) simulations are used to obtain the minimum energy configurations of various Ag-Cu-Ni ternary alloys in which the Ag content is systematically varied from 0 to 50%Ag while keeping the relative composition of Cu and Ni constant. Detailed compositional analyses of the final MC configurations are carried out. The generated microstructure comprised of surface segregated structures in which Ag atoms occupy low coordination sites such as corners, edges and faces. As the Ag content in the ternary alloy is increased, the surface sites get increasingly occupied with the lowest coordination sites being populated first. The Cu and Ni compositions in the interior of the cluster show compositional oscillation. The final alloy microstructure is dictated by the competition between the various entropic and energetic factors. Our analysis of the phonon density of states identifies various surface (low frequency) and bulk (high frequency) modes which is determined by their location in the nanocluster and the local environment. Systematic trends in the observed peak intensities and frequency shifts at the low and high frequency ends of the spectrum for the various alloy compositions are explained on the basis of bond-lengths, local coordination, extent of alloying, and neighboring elemental environment. We find that the characteristic microstructural features observed at the atomic scale are strongly correlated to the vibrational densities of states of the constituent atoms in nanoalloys. Comparisons with experimental investigations are made where possible. Such a characterization method provides a predictive tool for materials which are extremely important for catalytic applications and emerging energy technologies.

Subbaraman, Ram; Sankaranarayanan, Subramanian K. R. S.

2011-08-01

37

Creep Properties of Sn-1.0Ag-0.5Cu Lead-Free Solder with Ni Addition  

NASA Astrophysics Data System (ADS)

In this work, tensile creep tests for Sn-1.0Ag-0.5Cu-0.02Ni solder have been conducted at various temperatures and stress levels to determine its creep properties. The effects of stress level and temperature on creep strain rate were investigated. Creep constitutive models (such as the simple power-law model, hyperbolic sine model, double power-law model, and exponential model) have been reviewed, and the material constants of each model have been determined based on experimental results. The stress exponent and creep activation energy have been studied and compared with other researchers' results. These four creep constitutive models established in this paper were then implemented into a user-defined subroutine in the ANSYS finite-element analysis software to investigate the creep behavior of Sn-1.0Ag-0.5Cu-0.02Ni solder joints of thin fine-pitch ball grid array (TFBGA) packages for the purpose of model comparison and application. Similar simulation results of creep strain and creep strain energy density were achieved when using the different creep constitutive models, indicating that the creep models are consistent and accurate.

Che, F. X.; Zhu, W. H.; Poh, Edith S. W.; Zhang, X. R.; Zhang, Xiaowu; Chai, T. C.; Gao, S.

2011-03-01

38

Photocatalytic removal of M(2+) (Ni(2+), Cu(2+), Zn(2+), Cd(2+), Hg(2+) and Ag(+)) over new catalyst CuCrO(2).  

PubMed

The metal ions M(2+) (Ni(2+), Cu(2+), Zn(2+), Cd(2+), Hg(2+) and Ag(+)) are potentially toxic. Their electro deposition has been carried out in aqueous air-equilibrated CuCrO(2) suspension upon visible illumination. The delafossite CuCrO(2) is p-type semiconductor characterized by a low band gap (1.28 eV) and a long-term chemical stability. The corrosion rate is found to be 10(-2) micromol m(-2)month(-1) in aqua regia. The oxide has been elaborated through nitrate route where the specific surface area is increased via the surface/bulk ratio. A correlation exists between the dark M(2+) adsorption, the redox potential of M(2+/0) couple and the conduction band of CuCrO(2) positioned at -1.06 V(SCE). Ag(+) cannot be photoreduced because of its positive potential located far above the valence band. By contrast, Zn(2+) is efficiently deposited due to the large driving force at the interface. The improved photoactivity of copper with a deposition percentage (90%) is attributed to the strong dark adsorption onto the surface catalyst. The results indicate a competitive effect with the water reduction; it has been observed that the M(2+) deposition goes parallel with the hydrogen evolution. Such behavior is attributed to the low H(2) over voltage when ultra fine aggregate of M islands are photodeposited onto CuCrO(2) substrate. PMID:18384943

Ketir, W; Bouguelia, A; Trari, M

2008-02-16

39

Role of Ni and Cu metallization dissolution in various Ni\\/solder\\/Cu jointing sequences  

Microsoft Academic Search

This study was conducted to the Ni and Cu dissolution behaviors, and the cross-interaction during Ni\\/Sn3.5Ag\\/Cu joints fabrication. To form such joint structure, two common soldering sequences were employed: an as-reflow Cu\\/Sn3.5Ag solder bump jointed to Ni (Seq. I), and an as-reflow Ni\\/Sn3.5Ag solder bump jointed to Cu (Seq. II). The research results revealed that a ternary compound, (Cu, Ni)6Sn5,

C. S. Liu; C. E. Ho

2010-01-01

40

Stopping powers of Be, Al, Ti, V, Fe, Co, Ni, Cu, Zn, Mo, Rh, Ag, Sn, Ta, Pt and Au for 13 MeV deuterons  

Microsoft Academic Search

The stopping powers of Be, Al, Ti, V, Fe, Co, Ni, Cu, Zn, Mo, Rh, Ag, Sn, Ta, Pt and Au for 13 MeV deuterons were measured with an accuracy of 0.35% using a surface barrier silicon detector. The effect of the fringing field of the analyzing magnet was considered in the determination of the incident energy of the deuterons.

N. Shiomi-Tsuda; N. Sakamoto; R. Ishiwari

1994-01-01

41

Spatial Distribution of Atoms in Gas-Covered Pd-X Nanoparticles (X=Ag, Cu, Ni, Pt)  

NASA Astrophysics Data System (ADS)

A Monte-Carlo (MC) simulation procedure has been developed where the pair bond energies are allowed to take into account the various coordination numbers of surface atoms and the presence of adsorbates. The pair bond energies are calculated from partial bond energies of atoms which, in turn, are calculated from modified tight binding model in the second moment approximation. The model has been applied to study the role of adsorption of hydrogen, oxygen, carbon monoxide and nitric oxide on the surface composition and surface bond geometry of bimetallic Pd-X (X=Ag, Cu, Ni, Pt) nanoparticles having fcc cubo-octahedral geometry with 586 atoms. The results are compared with the known experimental results. Importance of the results in studying reactions on supported bimetallic catalysts has been highlighted.

Menon, Mahesh; Khanra, Badal C.

42

Proposed power-function N-body potential for the fcc structured metals Ag, Au, Cu, Ni, Pd, and Pt  

SciTech Connect

We propose, for the fcc structured Ag, Au, Cu, Ni, Pd, and Pt metals, an N-body potential with a simple power-function form, which significantly simplifies the fitting procedure and computation. The proposed potentials are able to correctly reproduce the lattice constants, cohesion energies, elastic constants, relative stabilities of different structures, formation energies of vacancy, and surface energies. In addition, the thermal properties, such as melting points and heat capacities, etc., are also satisfactorily determined from the proposed potentials. Moreover, the proposed potential is applied to calculate the trigonal and tetragonal paths between the fcc and bcc structures, and the calculated paths match well with those obtained from the first principles calculations.

Li, J. H.; Kong, Y.; Guo, H. B.; Liang, S. H.; Liu, B. X. [Advanced Materials Laboratory, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China)

2007-09-01

43

Alleviating coking in ethanol steam reforming by co-loading binary oxides Ni-M (M=Ag, Cu, Mn) on peony-like ceria  

NASA Astrophysics Data System (ADS)

Previously, hydrothermally prepared mesoporous peony-like ceria (PCO) material was shown to exhibit superior catalytic properties for CO oxidation and ethanol reforming. Ni supported PCO had been shown to have high activity for ethanol steam reforming at low temperature. In this work, Ag, Cu and Mn is co-loaded with Ni on PCO catalysts by impregnation method. The catalysts were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), and a combined thermogravimetry, differential scanning calorimetry, and mass spectrometry (TG-DSC-MS). It was found that all the catalysts gave 100% ethanol conversion above ca. 300C and exhibited similar H2 yield. It is found that the severe coking problem for the Ni-loaded PCO catalyst was alleviated significantly if Ag, Cu or Mn is co-loaded. Among them, the addition of Mn is the most effective in reducing carbon formation.

Xian, C. N.; Li, J. G.; Li, H.; Chen, L. Q.; Sun, J.; Lee, J. S.

2011-06-01

44

A study on interfacial reactions between electroless NiP under bump metallization and 95.5Sn4.0Ag0.5Cu alloy  

Microsoft Academic Search

Even though electroless Ni-P and Sn-Ag-Cu solders are widely used materials in flip-chip bumping technologies, interfacial\\u000a reactions of the ternary Cu-Ni-Sn system are not well understood. The growth of intermetallic compounds (IMCs) at the under\\u000a bump metallization (UBM)\\/solder interface can affect solder-joint reliability, so analysis of IMC phases and understanding\\u000a their growth kinetics are important. In this study, interfacial reactions

Young-Doo Jeon; Sabine Nieland; Andreas Ostmann; Herbert Reichl; Kyung-Wook Paik

2003-01-01

45

Ag-Cu System  

NSDL National Science Digital Library

The information provided for the Ag-Cu System consists of five parts: - Diagram: The diagram shows the calculated phase diagram of the system. - Status: The source and status of the analytical description of the Gibbs energies of the phases. - Additional Assessments: Bibliographic information for alternate thermodynamic descriptions. - Invariant Equilibria: Table with the calculated invariant equilibria of the system. The table lists the phases involved in the reaction, phase compositions and reaction temperature. - Phases: Table with the phases of the system. The table lists the crystal structure, common names of the phases and the model used for the thermodynamic description. Thermodynamic databases allow the compact storage of phase equilibria information in the form of Gibbs energy functions for each phase. The thermodynamic description of each phase in the binary system is derived from the assessment of the available phase equilibria and thermochemical data. The calculated phase diagram of the Ag-Cu system is presented.

Kattner, Ursula

2003-01-01

46

Effects of High-Temperature Treatment on the Reaction Between Sn-3%Ag-0.5%Cu Solder and Sputtered Ni-V Film on Ferrite Substrate  

NASA Astrophysics Data System (ADS)

We have demonstrated a novel sputtering method for lead-free thin metal films on ferrite substrates for surface-mount inductor applications. In a surface-mounting process, the cladding of enameled wire needs to be burnt off at high temperature, which requires the devices to withstand a high-temperature reliability test at 420C for 10 s. There are no reports that a sputtered film of thickness less than 6 ?m can withstand this test. In this work, we used Ag/Ni-7 wt.%V double metal layers for the metallization. The dissolution of Ni-7 wt.%V in Sn-3%Ag-0.5%Cu lead-free solder at various temperatures was studied in detail. Scanning electron microscopy with energy-dispersive x-ray spectroscopy was used to investigate the interfacial reaction between the sputtered films and the solder. The intermetallic compounds are mainly (Cu,Ni)6Sn5 at 250C; however, (Ni,Cu)3Sn4 becomes the predominant composition at 420C. In addition, although outdiffusion of V atoms from the Ni-V layer was observed, its effect on the intermetallic compound (IMC) was insignificant. We further confirmed that the proposed metallization is able to pass the aforementioned high-temperature reliability test.

Shen, Xiaohu; Jin, Hao; Dong, Shurong; Wong, Hei; Zhou, Jian; Guo, Zhaodi; Wang, Demiao

2012-11-01

47

Stopping powers of Be, Al, Ti, V, Fe, Co, Ni, Cu, Zn, Mo, Rh, Ag, Sn, Ta, Pt and Au For 6.5 MeV protons  

Microsoft Academic Search

The stopping powers of Be, Al, Ti, V, Fe, Co, Ni, Cu, Zn, Mo, Rh, Ag, Sn, Ta, Pt and Au for 6.5 MeV have been measured using a surface barrier silicon detector. The accuracy of the results is +\\/- 0.3%. The detail of the experimental procedures is described. The results have been compared with the Ris data and the

R. Ishiwari; N. Shiomi-Tsuda; N. Sakamoto

1988-01-01

48

A Ni-free ZrCuFeAlAg bulk metallic glass with potential for biomedical applications.  

PubMed

The mechanical properties and biocompatibility of an Ni-free Zr-based bulk metallic glass (BMG) Zr60.14Cu22.31Fe4.85Al9.7Ag3 were investigated in detail to evaluate its potential as a biomaterial. The BMG was found to have a low Young's modulus of 821.9GPa, a high strength of 172028MPa and a high fracture toughness of 9419MPam(1/2), as well as good fatigue strength over 400MPa. The corrosion behavior of the alloy was investigated in simulated body fluid (SBF) by electrochemical measurements, which indicates that the Zr-based BMG has a better corrosion resistance than pure Zr and Ti6Al4V. X-ray photoelectron spectroscopy analysis revealed that the passive film formed on the BMG surface is enriched in Al- and Zr-oxides, which could account for the good corrosion resistance of the BMG. On the other hand, metal ion release of the BMG in SBF was determined by inductively coupled plasma mass spectrometry after the BMG was immersed in SBF at 37C for 30days, showing a ppb (ngml(-1)) level of metal ion release. The in vitro test via cell culture indicates that the BMG exhibits a cytotoxicity of Grade 0-1, which is as good as Ti6Al4V alloy. Cell adhesion morphological analysis shows that the cells were flattened and well spread out on the surfaces of the BMG, showing that the BMG had good biocompatibility. The combination of good mechanical properties and biocompatibility demonstrates that the Ni-free Zr-based BMG studied in this work is a good candidate for a new type of load-bearing biomedical material. PMID:23429233

Liu, Yan; Wang, Yi-Mei; Pang, Hui-Fang; Zhao, Qiu; Liu, Lin

2013-02-18

49

Interfacial Reactions of Sn, Sn-3.0Ag-0.5Cu, and Sn-9Zn Lead-Free Solders with Fe-42Ni Substrates  

NASA Astrophysics Data System (ADS)

Interfacial reactions between Sn, Sn-3.0 wt.%Ag-0.5 wt.%Cu (SAC), and Sn-9 wt.%Zn (SZ) lead-free solders and Fe-42 wt.%Ni (alloy 42) substrates at 240C, 255C, and 270C were investigated in this study. FeSn2, (Fe,Ni, Cu)Sn2, and (Ni,Fe)5Zn21 phases were formed, respectively, at the interface in the Sn/alloy 42, SAC/alloy 42, and SZ/alloy 42 couples. As the reaction time and temperature were increased, the layered intermetallic compound (IMC) assumed two distinct structures, i.e., a thicker layer and a pillar-shaped IMC, in all couples. The IMC thickness of these couples increased with the increase of reaction time and temperature. The IMC thickness was also proportional to the square root of the reaction time. The interfacial reaction mechanism of these couples was diffusion controlled.

Yen, Yee-Wen; Hsieh, Yu-Ping; Jao, Chien-Chung; Chiu, Chao-Wei; Li, Yi-Shan

2013-09-01

50

Electromigration reliability of Sn37Pb and Sn3Ag1.5Cu\\/Sn3Ag0.5Cu composite flip-chip solder bumps with Ti\\/Ni(V)\\/Cu under bump metallurgy  

Microsoft Academic Search

We examine electromigration fatigue reliability and morphological patterns of Sn-37Pb and Sn-3Ag-1.5Cu\\/Sn-3Ag-0.5Cu composite solder bumps in a flip-chip package assembly. The test vehicle is subjected to test conditions of five combinations of applied electric currents and ambient temperatures, namely, 0.4 A\\/150 degC, 0.5 A\\/150 degC, 0.6 A\\/125 degC, 0.6 A\\/135 degC, and 0.6 A\\/150 degC. An electrothermal coupling analysis is

Yi-Shao Lai; Kuo-Ming Chen; Chiu-Wen Lee; Chin-Li Kao; Yu-Hsiu Shao

2005-01-01

51

Shear and Pull Testing of Sn3.0Ag0.5Cu Solder with Ti\\/Ni(V)\\/Cu Underbump Metallization During Aging  

Microsoft Academic Search

Ti\\/Ni(V)\\/Cu underbump metallization (UBM) is widely used in flip-chip technology today. The advantages of Ti\\/Ni(V)\\/Cu UBM\\u000a are a low reaction rate with solder and the lack of a magnetic effect during sputtering. Sn atoms diffuse into the Ni(V) layer\\u000a to form a Sn-rich phase, the so-called Sn-patch, during reflow and aging. In this study, the relationship between interfacial\\u000a reaction and

Kai-Jheng Wang; Jenq-Gong Duh

2009-01-01

52

Electronic Band-Structure Calculations of Ba8Me x Si46-x Clathrates with Me = Mg, Pd, Ni, Au, Ag, Cu, Zn, Al, Sn  

NASA Astrophysics Data System (ADS)

Clathrate materials of AlSi, CuSi or NiSi type consisting of abundant elements have a realistic chance of becoming useful thermoelectrics in the near future, because the rattling effect due to their crystal cage structure provides a large figure of merit ZT even in experiments measured under large temperature gradients. In the search for better thermoelectrics, new element combinations in the clathrate type I structure with cubic space group Pm3n were calculated using VASP ab initio software. Predictions of the Seebeck coefficient were made by checking the electronic band structure and density of states for a large variety of input data. For x values around 4 to 6 in the structural formula Ba8Me x Si46-x the substituents Cu, Au, and Ag are best for good thermoelectric behavior, which is discussed in this paper as a result of the low electron-phonon interaction parameter.

Wunderlich, Wilfried; Amano, Mao; Matsumura, Yoshihito

2013-10-01

53

Impact Testing of Sn3.0Ag0.5Cu Solder with Ti\\/Ni(V)\\/Cu Under Bump Metallization After Aging at 150C  

Microsoft Academic Search

Nonmagnetic Ni(V) metal and low consumption rate with solders are the advantages of sputtered Ti\\/Ni(V)\\/Cu under bump metallization\\u000a (UBM). However, a Sn-rich phase (Sn-patch herein) can form in the Ni(V) layer after reflow and aging. In lead-free solder,\\u000a Sn-patches form and grow more quickly than in Sn-Pb solder. Thus, the effect of Sn-patches on solder joint reliability becomes\\u000a critical. In

Kai-Jheng Wang; Jenq-Gong Duh; Bob Sykes; Dirk Schade

2010-01-01

54

Reinforced {110} textured Ag\\/Ni composite ribbons for biaxially oriented YBCO coated tapes  

Microsoft Academic Search

New, mechanically reinforced, {110} textured Ag composite ribbons were fabricated as possible inexpensive substrates for coated conductors without any buffer layer. The key part of this work was the use of a thin but textured Ag outlayer on an AgMg, Ni, or Ni alloys core that ensures the mechanical reinforcement while decreasing the amount of Ag. A thin Cu (50

Hongli Suo; J.-Y. Genoud; M. Schindl; E. Walker; R. Flukiger

2001-01-01

55

Magnetic hyperfine field of Fe interfaced with Ni, Cu, Ni\\/Cu, and Cu\\/Ni  

Microsoft Academic Search

Thin films grown in 10-6 Torr on polycrystalline substrates of Ni, Cu, Ni\\/Cu, and Cu\\/Ni are investigated by transmission Mssbauer spectroscopy at 300 K. The effect of the substrate on the structure of the Fe films is discussed. Fe films grown on Ni seem to assume fcc structure while those on Cu are bcc.

E. Colombo; G. Fratucello; A. Poggi; F. Ronconi

1986-01-01

56

Effect of reaction time and P content on mechanical strength of the interface formed between eutectic Sn-Ag solder and Au/electroless Ni(P)/Cu bond pad  

NASA Astrophysics Data System (ADS)

In this work, shear strengths of the solder joints for Sn-Ag eutectic alloy with the Au/electroless Ni(P)/Cu bond pad were measured for three different electroless Ni(P) layers. Sn-Ag eutectic solder alloy was kept in molten condition (240 C) on the Au/electroless Ni(P)/Cu bond pad for different time periods ranging from 0.5 min to 180 min to render the ultimate interfacial reaction and the consecutive shear strength. After the shear test, fracture surfaces were investigated by scanning electron microscopy equipped with energy dispersed x ray. Cross-sectional studies of the interfaces were also conducted to correlate with the fracture surfaces. It was found that formation of crystalline phosphorous-rich Ni layer at the solder interface of Au/electroless Ni(P)/Cu bond pad with Sn-Ag eutectic alloy deteriorates the mechanical strength of the joints significantly. It was also noticed that such weak P-rich Ni layer appears quickly for high-P content electroless Ni(P) layer. However, when this P-rich Ni layer disappears from a prolonged reaction, the shear strength increases again.

Alam, M. O.; Chan, Y. C.; Tu, K. N.

2003-09-01

57

Dissolution and Interfacial Reactions of (Cu,Ni)6Sn5 Intermetallic Compound in Molten Sn-Cu-Ni Solders  

NASA Astrophysics Data System (ADS)

(Cu,Ni)6Sn5 is an important intermetallic compound (IMC) in lead-free Sn-Ag-Cu solder joints on Ni substrate. The formation, growth, and microstructural evolution of (Cu,Ni)6Sn5 are closely correlated with the concentrations of Cu and Ni in the solder. This study reports the interfacial behaviors of (Cu,Ni)6Sn5 IMC (Sn-31 at.%Cu-24 at.%Ni) with various Sn-Cu, Sn-Ni, and Sn-Cu-Ni solders at 250C. The (Cu,Ni)6Sn5 substrate remained intact for Sn-0.7 wt.%Cu solder. When the Cu concentration was decreased to 0.3 wt.%, (Cu,Ni)6Sn5 significantly dissolved into the molten solder. Moreover, (Cu,Ni)6Sn5 dissolution and (Ni,Cu)3Sn4 formation occurred simultaneously for the Sn-0.1 wt.%Ni solder. In Sn-0.5 wt.%Cu-0.2 wt.%Ni solder, many tiny (Cu,Ni)6Sn5 particulates were formed and dispersed in the solder matrix, while in Sn-0.3 wt.%Cu-0.2 wt.%Ni a lot of (Ni,Cu)3Sn4 grains were produced. Based on the local equilibrium hypothesis, these results are further discussed based on the liquid-(Cu, Ni)6Sn5-(Ni,Cu)3Sn4 tie-triangle, and the liquid apex is suggested to be very close to Sn-0.4 wt.%Cu-0.2 wt.%Ni.

Wang, Chao-hong; Lai, Wei-han; Chen, Sinn-wen

2013-08-01

58

Direct determination of traces of Ag, Cd, Pb, Bi, Cr, Mn, Co, Ni, Li, Be, Cu and Sb in environmental waters and geological materials by simultaneous multi-element graphite furnace atomic absorption spectrometry with Zeeman-effect background correction  

Microsoft Academic Search

A method was developed for direct determination of minor and trace amounts of Cr, Mn, Cu, Ni, Co, Li, Pb, Cd, Bi, Sb, Be and Ag in silicate rock, lake and stream sediments using a microwave oven dissolution method and a multi-element graphite furnace atomic absorption spectrometer equipped with a Zeeman-effect background correction device. The measurement technique was also suitable

J. G. Sen Gupta; J. L. Bouvier

1995-01-01

59

Reliability and Failure Mechanism of Current-Stressed 99.3Sn0.7Cu\\/96.5Sn3Ag0.5Cu Composite Flip-Chip Solder Joints with Cu or Au\\/Ni\\/Cu Substrate Pad Metallization  

Microsoft Academic Search

Electromigration and thermomigration in the flip chip package are apparent in the reliability test. The 99.3Sn-0.7Cu\\/96.5Sn-3Ag-0.5Cu composite flip-chip solder joints with Ti\\/Ni(V)\\/Cu under bump metallurgy and different surface finishes are investigated when applied current density of 10 kA\\/cm2 and 15 kA\\/cm2 at 150degC and 125degC, respectively. Experimental results show the solder migrates to the Al trace in the chip when

Ying-Ta Chiu; Yu-Hsiu Shao; Yi-Shao Lai

2008-01-01

60

Effect of Cu content on the interfacial reliability of SnAgCu solder joints  

Microsoft Academic Search

NEMI recommended Sn3.9Ag0.6Cu to replace the eutectic SnPb solder, but solder joints of this alloy have poor performance in reliability tests of electronic packages, especially the board level drop test. In this paper, the effect of Cu content in solder is studied on the interfacial reliability of SnAgCu solder joints on the Ni\\/Au plated pads. After preconditioning (three reflows post

Kejun Zeng; Becky Holdford

2010-01-01

61

Group 10 and 11 metal boratranes (Ni, Pd, Pt, CuCl, AgCl, AuCl, and Au+) derived from a triphosphine-borane.  

PubMed

The ambiphilic triphosphine-borane ligand 1 {TPB = [o-iPr2P-(C6H4)3B} readily coordinates to all group 10 and 11 metals to afford a complete series of metal boratranes (TPB)[M] 2-8 (2: M = Ni, 3: M = Pd, 4: M = Pt, 5: M = CuCl, 6: M = AgCl, 7: M = AuCl, 8: M = Au+). Spectroscopic and structural characterization unambiguously establishes the presence of M-B interactions in all of these complexes. The first evidence for borane coordination to copper and silver is provided, and the Au-->B interaction is shown to persist upon chloride abstraction. Experimental and theoretical considerations indicate that the M-->B interaction is strongest in the Pt and Au complexes. The influence of the oxidation state and charge of the metal is substantiated, and the consequences of relativistic effects are discussed. The coordination of the sigma-acceptor borane ligand is found to induce a significant bathochromic shift of the UV-vis spectra, the Ni, Pd, and Pt complex presenting strong absorptions in the visible range. In addition, all of the group 10 and 11 metal boratranes adopt C3 symmetry both in the solid state and in solution. The central M-->B interaction is found to moderately influence the degree of helicity and configurational stability of these three-bladed propellers, and DFT calculations support a dissociative pathway for the inversion process. PMID:19554696

Sircoglou, Marie; Bontemps, Sbastien; Bouhadir, Ghenwa; Saffon, Nathalie; Miqueu, Karinne; Gu, Weixing; Mercy, Maxime; Chen, Chun-Hsing; Foxman, Bruce M; Maron, Laurent; Ozerov, Oleg V; Bourissou, Didier

2008-12-10

62

Method Development for Simultaneous Determination of Transition (Au, Ag, Cd, Cu, Mn, Ni, Pb, Zn) and Noble (Pd, Pt, Rh) Metal Volatile Species by Microwave-Induced Plasma Spectrometry Using Ultrasonic Micronebulizer Dual Capillary Sample Introduction System  

Microsoft Academic Search

The commercial ultrasonic nebulizer NOVA-DUO (Optolab, Warsaw, Poland) has been evaluated for the simultaneous determination of transition (Au, Ag, Cd, Cu, Mn, Ni, Pb, Zn) and noble (Pd, Pt, Rh) volatile metal species by microwave induced plasmaoptical emission spectrometry (MIP-OES). Simultaneous mixing and nebulization of the two solutions (acidified sample and reductant) on the piezoelectric transducer, with the possibility of

Henryk Matusiewicz; Mariusz Slachcinski

2010-01-01

63

Ag-Cu-Pb System  

NSDL National Science Digital Library

The information provided for the Ag-Cu-Pb System consists of five parts: - Diagram: The diagram shows the calculated liquidus projection. Shown are the isotherms and lines of two-fold saturation. - Status: The analytical descriptions of the Gibbs energies of the constituent binaries are combined for each phase and used to predict the multicomponent system. - Sources: Bibliographic information for the thermodynamic descriptions. - Invariant Equilibria: Table with the calculated invariant equilibria of the system. The table lists the phases involved in the reaction, phase compositions and reaction temperature. - Phases: Table with the phases of the system. The table lists the crystal structure, common names of the phases and the model used for the thermodynamic description. Thermodynamic databases allow the compact storage of phase equilibria information in form of Gibbs energy functions for each phase. There are basicly two types of thermodynamic descriptions of a ternary system: (1) extrapolated, i.e., the analytical descriptions of constituent binaries are combined and used to predict the multicomponent system, (2) assessed, i.e., the thermodynamic description is derived from the assessment of the available ternary phase equilibria and thermochemical data. If experimental data were only available or considered for part of the system then a partial assessment is possible. The calculated phase diagram of the Ag-Cu-Pb system is presented.

Kattner, Ursula

2003-01-01

64

Ag-Cu-Sn System  

NSDL National Science Digital Library

The information provided for the Ag-Cu-Sn System consists of five parts: - Diagrams: The diagrams show the calculated projection of the liquidus. Shown are the isotherms and lines of two-fold saturation. The first diagram shows the liquidus projection for the entire system, the second diagram shows an enlargement of the Sn-rich part of the system. - Status: The analytical descriptions of the Gibbs energies of the constituent binaries are combined for each phase and used to predict the multicomponent system. - Sources: Bibliographic information for the thermodynamic descriptions. - Invariant Equilibria: Table with the calculated invariant equilibria of the system. The table lists the phases involved in the reaction, phase compositions and reaction temperature. - Phases: Table with the phases of the system. The table lists the crystal structure, common names of the phases and the model used for the thermodynamic description. Thermodynamic databases allow the compact storage of phase equilibria information in form of Gibbs energy functions for each phase. There are basicly two types of thermodynamic descriptions of a ternary system: (1) extrapolated, i.e., the analytical descriptions of constituent binaries are combined and used to predict the multicomponent system, (2) assessed, i.e., the thermodynamic description is derived from the assessment of the available ternary phase equilibria and thermochemical data. If experimental data were only available or considered for part of the system then a partial assessment is possible. The calculated phase diagram of the Ag-Cu-Sn system is presented.

Kattner, Ursula

2003-01-01

65

Ag-Bi-Cu System  

NSDL National Science Digital Library

The information provided for the Ag-Bi-Cu System consists of five parts: - Diagram: The diagram shows the calculated liquidus projection. Shown are the isotherms and lines of two-fold saturation. - Status: The analytical descriptions of the Gibbs energies of the constituent binaries are combined for each phase and used to predict the multicomponent system. - Sources: Bibliographic information for the thermodynamic descriptions. - Invariant Equilibria: Table with the calculated invariant equilibria of the system. The table lists the phases involved in the reaction, phase compositions and reaction temperature. - Phases: Table with the phases of the system. The table lists the crystal structure, common names of the phases and the model used for the thermodynamic description. Thermodynamic databases allow the compact storage of phase equilibria information in form of Gibbs energy functions for each phase. There are basicly two types of thermodynamic descriptions of a ternary system: (1) extrapolated, i.e., the analytical descriptions of constituent binaries are combined and used to predict the multicomponent system, (2) assessed, i.e., the thermodynamic description is derived from the assessment of the available ternary phase equilibria and thermochemical data. If experimental data were only available or considered for part of the system then a partial assessment is possible. The calculated phase diagram of the Ag-Bi-Cu system is presented.

Kattner, Ursula

2003-01-01

66

Electromechanical switching behavior of individual molecular complexes of Cu and Ni on NaCl-covered Cu(111) and Ag(111)  

NASA Astrophysics Data System (ADS)

In a combined scanning tunneling microscopy (STM) and noncontact atomic force microscopy (nc-AFM) study, we characterize the reversible switching between two stable states of an organometallic complex, namely, bis-dibenzoylmethanato-copper [Cu(dbm)2] adsorbed on an insulating thin film. The switching is due to the transfer of an electron between the STM tip and the molecule, accompanied by a conformational change, i.e., a transition from a square-planar to a tetrahedral geometry. Evidence is given by STM topography and spectroscopy and nc-AFM electrostatic force measurements. Similar experiments conducted on bis-dibenzoylmethanato-nickel [Ni(dbm)2] show that this complex does not switch under comparable experimental conditions. We discuss these findings within the framework of crystal-field theory, stating that the occupation of the d orbitals determines the favored coordination geometry of a complex. Accordingly, only the copper complex can undergo a conformational change that facilitates stable storing of the additional electron.

Walch, Hermann; Leoni, Thomas; Guillermet, Olivier; Langlais, Vronique; Scheuermann, Andrew; Bonvoisin, Jacques; Gauthier, Sbastien

2012-08-01

67

A Study of SnAgNiCo vs Sn3.8AgO. 7Cu C5 Lead Free Solder Alloy on Mechanical Strength of BGA Solder Joint  

Microsoft Academic Search

RoHS Directive for environmental and health concerns have resulted in significant activities to find substitutes for lead-contained solders for microelectronics. The potential candidates such as Sn-Ag1 and Sn-Ag-Cu1 eutectic solders with melting temperatures of 221degC and 217degC, respectively are the most prominent solders because of their excellent mechanical properties as compared with that of eutectic Sn-Pb solder2. Other candidates as

Eu Poh Leng; Min Ding; Wong Tzu Ling; N. Amin; I. Ahmad; Mok Yong Lee; A. S. M. A. Haseeb

2008-01-01

68

Spectroscopic (IR, Raman, UV, 1H and 13C NMR) and microbiological studies of Fe(III), Ni(II), Cu(II), Zn(II) and Ag(I) picolinates  

NASA Astrophysics Data System (ADS)

The FT-IR, Raman spectra of picolinic acid as well as Fe(III), Zn(II), Cu(II), Ni(II) and Ag(I) picolinates were registered, assigned and compared. Some regularities in the spectra of studied picolinates within the regions: 1650 1340 cm-1 [?(CC)ar, ?as(COO-), ?s(COO-)]; 1300 1020 cm-1 [?(CH)]; 780 620 cm-1 [?(CH), ?(CCC)] were found. 1H and 13C NMR spectra for picolinic acid, Zn(II) and Ag(I) picolinates were recorded and studied as well. Moreover the UV spectra of picolinic and picolinates were registered and compared. The influence of Ag(I), Zn(II), Ni(II), Cu(II) and Fe(III) on the electronic system of picolinic acid was investigated. The microbiological activity of picolinates against two species of bacteria: Escherichia coli, Bacillus subtilis as well as two species of yeasts: Saccharomyces cerevisiae and Hansenula anomala was also studied.

Kalinowska, M.; Borawska, M.; ?wis?ocka, R.; Piekut, J.; Lewandowski, W.

2007-05-01

69

DSPRU Project at NSU: Evolution of Basic, Mantle-crust Granitoid Ore-magmatic Systems Resulting in Pt-Cu-Ni, Cu-Mo-porphiric and Epithermal Au-Ag Ore-bearing Mineralization.  

NASA Astrophysics Data System (ADS)

Education and Human Resources are one of the most important priorities of the Russian Government policy nowadays. This work covers the principally new Project of the Ministry for Russian Science and Education: 'Development of Scientific Potential for Russian Universities' (DSPRU). The purposes of the Project are: 1) to involve university students to research in most urgent problems of fundamental science; 2) to enhance the professional development of Russian educators; 3) to interest the most perspective researches in education process at Russian universities; 4) to broaden the educational process involving to the Project foreign students, educators and researchers. All the State Universities in Russia could participate in the Project (with the exception of Moscow State University, whose employees were the Project experts). At Novosibirsk State University (NSU) research teams of 13 Departments applied for the Project. Only 5 Projects turned out to be successful. From the Department of Geology and Geophysics 9 Projects were applied and the only one won: 'Evolution of Basic, Mantle-crust Granitoid Ore-magmatic Systems Resulting in Pt-Cu-Ni, Cu-Mo-porphiric and Epithermal Au-Ag Ore-bearing Mineralization'. The team of the above-mentioned Project includes: - nine university educators - five researchers from the Institutes of Siberian Branch of Russian Academy of Sciences - four PhD students - eight undergraduate students. The expecting results of the Project are: 1) obtaining new data for natural objects covered by the Project (Siberia, Mongolia, China, South Africa, Morocco); 2) creation of mathematical models of evolution for fluid ore-magmatic systems of various geochemical character and productivity; 3) improving the education process at the Department of Geology and Geophysics of NSU (creation of new courses and publications, professional development of the educators, participation of students and young researchers in scientific conferences). The work was supported by the Ministry for Russian Science and Education, Grant DSP.2.1.1.702.

Rakhmenkulova, I.; Sharapov, V.; Zhitova, L.

2006-05-01

70

Oscillation period of magnetoresistance and texture in Co\\/Cu-Ni and NiFe\\/Cu-Ni multilayers  

Microsoft Academic Search

We have investigated oscillations of magnetoresistance ratio and film texture in Co\\/Cu-Ni and Ni-Fe\\/Cu-Ni multilayers. As the non-magnetic layer thickness was changed, the magnetoresistance ratio oscillated in both the Co\\/Cu-Ni and the Ni-Fe\\/Cu-Ni multilayers. The film texture also oscillated between (100) and (111). As the Ni concentration of the Cuz.sbnd;Ni non-magnetic layers increased, the oscillation period of the magnetoresistance ratio

Ryoichi Nakatani; Katsumi Hoshino; Hiroyuki Hoshiya; Yutaka Sugita

1997-01-01

71

Electromigration failure mechanisms for SnAg3.5 solder bumps on Ti/Cr-Cu/Cu and Ni(P)/Au metallization pads  

SciTech Connect

The electromigration behavior of SnAg3.5 solder bumps is investigated under the current densities of 1x10{sup 4} A/cm{sup 2} and 5x10{sup 3} A/cm{sup 2} at 150 deg. C. Different failure modes were observed for the two stressing conditions. When stressed at 1x10{sup 4} A/cm{sup 2}, damage occurred in both the anode/chip side and the cathode/chip side. However, failure happened only in the cathode/chip side under the stressing of 5x10{sup 3}A/cm{sup 2}. A three-dimensional simulation of the current-density distribution was performed to provide a better understanding of the current-crowding behavior in the solder bump. The current-crowding effect was found to account for the failure in the cathode/chip side. In addition, both the temperature increase and the thermal gradients were measured during the two stressing conditions. The measured temperature increase due to Joule heating was as high as 54.5 deg. C, and the thermal gradient reached 365 deg. C/cm when stressed by 1x10{sup 4}A/cm{sup 2}. This induced thermal gradient may cause atoms to migrate from the chip side to the substrate side, contributing to the failure in the anode/chip side. Moreover, the formation of intermetallic compounds in the anode/chip side may also be responsible for the failure in the anode/chip side.

Shao, T.L.; Chen, Y.H.; Chiu, S.H.; Chen Chih [Department of Material Science and Engineering, National Chiao Tung University, Hsin-chu 300, Taiwan (China)

2004-10-15

72

Transition Metal Stannides with MgAgAs and MnCu2Al Type Structure.  

National Technical Information Service (NTIS)

The ternary phases ZrNiSn and ZrNi2Sn were found to crystallize with the MgAgAs (ordered CaF2) and MnCu2Al (ordered BiF3, Heusler) type structure, respectively. The atomic order in these phases has been established from quantitative X-ray data. Although t...

W. Jeitschko

1970-01-01

73

Electrodeposited NiCo/Cu Superlattices  

SciTech Connect

NiCo/Cu superlattices were electrodeposited on polycrystalline Cu substrates from a single electrolyte under potentiostatic control. The X-ray diffraction (XRD) patterns showed that NiCo/Cu superlattices have the same crystal structure and texture as in their substrates. The films exhibited giant magnetoresistance (GMR) or anisotropic magnetoresistance (AMR), depending on the Cu layer thicknesses.

Safak, M.; Alper, M. [Department of Physics, Faculty of Science and Literature, University of Uludag, Goeruekle, Bursa (Turkey)

2007-04-23

74

Optical properties and electronic structures of d- and f-electron metals and alloys, Ag-In, Ni-Cu, AuGa sub 2 , PtGa sub 2 ,. beta. prime -NiAl,. beta. prime -CoAl, CeSn sub 3 , and LaSn sub 3  

SciTech Connect

Optical properties and electronic structures of disordered Ag{sub 1- x}In{sub x}(x = 0.0, 0.04, 0.08, 0.12) and Ni{sub 1-x}Cu{sub x} (x = 0.0, 0.1, 0.3, 0.4) alloys and ordered AuGa{sub 2}, PtGa{sub 2}, {beta}{prime}-NiAl, {beta}{prime}-CoAl, CeSn{sub 3}, and LaSn{sub 3} have been studied. The complex dielectric functions have been determined for Ag{sub 1-x}In{sub x}, Ni{sub 1-x}Cu{sub x}, AuGa{sub 2}, and PtGa{sub 2} in the 1.2--5.5 eV region and for CeSn{sub 3} and LaSn{sub 3} in the 1.5--4.5 eV region using spectroscopic ellipsometry. Self-consistent relativistic band calculations using the linearized-augmented-plane-wave method have been performed for AuGa{sub 2}, PtGa{sub 2}, {beta}{prime}-NiAl, {beta}{prime}-CoAl, CeSn{sub 3}, and LaSn{sub 3} to interpret the experimental optical spectra.

Kim, Kwang Joo.

1990-10-17

75

Ag/Ni/Ag Multilayer Reflector for GaN-Based Vertical Light-Emitting Diode  

NASA Astrophysics Data System (ADS)

We investigate the effect of Ni insertion on the electrical and thermal properties of Ag-based reflectors for GaN-based light emitting diodes (LEDs). It is shown that after annealing at 500 C, the surface of Ag only sample becomes significantly roughened due to agglomeration, whereas the surface of Ni-inserted Ag sample get roughened with elongated Ag hillocks on an 100-nm-thick Ag film. The Ni-inserted Ag contacts show higher reflectance (at 460 nm) than the Ag only sample after annealing at 500 C. The 500-C-annealed Ni-inserted Ag samples exhibit lower specific contact resistance than the annealed Ag only contacts. LEDs fabricated with the 500-C-annealed Ni-inserted Ag contact give lower forward-bias voltage and series resistance as compared to those of LEDs with the 500-C-annealed Ag only contact. The LEDs with the 500-C-annealed Ni-inserted Ag contact exhibit 18% higher light output power (at 20 mA) than the LEDs with the Ag only contacts annealed at 500 C. Based on the X-ray photoelectron spectroscopy and scanning electron microscopy results, the temperature dependence of the electrical characteristics of the Ni-inserted Ag contacts is described and discussed.

Yum, Woong-Sun; Jeon, Joon-Woo; Sung, Jun-Suk; Jin, Sungho; Seong, Tae-Yeon

2013-05-01

76

Self-Diffusion of small Ag and Ni islands on Ag(111) and Ni(111) using the self-learning kinetic Monte Carlo method  

NASA Astrophysics Data System (ADS)

We have applied a modified Self-Learning Kinetic Monte Carlo (SLKMC) method [1] to examine the self-diffusion of small Ag and Ni islands, containing up to 10 atom, on the (111) surface of the respective metal. The pattern recognition scheme in this new SLKMC method allows occupancy of the fcc, hcp and top sites on the fcc(111) surface and employs them to identify the local neighborhood around a central atom. Molecular static calculations with semi empirical interatomic potential and reliable techniques for saddle point search revealed several new diffusion mechanisms that contribute to the diffusion of small islands. For comparison we have also evaluated the diffusion characteristics of Cu clusters on Cu(111) and compared results with previous findings [2]. Our results show a linear increase in effective energy barriers scaling almost as 0.043, 0.051 and 0.064 eV/atom for the Cu/Cu(111), Ag/Ag(111), and Ni/Ni(111) systems, respectively. For all three systems, diffusion of small islands proceeds mainly through concerted motion, although several multiple and single atom processes also contribute. [1] Oleg Trushin et al. Phys. Rev. B 72, 115401 (2005) [2] Altaf Karim et al. Phys. Rev. B 73, 165411 (2006)

Islamuddin Shah, Syed; Nandipati, Giridhar; Kara, Abdelkader; Rahman, Talat S.

2012-02-01

77

Fabrication and optical properties of metastable Cu-Ag alloys.  

PubMed

A series of single-phase metastable Cu-Ag solid solutions was deposited by magnetron sputtering at liquid-nitrogen temperature. The lattice constant increases with increasing Ag content. The spectroscopic ellipsometer measurements clearly show that with increasing Ag content, the Cu-like and Ag-like absorption edges in the visible wavelength range shift continuously toward the high-energy and the low-energy sides, respectively. PMID:12211572

Song, Jintao; Li, Heyin; Li, Jing; Wang, Songyou; Zhou, Shiming

2002-09-01

78

Optical Studies and Band Structure of Cu-Ni Alloys.  

National Technical Information Service (NTIS)

This paper reports on recent results of optical studies on the Cu-Ni alloy system. Reflectivity measurements have been made on Cu, 84 Cu-16 Ni, 39 Cu-61 Ni, and Ni from 0.2-10eV. Infrared absorption in the Cu-rich alloy indicates the existence of a virtua...

J. Feinleib W. J. Scouler J. Hanus

1969-01-01

79

How do the electronic properties of d9 impurities depend on metal-ligand distances? Application to Ni+, Cu2+ and Ag2+ systems  

Microsoft Academic Search

The dependence of the optical and spin-Hamiltonian parameters of NiF65- and NiF43- D4h units, with a b1g* ( approximately x2-y2) unpaired electron, upon the equatorial (Req) and axial (Rax) Ni+-F- distances has been studied through multiple-scattering X alpha and self-consistent charge extended Huckel methods. Both methods lead to the following main conclusions: (i) A charge-transfer transition like eu( pi +

J. A. Aramburu; M. Moreno; M. T. Barriuso

1992-01-01

80

Low temperature fired NiCuZn ferrite  

Microsoft Academic Search

Bismuth oxide (Bi2O3) and lead glass were introduced to NiCuZn ferrite to reduce the sintering temperatures from more than 950C to 875C for co-firing with the internal conductor, Ag. Both additives formed liquid phases in grain boundaries during the sintering process to enhance the densification of the specimens. The chip inductors made of the Bi2O3 doped ferrite exhibited higher DC

Jen-Yan Hsu; Wen-Song Ko; Hon-Dar Shen; Chi-Jen Chen

1994-01-01

81

Amorphous Cu-Ag Films with High Stability.  

National Technical Information Service (NTIS)

Films produced by quenching Cu-Ag vapour onto cooled substrates at liquid nitrogen temperature have been investigated using electron microscopy, electron diffraction and electrical resistivity measurements. In the composition range from 30 to 70 at% Cu th...

I. M. Reda J. Hafner P. Pongratz A. Wagendristel H. Bangert

1982-01-01

82

Oscillation period of magnetoresistance and texture in Co/Cu-Ni and Ni-Fe/Cu-Ni multilayers  

NASA Astrophysics Data System (ADS)

We have investigated oscillations of magnetoresistance ratio and film texture in Co/Cu-Ni and Ni-Fe/Cu-Ni multilayers. As the non-magnetic layer thickness was changed, the magnetoresistance ratio oscillated in both the Co/Cu-Ni and the Ni-Fe/Cu-Ni multilayers. The film texture also oscillated between (100) and (111). As the Ni concentration of the Cu-Ni non-magnetic layers increased, the oscillation period of the magnetoresistance ratio became longer in both the multilayers. The oscillation period of the texture also became longer. These results indicate that the changes of the neck diameter of the Fermi surface of the Cu-Ni layers vary the periods of the oscillations in both the magnetoresistance ratio and the texture.

Nakatani, R.; Hoshino, K.; Hoshiya, H.; Sugita, Y.

1997-02-01

83

Reliability evaluation of SnAgCu\\/SnAgCuCe solder joints based on finite element simulation and experiments  

Microsoft Academic Search

Purpose The purpose of this paper is to numerically evaluate the reliability of SnAgCuCe solder joints compared with that of SnAgCu. A trace amount of the rare earth (RE) element Ce was added into SnAgCu solder in order to improve the reliability of lead-free solder joints, which was evaluated based on finite element simulation and experiments. Design\\/methodology\\/approach A

Guang Zeng; Songbai Xue; Liang Zhang; Zhong Sheng; Lili Gao

2010-01-01

84

Tensile testing of free-standing Cu, Ag and Al thin films and Ag\\/Cu multilayers  

Microsoft Academic Search

Free standing polycrystalline thin films with a strong ?111? texture were tested in uniaxial tension. Studied were electron-beam deposited Ag, Cu and Al films, and Ag\\/Cu multilayers consisting of alternating Ag and Cu layers of equal thickness, between 1.5nm and 1.5?m (bilayer repeat length, ?, between 3nm and 3?m). The films had a total thickness of about 3?m. A thin

Haibo Huang; F. SPAEPEN

2000-01-01

85

Low-temperature solid state bonding method based on surface Cu-Ni alloying microcones  

NASA Astrophysics Data System (ADS)

A low-temperature solid state bonding method based on surface Cu-Ni alloying microcones for potential application in 3D integration is introduced. Surface Cu-Ni alloying microcones were fabricated by electroless deposition and bonded with Sn-3.0Ag-0.5Cu (wt.%) solder at 190 C (solid state) in ambient air. Microscopic observation showed that Cu-Ni microcones inserted into the soft solder effectively and a thin intermetallic compound layer formed along the bonding interface. The bonding joint strength was measured and the result showed that it was higher than that of reflow soldering.

Lu, Qin; Chen, Zhuo; Zhang, Wenjing; Hu, Anmin; Li, Ming

2013-03-01

86

Moment Disturbances in Ni--Cu Alloys.  

National Technical Information Service (NTIS)

Magnetic diffuse scattering of polarized neutrons from ferromagnetic Ni--Cu alloys with 19.8, 29.6, and 53.5 at. percent Cu was measured at 4.2 exp 0 K. Data show that the Cu atoms are not polarized and that the negative polarization exists only around th...

R. A. Medina J. W. Cable

1975-01-01

87

Dissolution and interfacial reactions of thin-film Ti\\/Ni\\/Ag metallizations in solder joints  

Microsoft Academic Search

The dissolution and interfacial reactions involving thin-film Ti\\/Ni\\/Ag metallizations on two semiconductor devices, diode and metal-oxide-semiconductor field-effect transistor (MOSFET), a Sn3.0Ag0.7Cu solder, and a Au-layer on the substrates are studied. To simulate the dissolution kinetics of the Ag-layer in liquid solder during the reflow process, the computational thermodynamics (Thermo-Calc) and kinetics (DICTRA: DIffusion Controlled TRAnsformations) tools are employed in conjunction

G. Ghosh

2001-01-01

88

Electroplating of Cu(Ag) thin films for interconnect applications  

Microsoft Academic Search

Electromigration effects in interconnect metallizations cause a need for materials with superior resistance against electromigration failure but with adequate electrical properties. In principle, Cu(Ag) alloys are potential candidates to become an interconnect material of the next generation of microelectronic devices. Therefore, in the following paper the electroplating of such Cu(Ag) alloys from a sulfuric acid electrolyte solution with varying silver

S. Strehle; S. Menzel; J. W. Bartha; K. Wetzig

2010-01-01

89

Surface and transport properties of Ag Cu liquid alloys  

NASA Astrophysics Data System (ADS)

The applicability of quasi-lattice theory (QLT) to describe surface and transport properties of Ag Cu liquid alloys is substantiated by surface tension experimental data. The surface tension of molten Ag, Cu and Ag Cu alloys has been measured by the pinned-sessile drop method over a temperature range. The results obtained are in good agreement with other reported measurements on pure elements and their alloys as well as with calculated surface tension values. The phase diagram of Ag Cu system shows the existence of a simple eutectic indicating a tendency towards phase separation. The mixing behaviour of Ag Cu regular alloys has been analysed through the study of surface properties (surface tension and surface composition), dynamic properties (chemical diffusion and viscosity) and microscopic functions (concentration fluctuations in the long-wavelength limit and chemical short-range order parameter) in the frame of quasi-lattice theory combined with a statistical mechanical theory.

Novakovic, R.; Ricci, E.; Giuranno, D.; Passerone, A.

2005-02-01

90

Interfacial reactions and shear strengths between Sn-Ag-based Pb-free solder balls and Au\\/EN\\/Cu metallization  

Microsoft Academic Search

The morphological and compositional evolutions of intermetallic compounds (IMCs) formed at three Pb-free solder\\/electroless\\u000a Ni-P interface were investigated with respect to the solder compositions and reflow times. The three Pb-free solder alloys\\u000a were Sn3.5Ag, Sn3.5Ag0.75Cu, and Sn3Ag6Bi2In (in wt.%). After reflow reaction, three distinctive layers, Ni3Sn4 (or Ni-Cu-Sn for Sn3.5Ag0.75Cu solder), NiSnP, and Ni3P, were formed on the electroless Ni-P

Sang-Won Kim; Jeong-Won Yoon; Seung-Boo Jung

2004-01-01

91

Temperature dependent effects during Ag deposition on Cu(110)  

SciTech Connect

The composition, structure, and morphology of ultrathin films grown by Ag deposition on Cu(110) were monitored as a function of temperature using low-energy electron diffraction (LEED), Auger electron spectroscopy (AES), and medium energy ion scattering (MEIS). Aligned backscattering measurements with 150 keV He ions indicate that the Ag resides on top of the Cu and there is no significant surface compound formation. Measurements with LEED show that the Ag is initially confined to the substrate troughs. Further deposition forces the Ag out of the troughs and results in a split c(2 {times} 4) LEED pattern, which is characteristic of a distorted Ag(111) monolayer template. As verified by both AES and MEIS measurements, postmonolayer deposition of Ag on Cu(110) at 300K leads to a pronounced 3-dimensional clustering. Ion blocking analysis of the Ag clusters show that the crystallites have a (110)-like growth orientation, implying that the Ag monolayer template undergoes a rearrangement. These data are confirmed by low temperature LEED results in the absence of clusters, which indicate that Ag multilayers grow from a Ag--Cu interface where the Ag is captured in the troughs. Changes observed in the film structure and morphology are consistent with a film growth mechanism that is driven by overlayer strain response to the substrate corrugation. 16 refs., 4 figs.

Taylor, T.N.; Muenchausen, R.E.; Hoffbauer, M.A.; Denier van der Gon, A.W.; van der Veen, J.F. (Los Alamos National Lab., NM (USA); FOM-Instituut voor Atoom-en Molecuulfysica, Amsterdam (Netherlands))

1989-01-01

92

Magnetoresistance in cosputtered CuNiFe films (abstract)  

Microsoft Academic Search

The magnetoresistance effect, especially the giant magnetoresistance (GMR) effect, has received much attention in recent years. In this study, we discuss the magnetoresistance behavior in CuNiFe thin films with Cu content varied from 40 to 90 at.%, prepared by the cosputtering of both Cu and Fe50Ni50 targets. Films with low Cu content, for example, Cu50Ni25Fe25 and Cu40Ni30Fe30, exhibit a mixed

L. H. Chen; S. Jin; T. H. Tiefel

1997-01-01

93

Cr\\/Cu\\/Ni underbump metallization study  

Microsoft Academic Search

In flip chip interconnection using eutectic Pb\\/Sn solder bumps, a highly reliable underbump metallization (UBM) is required to maintain adhesion and solder wettability. An experimental study investigated the thermal stability of the Cr\\/Cu\\/Ni UBM-where Cr act as an adhesive, Cu a solder wettable layer and Ni a barrier. The process window for good thermal stability will reduce silicon cratering failure

Tay Hui Leng; Galen Kirkpatrick; Andrew Tay; Lu Li

2001-01-01

94

Electromigration in eutectic SnPb solder bumps with Ni\\/Cu UBM  

Microsoft Academic Search

This study investigates the electromigration behavior of eutectic SnPb solder bumps with Ni\\/Cu UBM, in which the thickness of the Ni and Cu layer is 3 ?m and 5 ?m, respectively. It was found that the SnPb solder joints have better electromigration resistance than that of SnAg bumps with thin film UBM. The thermal characteristic of SnPb solder joints under

Sheng-Hsiang Chiu; Shih-Wei Liang; Chih Chen; S. S. Lin; C. M. Chou; Y. C. Liu; K. H. Chen

2005-01-01

95

Chemical Preparation and Characterization of Elemental Cu, Ni, and Cu/Ni Core/Shell Nanoparticles  

NASA Astrophysics Data System (ADS)

Elemental Ni, Cu, and Cu core/Ni shell nanoparticles have been prepared in a polyol-type process. The elemental nanoparticles were prepared by dissolving NiCl2.6H2O and/or CuCl2.2H2O in ethylene glycol (EG) and heating the solution to reflux prior to the addition of NaOH. The resulting precipitate was then extracted, dried, and characterized by scanning electron microscopy (SEM) with elemental analysis, x-ray diffraction (XRD), and in the case of the elemental Ni nanoparticles, vibrating sample magnetometry (VSM) measurements. The best fit lattice parameters obtained from the elemental Ni and Cu nanoparticles were 0.35289(28) and 0.36171(23) nm, respectively, in good agreement with the corresponding bulk values. On the other hand, the measured saturation magnetization of about 49 emu/g was somewhat smaller than the bulk Ni value. In the case of the Cu/Ni nanoparticles, the best fit lattice parameters for the Ni and Cu components of the core/shell structure were 0.35299(26) and 0.36101(10) nm, indicating the formation of an essentially pure Ni shell and a slight amount of Ni incorporation in the Cu core.

Higgins, Laura; Lattanzi, Michael; Kelly, Brian; Poirier, Gerald; Unruh, Karl

2011-03-01

96

Embedded Atom Method Potential for Ni-Cu Alloys and Its Applications for Ni, Cu growth on Cu(111)  

NASA Astrophysics Data System (ADS)

We developed a semi-empirical, many-body type model potential to investigate static and dynamic properties of Ni-Cu alloys. The formalism is based on the embedded atom method with improved optimization techniques. The Ni-Cu alloy potential was determined by fitting to data on lattice parameters, cohesive energies for L10, L11, L12, and L13 phases, together with vacancy formation energies, bulk modulus and elastic properties for L12, L13 phases. Our preliminary calculations for energy barriers for the diffusing Ni and Cu atoms on Cu(111) based on the nudged elastic band method are found to be consistent with the available experimental and other theoretical results. Our ultimate goal is to describe the varying characteristics in growing islands of pure Cu, Ni atoms and mixed Ni-Cu combinations on Cu(111) [S. Pons et al., Surf. Sci., 511, 449, (2002)].

Onat, Berk; Durukanoglu, Sondan

2012-02-01

97

Microstructure and shear strength evolution of Sn-Ag-Cu solder bumps during aging at different temperatures  

NASA Astrophysics Data System (ADS)

Flip-chip devices with Sn-3.8Ag-0.7Cu solder on electroless Ni (EN) without immersion Au were studied after aging at different temperatures. The (Cu,Ni)6Sn5 intermetallics (IMCs) growth was volume diffusion controlled and Kirkendall voids were found in the Ni3P layer even at the initial stage of high-temperature aging due to the faster diffusion of Ni in the Ni3P layer via its column structure boundaries. The Ag3Sn IMCs were distributed in the bulk solder, existing as plate- or lamella-like phases or as small particles around the ?-Sn dendrites, and the (Cu,Ni)6Sn5 IMCs existed as facet-like phases. The plate- and lamella-like Ag3Sn phases break up into small parts and these broken parts, together with small Ag3Sn particles, coarsen into pebble-like phases during high-temperature aging. Shear tests showed that all the solder bumps fractured in the bulk solder. The shear strength of solder bumps decreases at the initial stage of aging at 150C and 175C, and the strength degradation during aging may be caused by the coarsening of small Ag3Sn particles.

Li, Dezhi; Liu, Changqing; Conway, Paul P.

2006-03-01

98

Infrared Brazing Ti50Ni50 and Invar Using Ag-Based Filler Foils  

NASA Astrophysics Data System (ADS)

Infrared brazing Ti50Ni50 and Invar using BAg-8 and Cusil-ABA foils was investigated. The Ag-Cu eutectic matrix dominates both brazed joints. The maximum shear strengths of the brazed joints using BAg-8 and Cusil-ABA fillers are 158 and 249 MPa. Failure of interfacial Fe2Ti/Ni3Ti reaction layers is responsible for the BAg-8 joint. In contrast, the Cusil-ABA brazed joint is fractured along the interfacial Fe2Ti intermetallic compound. Both fractographs are characterized with cleavage dominated fracture.

Shiue, R. K.; Chang, Y. H.; Wu, S. K.

2013-10-01

99

Growth and stability of Ag layers on Cu(110)  

SciTech Connect

Combined surface science and high energy ion beam techniques have been used to characterize the composition, structure and thermal stability of Ag layers < 900A thick on Cu(110). A uniform Ag/Cu surface composite is formed for one monolayer coverage. Analysis of its growth with LEED shows that the Ag is initially confined to the (110) troughs and that further deposition results in a Ag(111) layer exhibiting c(2 x 4) symmetry. This surface science determination of Ag coverage is consistent with absolute coverages measured with Rutherford backscattering. Beyond one monolayer coverage, the deposition of Ag at 300K produces clustering (Stranski-Krastanov mechanism) in contrast to a poorly ordered but more uniform layering mode when deposited at 130K. Following nucleation for a deposition between one and two monolayers at 300K, Ag clusters approx.20 A thick grow laterally across the surface up to 5 or 6 monolayers deposition. Continuous films grown cold at thicknesses less than or equal to 115A are found to agglomerate above 500K exposing a tenacious Ag-Cu interface like that formed by one monolayer Ag deposition.

Taylor, T.N.; Hoffbauer, M.A.; Maggiore, C.J.; Beery, J.G.

1986-01-01

100

Wetting process and interfacial characteristic of Sn-3.0Ag-0.5Cu on different substrates at temperatures ranging from 503 K to 673 K  

NASA Astrophysics Data System (ADS)

Wetting process and interfacial characteristic of Sn-3.0Ag-0.5Cu have been investigated at temperatures ranging from 503 K to 673 K on Cu, Ni, stainless steel and quartz, respectively. The reactive wetting behavior of Sn-3.0Ag-0.5Cu melt alloy on Cu and Ni substrates were investigated. Contact angles decrease as exponential decay and equilibrium contact angles decrease between the solder and Cu, Ni substrates monotonously with the temperature increasing. The configuration of the triple line of Sn-3.0Ag-0.5Cu/Cu is discussed by the description of equilibrium. The calculated results based on experimental values of tension balances along each of the three interfaces at this final state show good agreement with theoretical analysis. Intermetallics of the Sn-3.0Ag-0.5Cu/Ni interface are identified as (Cu, Ni) 6Sn 5 adjacent to the solder and Ni 3Sn 4 adjacent to the Ni substrate, respectively. The contact angles between Sn-3.0Ag-0.5Cu and quartz, stainless steel substrates were measured to be greater than 90, which means non-wetting, in the temperature range from 503 K to 673 K. Liquid-solid interfacial energy between the solder and different substrates are obtained based on the surface tension of molten solder and equilibrium contact angles at different temperatures. These results are of practical interest for composite lead-free solders preparations and joining of Sn-3.0Ag-0.5Cu to various substrates.

Zang, Likun; Yuan, Zhangfu; Xu, Hongyan; Xu, Bingsheng

2011-03-01

101

Investigation on plated Ni/Cu contact for mono-crystalline silicon solar cells  

NASA Astrophysics Data System (ADS)

Silicon solar cells are required to be processed with low cost and high efficiency. Ag paste, which is frequently used for the front contact of commercial screen-printed solar cells, has high contact resistance and high cost. Therefore, it is necessary to develop an inexpensive metallization technique with improved cell performance. As an alternative, plated Ni/Cu contact was used to fabricate low cost and high efficiency solar cells in this paper. Ni/Cu metals have low cost, low contact resistance and high conductivity. Ni was formed for low contact resistance and barrier to plated Cu, which was the main contact for low cost and high conductivity. In particular, a plated Ni layer is a very crucial factor that determines performance of the contact for plated Ni/Cu solar cells. A plated Ni layer has a decisive effect on contact resistance, series resistance and fill factor. In this paper, Ni electroless plating conditions (deposition time and pH) were varied to form a well plated Ni layer. For an optimized Ni electroless plating condition (5 min of deposition time and 8.5 of pH), the efficiency of plated Ni/Cu contact solar cells recorded 18.68%.

Kim, Dong Ho; Lee, Soo Hong

2013-09-01

102

Anomalous temperature dependence of the giant magnetoresistance in Ni\\/Cu, Ni 95Co 5\\/Cu and Ni 95Fe 5\\/Cu multilayer films  

Microsoft Academic Search

In this paper we examine the temperature dependence of the giant magnetoresistance (GMR) of Ni\\/Cu, Ni95Co5\\/Cu and Ni95Fe5\\/Cu multilayers in the temperature range 4.2350 K. The samples were prepared by magnetron sputtering on glass substrates. In all the multilayers examined, oscillations of the MR ratio as a function of the Cu thickness were observed at room temperature. However, in the

Hitoshi Kubota; Masashige Sato; Terunobu Miyazaki

1997-01-01

103

Microstructure of electrodeposited Cu-Ni binary alloy films  

Microsoft Academic Search

The codeposition of Cu and Ni in the electrodeposition method without a complexing agent is difficult, since the standard electrode potentials of Cu and Ni differ by approximately 600 mV. In this study, the electrodeposited Cu-Ni alloy films with various compositions were obtained using glycine as the complexing agent. Consequently, composition of the deposited Cu-Ni alloy films can be controlled

Io Mizushima; Masatoshi Chikazawa; Tohru Watanabe

1996-01-01

104

Strain, interdiffusion, magnetism and magnetic anisotropy in Cu\\/Ni\\/Cu (0 0 1) sandwiches  

Microsoft Academic Search

The effects of interface, strain and interdiffusion on magnetic moments and magnetocrystalline anisotropy in Cu\\/Ni\\/Cu(0 0 1) trilayers have been studied by first-principles spin-polarized relativistic band-structure calculations. Ideal Cu\\/Nin\\/Cu(0 0 1) trilayers are modelled by NinCu5(0 0 1) superlattices (n = 1, 3, 5) whilst Ni\\/Cu interdiffusion is simulated by (NiCu)2Nin(NiCu)2Cu3(0 0 1) superlattices (n = 3, 5, 7) containing

G. Y. Guo

1997-01-01

105

Communication: Kinetics of chemical ordering in Ag-Au and Ag-Ni nanoalloys  

NASA Astrophysics Data System (ADS)

The energy landscape and kinetics of medium-sized Ag-Au and Ag-Ni nanoalloy particles are explored via a discrete path sampling approach, focusing on rearrangements connecting regions differing in chemical order. The highly miscible Ag27Au28 supports a large number of nearly degenerate icosahedral homotops. The transformation from reverse core-shell to core-shell involves large displacements away from the icosahedron through elementary steps corresponding to surface diffusion and vacancy formation. The immiscible Ag42Ni13 naturally forms an asymmetric core-shell structure, and about 10 eV is required to extrude the nickel core to the surface. The corresponding transformation occurs via a long and smooth sequence of surface displacements. For both systems the rearrangement kinetics exhibit Arrhenius behavior. These results are discussed in the light of experimental observations.

Calvo, F.; Fortunelli, A.; Negreiros, F.; Wales, D. J.

2013-09-01

106

Communication: Kinetics of chemical ordering in Ag-Au and Ag-Ni nanoalloys.  

PubMed

The energy landscape and kinetics of medium-sized Ag-Au and Ag-Ni nanoalloy particles are explored via a discrete path sampling approach, focusing on rearrangements connecting regions differing in chemical order. The highly miscible Ag27Au28 supports a large number of nearly degenerate icosahedral homotops. The transformation from reverse core-shell to core-shell involves large displacements away from the icosahedron through elementary steps corresponding to surface diffusion and vacancy formation. The immiscible Ag42Ni13 naturally forms an asymmetric core-shell structure, and about 10 eV is required to extrude the nickel core to the surface. The corresponding transformation occurs via a long and smooth sequence of surface displacements. For both systems the rearrangement kinetics exhibit Arrhenius behavior. These results are discussed in the light of experimental observations. PMID:24070271

Calvo, F; Fortunelli, A; Negreiros, F; Wales, D J

2013-09-21

107

Magnetic properties of Ni\\/Cu\\/Ni epitaxial films with perpendicular anisotropy  

Microsoft Academic Search

The effective magnetic anisotropy Keff has been studied at room temperature in Cu\\/Ni\\/Cu\\/Ni\\/Cu(001) epitaxial films with perpendicular magnetization as a function of the interleaving Cu block thickness tCu ranging from 0 nm to 6 nm and being the Ni blocks 3 nm thick. We have found that the value of Keff decreases when comparing the structures with tCu = 0

Edna C. Corredor; Jos Luis Diez-Ferrer; David Coffey; Jos I. Arnaudas; Miguel Ciria

2010-01-01

108

Porous NiO\\/Ag composite film for electrochemical capacitor application  

Microsoft Academic Search

A highly porous NiO\\/Ag composite film is prepared by the combination of chemical bath deposition and silver mirror reaction. The as-prepared NiO\\/Ag composite film has an interconnecting reticular morphology made up of NiO flakes with highly dispersed Ag nanoparticles of about 6nm. The pseudocapacitive behavior of the NiO\\/Ag composite film is investigated by cyclic voltammograms (CV) and galvanostatic chargedischarge tests

J. B. Wu; Z. G. Li; Y. Lin

2011-01-01

109

Magnetic phase transition in Co/Cu/Ni/Cu(100) and Co/Fe/Ni/Cu(100).  

PubMed

Magnetic phase transitions in coupled magnetic sandwiches of Cu/Co/Cu/Ni/Cu(100) and Cu/Co/Fe/Ni/Cu(100) are investigated by photoemission electron microscopy. Element-specific magnetic domains are taken at room temperature to reveal the critical thickness at which the magnetic phase transition occurs. The results show that a coupled magnetic sandwich undergoes three types of magnetic phase transitions depending on the two ferromagnetic films' thickness. A phase diagram is constructed and explained in the process of constructing Monte Carlo simulations, which corroborate the experimental results. PMID:14611550

Won, C; Wu, Y Z; Scholl, A; Doran, A; Kurahashi, N; Zhao, H W; Qiu, Z Q

2003-09-30

110

Rolling and recrystallisation textures in CuAl, CuMn and CuNi alloys  

Microsoft Academic Search

The development of strongly cube textured Cu based substrates is important in the cost effective production of long lengths\\u000a of high temperature superconducting cables. The present paper reports textures (deformation and recrystallisation) development\\u000a in pure Cu, CuAl, CuMn (with a solute content of 13at.%) and Cu35 at.% Ni alloys.

Subramanya Sarma Vadlamani; Joerg Eickemeyer; Ludwig Schultz; Bernhard Holzapfel

2007-01-01

111

Simulation of an Amorphous Metalic Alloy: Ag-Cu  

NASA Astrophysics Data System (ADS)

The development of new metallic alloys which form bulk glasses at low cooling rates has led to significant advances in the study of undercooled liquid metals and the glass transition in metallic systems. These new materials exhibit a rich variety of phenomena, such as liquid-crystal phase separation and nanocrystalline phase formation, and have interesting potential as engineering materials. We have re-parametrized empirical analytical many body potentials of Sutton-Chen type for FCC metals in order to study the thermophysical properties of these metals and their alloys. The properties we studied are viscosity, diffusion, melting, and glass formation. In this talk, we will present molecular dynamics studies on Ag, Cu, and Ag-Cu binary alloy. Ag-Cu alloy is a perfect model system for a glass former, since the elements Ag and Cu have considerably different atomic radii. Using molecular dynamics method under constant pressure, constant temperature we studied the melting and glass tranformation for this alloy at the eutectic composition. We report glass transition temperature as a function of cooling rate; structural and thermodynamic properties of the model Ag-Cu glass.

Qi, Yue; Cagin, Tahir; Goddard, William A., III

1998-03-01

112

Nanoindentation on SnAgCu lead-free solder joints and analysis  

NASA Astrophysics Data System (ADS)

The lead-free SnAgCu (SAC) solder joint on copper pad with organic solderability preservative (Cu-OSP) and electroless nickel and immersion gold (ENIG) subjected to thermal testing leads to intermetallic growth. It causes corresponding reliability concerns at the interface. Nanoindentation characterization on SnAgCu solder alloy, intermetallic compounds (IMCs), and the substrates subjected to thermal aging is reported. The modulus and hardness of thin IMC layers were measured by nanoindentation continuous stiffness measurement (CSM) from planar IMC surface. When SAC/Ni(Au) solder joints were subject to thermal aging, the Youngs modulus of the NiCuSn IMC at the SAC/ENIG specimen changed from 207 GPa to 146 GPa with different aging times up to 500 h. The hardness decreased from 10.0 GPa to 7.3 GPa. For the SAC/Cu-OSP reaction couple, the Youngs modulus of Cu6Sn5 stayed constant at 97.0 GPa and hardness about 5.7 GPa. Electron-probe microanalysis (EPMA) was used to thermal aging. The creep effect on the measured result was analyzed when measuring SnAgCu solder; it was found that the indentation penetration, and thus the hardness, is loading rate dependent. With the proposed constant P/P experiment, a constant indentation strain rate h/h and hardness could be achieved. The log-log plot of indentation strain rate versus hardness for the data from the constant P/P experiments yields a slope of 7.52. With the optimized test method and CSM Technique, the Modulus of SAC387 solder alloy and all the layers in a solder joint were investigated.

Xu, Luhua; Pang, John H. L.

2006-12-01

113

Microstructure of electrodeposited Cu-Ni binary alloy films  

SciTech Connect

The codeposition of Cu and Ni in the electrodeposition method without a complexing agent is difficult, since the standard electrode potentials of Cu and Ni differ by approximately 600 mV. In this study, the electrodeposited Cu-Ni alloy films with various compositions were obtained using glycine as the complexing agent. Consequently, composition of the deposited Cu-Ni alloy films can be controlled by bath composition and pH, and the crystallographic structure of all the deposited Cu-Ni alloy films consists of a single solid solution and is not influenced by pH.

Mizushima, Io; Chikazawa, Masatoshi; Watanabe, Tohru [Tokyo Metropolitan Univ. (Japan). Dept. of Industrial Chemistry

1996-06-01

114

Heterobimetallic coordination polymers incorporating [M(CN)(2)](-) (M = Cu, Ag) and [Ag(2)(CN)(3)](-) units: increasing structural dimensionality via M-M' and M...NC interactions.  

PubMed

A series of new heterometallic coordination polymers has been prepared from the reaction of metal-ligand cations and KAg(CN)(2) units. Many of these contain silver-silver (argentophilic) interactions, analogous to gold-gold interactions, which serve to increase supramolecular structural dimensionality. Compared to [Au(CN)(2)](-) analogues, these polymers display new trends specific to [Ag(CN)(2)](-), including the formation of [Ag(2)(CN)(3)](-) and the presence of Ag...N interactions. [Cu(en)(2)][Ag(2)(CN)(3)][Ag(CN)(2)] (1, en = ethylenediamine) forms 1-D chains of alternating [Ag(CN)(2)](-) and [Ag(2)(CN)(3)](-) units via argentophilic interactions of 3.102(1) A. These chains are connected into a 2-D array by strong cyano(N)-Ag interactions of 2.572(3) A. [Cu(dien)Ag(CN)(2)](2)[Ag(2)(CN)(3)][Ag(CN)(2)] (2, dien = diethylenetriamine) forms a 1-D chain of alternating [Cu(dien)](2+) and [Ag(CN)(2)](-) ions with the Cu(II) atoms connected in an apical/equatorial fashion. These chains are cross-linked by [Ag(2)(CN)(3)](-) units via argentophilic interactions of 3.1718(8) A and held weakly in a 3-D array by argentophilic interactions of 3.2889(5) A between the [Ag(CN)(2)](-) in the 2-D array and the remaining free [Ag(CN)(2)](-). [Ni(en)][Ni(CN)(4)].2.5H(2)O (4) was identified as a byproduct in the reaction to prepare the previously reported [Ni(en)(2)Ag(2)(CN)(3)][Ag(CN)(2)] (3). In [Ni(tren)Ag(CN)(2)][Ag(CN)(2)] (5, tren = tris(2-aminoethyl)amine), [Ni(tren)](2+) cations are linked in a cis fashion by [Ag(CN)(2)](-) anions to form a 1-D chain similar to the [Au(CN)(2)](-) analogue. [Cu(en)Cu(CN)(2)Ag(CN)(2)] (6) is a trimetallic polymer consisting of interpenetrating (6,3) nets stabilized by d(10)-d(10) interactions between Cu(I)-Ag(I) (3.1000(4) A). Weak antiferromagnetic coupling has been observed in 2, and a slightly stronger exchange has been observed in 6. The Ni(II) complexes, 4 and 5, display weak antiferromagnetic interactions as indicated by their relatively larger D values compared to that of 3. Magnetic measurements on isostructural [Ni(tren)M(CN)(2)][M(CN)(2)] (M = Ag, Au) show that Ag(I) is a more efficient mediator of magnetic exchange as compared to Au(I). The formation of [Ni(CN)(4)](2)(-), [Ag(2)(CN)(3)](-), and [Cu(CN)(2)](-) are all attributed to secondary reactions of the dissociation products of the labile KAg(CN)(2). PMID:12470070

Shorrock, Carolyn J; Xue, Bao-Yu; Kim, Peter B; Batchelor, Raymond J; Patrick, Brian O; Leznoff, Daniel B

2002-12-16

115

Misfit dislocations in epitaxial Ni/Cu bilayer and Cu/Ni/Cu trilayer thin films.  

SciTech Connect

Misfit dislocations at the interfaces of bilayer (Ni/Cu) and trilayer (Cu/Ni/Cu) thin films are examined by plan-view TEM observation. In the bilayers, the spacing of misfit dislocations is measured as a fiinction of nickel layer thickness. The critical thickness, at which misfit dislocations start to appear with the loss of coherency, was found to be about 2 nm. The spacing of the misfit dislocations decreases with increasing nickel layer thickness and reaches a plateau at the thickness of 30 nm. The minimum spacing is observed to be about 20 nm. g {center_dot} b analysis of the cross-grid of misfit dislocations revealed 90{sup o} Lomer dislocations of <110>{l_brace}001{r_brace} type lying in the (001) interface plane at the relatively large thickness of nickel layer, but 60{sup o} glide dislocations of <110>{l_brace}111{r_brace} type at the relatively small thickness of nickel layer. In the trilayers, misfit dislocations formed at both interfaces. The spacing of the misfit dislocation is in agreement with that of the bilayers with similar nickel layer thickness. The misfit dislocation arrays at the two interfaces, having the same line directions, are 60{sup o} dislocations with edge components with opposite signs but are displaced with respect to each other in the two different interface planes. This suggests that the strain field of the dislocations has a strong influence on the position of the misfit dislocations at the subsequent interface.

Misra, A. (Amit); Hoagland R. G. (Richard G.); Nastasi, Michael Anthony,; Kung, H. (Harriett); Hirth, John Price,; Yamamoto, T. (Tadashi)

2001-01-01

116

A comparative study of microstructure and mechanical properties among Cu\\/Sn\\/Cu, Ni\\/Sn\\/Ni and Cu\\/Sn\\/Ni solder joints  

Microsoft Academic Search

Purpose The purpose of this paper is to identify the solder joint with optimal mechanical properties among Cu\\/Sn\\/Cu, Ni\\/Sn\\/Ni and Cu\\/Sn\\/Ni solder joints. Design\\/methodology\\/approach Solder joints with the same specimen shape were prepared by reflow. The microstructures were observed and analyzed by scanning electron microscopy and tensile testing was carried out to investigate the mechanical properties. Findings

Bo Wang; Fengshun Wu; Yiping Wu; Bing An; Hui Liu; Jian Zou

2011-01-01

117

Increase of the thermoelectric power factor in Cu\\/Bi\\/Cu,Ni\\/Bi\\/Ni, and Cu\\/Bi\\/Ni composite materials  

Microsoft Academic Search

The resultant thermoelectric power factors P of three types of Cu\\/Bi\\/Cu,Ni\\/Bi\\/Ni, and Cu\\/Bi\\/Ni composite materials welded with Bi were measured at 298 K as a function of relative thickness of Bi and compared with P values calculated by treating these devices as an electrical and thermal circuit. It was first demonstrated experimentally that the observed P values of composite devices

Hirotaka Odahara; Osamu Yamashita; Kouji Satou; Shoichi Tomiyoshi; Jun-Ichi Tani; Hiroyasu Kido

2005-01-01

118

Nanoindentation characterization of NiCuSn IMC layer subject to isothermal aging  

Microsoft Academic Search

Lead-free SnAgCu(SAC) solder joint on CuOSP and ENIG subject to thermal testing leads to IMC growth and causes corresponding reliability concerns at the interface. Modulus and hardness of these IMCs were characterized by Nanoindentation CSM from plan view in this study. A plan-view IMC surface was prepared by deep etching and slight polishing method. When SAC\\/Ni(Au) solder joint were subject

Luhua Xu; John H. L. Pang

2006-01-01

119

Preparation and magnetotransport properties of Ni-Bi and Ni-Cu magnetic multilayers  

NASA Astrophysics Data System (ADS)

We have investigated the magnetotransport properties of binary metallic systems formed by Ni-Bi and Cu-Ni multilayers. The samples were prepared by electrochemical deposition. Ni-Bi systems were obtained from two separate solutions and Cu-Ni systems from a single electrolyte. The films have been characterized using spectro-ellipsometry. Field dependence of the Hall resistivity and magnetoresistance for both the multilayer deposited structures were measured. Anisotropic magnetoresistance for Cu-Ni structures was found.

Hutanu, Vladimir M.; Dolocan, Voicu

2000-02-01

120

Magnetic Properties of Compositionally Modulated Cu-Ni Thin Films  

NASA Astrophysics Data System (ADS)

The magnetic properties of modulated Cu-Ni films with Ni thickness ranging from 6 to 60 and for various Cu thickness have been measured at room temperature, 77K, and 4.2K. The results show that the magnetic properties do not depend on the Cu thickness but only on the surface to volume ratio of the Ni. The Ni behavior is interpreted in terms of a large surface anisotropy, and not in terms of an enhanced moment.

Gyorgy, E. M.; Dillon, J. F., Jr.; McWhan, D. B.; Rupp, L. W., Jr.; Testardi, L. R.; Flanders, P. J.

1980-07-01

121

Magnetic Properties of Compositionally Modulated Cu-Ni Thin Films  

Microsoft Academic Search

The magnetic properties of modulated Cu-Ni films with Ni thickness ranging from 6 to 60 and for various Cu thickness have been measured at room temperature, 77K, and 4.2K. The results show that the magnetic properties do not depend on the Cu thickness but only on the surface to volume ratio of the Ni. The Ni behavior is interpreted

E. M. Gyorgy; J. F. Dillon Jr.; D. B. McWhan; L. W. Rupp Jr.; L. R. Testardi; P. J. Flanders

1980-01-01

122

Pb-free Sn-Ag-Cu ternary eutectic solder  

DOEpatents

A Pb-free solder includes a ternary eutectic composition consisting essentially of about 93.6 weight % Sn-about 4.7 weight % Ag-about 1.7 weight % Cu having a eutectic melting temperature of about 217 C and variants of the ternary composition wherein the relative concentrations of Sn, Ag, and Cu deviate from the ternary eutectic composition to provide a controlled melting temperature range (liquid-solid ``mushy`` zone) relative to the eutectic melting temperature (e.g. up to 15 C above the eutectic melting temperature). 5 figs.

Anderson, I.E.; Yost, F.G.; Smith, J.F.; Miller, C.M.; Terpstra, R.L.

1996-06-18

123

Photoemission from Ag, Cu, and CsI  

SciTech Connect

Photoemission characteristics of three different cathodes, CsI, Ag film and Cu were investigated. CsI, upon irradiation by 213 nm, 10ps laser pulse yields a quantum efficiency of 4% at O.2[mu]J input energy. The saturation mechanism observed at higher input energies require further investigation. Ag film, upon irradiation by 630 nm, 300 fs laser emit prompt photoelectrons after absorbing 2 photons. There was no evidence of optical damage of the film up to 10[sup 11] W/cm[sup 2]. At low intensities, photoemission from Cu is a simple [nu]-e[sup [minus

Srinivasan-Rao, T.; Fischer, J.; Tsang, T.

1992-06-01

124

Graphene decorated with Ni(OH)2 and Ag deposited Ni(OH)2 stacked nanoplate for supercapacitor application  

NASA Astrophysics Data System (ADS)

In this letter hydrothermally synthesized hierarchical stacked nanoplate of Ni(OH)2 and Ag deposited Ni(OH)2 have been successfully fabricated on graphene nanosheet. The prepared Ni(OH)2, Ag deposited Ni(OH)2 and their graphene based composites were characterized by XRD, FESEM and TEM analysis. Graphene increases the utility of the pseudocapacitive Ni(OH)2 and Ag deposited Ni(OH)2 as electrode material. Electrochemical characterizations in 6 M KOH electrolyte revealed superior electrode performance of the Ag deposited Ni(OH)2/graphene composite over Ni(OH)2/graphene composite with maximum specific capacitance of 496 F/g at 1 A/g current density accompanying 93% specific capacitance retention at the end of 500 consecutive charge discharge cycles.

Ghosh, Debasis; Giri, Soumen; Mandal, Avinandan; Das, Chapal Kumar

2013-06-01

125

Transverse magnetization in Cu/Ni/Cu epitaxial nanorings  

NASA Astrophysics Data System (ADS)

The micromagnetic structure in epitaxial (001)-oriented Cu/Ni(14 nm)/Cu rings fabricated by electron beam and focused ion beam lithographies with external diameter of 3 ?m and linewidths between 100 and 500 nm is presented. We found that a state with radial orientation of the magnetization prevails at remanence. The evaluation of the magnetoelastic, magnetocrystalline and magnetostatic energies shows that a value as low as 1.5 10-3 for the anisotropic relaxation of the in-plane strain components is enough to induce an effective radial easy magnetization direction.

Corredor, Edna C.; Coffey, David; Arnaudas, Jos I.; Ibarra, Alfonso; Ross, Caroline A.; Ciria, Miguel

2013-04-01

126

Constitutive Modeling of Sn\\/Ag and Sn\\/Ag\\/Cu Solder Alloys  

Microsoft Academic Search

In this paper, we report some results from a recent study on developing constitutive laws suitable for Sn\\/Ag and Sn\\/Ag\\/Cu based solder materials. Extensive thermomechanical testing has been conducted on these lead-free solder alloys under various temperature (-55C-150C) and strain rate (10-7\\/s-10-1\\/s), subjected to both monotonic and cyclic loading. The experimental data are then used to develop a viscoplastic constitutive

Min Pei; Jianmin Qu

2006-01-01

127

Activation Energy for Loop Growth in Cu and Cu-Ni Alloys.  

National Technical Information Service (NTIS)

The apparent activation energy for the growth of interstitial dislocation loops in copper, Cu-1%Ni, Cu-2%Ni, and Cu-5%Ni during high voltage electron microscope irradiation was determined. The apparent activation energy for loop growth in all these materi...

P. Barlow T. Leffers B. N. Singh

1978-01-01

128

Pb-free BGA Solder Joint Reliability Improvement with Sn3.5Ag Solder Alloy on Ni\\/Au Finish  

Microsoft Academic Search

In this work, Sn3.5Ag solder alloy was being studied for the purpose of Pb-free solder joint reliability improvement over conventional Sn3.8AgO.7Cu solder balls on Ball Grid Array (BGA) packages with Ni\\/Au pad finishing. The study was carried out in different levels. At individual solder joint level, Sn3.5Ag showed no intermetallic brittle failure in cold ball pull test even up to

Eu Poh Leng; Min Ding; W. Lindsay; S. Chopin; I. Ahmad; A. Jalar

2007-01-01

129

Giant magnetoresistance and magnetic properties of electrodeposited NiCoCu\\/Cu multilayers  

Microsoft Academic Search

The room-temperature magnetoresistance (MR) and magnetization characteristics were investigated for electrodeposited NiCoCu(3nm)\\/Cu(dCu) multilayers with dCu=1 and 2nm as a function of the ratio of Co to Ni in the magnetic layer. The maximum giant magnetoresistance (GMR) was obtained when the Co- and Ni-contents of the magnetic layer were approximately equal for dCu=1nm, whereas a significantly smaller GMR with no systematic

G. Nabiyouni; W. Schwarzacher; Z. Rolik; I. Bakonyi

2002-01-01

130

Dynamic viscosities of pure tin and Sn-Ag, Sn-Cu, and Sn-Ag-Cu eutectic melts  

NASA Astrophysics Data System (ADS)

The dynamic viscosities of the melts of pure tin and eutectic Sn-Ag, Sn-Cu, and Sn-Ag-Cu alloys are studied in heating followed by cooling, and the maximum heating temperature was 1200C. An irreversible decrease in the viscosity is found in the temperature range 800-1000C in the polytherms of all melts. This finding is related to the loss of a local order in a melt and can be used to develop temperature regimes for the production of lead-free solders.

Rozhitsina, E. V.; Gruner, S.; Kaban, I.; Hoyer, W.; Sidorov, V. E.; Popel', P. S.

2011-02-01

131

Ag3Sn plate formation in the solidification of near-ternary eutectic Sn-Ag-Cu  

NASA Astrophysics Data System (ADS)

Near-ternary eutectic Sn-Ag-Cu alloys are leading lead-free candidate solders for various applications. These alloys yield three phases upon solidification: ?-Sn,Ag3Sn, and Cu6Sn5. Large, plate-like, pro-eutectic Ag3Sn structures can grow rapidly within the liquid phase, potentially adversely affecting the mechanical behavior and reducing the fatigue life of solder joints. This article reports on the formation of such plates in Sn-Ag-Cu solder balls and joints and demonstrates how large Ag3Sn plate formation can be minimized.

Kang, Sung K.; Shih, Da-Yuan; Donald, Ny.; Henderson, W.; Gosselin, Timothy; Sarkhel, Amit; Charles Goldsmith, Ny.; Puttlitz, Karl J.; Choi, Won Kyoung

2003-06-01

132

Selective Extraction of Cu and Ag Ions from Sulfuric Acid by Synergistic Combinations of Tetradentate Thia Macrocycles with Dioodecylnaphthalene Sulfonic Acid  

Microsoft Academic Search

The aqueous-insoluble thia macrocycles tetrathia-14-crown-4 (TT14C4) and tetrathia-16-crown-4 (TT16C4) strongly and selectively synergize the extraction of Cu and Ag ions from aqueous sulfuric acid solutions by the organophilic cation exchanger didodecylnaphthalene sulfonlc acid (HDDNS) in toluene diluent. Over a range of sulfuric acid concentrations, the selectivity is given by the order Ag > Cu > Mn, Fe, Fe, Co, Ni,

Bruce A. Moyer; Curtis L. Westerfield; W. J. Mcdowell; G. N. Case

1988-01-01

133

Magnetic anisotropy, magnetic moments and coupling of Cu/Co/Cu/Ni/Cu(001) trilayer  

NASA Astrophysics Data System (ADS)

Polar magneto-optic Kerr effect (MOKE) measurements on an epitaxial Cu/Co (23 )/Cu (0-49 )/Ni (53 )/Cu/Si(001) structure reveal that the Ni magnetization is aligned in plane for zero Cu spacer layer thickness and becomes increasingly aligned out of plane with increasing Cu spacer layer thickness, whereas an in-plane remanent magnetization for Co is always observed. Layer selective polarized neutron reflection (PNR) measurements yield almost bulk-like magnetic moments of 1.57+/-0.08 B for Co and 0.50+/-0.04 B for Ni for a Cu/Co (22 )/Cu (10 )/Ni (53 )/Cu/Si(001) structure at room temperature. A reduced remanence is observed for both the out-of plane magnetization by polar MOKE, and the in-plane magnetization for Co and Ni by PNR. This could suggest either a canted magnetization or multidomain state at remanence.

Lauhoff, G.; Hirohita, A.; Bland, J. A. C.; Lee, J.; Langridge, S.; Penfold, J.

1999-09-01

134

Perpendicular GMI Effect in Meander NiFe and NiFe\\/Cu\\/NiFe Film  

Microsoft Academic Search

We have evaluated the perpendicular giant magnetoimpedance effect (GMI) in both NiFe and NiFe\\/Cu\\/NiFe films with meander geometry in the >1 MHz high-frequency range. With the magnetic field, the perpendicular GMI effect shows an intense GMI peak value at a certain field. This effect is comparable to the longitudinal GMI effect in both profile and peak value amplitude. The experimental

Zhimin Zhou; Yong Zhou; Lei Chen

2008-01-01

135

Structural changes during annealing of multilayer films of Cu-Co and Ag-Cu systems  

NASA Astrophysics Data System (ADS)

Characterizations of as-deposited and annealed multilayers of Cu-Co and Ag-Cu systems show that the periodically layered structures are rather unstable. However, computer simulations based on the nonlinear diffusion equation and TEM observations of spinodal alloys indicate that such periodic structures should be stable. This suggests that there is high probability of obtaining stable multilayers.

Doi, M.; Miyazaki, T.

1993-09-01

136

Industrial Cu-Ni alloys for HTS coated conductor tape  

Microsoft Academic Search

Copper rich Cu-Ni alloys have been textured with the RABiTS method in order to get non-magnetic and cost efficient substrates for coated conductor wires. The study is focused on two industrial compositions: Cu55Ni45 (Constantan) and Cu70Ni30. Studies on surface roughness have been done. The effects of annealing conditions (temperature and atmosphere) on the grain boundaries deepness were analyzed. Electrolytic polishing

A Girard; C E Bruzek; J L Jorda; L Ortega; J L Soubeyroux

2006-01-01

137

Controlled epitaxial growth of Cu and Ni islands on oxygen-preadsorbed Cu(100) surfaces  

Microsoft Academic Search

Growth of Cu and Ni islands was studied on the two oxygen-preadsorbed Cu(100) surfaces, a Cu(100) surface covered with nanometer size c(22)O domains and a reconstructed (222)R45Cu(100)O surface. Preadsorbed oxygen on Cu(100) migrates onto the epitaxially grown metal islands. Homoepitaxial growth of Cu on a nanometer-size c(22)O Cu(100) surface forms monolayered rectangular Cu islands which grow in the [010] and

Takaya Fujita; Ken-ichi Tanaka

1998-01-01

138

Deformation characteristics and microstructural evolution of SnAgCu solder joints  

Microsoft Academic Search

Three SnAgCu solder alloys (Sn2AgO.5Cu, Sn3.4AgO.8Cu, Sn4AgO.5Cu) have been tested to determine their deformation behavior in the temperature range 23-110C, strain-rates varying 10-7-10-1 1\\/s. It is shown by optical micro-graphs of CSP solder joints that microstructure of SnAgCu may undergo through significant changes due to various loading conditions, which can occur during usage of microelectronic devices, such as thermal cycling,

T. O. Reinikainen; P. Marjamaki; J. K. Kivilahti

2005-01-01

139

Analysis of the interfacial structure of a twinned variant of Ag precipitate in Cu-Ag alloys  

SciTech Connect

There have been numerous studies of orientation relationships (ORs) between precipitate and matrix phases in alloys. In contrast, there have been very few reports in the literature of the hetero-twin OR, where the lattice planes in the precipitate phase are in twin orientation with respect to the corresponding lattice planes in the parent phase. Examples of such an OR have been observed in metal silicide/Si systems. When a Co film is deposited on (111) Si, the CoSi[sub 2] reaction product displays two variants. One of these variants was found to have the hetero-twin orientation with respect to the underlying substrate. Similar ORs have also been observed in the NiSi[sub 2] system. In this study the authors report experimental results obtained on a binary Cu-Ag alloy consisting of Ag-rich precipitates in a Cu-rich matrix. The OR between some of the precipitates and the matrix is the hetero-twin orientation. The structural ledge (SL) theory is used to analyze the OR and to predict the habit plane.

Rao, G.; Wynblatt, P. (Carnegie Mellon Univ., Pittsburgh, PA (United States). Dept of Materials Science and Engineering); Howe, J.M. (Univ. of Virginia, Charlottesville, VA (United States). Dept. of Materials Science and Engineering)

1994-03-15

140

Effects of cooling speed on microstructure and tensile properties of SnAgCu alloys  

Microsoft Academic Search

The microstructures and tensile properties of three typical SnAgCu alloys, Sn3.0wt.%Ag0.5wt.%Cu, Sn3.5wt.%Ag0.7wt.%Cu and Sn3.9wt.%Ag0.6wt.%Cu, prepared under three different cooling conditions were evaluated after casting. The microstructures of all rapidly cooled specimens consisted of the eutectic phase of ?-Sn with fine fibrous Ag3Sn dispersion surrounding primary ?-Sn grains. The slowly cooled Sn3.5Ag0.7Cu and Sn3.9Ag0.6Cu alloys exhibited additional large primary Ag3Sn platelets,

K. S Kim; S. H Huh; K Suganuma

2002-01-01

141

Ag 3 Sn plate formation in the solidification of near-ternary eutectic Sn-Ag-Cu  

Microsoft Academic Search

Near-ternary eutectic Sn-Ag-Cu alloys are leading lead-free candidate solders for various applications. These alloys yield\\u000a three phases upon solidification: ?-Sn,Ag3Sn, and Cu6Sn5. Large, plate-like, pro-eutectic Ag3Sn structures can grow rapidly within the liquid phase, potentially adversely affecting the mechanical behavior and reducing\\u000a the fatigue life of solder joints. This article reports on the formation of such plates in Sn-Ag-Cu solder

Sung K. Kang; Da-Yuan Shih; Ny. Donald; W. Henderson; Timothy Gosselin; Amit Sarkhel; N. Y. Charles Goldsmith; Karl J. Puttlitz; Won Kyoung Choi

2003-01-01

142

Intermetallic compound layer growth at the interface between SnCuNi solder and Cu substrate  

Microsoft Academic Search

Phase analysis and growth kinetics of intermetallic compound (IMC) layers formed between low cost SnCuNi solder for wave soldering and Cu substrate by solid state isothermal aging were examined at temperatures between 80 and 150C for 0 to 60 days. The IMC layer was composed of two phases; Cu6Sn5 (also (Cu,Ni)6Sn5) adjacent to the solder, Cu3Sn adjacent to the copper.

Jeong-Won Yoon; Young-Ho Lee; Dae-Gon Kim; Han-Byul Kang; Su-Jeong Suh; Cheol-Woong Yang; Chang-Bae Lee; Jong-Man Jung; Choong-Sik Yoo; Seung-Boo Jung

2004-01-01

143

Exchange bias field and coercivity of [NiFe/NiFeCuMo/NiFe]/FeMn multilayers  

NASA Astrophysics Data System (ADS)

The exchange bias field ( H EX ) and the coercivity ( H C ) of the intermediate, super-soft magnetic NiFeCuMo layer were investigated for different thicknesses of the bottom NiFe layer. The H EX of the triple-pinned NiFe (4 nm)/NiFeCuMo ( t NiFeCuMo = 1 nm)/NiFe (4 nm)/FeMn multilayer has a maximum value of 77 Oe, which is more than that of a single-pinned NiFe (8 nm)/FeMn layer (42 Oe). A multilayer system with the NiFeCuMo layer inserted between the pinned and the free NiFe layers can be used as a giant magnetoresistive spin-valve device for biosensors with improved magnetic sensitivity.

Choi, Jong-Gu; Hwang, Do-Guwn; Lee, Sang-Suk; Rhee, Jang-Roh

2013-06-01

144

Photoemission from Ag, Cu, and CsI  

SciTech Connect

Photoemission characteristics of three different cathodes, CsI, Ag film and Cu were investigated. CsI, upon irradiation by 213 nm, 10ps laser pulse yields a quantum efficiency of 4% at O.2{mu}J input energy. The saturation mechanism observed at higher input energies require further investigation. Ag film, upon irradiation by 630 nm, 300 fs laser emit prompt photoelectrons after absorbing 2 photons. There was no evidence of optical damage of the film up to 10{sup 11} W/cm{sup 2}. At low intensities, photoemission from Cu is a simple {nu}-e{sup {minus}} interaction, the nonlinearity of the process depending strongly on trace impurities. At higher intensities, there appears to be a change in the emission mechanism.

Srinivasan-Rao, T.; Fischer, J.; Tsang, T.

1992-06-01

145

Residual stress and interfacial reaction of the electroplated Ni-Cu alloy under bump metallurgy in the flip-chip solder joint  

NASA Astrophysics Data System (ADS)

Pure Ni, the Ni-Cu alloy, and pure Cu layers as the under bump metallurgy (UBM) for a flip-chip solder joint were deposited by electrolytic plating. For the pure Ni layer, residual stress can be controlled by adding a wetting agent and decreasing current density, and it is always under tensile stress. The Ni-Cu alloys of different Cu compositions from 20wt.%Cu to 100wt.%Cu were deposited with varying current density in a single bath. The residual stress was a strong function of current density and Cu composition. Decreasing current density and increasing Cu content simultaneously causes the residual stress of the metal layers to sharply decrease. For the pure Cu layer, the stress is compressive. The Cu layer acts as a cushion layer for the UBM. The residual stress of the UBM strongly depends on the fraction of the Cu cushion layer. Interfacial reaction of the UBM with Sn-3.5 wt.% Ag was studied. As the Cu contents of Ni-Cu alloys increased, the dissolution rate increased. Several different intermetallic compounds (IMCs) were found. The lattice constants of alloys and the IMC increase with increasing Cu contents because the larger Cu atoms substitute for the smaller Ni atoms in the crystallites. The Cu content of the IMC are strongly dependent on the composition of the alloys. Ball shear tests were done with different metal-layer schemes. The failure occurs through the IMC and solder.

Kim, S.-H.; Kim, J.-Y.; Yu, J.; Lee, T. Y.

2004-09-01

146

Effect of SnAgCu composition on soldering performance  

Microsoft Academic Search

Purpose Tombstoning and voiding have been plaguing the surface mount assembly industry for decades. The recent global move toward lead-free soldering and the extensive adoption of microvia technology further aggravate the problems. The present study investigates the impact of SnAgCu (SAC) alloy composition on these important issues. Design\\/methodology\\/approach In this study, tombstoning and voiding at microvias are studied

Benlih Huang; Arnab Dasgupta; Ning-Cheng Lee

2005-01-01

147

Reactive interdiffusion between a lead-free solder and Ti\\/Ni\\/Ag thin-film metallizations  

Microsoft Academic Search

The reactive interdiffusion between a Sn-3.0wt.%Ag-0.7wt.%Cu solder and thin-film Ti\\/Ni\\/Ag metallizations on two semiconductor\\u000a devices, a diode and a metal-oxide-semiconductor field-effect transistor (MOSFET), and a Au-layer on the substrates are studied.\\u000a Comprehensive microanalytical techniques, scanning electron microscopy, transmission electron microscopy (TEM), and analytical\\u000a electron microscopy (AEM) are employed to identify the interdiffusion processes during fabrication and service of the devices.

G. Ghosh

2004-01-01

148

Cascade Collapse of Heavy-Ion Irradiated Cu-Ni Alloys.  

National Technical Information Service (NTIS)

To evaluate the role of material properties on the probability of a displacement cascade collapsing to a vacancy dislocation loop, the alloy content in Cu-Ni has been varied over the complete composition range. Cu-90wt%Ni, Cu-80wt%Ni, Cu-60wt%Ni, Cu-40wt%...

K. S. Smalinskas

1988-01-01

149

Unusual magnetic properties in Cu\\/Ni multilayered films  

Microsoft Academic Search

Cu\\/Ni multilayered films of different layer thicknesses were made by the sputtering technique. In all samples the Cu and Ni layers had the same thickness, and the total thickness of the sample was 5000 A?. Each sample was cooled in zero field to 5 K and the magnetization versus temperature was measured after a magnetic field was applied and kept

W. Abdul-Razzaq

1990-01-01

150

Giant magnetoresistance in electrodeposited Ni-Cu\\/Cu multilayers and anisotropic magnetoresistance in pulse-plated NixCu1-x alloy films  

Microsoft Academic Search

Ni-Cu\\/Cu multilayers and Ni xCu 1- x alloy films were electrodeposited on Au-coated glass substrates from a sulfamate-based electrolyte. The room-temperature magnetoresistance of the multilayers was studied as a function of the ferromagnetic Ni-Cu layer thickness. Giant magnetoresistance was observed, which peaked at about 1% for a Ni-Cu layer thickness around 15. Magnetoresistance measurements of Ni xCu 1- x films

I. Kazeminezhad; W. Schwarzacher

2004-01-01

151

High thermally stable Ni/Ag(Al) alloy contacts on p-GaN  

SciTech Connect

Ag agglomeration was found to occur at Ni/Ag to p-GaN contacts after annealing at 500 degree sign C. This Ag agglomeration led to the poor thermal stability showed by the Ni/Ag contacts in relation to the reflectivity and electrical properties. However, after alloying with 10 at. % Al by e-gun deposition, the Ni/Ag(Al) p-GaN contacts were found to effectively retard Ag agglomeration thereby greatly enhancing the thermal stability. Based on the x-ray photoelectron spectroscopy analysis, the authors believe that the key for the retardation of Ag agglomeration was the formation of ternary Al-Ni-O layer at p-GaN interface.

Chou, C. H.; Lin, C. L.; Chuang, Y. C.; Bor, H. Y.; Liu, C. Y. [Department of Chemical and Materials Engineering, National Central University, Jhong-Li, 32001, Taiwan (China); Materials and Electro-Optical Research Division, Chung Shan Institute of Science and Technology, Longtan, 32546 (China); Institute of Materials Science and Engineering, National Central University, Jhong-Li, 32001, Taiwan (China)

2007-01-08

152

Oxidation behaviour of Cu-Ni(Mn) (constantan) films  

Microsoft Academic Search

The oxidation of constantan films has been investigated using Cu-Ni(Mn) single films and (Cu-Ni(Mn))-NiCr film configurations by measurements of electrical resistance and Auger electron spectra depth profiling, as well as by thermogravimetric and differential thermoanalytical studies. Oxidation starts under air and argon atmosphere between 300 and 350 C. Under an N2-H2 gas mixture a passivating film formed by a double

W. Brckner; S. Baunack; G. Reiss; G. Leitner; Th. Knuth

1995-01-01

153

Micromagnetic properties of the Cu\\/Ni crossed-wedge film on Cu(0 0 1)  

Microsoft Academic Search

The micromagnetic properties of a Ni film in a Cu\\/Ni crossed-wedge on Cu(001) are investigated by a combination of photoelectron emission microscopy and X-ray magnetic circular dichroism. Two spin-reorientation transitions (SRT) from in-plane to perpendicular to the film plane and back to in-plane were observed with increasing Ni thickness. Whereas no clear Cu thickness dependence of the former SRT has

Keiki Fukumoto; Hiroshi Daimon; Liviu Chelaru; Francesco Offi; Wolfgang Kuch; Jrgen Kirschner

2002-01-01

154

Optical Properties of Thin Films of Ni, Cu, and Ni + 60% Cu in the Wavelength Range 3000-6000 Angstron.  

National Technical Information Service (NTIS)

The optical absorption coefficients are measured for thin films of Ni, Cu, and Ni + 60% Cu in the wavelength range 3000-6000 A. Local areas are examined by transmission electron microscopy using both bright and dark-field techniques in order to characteri...

L. E. Murr

1969-01-01

155

Failure Morphology After Drop Impact Test of Ball Grid Array (BGA) Package With Lead-Free Sn3.8Ag0.7Cu and Eutectic SnPb Solders  

Microsoft Academic Search

High strain-rate drop impact tests were performed on ball grid array (BGA) packages with solder compositions of (in wt%) Sn-3.8Ag-0.7Cu (SnAgCu) and eutectic Sn-37Pb (SnPb). Solder balls were joined to the metallizations of plated Ni on the device side and plated Cu on the board side. The BGA packages were tested at 1500 g within 0.5 ms, resulting in an

Jin-Wook Jang; Ananda P. De Silva; James E. Drye; Steve L. Post; Norman L. Owens; Jong-Kai Lin; Darrel R. Frear

2007-01-01

156

Ordering in 3d 5d (CuAu) and segregation in 3d 4d (CuAg) systems  

NASA Astrophysics Data System (ADS)

We show the differences in the stability of 3d 5d (CuAu) and 3d 4d (CuAg) alloys arise mainly due to relativistic corrections. We examine the effect of relativistic corrections to the pair energies and order disorder transition temperatures in these alloys. The short-ranged order or segregation patterns in CuAu/CuAg alloys is also studied using the Krivoglaz Moss Clapp model.

Paudyal, Durga; Mookerjee, Abhijit

2005-09-01

157

Core-shell structure disclosed in self-assembled Cu-Ag nanoalloy particles.  

PubMed

Core-shell segregation of copper and silver in self-assembled, free nanoparticles is established by means of photoelectron spectroscopy in a wide range of relative Cu-Ag concentrations. These conclusions are based on the analysis of the photon-energy-dependent changes of the Cu 3d and Ag 4d photoelectron spectra. The nanoparticles are formed from mixed Cu-Ag atomic vapor created by magnetron sputtering of a bimetallic sample in a gas-aggregation cluster source. Even at similar Cu and Ag fractions in the primary vapor the surface of the nanoparticles is dominated by silver. Only at low Ag concentration copper appears on the surface of nanoparticles. For the latter case, a threefold decrease in the Ag 4d spin-orbit splitting has been detected. The specific component distribution and electronic structure changes are discussed in connection with the earlier results on Cu-Ag macroscopic and surface alloys. PMID:23514485

Tchaplyguine, M; Andersson, T; Zhang, Ch; Bjrneholm, O

2013-03-14

158

Core-shell structure disclosed in self-assembled Cu-Ag nanoalloy particles  

NASA Astrophysics Data System (ADS)

Core-shell segregation of copper and silver in self-assembled, free nanoparticles is established by means of photoelectron spectroscopy in a wide range of relative Cu-Ag concentrations. These conclusions are based on the analysis of the photon-energy-dependent changes of the Cu 3d and Ag 4d photoelectron spectra. The nanoparticles are formed from mixed Cu-Ag atomic vapor created by magnetron sputtering of a bimetallic sample in a gas-aggregation cluster source. Even at similar Cu and Ag fractions in the primary vapor the surface of the nanoparticles is dominated by silver. Only at low Ag concentration copper appears on the surface of nanoparticles. For the latter case, a threefold decrease in the Ag 4d spin-orbit splitting has been detected. The specific component distribution and electronic structure changes are discussed in connection with the earlier results on Cu-Ag macroscopic and surface alloys.

Tchaplyguine, M.; Andersson, T.; Zhang, Ch.; Bjrneholm, O.

2013-03-01

159

Interactions of oxygen and ethylene with submonolayer Ag films supported on Ni(111)  

Microsoft Academic Search

We investigate the oxidation of, and the reaction of ethylene with, Ni(111) with and without sub-monolayer Ag adlayers as a function of temperature. The addition of Ag to Ni(111) is shown to enhance the activity towards the ethylene epoxidation reaction, and increase the temperature at which ethylene oxide is stable on the surface. We present a systematic study of the

Robert E. Rettew; Axel Meyer; Sanjaya D. Senanayake; Tsung-Liang Chen; Cole Petersburg; J. Ingo Flege; Jens Falta; Faisal M. Alamgir

2011-01-01

160

Effects of Ni film thickness on the structural stability of Si\\/Ni\\/Cu film electrodes  

Microsoft Academic Search

The electrochemical properties of Si\\/Ni\\/Cu film electrodes fabricated with different Ni film thicknesses were evaluated by investigating their structural properties. As the Ni film thickness increased from 0.5 to 3.5 ?m, the growth behavior of the Ni film was changed from a fine grain structure to a column structure grown preferentially. The morphology of Ni clusters was also changed from

Gyu Bong Cho; Kwon Koo Cho; Ki Won Kim

2006-01-01

161

Optical spectroscopy of Cu sup + /Ag sup + doped. beta. double prime -alumina  

SciTech Connect

Crystalline {beta}{double prime}-alumina doped with both Ag{sup +} and Cu{sup +} is luminescent at temperatures between 10 and 450 K. The mobility of the ions in the conduction plane at room temperature gives rise to unusual spectroscopic properties. The dominant emission band at 640 nm originates from (CuAg){sup 2+} exciplex emission. Absorption of a photon by mobile monomeric ions leads to excited state dimer formation. Emission from (CuCu){sup 2+} excimers at 550 nm and from Cu{sup +} monomers at 400-450 nm are also observed. No emission from Ag{sup +} monomers or (AgAg){sup 2+} excimers is found. The Cu{sup +}/Ag{sup +} doped crystals exhibit optical memory. Irradiation of a spot on a crystal during cooling of the crystal preferentially forms dimers in the irradiated region which are trapped when the ion mobility decreases.

Kim Shin, Kyeongsook; Barrie, J.D.; Dunn, B.; Zink, J.I. (Univ. of California, Los Angeles (USA))

1990-07-18

162

Layer-dependent magnetic-moment distribution in an epitaxial double spin valve structure: Si(001)/Cu/FeNi/Cu/Co/Cu/FeNi/Cu  

NASA Astrophysics Data System (ADS)

Polarized neutron reflectivity was used to determine, layer selectively, the magnetic moments, spin orientations, and thicknesses of an epitaxial double spin valve structure of the form Si(001)/Cu/FeNi/Cu/Co/Cu/FeNi/Cu. Absolute values of the average magnetic moment per atom were determined within an error of ~+/-5%. At saturation, the layer-averaged magnetic moment per Co atom was found to be 1.71+/-0.08?B, while the top (bottom) FeNi layer moment was 1.08+/-0.06?B (0.95+/-0.08?B). For an applied field strength Ha smaller than the Co layer coercive field of ~100 Oe, the Co and FeNi layer magnetization vectors are found to lie in plane but canted with respect to each other in contrast to the fully antiparallel state predicted by simple energy minimization. The observed canting is attributed to the presence of magnetic domains in the Co layer.

Samad, A.; Choi, B. C.; Langridge, S.; Penfold, J.; Bland, J. A. C.

1999-09-01

163

Mechanochemical synthesis, thermal stability and selective electrochemical dissolution of CuAg solid solutions  

Microsoft Academic Search

Supersaturated nanocrystalline (1619nm) Cu50Ag50 and Cu70Ag30 solid solutions are synthesized by high-energy ball milling. Varying the milling time fcc solid solutions with different lattice parameters are obtained. Thus an increase of the lattice constant that levels off after 20h of milling is registered for the Cu50Ag50 solid solution. At the same time broad overlapped exothermic effects in the temperature range

T. Spassov; L. Lyubenova; Y. Liu; S. Bliznakov; M. Spassova; N. Dimitrov

2009-01-01

164

Thermal Fatigue Behavior of SnAgCu Soldered Joints in Fine Pitch Devices  

Microsoft Academic Search

This paper presents the fatigue life of fine pitch devices with SnAgCu soldered joints calculated by experiments and numerical simulation. Special test vehicles were selected with SnAgCu soldered joints for testing, and thus the fatigue life of the SnAgCu soldered joints was 1150 cycles under ?55125 C test condition. On the other hand finite element code ANSYS was used to

Zhang Liang; Xue Songbai; Gao Lili; Zeng Guang; Yu Shenglin; Sheng Zhong

2010-01-01

165

Driving forces for Ag-induced periodic faceting of vicinal Cu (1 1 1)  

Microsoft Academic Search

Adsorption of submonolayer amounts of Ag on vicinal Cu(111) induces periodic faceting. The equilibrium structure is characterized by Ag-covered facets that alternate with clean Cu stripes. In the atomic scale, the driving force is the matching of Ag(111)-like packed rows with Cu(111) terraces underneath. This determines the preference for the facet orientation and the evolution of different phases as a

A. R. Bachmann; S. Speller; A. Mugarza; J. E. Ortega

2003-01-01

166

Passivation and ClInduced Depassivation of Cu-Ag Alloys in  

Microsoft Academic Search

The electrochemical behaviour of two Cu-Ag alloys, namely (20wt%Cu + 80wt%Ag) and (80wt%Cu + 20wt%Ag) alloys, was studied in 0.15 M borax and 0.15 M boric acid buffer solution, pH =8.45, by means of cyclic voltammetry, potentiodynamic anodic polarization and current\\/ time transients techniques. SEM and XRD microanalysis were used to examine the changes caused by the electrochemical perturbations. The

167

Flexible bottom-emitting white organic light-emitting diodes with semitransparent Ni/Ag/Ni anode.  

PubMed

We fabricated a flexible bottom-emitting white organic light-emitting diode (BEWOLED) with a structure of PET/Ni/Ag/Ni (3/6/3 nm)/ NPB (50 nm)/mCP (10 nm)/7% FIrpic:mCP (10 nm)/3% Ir(pq)(2) acac:TPBi (5 nm)/7% FIrpic:TPBi (5 nm)/TPBi (10 nm)/Liq (2 nm)/ Al (100 nm). To improve the performance of the BEWOLED, a multilayered metal stack anode of Ni/Ag/Ni treated with oxygen plasma for 60 sec was introduced into the OLED devices. The Ni/Ag/Ni anode effectively enhanced the probability of hole-electron recombination due to an efficient hole injection into and charge balance in an emitting layer. By comparing with a reference WOLED using ITO on glass, it is verified that the flexible BEWOLED showed a similar or better electroluminescence (EL) performance. PMID:23669964

Koo, Ja-Ryong; Lee, Seok Jae; Lee, Ho Won; Lee, Dong Hyung; Yang, Hyung Jin; Kim, Woo Young; Kim, Young Kwan

2013-05-01

168

Characterization and device performance of (AgCu)(InGa)Se2 absorber layers  

SciTech Connect

The study of (AgCu)(InGa)Se2 absorber layers is of interest in that Ag-chalcopyrites exhibit both wider bandgaps and lower melting points than their Cu counterparts. (AgCu)(InGa)Se2 absorber layers were deposited over the composition range 0 < Ag/(Ag+Cu) < 1 and 0.3 < Ga/(In+Ga) < 1.0 using a variety of elemental co-evaporation processes. Films were found to be singlephase over the entire composition range, in contrast to prior studies. Devices with Ga content 0.3 < Ga/(In+Ga) <0.5 tolerated Ag incorporation up to Ag/(Ag+Cu) = 0.5 without appreciable performance loss. Ag-containing films with Ga/(In+Ga) = 0.8 showed improved device characteristics over Cu-only control samples, in particular a 30-40% increase in short-circuit current. An absorber layer with composition Ag/(Ag+Cu) = 0.75 and Ga/(In+Ga) = 0.8 yielded a device with VOC = 890 mV, JSC = 20.5mA/cm2, fill factor = 71.3%, and ? = 13.0%.

Hanket, Gregory; Boyle, Jonathan H.; Shafarman, William N.

2009-06-08

169

Strain, inter-diffusion, magnetism and magnetic anisotropy in Cu\\/Ni\\/Cu (0 0 1) sandwiches  

Microsoft Academic Search

The effects of interface, strain and interdiffusion on magnetic moments and magnetocrystalline anisotropy in Cu\\/Ni\\/Cu(0 0 1) trilayers have been studied by first-principles spin-polarized relativistic band-structure calculations. Ideal Cu\\/Nin\\/Cu(0 0 1) trilayers are modelled by NinCu5(0 0 1) superlattices (n = 1, 3, 5) whilst Ni\\/Cu interdiffusion is simulated by (NiCu)2Nin(NiCu)2Cu3(0 0 1) superlattices (n = 3, 5, 7) containing

G. Y. Guo

1997-01-01

170

C-C bond coupling between the organometallic cations CH3Ag2+, CH3Cu2+ and CH3AgCu+ and allyliodide.  

PubMed

Electrospray ionisation on a mixture of AgNO(3) (in MeOH/H(2)O/acetic acid), (CH(3)CO(2))(2)Cu (in MeOH) and acetic acid (in MeOH) yields the metal carboxylate cations CH(3)CO(2)Ag(2)(+), CH(3)CO(2)AgCu(+) and CH(3)CO(2)Cu(2)(+). Collision induced dissociation of these carboxylate cations yields the organometallic cations CH(3)Ag(2)(+), CH(3)AgCu(+) and CH(3)Cu(2)(+). The ion-molecule reactions of these organometallic cations with allyliodide were studied in a quadrupole ion trap mass spectrometer. C-C bond coupling occurred to yield the ionic products Ag(2)I(+), AgCuI(+) and Cu(2)I(+). DFT calculations were carried out on these C-C bond coupling reactions. In all cases, the reactions are highly exothermic and involve initial coordination of the allyliodide to both metal atoms, with the iodine coordinating to one atom and the alkene moiety coordinating to the other. The overall mechanism of C-C bond coupling involves oxidative addition of the allyliodide followed by reductive elimination of 1-butene. PMID:19333507

Khairallah, George N; Waters, Tom; O'Hair, Richard A J

2009-02-20

171

Diffusion of Six-Atom Cu Islands on Cu(111) and Ag(111)  

NASA Astrophysics Data System (ADS)

Diffusion of Cu hexamer islands on Cu(111) and Ag(111) is studied using a molecular dynamics simulation technique with many-body potentials obtained from the embedded atom method. Simulations are carried out at temperatures 300, 500 and 700 K, showing that shape-changing multiple-atom processes are more helpful for the diffusion rather than concerted motion of islands. Arrhenius plots of the diffusion coefficients provide effective energy barrier values of 161.29 5 meV for Cu(111) and 179.34 5 meV for Ag(111) surfaces. At 700K, one popup atom among island atoms is observed with correlative changes in the position and shape of the lower-layer adatoms.

Sardar Sikandar, Hayat; I., Ahmad; M. Arshad, Choudhry

2011-05-01

172

Determination of Anand parameters for SnAgCuCe solder  

Microsoft Academic Search

A unified viscoplastic constitutive model, Anand equations, was used to represent the inelastic deformation behavior for Sn3.8Ag0.7Cu\\/Sn3.8Ag0.7 Cu0.03Ce solders in surface mount technology. The Anand parameters of the constitutive equations for the SnAgCu and SnAgCuCe solders were determined from separated constitutive relations and experimental results. Non-linear least-squares fitting was selected to determine the model constants. Comparisons were then made with

Liang Zhang; Songbai Xue; Lili Gao; Guang Zeng; Zhong Sheng; Yan Chen; Shenglin Yu

2009-01-01

173

Microwave-absorbing characteristics of epoxy resin composites containing nanoparticles of NiZn- and NiCuZn-ferrites  

Microsoft Academic Search

NiZn- and NiCuZn-ferrite nanoparticles (50-70 nm) with the chemical formula Ni0.5 Zn0.5Fe2O4 (NiZn) and Ni0.35Cu0.15Zn0.5Fe2O4 (NiCuZn) were synthesized by a combustion synthesis method. The nanocrystallite of these materials was characterized by structural and magnetic methods. Saturation magnetization increases from 83 emu\\/g (NiZn) to 91 emu\\/g (NiCuZn). Magnetic permeability and dielectric permittivity were measured on sintered samples (pellets and toroids) in

J. C. Aphesteguy; Abel Damiani; Dalmas Digiovanni; S. E. Jacobo

2009-01-01

174

Microwave-absorbing characteristics of epoxy resin composites containing nanoparticles of NiZn- and NiCuZn-ferrites  

Microsoft Academic Search

NiZn- and NiCuZn-ferrite nanoparticles (5070nm) with the chemical formula Ni0.5 Zn0.5Fe2O4 (NiZn) and Ni0.35Cu0.15Zn0.5Fe2O4 (NiCuZn) were synthesized by a combustion synthesis method. The nanocrystallite of these materials was characterized by structural and magnetic methods. Saturation magnetization increases from 83emu\\/g (NiZn) to 91emu\\/g (NiCuZn). Magnetic permeability and dielectric permittivity were measured on sintered samples (pellets and toroids) in the frequency range

J. C. Aphesteguy; Abel Damiani; Dalmas DiGiovanni; S. E. Jacobo

2009-01-01

175

Attenuation of 618 MHz SAW in multilayer Ni-Cu-Ni thin films  

Microsoft Academic Search

The authors report on the magnetic field (H) dependence of attenuation ?(H) of 618-MHz SAW (surface acoustic waves) propagating in vacuum-evaporated multilayer Ni-Cu-Ni thin-film samples. Experimental results indicate that the magnetoelastic ?( H) response of ≈200- single layers of Ni (?(H)≈22 dB\\/cm) is not affected by the deposition of overlayers of 75 and 180 of Cu; however, the

R. F. Wiegert; M. Levy

1988-01-01

176

Electrocatalytic oxidation of methanol on Ni and NiCu alloy modified glassy carbon electrode  

Microsoft Academic Search

Nickel and nickelcopper alloy modified glassy carbon electrodes (GC\\/Ni and GC\\/NiCu) prepared by galvanostatic deposition were examined for their redox process and electrocatalytic activities towards the oxidation of methanol in alkaline solutions. The methods of cyclic voltammetery (CV) and chronoamperometry (CA) were employed. The cyclic voltammogram of NiCu alloy demonstrates the formation of ?\\/? crystallographic forms of the nickel oxyhydroxide

I. Danaee; M. Jafarian; F. Forouzandeh; F. Gobal; M. G. Mahjani

2008-01-01

177

Spin waves in PdNi and CuNi alloys near the critical concentration  

NASA Astrophysics Data System (ADS)

The spin wave stiffness in CuNi and PdNi alloys has been studied for Ni concentrations in the vicinity of the critical concentration cf for the onset of ferromagnetism. Well defined excitations were found at all temperatures below Tc suggesting that despite the inhomogeneities in the magnetisation in these alloys there is little transverse disorder.

Lindley, E. J.; Rainford, B. D.; Paul, D. Mck.; Cywinski, R.; Burke, S. K.

1986-02-01

178

Thin-film interdiffusions in Cu\\/Pd, Cu\\/Pt, Cu\\/Ni, Cu\\/NiB, Cu\\/Co, Cu\\/Cr, Cu\\/Ti, and Cu\\/TiN bilayer films: Correlations of sheet resistance with Rutherford backscattering spectrometries  

Microsoft Academic Search

Interdiffusion in the Cu-based Cu\\/Pd, Cu\\/Pt, Cu\\/Ni, Cu\\/NiB, Cu\\/Co, Cu\\/Cr, Cu\\/Ti, and Cu\\/TiN bilayer films has been investigated for anneal temperatures ranging from 150 to 400 C in forming gas (N2-10%H2). The diffusion of Pd, Pt, and Ni into Cu has resulted in a significant increase in the sheet resistance of the film, which is correlated with the concentration profiles

D.-Y. Shih; C.-A. Chang; J. Paraszczak; S. Nunes; J. Cataldo

1991-01-01

179

Electrical resistivity and magnetic investigations of the orthorhombic Tb(Ni, Cu)2 system  

Microsoft Academic Search

The orthorhombic Tb(Ni, Cu)2 and Gd(Ni, Cu)2 systems (CeCu2 structure) are closely similar according to electrical resistivity and magnetic results. The Tb(NixCu1-x)2 system presents a transition from antiferromagnetism (AF) for x <= 8% Ni to ferromagnetism (FM) for x > 8% Ni. The CeCu2 structure becomes unstable for x > 45% Ni. The AF samples show metamagnetism at 4.2 K

C. A. Poldy; E. Gratz

1978-01-01

180

Enthalpy of mixing of liquid Ni-Zr and Cu-Ni-Zr alloys  

NASA Astrophysics Data System (ADS)

The partial (?(? overline H _i ) and the integral (? H) enthalpies of mixing of liquid Ni-Zr and Cu-Ni-Zr alloys have been determined by high-temperature isoperibolic calorimetry at 1565 5 K. The heat capacity ( C p) of liquid Ni26Zr74 has been measured by adiabatic calorimetry ( C p=53.52.2 J mol-1 K-1 at 126115 K). The integral enthalpy of mixing changes with composition from a small positive (Cu-Ni, ? H ( x Ni=0.50, T=1473 to 1750 K)=2.9 kJ mol-1) to a moderate negative (Cu-Zr; ? H( x Zr=0.46, T=1485 K)=-16.2 kJ mol-1) and a high negative value (Ni-Zr; ? H( x Zr=0.37, T=1565 K)=-45.8 kJ mol-1). Regression analysis of new data, together with the literature data for liquid Ni-Zr alloys, results in the following relationships in kJ mol-1 (standard states: Cu (1), Ni (1), and Zr (1)):for Ni-Zr (1281? T?2270 K), begin{gathered} ? bar H_{Ni} = x^2 \\ left( {begin{array}{*{20}c} {(333 55) + ( - 1.39 0.20) \\cdot {10^5 }/T + (3.89 0.40) \\cdot {10^7 }/{T^2 } + ( - 4468 226)x} \\ { + (1.29 0.36) \\cdot {10^5 x}/T + (11,451 1178)x^2 + ( - 11,431 1473)x^3 + (4053 826)x^4 } \\ } right) \\ begin{gathered} ? bar H_{Zr} = (1 - x)^2 \\ left( {begin{array}{*{20}c} {( - 130.0 7.9) + ( - 7.45 0.32) \\cdot {10^4 }/T + (3.89 0.40) \\cdot {10^7 }/{T^2 } + ( - 928 108)x} \\ { + (1.29 0.36) \\cdot {10^5 x}/T + (5310 658)x^2 + ( - 8189 1302)x^3 + (4053 826)x^4 } \\ } right) \\ ? H = (1 - x)? _{Ni - Zr} begin{array}{*{20}c} {? _{Ni - Zr} = ( - 130.0 7.9) + ( - 7.45 0.32) \\cdot {10^4 }/T + (3.89 0.40) \\cdot {10^7 }/{T^2 } + ( - 464 54)x} \\ { + (6.43 1.82) \\cdot {10^4 x}/T + (1769 219)x^2 + ( - 2047 326)x^3 + (811 171)x^4 } \\ for Cu-Ni-Zr ( T=15655 K), ? H = x_{Cu} x_{Ni} ? _{Cu - Ni} + x_{Cu} x_{Zr} ? _{Cu - Zr} + x_{Ni} x_{Zr} ? _{Ni - Zr} + x_{Cu} x_{Ni} x_{Zr} ? _{Cu - Ni - Zr} begin{gathered} ? _{Cu - Ni} = (11.1 0.6) + (1.1 0.1)x_{Ni} \\ ? _{Cu - Zr} = ( - 42.9 5.2) + ( - 44.2 10.3)x_{Cu} + (30.2 10.6)x_{Cu}^5 \\ ? _{Cu - Ni - Zr} = ( - 570.4 28.8) + (3010.9 184.9)x_{Zr} - (3349.8 268.6)x_{Zr}^2 + ( - 942.8 55.7)x \\

Witusiewicz, Victor T.; Sommer, Ferdinand

2000-04-01

181

RBS, ERDA and XPS study of Ag and Cu diffusion in PET and PI polymer foils  

NASA Astrophysics Data System (ADS)

Diffusion of Ag and Cu atoms in polyethyleneterephtalate (PET) and polyimide (PI) was studied using Rutherford backscattering spectroscopy (RBS) and elastic recoil detection analysis (ERDA). The samples were prepared by deposition of Ag and Cu thin layers on polymer surface using CVD and diode sputtering techniques. Samples were annealed at temperatures up to 240 C. X-ray Photoelectron Spectroscopy (XPS) was used for determination of metal polymer interaction and chemical state of atoms on metal polymer interface. Faster diffusion of Ag atoms was observed from non-compact Ag layers prepared by diode sputtering than from those prepared by CVD technique. Ag atoms show higher mobility in PET in comparison with PI. XPS measurement gives an evidence of Ag clustering in Ag-PET samples prepared by cathode sputtering. In PI the Cu atoms exhibit higher diffusivity than Ag atoms due to their lower atomic radius.

Mackov, Anna; Pe?ina, Vratislav; vor?k, Vclav; Zemek, Josef

2005-10-01

182

Stripe-to-bubble transition of magnetic domains at the spin reorientation of (Fe/Ni)/Cu/Ni/Cu(001)  

SciTech Connect

Magnetic domain evolution at the spin reorientation transition (SRT) of (Fe/Ni)/Cu/Ni/Cu(001) is investigated using photoemission electron microscopy. While the (Fe/Ni) layer exhibits the SRT, the interlayer coupling of the perpendicularly magnetized Ni layer to the (Fe/Ni) layer serves as a virtual perpendicular magnetic field exerted on the (Fe/Ni) layer. We find that the perpendicular virtual magnetic field breaks the up-down symmetry of the (Fe/Ni) stripe domains to induce a net magnetization in the normal direction of the film. Moreover, as the virtual magnetic field increases to exceed a critical field, the stripe domain phase evolves into a bubble domain phase. Although the critical field depends on the Fe film thickness, we show that the area fraction of the minority domain exhibits a universal value that determines the stripe-to-bubble phase transition.

Wu, J.; Choi, J.; Won, C.; Wu, Y. Z.; Scholl, A.; Doran, A.; Hwang, Chanyong; Qiu, Z.

2010-06-09

183

Solder joint reliability and characteristics of deformation and crack growth of Sn-Ag-Cu versus eutectic Sn-Pb on a WLP in a thermal cycling test  

Microsoft Academic Search

Sn-Ag-Cu (SAC) is now recognized as the standard lead free solder alloy for packaging interconnect in the electronics industry. This paper analyzes the performance of both SAC and eutectic Sn-Pb solder alloys on Kulicke & Soffa's (K&S') Ultra CSP wafer level package (WLP) at a thermal cycling (TC) test. The Ultra CSP standard Al\\/Ni-V\\/Cu under bump metallurgy (UBM) system was

Deok-Hoon Kim; Peter Elenius; Scott Barrett

2002-01-01

184

Ferromagnetic resonance in compositionally modulated Cu-Ni thin films  

Microsoft Academic Search

Ferromagnetic resonance at 12 GHz has been studied in some of the same compositionally modulated CuNi films on which magnetization measurements were reported recently. The best samples, e.g., a film designated [20‖10]880 (i.e, 880 repetitions of [20A? Cu on 10A? Ni]) show the 295 K resonance behavior expected for a magnetic material with an easy plane uniaxial anisotropy and a

J. F. Dillon; E. M. Gyorgy; L. W. Rupp; Y. Yafet; L. R. Testardi

1981-01-01

185

Surface relief of TiNiCu thin films  

Microsoft Academic Search

TiNiCu thin film shape memory alloys are potential materials for microactuator. In our previous research, the various natural surface relief of crystallized TiNiCu thin film was observed, and it was related with compositions and the sputtering deposition conditions. In order to understand the origin and nature of the surface relief, the temperature-resistance measurement, X-ray diffraction and atomic fore microscopic study

Xiulan Cheng; Dong Xu; Bingchu Cai; Li Wang; Jian Chen; Gang Li; Shi Xu

2001-01-01

186

Perpendicular giant magnetoresistance of NiFe\\/Cu and Co\\/Cu multilayered nanowires  

Microsoft Academic Search

We report a comparative study of the giant magnetoresistance (GMR) in CPP (current perpendicular to the planes) geometry in two different types of multilayered nanowire systems: Co\\/Cu and Ni80Fe20\\/Cu. The nanowires were produced in the cylindrical pores of a polymer membrane using a pulsed electrodeposition technique. A GMR ratio as large as 78% was obtained for Ni80Fe20\\/Cu multilayered nanowires. Using

S. Dubois; J. M. Beuken; L. Piraux; J. L. Duvail; A. Fert; J. M. George; J. L. Maurice

1997-01-01

187

Interface dependent magnetic moments in Cu/Co,Ni/Cu/Si(0 0 1) epitaxial structures  

NASA Astrophysics Data System (ADS)

The effect of the interface on the magnetic moment of Cu/Co,Ni/Cu/Si(0 0 1) epitaxial structures was studied by polarised neutron reflection (PNR). The structure consists of a specially designed three-step sample (single 60 Ni and 10 Co films and a 10 Co/60 Ni bilayer) grown under the same conditions in order to eliminate variations in the magnetic properties that could result from different growth environments. Independent structural characterisation of the samples was also determined from grazing incidence X-ray scattering, therefore increasing the confidence of the PNR fits. High precision PNR measurements performed at room temperature up to a wavevector range of 0.05 yield values of 0.580.03? and 0.590.03? per Ni atom for the Ni/Cu(0 0 1) and Co/Ni/Cu(0 0 1) samples, respectively; for the Co layers, the moments per Co atom are 1.630.13? and 1.680.11? for the Co/Ni/Cu(0 0 1) and Co/Cu(0 0 1) samples, respectively. Our results show that there are no significant changes in the respective Co and Ni magnetic moments at the Co/Ni interface.

Vaz, C. A. F.; Lauhoff, G.; Bland, J. A. C.; Langridge, S.; Bucknall, D. G.; Penfold, J.; Clarke, J.; Halder, S. K.; Tanner, B. K.

2007-06-01

188

Structure, microstructure, and giant magnetoresistance in nanogranular FeAgNi thin films.  

PubMed

Structural, microstructural, and magnetoresistive properties of metallic Fe(x)Ag(y)Ni(z) granular thin films were studied. These films with several compositions were prepared by dc magnetron sputtering. X-ray diffraction (XRD) measurements carried out on the samples show only Ag(111) peaks. The d-spacings determined from the Ag(111) peaks are smaller than the standard value for bulk Ag indicating a partial intermixing of Fe and Ni atoms in Ag. The diffraction pattern obtained using Transmission electron microscope (TEM) shows a number of Ag rings. Both XRD and TEM studies did not reveal any diffraction peaks due to Fe or Ni. The average particle size determined from the TEM micrograph is 5.5 nm whereas that determined from the XRD patterns is always higher. The magnetoresistance ratio for all the samples lies in the range 3 to 4.3%, except for a sample. PMID:17654995

Tiwari, Ajay; Rout, S; Patil, P B; Kumar, M Senthil

2007-06-01

189

Preparation of high-permeability NiCuZn ferrite*  

PubMed Central

Appropriate addition of CuO/V2O5 and the reduction of the granularity of the raw materials particle decrease the sintering temperature of NiZn ferrite from 1200 C to 930 C. Furthermore, the magnetic properties of the NiZn ferrite prepared at low temperature of 930 C is superior to that of the NiZn ferrite prepared by sintering at high temperature of 1200 C because the microstructure of the NiZn ferrite sintered at 930 C is more uniform and compact than that of the NiZn ferrite sintered at 1200 C. The high permeability of 1700 and relative loss coefficient tan?/?i of 9.010?6 at 100 kHz was achieved in the (Ni0.17Zn0.63Cu0.20)Fe1.915O4 ferrite.

Hu, Jun; Yan, Mi

2005-01-01

190

Resistance switching properties of planner Ag/Li:NiO/Ag structures induced by swift heavy ion irradiation  

SciTech Connect

We report on the resistance switching induced by swift heavy ion (SHI) irradiation in lithium doped nanostructured NiO thin films grown on MgO (100) substrates by chemical solution deposition. Hysteresis in current-voltage curves were observed for the Ag/Li:NiO/Ag planner structures irradiated with 100 MeV Ag{sup +14} ions, whereas pristine samples showed only linear I-V characteristics. No preferential oxygen loss from the film surface has been detected in on-line elastic recoil detection analysis. This suggests that change in the defect density created by SHI irradiation that may contribute to the metallic filaments play a major role as compared to the interfacial oxygen vacancies in resistance switching of NiO.

Joshi, U. S.; Trivedi, S. J.; Bhavsar, K. H. [Department of Physics, School of Sciences, Gujarat University, Ahmedabad 380 009 (India); Trivedi, U. N. [Department of Instruments and Control Engineering, Vishwakarma Government Engineering College, Chandkheda, Gandhinagar 382 424 (India); Khan, S. A.; Avasthi, D. K. [Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110 067 (India)

2009-04-01

191

On the elastic moduli of nanocrystalline Fe, Cu, Ni, and Cu--Ni alloys prepared by mechanical milling/alloying  

SciTech Connect

The Young`s moduli of nanocrystalline, Fe, Cu, Ni, and Cu--Ni alloys prepared by mechanical milling/alloying have been measured by the nanoindentation technique. The results indicate that the Young`s moduli of nanocrystalline Cu, Ni, and Cu--Ni alloys with a grain size ranging from 17 to 26 nm are similar to those of the corresponding polycrystals. The dependence of Young`s modulus of nanocrystalline Fe on grain size corresponds well to a theoretical prediction, which suggests that the change in the Young and shear moduli of nanocrystalline materials, free of porosity, with a grain size larger than about 4 nm, should be very limited ({lt}10%). It is likely that reported large decreases in the Young and shear moduli of nanocrystalline materials prepared by gas-condensation/vacuum consolidation result from a relatively large volume fraction of pores. {copyright} 1995 {ital Materials} {ital Research} {ital Society}.

Shen, T.D.; Koch, C.C. [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695-7907 (United States); Tsui, T.Y.; Pharr, G.M. [Department of Materials Science, Rice University, Houston, Texas 77251-1892 (United States)

1995-11-01

192

X-ray absorption spectroscopy study of the chemical ordering in UCu5-xMx (M = Ni, Ag) compounds  

NASA Astrophysics Data System (ADS)

This work reports the x-ray absorption spectroscopy study of the chemical ordering in UCu5-xMx (M = Ni, Ag) compounds. The comparison between the experimental Cu K-edge XANES spectra and theoretical computations based on multiple-scattering theory shows that standard single-channel calculations are capable of reproducing the experimental spectra. On this subject, an extensive discussion is presented concerning the role of both the cluster size and the final state potential in obtaining a good reproduction of the experimental XANES spectra of these UCu5-based alloys. The agreement between the theoretical and experimental spectra points to the existence of crystallographic disorder in both UCu4Ag and UCu4Ni systems. Possessing the distinct low temperature electrical, magnetic and thermal properties exhibited by UCu4Ni, our results suggest that Ni doping must induce dramatic changes in the electronic structure, as confirmed by the thermopower measurements. These results point to the imbalance between the RKKY and Kondo interactions as the source of the NFL behaviour observed in UCu4Ni, thus supporting an interpretation of the NFL behaviour in terms of the Griffiths phase model.

Chaboy, J.; Boada, R.; Dur, O. J.; Lpez de la Torre, M. A.

2008-10-01

193

Study on synthesis of ultrafine Cu-Ag core-shell powders with high electrical conductivity  

NASA Astrophysics Data System (ADS)

Cu-Ag composite powders with high electrical conductivity were synthesized by electroless plating of silver sulfate, copper powders with eco-friendly sodium citrate as reducing agent, dispersant and chelating agent in an aqueous system. The influences of sodium citrate/Ag ratio on Ag coatings of Cu powders were investigated. Ag was formed a dense coating on the surface of Cu powders at a molar ratio of sodium citrate/Ag = 0.07/1. SEM showed an uniformity of Ag coatings on Cu powders. SEM-EDX also revealed that Cu cores were covered by Ag shells on the whole. The surface composition analysis by XPS indicated that without Cu or Ag atoms in the surface were oxidized. The resistivity measurements of Cu-Ag paste shows that they have closer resistivity as the pure silver paste's after 250 C for 30 min heat-treatment (2.55 10?4 ? cm) and 350 C for 30 min heat-treatment (1.425 10?4 ? cm).

Peng, Yu-hsien; Yang, Chih-hao; Chen, Kuan-ting; Popuri, Srinivasa R.; Lee, Ching-Hwa; Tang, Bo-Shin

2012-12-01

194

Irradiation induced dissolution of Cu and growth of Ag nanoclusters in Cu\\/Ag ion-exchanged soda-lime glass  

Microsoft Academic Search

Complex metal nanoclusters of Cu\\/Ag are formed in a soda-lime glass matrix by sequential copper and silver ion-exchange followed by ion irradiation. Optical absorption measurements showed signature of copper clusters alone in the Cu\\/Ag ion-exchanged sample. Irradiation of the ion-exchanged sample with He+ ions of energy 100 keV of different fluences resulted in the growth of the silver clusters with,

D. Manikandan; S. Mohan; P. Magudapathy; K. G. M Nair

2002-01-01

195

Anodic vacuum arc developed nanocrystalline Cu-Ni and Fe-Ni thin film thermocouples  

SciTech Connect

This paper deals with the development of nanocrystalline Cu-Ni and Fe-Ni thin film thermocouples (TFTCs) by using ion-assisted anodic vacuum arc deposition technique. The crystallographic structure and surface morphology of individual layer films have been studied by x-ray diffraction and scanning electron microscopy, respectively. The resistivity, temperature coefficient of resistance, and thermoelectric power of as deposited and annealed films have been measured. The observed departure of these transport parameters from their respective bulk values can be understood in terms of intrinsic scattering due to enhanced crystallite boundaries. From the measured values of thermoelectric power and the corresponding temperature coefficient of resistance of annealed Cu, Ni, and Fe films, the calculated values of log derivative of the mean free path of conduction electrons at the Fermi surface with respect to energy (U) are found to be -0.51, 3.22, and -8.39, respectively. The thermoelectric response of annealed Cu-Ni and Fe-Ni TFTCs has been studied up to a maximum temperature difference of 300 deg. C. Reproducibility of TFTCs has been examined in terms of the standard deviation in thermoelectric response of 16 test samples for each pair. Cu-Ni and Fe-Ni TFTCs agree well with their wire thermocouple equivalents. The thermoelectric power values of Cu-Ni and Fe-Ni TFTCs at 300 deg. C are found to be 0.0178 and 0.0279 mV/ deg. C, respectively.

Mukherjee, S. K.; Sinha, M. K.; Pathak, B.; Rout, S. K.; Barhai, P. K. [Department of Applied Physics, Birla Institute of Technology Mesra, Ranchi, Jharkhand 835215 (India)

2009-12-01

196

Anodic vacuum arc developed nanocrystalline Cu-Ni and Fe-Ni thin film thermocouples  

NASA Astrophysics Data System (ADS)

This paper deals with the development of nanocrystalline Cu-Ni and Fe-Ni thin film thermocouples (TFTCs) by using ion-assisted anodic vacuum arc deposition technique. The crystallographic structure and surface morphology of individual layer films have been studied by x-ray diffraction and scanning electron microscopy, respectively. The resistivity, temperature coefficient of resistance, and thermoelectric power of as deposited and annealed films have been measured. The observed departure of these transport parameters from their respective bulk values can be understood in terms of intrinsic scattering due to enhanced crystallite boundaries. From the measured values of thermoelectric power and the corresponding temperature coefficient of resistance of annealed Cu, Ni, and Fe films, the calculated values of log derivative of the mean free path of conduction electrons at the Fermi surface with respect to energy (U) are found to be -0.51, 3.22, and -8.39, respectively. The thermoelectric response of annealed Cu-Ni and Fe-Ni TFTCs has been studied up to a maximum temperature difference of 300 C. Reproducibility of TFTCs has been examined in terms of the standard deviation in thermoelectric response of 16 test samples for each pair. Cu-Ni and Fe-Ni TFTCs agree well with their wire thermocouple equivalents. The thermoelectric power values of Cu-Ni and Fe-Ni TFTCs at 300 C are found to be 0.0178 and 0.0279 mV/C, respectively.

Mukherjee, S. K.; Sinha, M. K.; Pathak, B.; Rout, S. K.; Barhai, P. K.

2009-12-01

197

Experimental and thermodynamic assessment of Sn-Ag-Cu solder alloys  

Microsoft Academic Search

Sn-rich alloys in the Sn-Ag-Cu system are being studied for their potential as Pb-free solders. Thus, the location of the\\u000a ternary eutectic involving L, (Sn), Ag3Sn and Cu6Sn5 phases is of critical interest. Phase diagram data in the Sn-rich corner of the Sn-Ag-Cu system are measured. The ternary\\u000a eutectic is confirmed to be at a composition of 3.5 wt.% Ag,

K.-W. Moon; W. J. Boettinger; U. R. Kattner; F. S. Biancaniello; C. A. Handwerker

2000-01-01

198

The effect of Ag content on the formation of Ag3Sn plates in Sn-Ag-Cu lead-free solder  

NASA Astrophysics Data System (ADS)

The formation of Ag3Sn plates in the Sn-Ag-Cu lead-free solder joints for two different Ag content solder balls was investigated in wafer level chip scale packages (WLCSPs). After an appropriate surface mount technology reflow process on a printed circuit board, samples were subjected to 150C high-temperature storage (HTS), 1,000 h aging, or 1,000 cycles thermal cycling test (TCT). Sequentially, the cross-sectional analysis was scrutinized using a scanning electron microscope/energy dispersive spectrometer (SEM/EDX) to observe the metallurgical evolution of the amount of the Ag3Sn plates at the interface and the solder bulk itself. Pull and shear tests were also performed on samples. It was found that the interfacial intermetallic compound (IMC) thickness, the overall IMC area, and the numbers of Ag3Sn plates increase with increasing HTS and TCT cycles. The amount of large Ag3Sn plates found in the Sn-4.0Ag-0.5 Cu solder balls is much greater than that found in the Sn-2.6Ag-0.5Cu solder balls; however, no significant difference was found in the joint strength between two different Ag content solder joints.

Chiang, Huann-Wu; Chang, Kenndy; Chen, Jun-Yuan

2006-12-01

199

Enthalpy of mixing of liquid Ni-Zr and Cu-Ni-Zr alloys  

Microsoft Academic Search

The partial (?\\u000a $$(\\\\Delta \\\\overline H _i )$$\\u000a and the integral (?H) enthalpies of mixing of liquid Ni-Zr and Cu-Ni-Zr alloys have been determined by high-temperature isoperibolic calorimetry\\u000a at 1565 5 K. The heat capacity (C\\u000a p) of liquid Ni26Zr74 has been measured by adiabatic calorimetry (C\\u000a p=53.52.2 J mol?1 K?1 at 126115 K). The integral enthalpy of mixing

Victor T. Witusiewicz; Ferdinand Sommer

2000-01-01

200

Measurement of Gain Duration for Ne-like Ni and Ni-like Ag  

NASA Astrophysics Data System (ADS)

A simple streaked slit diagnostic was developed to record resonance line emission from the plasmas used to produce Ne-like nickel and Ni-like silver X-ray lasing. A Kentech streak camera with a 500 mum wide horizontal timing slit viewing the plasma transversely with a space resolving slit of width 270 mum positioned normal to the timing slit to give spatial resolution along the line focus length. An estimate of the duration of X-ray laser gain is obtained by temporally resolving resonance line emission from states near in energy to the upper lasing level. The emission duration was measured to be 33 - 40 ps for Ni and 19 - 22 ps for Ag. We may expect the duration of this emission to be an upper bound on the gain duration. The travelling wave velocity at the leading edge of the main pulse was measured to be close to the speed of light.

Abou-Ali, Y.; Tallents, G. J.; Edwards, M. H.; Keenan, R.; Topping, S. J.; Lewis, C. L. S.; Guilbaud, O.; Klisnick, A.; Ros, D.

2002-11-01

201

Spin-Mixing Conductances of Ni-Based Films Attached to Cu(100) Leads  

NASA Astrophysics Data System (ADS)

The complex spin-mixing conductance of epitaxial Cu/Ni/Cu(100) systems is predicted to oscillate as a function of Ni thickness. The oscillation period is explained in terms of spin-resolved Fermi surface properties of bulk nickel. Stability of the oscillations with respect to interface Cu-Ni interdiffusion and to alloying in the Ni film is investigated as well.

Turek, I.; Carva, K.

2008-01-01

202

Structural and magnetic properties of Cu Ni Cr spinel oxides  

NASA Astrophysics Data System (ADS)

The compounds CuCr2O4 and NiCr2O4 crystallize at room temperature in a tetragonal distorted spinel structure, s.g. I41/amd, with axes ratio c/a<1 and >1, respectively. The distortion is caused by the Jahn Teller ions Cu2+ and Ni2+ which flatten or elongate their surrounding oxygen tetrahedron. CuCr2O4 and NiCr2O4 form a complete solid solution series Cu1-xNixCr2O4 where for 0.825CuCr2O4) and 310 K (NiCr2O4). The phase Cu0.15Ni0.85Cr2O4 undergoes a second crystallographic transition to orthorhombic symmetry, space group Fddd, at T=300 K. The neutron diffraction experiments as well as SQUID measurements reveal magnetic ordering of the ions between 150 and 50 K which partially occurs as a two-step mechanism.

Tovar, M.; Torabi, R.; Welker, C.; Fleischer, F.

2006-11-01

203

Diffusion bonding of commercially pure Ni using Cu interlayer  

SciTech Connect

The concentration dependence of diffusivity in a multi-component diffusion system makes it complicated to predict the concentration profiles of diffusing species. This so called chemical diffusivity can be expressed as a function of thermodynamic and kinetic data. DICTRA software can calculate the concentration profiles using appropriate mobility and thermodynamic data. It can also optimize the diffusivity data using experimental diffusivity data. Then the optimized diffusivity data is stored as mobility data which is a linear function of temperature. In this work, diffusion bonding of commercially pure Ni using Cu interlayers is reported. The mobility parameters of Ni-Cu alloy binary systems were optimized using DICTRA/Thermocalc software from the available self-, tracer and chemical diffusion coefficients. The optimized mobility parameters were used to simulate concentration profiles of Ni-Cu diffusion joints using DICTRA/Thermocalc software. The calculated and experimental concentration profiles agreed well at 1100 Degree-Sign C. Agreement between the simulated and experimental profiles was less good at 1050 Degree-Sign C due to the grain boundary contribution to the overall diffusion. - Highlights: Black-Right-Pointing-Pointer The concentration profiles of Cu in Ni-Cu diffusion joints are modeled. Black-Right-Pointing-Pointer Interdiffusion coefficients in Ni-Cu system are optimized. Black-Right-Pointing-Pointer Optimized interdiffusion coefficients are expressed as mobility parameters. Black-Right-Pointing-Pointer Simulated profiles are comparable with experimental profiles.

Rahman, A.H.M.E., E-mail: a.rahman@my.und.edu; Cavalli, M.N.

2012-07-15

204

Optical properties of Ni and Cu nanowire arrays and Ni/Cu superlattice nanowire arrays.  

PubMed

: In this study, Ni and Cu nanowire arrays and Ni/Cu superlattice nanowire arrays are fabricated using standard techniques such as electrochemical deposition of metals into porous anodic alumina oxide templates having pore diameters of about 50 nm. We perform optical measurements on these nanowire array structures. Optical reflectance (OR) of the as-prepared samples is recorded using an imaging spectrometer in the wavelength range from 400 to 2,000 nm (i.e., from visible to near-infrared bandwidth). The measurements are carried out at temperatures set to be 4.2, 70, 150, and 200 K and at room temperature. We find that the intensity of the OR spectrum for nanowire arrays depends strongly on the temperature. The strongest OR can be observed at about T?=?200 K for all samples in visible regime. The OR spectra for these samples show different features in the visible and near-infrared bandwidths. We discuss the physical mechanisms responsible for these interesting experimental findings. This study is relevant to the application of metal nanowire arrays as optical and optoelectronic devices. PMID:23067299

Zhang, Yaya; Xu, Wen; Xu, Shaohui; Fei, Guangtao; Xiao, Yiming; Hu, Jiaguang

2012-10-15

205

Optical properties of Ni and Cu nanowire arrays and Ni/Cu superlattice nanowire arrays  

PubMed Central

In this study, Ni and Cu nanowire arrays and Ni/Cu superlattice nanowire arrays are fabricated using standard techniques such as electrochemical deposition of metals into porous anodic alumina oxide templates having pore diameters of about 50 nm. We perform optical measurements on these nanowire array structures. Optical reflectance (OR) of the as-prepared samples is recorded using an imaging spectrometer in the wavelength range from 400 to 2,000 nm (i.e., from visible to near-infrared bandwidth). The measurements are carried out at temperatures set to be 4.2, 70, 150, and 200 K and at room temperature. We find that the intensity of the OR spectrum for nanowire arrays depends strongly on the temperature. The strongest OR can be observed at about T?=?200 K for all samples in visible regime. The OR spectra for these samples show different features in the visible and near-infrared bandwidths. We discuss the physical mechanisms responsible for these interesting experimental findings. This study is relevant to the application of metal nanowire arrays as optical and optoelectronic devices.

2012-01-01

206

Electronic, magnetic and optical properties of Cu, Ag, Au-doped Si clusters.  

PubMed

The structural, optical and magnetic properties of Cu, Ag, Au-doped Si7 Clusters have been systematically investigated using density functional theory calculations. The global optimized structures of Cu, Ag, Au-doped Si clusters are predicted to have a lower HOMO-LUMO gap and higher magnetic moment. M-doping (M?=?Cu, Ag, Au) in Si cluster widens a range of adsorption wavelength, especially Au-doping. The characteristics in electronic density of states (DOSs) show that C5v-Si6Cu has a big asymmetrical spin-up and spin-down. The average atomic moment is 0.428 m?B per atom for the Si6Cu cluster with C5v symmetry, while the average paramagnetic moment is 0.143 m?B per atom for other M-doped (M?=?Cu, Ag, Au) Si7 clusters. PMID:23955703

Ma, Wenqiang; Chen, Fuyi

2013-08-17

207

Magnetization behaviour in ultrathin Co/Cu/Ni/Cu(001) trilayers.  

PubMed

The magnetization of ultrathin multilayer systems depends in a very sensitive way on their composition. We consider the temperature dependence of magnetization and its orientation in three types of trilayers: 2ML Co/2ML Cu/4ML Ni/Cu(001), 1ML Co/2ML Cu/4ML Ni/Cu(001) and 1ML Co/2ML Cu/3ML Ni/Cu(001). The composition of each system leads to different interdependence of ordering temperatures characterizing the ferromagnetic films. It is shown that in all cases the sublayer magnetizations change gradually their directions as a function of temperature. The use of Nel sublattices concept in Valenta approach allows us to present all dependences in a layer resolved mode which leads to the conclusion that the spin reorientation process runs through non collinear magnetic superstructures. PMID:21446429

Zasada, I

2011-01-01

208

Interdiffusion in liquid Al-Cu and Ni-Cu alloys  

NASA Astrophysics Data System (ADS)

The interdiffusion processes in liquid Al-Cu and Ni-Cu alloys are studied by using molecular dynamics simulation method. The Maxwell-Stefan (MS) diffusivities are calculated over a wide composition range with both the Green-Kubo method and the Darken relation. Comparisons show that the Darken relation predicts well the MS diffusivity for Ni-Cu alloy, while overestimates the value for Al-Cu alloy, especially in the medium concentration region. Based on the calculated MS diffusivities and the activities of the alloys, the Fickian interdiffusivities are predicted. The results show strong dependences on the compositions of the alloys. In addition, the Fickian interdiffusivities of Al60Cu40 and Ni50Cu50 melts as a function of undercooling are estimated, which is proved to be beneficial in improving the quantitative predictions of dendrite growth velocity in solidification.

Cheng, H.; L, Y. J.; Chen, M.

2009-07-01

209

Interdiffusion in liquid Al-Cu and Ni-Cu alloys.  

PubMed

The interdiffusion processes in liquid Al-Cu and Ni-Cu alloys are studied by using molecular dynamics simulation method. The Maxwell-Stefan (MS) diffusivities are calculated over a wide composition range with both the Green-Kubo method and the Darken relation. Comparisons show that the Darken relation predicts well the MS diffusivity for Ni-Cu alloy, while overestimates the value for Al-Cu alloy, especially in the medium concentration region. Based on the calculated MS diffusivities and the activities of the alloys, the Fickian interdiffusivities are predicted. The results show strong dependences on the compositions of the alloys. In addition, the Fickian interdiffusivities of Al(60)Cu(40) and Ni(50)Cu(50) melts as a function of undercooling are estimated, which is proved to be beneficial in improving the quantitative predictions of dendrite growth velocity in solidification. PMID:19655889

Cheng, H; L, Y J; Chen, M

2009-07-28

210

Monolithic CuNi-based catalyst for reforming hydrocarbon fuel sources  

Microsoft Academic Search

A monolithic CuNi-based catalyst was fabricated by partial reduction reaction of a solid solution of (Cu, Ni, Mg)O. The deposited CuNi particles, 510nm in diameter, were embedded in (Ni, Mg)O ceramic substrate, and dispersed homogeneously. CO2 reforming of methane and steam reforming of methanol were conducted using this catalyst. Although the amount of the deposited CuNi particles was quite small

Tomohiro Suetsuna; Seiichi Suenaga; Takayuki Fukasawa

2004-01-01

211

Intermetallic Compounds Formed in Sn-20In-2.8Ag Solder BGA Packages with Ag/Cu Pads  

NASA Astrophysics Data System (ADS)

The interfacial reactions in a Sn-20In-2.8Ag solder ball grid array (BGA) package with immersion Ag surface finish are investigated. After reflow, the Ag thin film dissolves quickly into the solder matrix, and scallop-shaped intermetallic layers, with compositions of (Cu0.98Ag0.02)6(In0.59Sn0.41)5, appear at the interfaces between Sn-20In-2.8Ag solder ball and Cu pad. No evident growth of the (Cu0.98Ag0.02)6(Sn0.59In0.41)5 intermetallic compounds was observed after prolonged aging at 100 C. However, the growth accelerated at 150 C, with more intermetallic scallops floating into the solder matrix. The intermetallic thickness versus the square root of reaction time ( t 1/2) shows a linear relation, indicating that the growth of intermetallic compounds is diffusion-controlled. Ball shear tests show that the strength of Sn-20In-2.8Ag solder joints after reflow is 4.4 N, which increases to 5.18 N and 5.14 N after aging at 100 and 150 C, respectively.

Jain, C. C.; Wang, S. S.; Huang, K. W.; Chuang, T. H.

2009-03-01

212

Facile chemical synthesis of W-Ag and W-Cu nanocomposites at low temperature.  

PubMed

W-Ag (80.2W-19.8Ag, 70.4W-29.6Ag and 60.5W-39.5Ag) and W-Cu (79.7W-20.3Cu, 70.5W-29.5Cu and 59.8W-40.2Cu) nanocomposites in the size range of 24-30 nm have been synthesized by thermal decomposition of W(CO)6/CH3COOAg and W(CO)6/Cu(acac)2 in diphenyl ether as solvent at 220 degrees C in presence of oleic acid and hexadecyl amine and characterized. FTIR spectra have been used to explain the role of oleic acid and hexadecyl amine in the synthesis of W-Ag and W-Cu composite powders. XRD studies show that the tungsten phase is amorphous, whereas both Ag and Cu crystallize in fcc for as-synthesized W-Ag and W-Cu nanocomposites. These composite powders when annealed at 700 degrees C results in the formation of bcc tungsten and peaks corresponding to fcc silver and copper still persists. The particle size, shape and distribution of these nanocomposites of various compositions have been studied by SAXS, ESEM and TEM and found to be nearly spherical with the average diameters below 30 nm. PMID:21449414

Sahoo, Prasanta Kumar; Kamal, Sarika Srinivas Kalyan; Singh, Ashok Kumar; Sreedhar, Bojja; Durai, Loganathan; Srivastava, Suneel Kumar

2011-03-01

213

Nanoindentation on SnAgCu lead-free solder joints and analysis  

Microsoft Academic Search

The lead-free SnAgCu (SAC) solder joint on copper pad with organic solderability preservative (Cu-OSP) and electroless nickel\\u000a and immersion gold (ENIG) subjected to thermal testing leads to intermetallic growth. It causes corresponding reliability\\u000a concerns at the interface. Nanoindentation characterization on SnAgCu solder alloy, intermetallic compounds (IMCs), and the\\u000a substrates subjected to thermal aging is reported. The modulus and hardness of

Luhua Xu; John H. L. Pang

2006-01-01

214

The connective tissue response to Ti, NiCr and AgPd alloys.  

PubMed

The aim of the study was to compare the connective tissue response of Lewis rats to Ti, NiCr and AgPd alloys. It was found that implants were covered by collagen-rich, well vascularized capsules. Titanium was covered by the thinnest capsule (57 20 ?m) and AgPd alloy was covered by the thickest capsule (239 50 ?m). The PCNA+ cell prevalence in the capsules was lower for titanium than for AgPd and NiCr. Mast cells formed a gradient to a depth of 1200 ?m only for titanium implants. Cells with brown to black silver granules in the cytoplasm were observed close to AgPd implants. The results suggest that titanium implants induce a weaker connective tissue response than implants made from NiCr and AgPd alloys. PMID:21071336

?ukomska-Syma?ska, Monika; Brzezi?ski, Piotr M; Zieli?ski, Andrzej; Soko?owski, Jerzy

2010-09-30

215

Dual Bonding between H2O/H2S and AgCl/CuCl: Cu/Ag Bond, Sister Bond to Au Bond.  

PubMed

Recently, Legon et al. reported the first generation and characterization of H2O/H2SAgCl complexes by rotational spectroscopy and proposed whether there is a silver bond analogous to the more familiar hydrogen and halogen bonds. In this study, a theoretical investigation was performed to answer this question and to deepen the nature of intermolecular interactions for H2O/H2SM-Cl (M = Cu, Ag, and Au) complexes. NBO analyses reveal that two types of delocalization interactions coexist in these complexes. Apart from the expected ?-donation interaction, the hyperconjugation interaction between H2O/H2S and M-Cl also takes part in the bonding. On the basis of such a dual-bonding mechanism, one class of bond, termed Cu/Ag bond, was defined in this study. In addition, the topological properties at a bond critical point, binding energies, and stretching frequency shifts studied here support that Cu/Ag bond is a sister bond to Au bond put forward previously by Sadlej et al. The Cu/Ag/Au bond is partially covalent and partially electrostatic in nature. Finally, the dual-bonding mechanism of Cu/Ag/Au bond was further discussed. This dual-bonding scheme may be considered a new synergistic bonding model for coordination compounds. PMID:24070212

Zhang, Guiqiu; Zhao, Xingjuan; Chen, Dezhan

2013-10-10

216

Influence of Ag on the microstructure and magnetic properties of perpendicular exchange coupled composite L10-[FePt-Ag]/[Co/Ni]N films  

NASA Astrophysics Data System (ADS)

Two series of exchange coupled composite films with and without Ag interlayer, L10-[FePt-Ag]/[Co/Ni]N (FC-Ag-N) and FePt/[Co/Ni]N (FC-N), were prepared and well studied. Coercivities of both series decrease with the increase of the soft [Co/Ni]N thickness. However, well-isolated sphere grains are observed in FC-Ag-N samples, instead of a ledge-type structure in FC-N samples. The average grain size is almost constant for FC-Ag-N films, regardless of the thickness of Co/Ni multilayer. It indicates that Ag effectively suppresses the grain coarseness during the deposition of [Co/Ni]N.

Guo, H. H.; Chu, H. G.; Ma, B.; Zhang, Z. Z.; Jin, Q. Y.; Wang, H.; Wang, J. P.

2013-06-01

217

SEMICONDUCTOR DEVICES: Ag/PEPC/NiPc/ZnO/Ag thin film capacitive and resistive humidity sensors  

NASA Astrophysics Data System (ADS)

A thin film of blended poly-N-epoxypropylcarbazole (PEPC) (25 wt.%), nickel phthalocyanine (NiPc) (50 wt.%) and ZnO nano-powder (25 wt.%) in benzene (5 wt.%) was spin-coated on a glass substrate with silver electrodes to produce a surface-type Ag/PEPC/NiPc/ZnO/Ag capacitive and resistive sensor. Sensors with two different PEPC/NiPc/ZnO film thicknesses (330 and 400 nm) were fabricated and compared. The effects of humidity on capacitance and resistance of the Ag/PEPC/NiPc/ZnO/Ag sensors were investigated at two frequencies of the applied voltage: 120 Hz and 1 kHz. It was observed that at 120 Hz under humidity of up to 95% RH the capacitance of the sensors increased by 540 times and resistance decreased by 450 times with respect to humidity conditions of 50% RH. It was found that the sensor with a thinner semiconducting film (330 nm) was more sensitive than the sensor with a thicker film (400 nm). The sensitivity was improved when the sensor was used at a lower frequency as compared with a high frequency. It is assumed that the humidity response of the sensors is associated with absorption of water vapors and doping of water molecules in the semiconductor blend layer. This had been proven by simulation of the capacitance-humidity relationship.

Karimov, Kh. S.; Yew Cheong, Kuan; Saleem, M.; Murtaza, Imran; Farooq, M.; Fauzi Mohd Noor, Ahmad

2010-05-01

218

Surface relief of TiNiCu thin films  

NASA Astrophysics Data System (ADS)

TiNiCu thin film shape memory alloys are potential materials for microactuator. In our previous research, the various natural surface relief of crystallized TiNiCu thin film was observed, and it was related with compositions and the sputtering deposition conditions. In order to understand the origin and nature of the surface relief, the temperature-resistance measurement, X-ray diffraction and atomic fore microscopic study were performed. For Ti48.4Ni46.3Cu5.3 thin films, the transformation temperatures are below 0 degree(s)C, and the natural surface is smooth at 12 degree(s)C since the microstructure is austenite. For Ti51Ni44Cu5 thin films, two typical kinds of surface relief, e.g., chrysanthemum and rock candy, were observed at 12 degree(s)C. The chrysanthemum on the martensitic block relief is Ti-rich G.P. zone and will not disappear in thermal cycles later. It is also found that the Ti-rich G.P. zone is related with the thin films formed under lower sputtering Ar pressure. The rock candy relief is a typical martensite surface relief and will disappear when heating to the austenite phase. During crystallization process, the inherent compressive stress introduced under the condition of higher sputtering pressure is helpful to the transition from G.P. zones to Ti2(NiCu) precipitates and the increase of the transformation temperatures.

Cheng, Xiulan; Xu, Dong; Cai, Bingchu; Wang, Li; Chen, Jian; Li, Gang; Xu, Shi

2001-10-01

219

Origin of the Co uniaxial volume anisotropy of the fcc Co/Ni/Cu(001) system  

NASA Astrophysics Data System (ADS)

We studied layer selectively the magnetic moments on a Cu/9 Co/50 Ni/Cu/Si(001) and a Cu/50 Ni/Cu/Si(001) structure using polarized neutron reflection. The magnetic moments for the Cu/Co/Ni/Cu structure are 1.70+/-0.20 ?B and 0.57+/-0.05?B for the Co and Ni, respectively, and within error the same as the relevant bulk magnetic moments at room temperature. For the Cu/Ni/Cu sample the magnetic moment per Ni atom of 0.53+/-0.03?B is only slightly lower than the bulk value. Within error the same magnetic moments are determined for a Cu/22 Co/11 Cu/53 Ni/Cu/Si(001) structure supporting the results on the Cu/Co/Ni/Cu(001) and Cu/Ni/Cu(001) structures. Using the magnetic moments values determined by polarized neutron reflection, we conclude that the uniaxial Co volume anisotropy for the Cu/Co/60 Ni/Cu(001) structures can be attributed to the Co shape anisotropy alone.

Lauhoff, G.; Bland, J. A. C.; Lee, J.; Langridge, S.; Penfold, J.

1999-08-01

220

Electrochemical impedance studies of methanol oxidation on GC\\/Ni and GC\\/NiCu electrode  

Microsoft Academic Search

The electro-oxidation of methanol on nickel and nickelcopper alloy modified glassy carbon electrodes (GC\\/Ni and GC\\/NiCu) in a 1M NaOH solution at different concentrations of methanol was studied by the method of ac-impedance spectroscopy. Two semicircles in the first quadrant of a Nyquist diagram were observed for electro-oxidation of methanol on GC\\/Ni corresponding to charge transfer resistance and adsorption of

I. Danaee; M. Jafarian; F. Forouzandeh; F. Gobal; M. G. Mahjani

2009-01-01

221

Molecular dynamics study on the equal biaxial tension of Cu/Ag bilayer films  

NASA Astrophysics Data System (ADS)

The mechanical behavior, dislocation nucleation and development, and the evolution of interface in Cu/Ag bilayer films during an equal biaxial tension were studied using molecular dynamics simulations. The results show that dislocations are prone to nucleate at the interface of Cu/Ag bilayer film, and then propagate toward the free surface. The deformation defects consist of partial dislocations and intrinsic stacking faults, accompanying with some extrinsic stacking faults and stacking fault tetrahedra which just occur at the interface and propagate in the Cu layer. Compared with Cu and Ag films, Cu/Ag bilayer films have the maximal yield strain. The surface roughness reaches maximum at the yield strain, and then rapidly decreases with the increase of strain. Atoms in stacking faults increase with the strain at the high strain rate, while the rule is reversed at the low strain rate.

Yuan, Lin; Xu, Zhenhai; Shan, Debin; Guo, Bin

2013-10-01

222

Experimental characterization and mechanical behavior analysis on intermetallic compounds of 96.5Sn3.5Ag and 63Sn37Pb solder bump with Ti-Cu-Ni UBM on copper chip  

Microsoft Academic Search

This study investigated the mechanical behavior of flip-chip lead-free solder bumps affected by solder\\/UBM intermetallic compound formation in the duration of isothermal aging. To attain the objective, test vehicles of Sn-Ag (lead-free) and Sn-Pb (lead-containing) solder bump systems were used to experimentally characterize and analyze their mechanical behavior. By way of metallurgical microscopy and SEM observation, the interfacial microstructure of

Chih-Tang Peng; Chia-Tai Kuo; Kuo-Ning Chiang; Terry Ku; Kenny Chang

2004-01-01

223

Preparation and optical properties of silica@Ag Cu alloy core-shell composite colloids  

NASA Astrophysics Data System (ADS)

The silica@Ag Cu alloy core-shell composite colloids have been successfully synthesized by an electroless plating approach to explore the possibility of modifying the plasmon resonance at the nanoshell surface by varying the metal nanoshell composition for the first time. The surface plasmon resonance of the composite colloids increases in intensity and shifts towards longer, then shorter wavelengths as the Cu/Ag ratio in the alloy shell is increased. The variations in intensity of the surface plasmon resonance with the Cu/Ag ratio obviously affect the Raman bands of the silica colloid core. The report here may supply a new technique to effectively modify the surface plasmon resonance.

Zhang, Jianhui; Liu, Huaiyong; Wang, Zhenlin; Ming, Naiben

2007-04-01

224

Fast diffusion in ZrTiCuNiBe melts  

NASA Astrophysics Data System (ADS)

Atomic transport in Zr41.2Ti13.8Cu12.5Ni10Be22.5 and Zr46.8Ti8.2Cu7.5Ni10Be27.5 melts has been investigated with incoherent, quasielastic neutron scattering. From the q dependence of the quasielastic signal an average self-diffusion coefficient of the incoherent scatterers Ni and Ti has been obtained. Values are on a 10-10 m2 s-1 scale. In contrast to the viscosity, the diffusion coefficient is rather independent of the alloy's composition. Above the liquidus temperature times scales for Ni and Ti self diffusion and for viscous flow differ by up to two orders of magnitude: It appears, that the smaller atoms diffuse in a relative immobile Zr matrix.

Meyer, A.; Petry, W.; Koza, M.; Macht, M.-P.

2003-11-01

225

Strain-induced magnetocrystalline anisotropy in Ni on Cu(001)  

SciTech Connect

The origin of the observed perpendicular magnetic anisotropy (PMA) in Ni/Cu(001) for thick Ni layers is investigated using the {ital ab initio} full potential linearized augmented plane wave method. With the aid of the state tracking and torque approaches, very stable results are obtained for the magnetocrystalline anisotropy (MCA) energies for both the Ni/Cu(001) overlayer systems and the distorted bulk fct Ni. We find that the PMA is due mainly to the strain induced bulk contribution rather than to interfacial hybridization. The calculated value of the bulk MCA energy, 65 {mu}eV/atom, is very close to recent experimental data extrapolated to zero temperature, 70 {mu}eV/atom. {copyright} {ital 1997 American Institute of Physics.}

Wu, R.; Chen, L. [Department of Physics Astronomy, California State University, Northridge, California 91330-8268 (United States); Freeman, A.J. [Department of Physics Astronomy, Northwestern University, Evanston, Illinois 60208-3112 (United States)

1997-04-01

226

Study on the nano-composite electroless coating of NiP\\/Ag  

Microsoft Academic Search

The nano-composite coating of NiP\\/Ag was obtained by adding silver nanoparticles to the NiP electroless plating solutions. The properties of the coating were tested by scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), differential scanning calorimeter (DSC), X-ray diffraction (XRD) and microsclerometer. Silver nanoparticles changed the properties of the composite coating. The NiP electroless coating contains 12.23wt.% P while the

Hongfang Ma; Fang Tian; Dan Li; Qiang Guo

2009-01-01

227

Auger electron diffraction from NiO(100) layers on Ag(100)  

Microsoft Academic Search

NiO(100) films have been prepared by deposition of Ni onto Ag(100) in an O2 atmosphere. As deduced from low-energy electron diffraction and photoelectron spectroscopy the films are ordered and grow in a layer-by-layer mode. Auger electron diffraction of such films has been measured for the O (512 eV) and Ni (848 eV) Auger transitions in the entire halfspace above the

K. Marre; H. Neddermeyer; A. Chass; P. Rennert

1996-01-01

228

Solid-phase synthesis of solid solutions in Cu/Ni(001) epitaxial nanofilms  

NASA Astrophysics Data System (ADS)

Solid-phase synthesis of solid solutions in the epitaxial Cu/Ni(001) bilayer film systems of compositions 3Cu: 1Ni, 1Cu: 1Ni, and 1Cu: 3Ni has been studied using the X-ray diffraction methods. The saturation magnetization and the magnetic crystallographic anisotropy constant on nickel vary in accordance with the solid solution formation. The initiation temperature of the solid solutions is about 350 C and is independent of the Ni: Cu layer thickness ratio. The solid-phase synthesis of the solid solutions is presumably attributed to the transport of the Cu atoms to the epitaxial Ni(001) layer. It is found that the solid-phase synthesis in the Cu/Ni bilayer nanofilms and multilayers is determined by the spinodal decomposition in the Cu-Ni system.

Myagkov, V. G.; Bykova, L. E.; Bondarenko, G. N.; Zhigalov, V. S.

2008-12-01

229

Nanogranular Fe-Cu-Ag thin films: structure, microstructure and giant magnetoresistance.  

PubMed

Fe(x)Cu(y)Ag(z) granular thin films with several compositions were prepared by dc magnetron sputtering. These films consist of small Fe magnetic particles embedded in a nonmagnetic CuAg matrix. Structure, microstructure, morphology and magnetotransport properties were studied. The compositions of these samples were determined by energy-dispersive X-ray analysis. X-ray diffraction results showed strong Ag(111) peaks and broad Cu(111) peaks in all the samples. The variation of the (111) lattice spacings indicates a partial intermixing of Fe, Cu and Ag atoms. Microstructural studies using transmission electron microscopy (TEM) on a selected sample showed only Ag reflections and no reflection from Cu and Fe. Both XRD and TEM studies did not reveal any diffraction peak due to Fe and Cu for this sample. The fitting of the experimental grain size data obtained from TEM micrograph to the lognormal distribution function has allowed an estimation of the average grain diameter of 3.7 nm. The surface image of the Fe22Ag78 film observed using a scanning electron microscope showed the presence of droplet like Ag particles on the film surface. The Cu substitution results in smooth films without any Ag particles on the surface. Surface morphology by atomic force microscopy shows that the Fe39Cu13Ag48 film has a surface roughness of 0.75 nm. Finally, we have obtained a maximum giant magnetoresistance ratio of 3.2% in these films measured at 300 K for an in-plane magnetic field of 20 kOe. PMID:18681032

Rout, S; Kumar, M Senthil; Bhattacharya, S; Aswal, D K; Gupta, S K

2008-06-01

230

Electrical resistivity and magnetic behavior of PdNi and CuNi thin films  

NASA Astrophysics Data System (ADS)

Electrical and magnetic properties of sputtered Pd86Ni14 , Cu46Ni54 , and Cu42Ni58 thin films have been investigated. Pd86Ni14 shows clear ferromagnetic properties even if magnetic clusters of 4.6?B are observed above the Curie-Weiss temperature, TCW . Different magnetic properties are observed in CuNi alloys. Below TCW , the field cooling susceptibility increases quasilinearly, while very large magnetic clusters, up to 10-12?B , are observed above TCW . The temperature behavior of the resistivity of the thin films of the three alloys shows some common features. In particular, after a minimum the resistivity increases, probably due to the scattering of conduction electrons with Ni clusters. The temperature at which the minimum appears does not seem to depend on the host metal (Pd or Cu) and on the Ni concentration. These magnetic clusters affect the resistance behavior in the temperature range where the alloys are paramagnetic or close to their magnetic transition.

Iannone, G.; Zola, D.; Armenio, A. Angrisani; Polichetti, M.; Attanasio, C.

2007-02-01

231

Crossover phenomenon in surface segregation of Cu-Ni alloys  

NASA Astrophysics Data System (ADS)

An electronic theory of surface segregation for binary alloys, which uses the tight-binding Hartree Hamiltonian and the cluster-Bethe-lattice approximation, shows a crossover at x=0.75 for CuxNi1-x alloys if the condition of charge neutrality of the system is required. A previous theory, which used a similar approach, did not show a crossover as the theory did not preserve charge neutrality of the system. This result suggests that the crossover in Cu segregation may be due to the shift in the atomic levels of Cu and Ni at the surface.

Cheng, Yi-Chen

1986-11-01

232

Magnetic Properties of Cd Substituted Ni-Cu Ferrites  

NASA Astrophysics Data System (ADS)

Cadmium substituted Ni-Cu Ferrites with the general formula Ni0.95-xCdxCu0.05Fe2O4 (x = 0.1, 0.2 and 0.3) were prepared by the standard double sintering ceramic method. The existences of single phase formation with crystalline size of 25-38 nm were confirmed from XRD measurements. The magnetic properties such as saturation magnetization (Ms) and Magnetic moment (?B) were studied by VSM analysis. The existence of multidomain (MD) particles in the samples was revealed from the small values of Mr/Ms.

Belavi, P. B.; Chavan, G. N.; Bammannavar, B. K.; Naik, L. R.; Kotnala, R. K.

2011-07-01

233

Effects of the crystallographic orientation of Sn on the electromigration of Cu/Sn?Ag?Cu/Cu ball joints  

SciTech Connect

Electromigration behavior and fast circuit failure with respect to crystallographic orientation of Sn grains were examined. The test vehicle was Cu/Sn-3.0 wt% Ag-0.5 wt% Cu/Cu ball joints, and the applied current density was 15 kA/cm{sup 2} at 160 C. The experimental results indicate that most of the solder bumps show different microstructural changes with respect to the crystallographic orientation of Sn grains. Fast failure of the bump occurred due to the dissolution of the Cu circuit on the cathode side caused by the fast interstitial diffusion of Cu atoms along the c-axis of the Sn grains when the c-axis was parallel to the electron flow. Slight microstructural changes were observed when the c-axis was perpendicular to the electron flow. In addition, Cu{sub 6}Sn{sub 5} intermetallic compound (IMC) was formed along the direction of the c-axis of the Sn grains instead of the direction of electron flow in all solder ball joints.

Lee, Kiju; Kim, Keun-Soo; Tsukada, Yutaka; Suganuma, Katsuaki; Yamanaka, Kimihiro; Kuritani, Soichi; Ueshima, Minoru (Senju); (Kyocera); (Espec); (Osaka)

2011-11-17

234

Enhancement of light reflectance and thermal stability in Ag-Cu alloy contacts on p-type GaN  

Microsoft Academic Search

The mechanism for thermally stable Ag-Cu alloy Ohmic contact on p-type GaN was investigated. Ag-Cu contact showed lower contact resistivity as low as 8.610-6 Omega cm2, higher reflectance of 84% at 460 nm, and better thermal stability than Ag contact after annealing in air ambient. The formation of Ag-Ga solid solution lowered the contact resistivity. Additionally the formation of Cu

Jun Ho Son; Gwan Ho Jung; Jong-Lam Lee

2008-01-01

235

Ni/Ag as low resistive ohmic contact to p-type AlGaN for UV LEDs  

NASA Astrophysics Data System (ADS)

Reflective (thick) and semi-transparent (thin) Ni/Ag/Ni contacts were prepared on GaInN-based light-emitting diodes (LEDs) and p-GaN/p-Al0.15Ga0.85N layer sequences. A light output power enhancement of 41% and forward voltage reduction of 0.59 V were obtained compared to a Ni/Au contact for LEDs emitting at 400 nm with thick p-GaN contact layers. The specific contact resistance of the Ni/Ag/Ni contacts on p-GaN/p-Al0.15Ga0.85N with varying p-GaN thickness (5-20 nm) were determined by transmission line method and compared to Ni/Au contacts. Low resistive ohmic contacts were obtained for a p-GaN thickness of less than 10 nm. The p-GaN layer can be completely omitted for the reflective Ni/Ag/Ni contact. In addition, reflection and transmission of the Ni/Ag/Ni metallization schemes were investigated in the ultra-violet spectral range. Thick Ni/Ag/Ni and thin Ni/Ag/Ni covered by Al are promising to serve as reflective contacts for ultra-violet LEDs. The former for wavelength around 350 nm and the latter for wavelengths below 350 nm.

Passow, T.; Gutt, R.; Maier, M.; Pletschen, W.; Kunzer, M.; Schmidt, R.; Wiegert, J.; Luick, D.; Liu, S.; Khler, K.; Wagner, J.

2010-02-01

236

Sm(Co, Cu, Ni) thin films with giant coercivity  

Microsoft Academic Search

Nanostructured Sm(Co, Ni, Cu) thin films have been obtained by heat treating as-deposited sputtered amorphous films. The room-temperature coercivity increases from less than 100 Oe in the amorphous state to 42 kOe in a SmCo2Cu3 sample annealed 30 min at 550 C. Structural data in the optimum samples suggest a particle size around 10 mn. Magnetic viscosity measurements indicated that

C. Prados; G. C. Hadjipanayis

1999-01-01

237

Interdiffusion and magnetism in Cu/Ni/Cu sandwiches  

NASA Astrophysics Data System (ADS)

Results are presented for the magnetic-moment distribution in a (111) sandwich consisting originally of three perfect layers of nickel bounded on each side by a semi-infinite copper crystal, for different degrees of interdiffusion. The approach used is a combination of the recently developed layer Korringa-Kohn-Rostoker method, with the multiple-scattering spin-polarized version of the coherent-potential approximation. When applied to bulk homogeneous CuxNi1-x, it yields average and Ni moments in excellent agreement with experiment. The sandwich geometry is found to favor magnetism at Ni concentrations far below the bulk critical value.

Crampin, S.; Monnier, R.; Schulthess, T.; Schadler, G. H.; Vvedensky, D. D.

1992-01-01

238

HRTEM studies of amorphous ZrNiTiCu nanocrystalline composites.  

PubMed

Ball milling of easy glass forming Ti(25)Zr(17)Ni(29)Cu(29) alloys lead to the formation of an amorphous structure accompanied by a substantial increase of powder microhardness. The powders show clear glass transition effect and a few stage crystallization starting above 500 degrees C. High-resolution transmission electron microscope technique allowed identifying nanocrystalline inclusions as Cu(12)NiTi(7) within the amorphous powder. The amorphous powders mixed with nanocrystalline iron or silver powders were hot pressed to form composites. A narrow 200 nm broad intermediate single-phase layer at the amorphous-phase/iron interface containing all elements present in the composite was identified using transmission electron microscope and high-angle annular dark field detector techniques. scanning transmission electron microscopy energy dispersive spectroscopy line profile showed gradual change of composition within the intermediate zone. Amorphous phase contains small nanocrystals of size close to 10 nm identified using High-resolution transmission electron microscope as Cu(12)NiTi(7.) Compression tests have shown better plasticity of composites than in the case of pure hot-pressed amorphous powder; furthermore, high elastic limit of composites and the ultimate compression stress of about 1800 MPa for composites containing 20% Fe and near 700 MPa for those with 20% Ag. PMID:20500372

Dutkiewicz, J; Lity?ska-Dobrzy?ska, L; Kovacova, A; Molnarova, M; Rogal, L; Maziarz, W

2010-03-01

239

Optical and quantum efficiency analysis of (Ag,Cu)(In,Ga)Se2 absorber layers  

SciTech Connect

(Ag,Cu)(In,Ga)Se2 thin films have been deposited by elemental co-evaporation over a wide range of compositions and their optical properties characterized by transmission and reflection measurements and by relative shift analysis of quantum efficiency device measurements. The optical bandgaps were determined by performing linear fits of (?h?)2 vs. h?, and the quantum efficiency bandgaps were determined by relative shift analysis of device curves with fixed Ga/(In+Ga) composition, but varying Ag/(Cu+Ag) composition. The determined experimental optical bandgap ranges of the Ga/(In+Ga) = 0.31, 0.52, and 0.82 groups, with Ag/(Cu+Ag) ranging from 0 to 1, were 1.19-1.45 eV, 1.32-1.56 eV, and 1.52-1.76 eV, respectively. The optical bowing parameter of the different Ga/(In+Ga) groups was also determined.

Boyle, Jonathan; Hanket, Gregory; Shafarman, William

2009-06-09

240

The compression stress-strain behavior of Sn-Ag-Cu solder  

Microsoft Academic Search

The yield-stress behavior was investigated for the 95.5Sn-4.3Ag-0.2Cu (wt.%), 95.5Sn-3.9Ag-0.6Cu, and 95.5Sn-3.8Ag-0.7Cu ternary\\u000a lead-free solders using the compression stress-strain test technique. Cylindrical specimens were evaluated in the as-cast\\u000a or aged (125C, 24 h) condition. The tests were performed at ?25C, 25C, 75C, 125C, and 160C using strain rates of 4.210?5s?1 or 8.310?4s?1. Specially designed Sn-Ag-0.6Cu samples were fabricated to compare

Paul T. Vianco; Jerome A. Rejent; Joseph J. Martin

2003-01-01

241

The compression stress-strain behavior of Sn-Ag-Cu solder  

Microsoft Academic Search

The yield-stress behavior was investigated for the 95.5Sn-4.3Ag-0.2Cu (wt.%), 95.5Sn-3.9Ag-0.6Cu, and 95.5Sn-3.8Ag-0.7Cu ternary lead-free solders using the compression stress-strain test technique. Cylindrical specimens were evaluated in the as-cast or aged (125C, 24 h) condition. The tests were performed at -25C, 25C, 75C, 125C, and 160C using strain rates of 4.210-5s-1 or 8.310-4s-1. Specially designed Sn-Ag-0.6Cu samples were fabricated to compare

Paul T. Vianco; Jerome A. Rejent; Joseph J. Martin

2003-01-01

242

The compression stress-strain behavior of Sn-Ag-Cu solder  

NASA Astrophysics Data System (ADS)

The yield-stress behavior was investigated for the 95.5Sn-4.3Ag-0.2Cu (wt.%), 95.5Sn-3.9Ag-0.6Cu, and 95.5Sn-3.8Ag-0.7Cu ternary lead-free solders using the compression stress-strain test technique. Cylindrical specimens were evaluated in the as-cast or aged (125C, 24 h) condition. The tests were performed at -25C, 25C, 75C, 125C, and 160C using strain rates of 4.210-5s-1 or 8.310-4s-1. Specially designed Sn-Ag-0.6Cu samples were fabricated to compare the yield stress of the dendritic microstructure versus that of the equiaxed microstructure that occurs in this alloy.

Vianco, Paul T.; Rejent, Jerome A.; Martin, Joseph J.

2003-06-01

243

Correlation Between Sn Grain Orientation and Corrosion in Sn-Ag-Cu Solder Interconnects  

NASA Astrophysics Data System (ADS)

The impact of a marine environment on Sn-Ag-Cu interconnect reliability is examined using salt spray exposure followed by thermal cycling. Sn-Ag-Cu solder alloy wafer-level packages, with and without pretreatment with 5% NaCl salt spray, were thermally cycled to failure. The prior salt spray reduced the characteristic lifetime of the Sn-Ag-Cu solder joints by over 43%. Although Sn-based materials show strong resistance to corrosion, the nature of localized corroded areas at critical locations in the solder joint caused significant degradation in the Sn-Ag-Cu solder joints. An important link between the corrosion path and Sn grain orientation was observed using orientation imaging microscopy (OIM). A strong correlation between the corrosion path and grain orientation was identified, indicating that the corrosion attack preferentially followed the basal plane of the Sn lattice.

Lee, Tae-Kyu; Liu, Bo; Zhou, Bite; Bieler, Thomas; Liu, Kuo-Chuan

2011-09-01

244

New bulk glassy alloys in Cu-Zr-Ag ternary system prepared by casting and milling  

NASA Astrophysics Data System (ADS)

The thermal stability, crystallization behaviour and glass forming ability of Cu-Zr-Ag system have been investigated on the basis of a ternary phase diagram. We altered the concentration of the alloys from the Cu58Zr42 to the concentration of the deep eutectic point of the Cu-Zr-Ag ternary system and we calculated the glass forming ability parameters. This paper summerises the results of the procedure during which Cu-Zr-Ag amorphous alloys with different Ag content (0-25%) were prepared by casting and ball-milling. Wedge-shaped samples were prepared from the ingots by centrifugal casting into copper mold. The supercooled liquid region (?Tx) exceeded 75K. Following the characterization of the cast alloys, master alloys of identical composition were milled in a Fritsch Pulverisette 2 ball-mill. The powders, milled for various periods of time were analysed by XRD in order to define the amorphous fraction.

Janovszky, D.; Tomolya, K.; Sveda, M.; Solyom, J.; Roosz, A.

2009-01-01

245

Hydrogen permeation of PdAg alloy coated V15Ni composite membrane: effects of overlayer composition  

Microsoft Academic Search

Effects of Ag concentration (045at.%) on the hydrogen permeation of PdAg coated V15Ni composite membranes were investigated in the temperature range of 423673K, using gas permeation technique. Dense and uniform PdAg alloy overlayer was obtained using a DC multi-target sputtering system. At temperatures higher than 473K, the hydrogen permeation through the V15Ni\\/PdAg composite membranes was mainly bulk-diffusion limited and had

Y. Zhang; T. Ozaki; M. Komaki; C. Nishimura

2003-01-01

246

Study of dipole interaction in micron-width NiFe/Cu/NiFe/NiO wire using exchange anisotropy  

SciTech Connect

The dipole interaction between a NiFe layer pinned by a NiO and a free NiFe layer in a micron-wide NiFe/Cu/NiFe/NiO wire was studied by changing the direction of the exchange bias from the NiO layer. The effect of the dipole interaction when the exchange bias was perpendicular to the wire axis was larger than that when the exchange bias was parallel to the wire axis, and was consistently explained by the stray field caused by the magnetic charges of the pinned layer. It was demonstrated that this method, using exchange anisotropy, is useful for investigating the dipole interaction between ferromagnetic materials separated by a nonmagnetic material in small-scale magnetic multilayers. {copyright} 2001 American Institute of Physics.

Kimura, Takashi; Itagaki, Yoshio; Wakaya, Fujio; Gamo, Kenji

2001-06-18

247

Effects of C + implantation on the interdiffusion and resistivity of Cu\\/Ni\\/Au thin films  

Microsoft Academic Search

The effect of C+ implantation on the interdiffusion of Cu\\/Au and Cu\\/Ni\\/Au thin-film structures was investigated at temperatures ranging from 200 to 600 C, and for different annealing times at 400 C. For comparison, unimplanted Cu\\/Ni\\/Au and Cu\\/C\\/Ni\\/Au thin-film structures were also studied. The implantation of carbon ions has very little effect on the interdiffusion of Cu and Au at

Peter Madakson; J. Karasinski

1990-01-01

248

Fabrication of biaxially textured CuNi alloy tapes for YBCO coated conductor  

Microsoft Academic Search

Nickel is well suited as a substrate material for YBa2Cu3O7?x coated conductors. However, nickels ferromagnetism leads to AC losses when it is used in AC applications. In this paper, CuNi non-magnetic tapes were made for YBa2Cu3O7?x film deposition. The biaxially textured CuNi alloy tapes were formed through heavy cold rolling followed by recrystallization heat treatment. CuNi alloy tapes with sharp

K. Shi; Y. Zhou; J. Meng; J. Yang; G. Y. Hu; H. W. Gu; G. S. Yuan

2003-01-01

249

Effect of Cross-Interaction between Ni and Cu on Growth Kinetics of Intermetallic Compounds in Ni/Sn/Cu Diffusion Couples during Aging  

NASA Astrophysics Data System (ADS)

The solid-state, cross-interaction between the Ni layer on the component side and the Cu pad on the printed circuit board (PCB) side in ball grid array (BGA) solder joints was investigated by employing Ni(15 ?m)/Sn(65 ?m)/Cu ternary diffusion couples. The ternary diffusion couples were prepared by sequentially electroplating Sn and Ni on a Cu foil and were aged isothermally at 150, 180, and 200C. The growth of the intermetallic compound (IMC) layer on the Ni side was coupled with that on the Cu side by the mass flux across the Sn layer that was caused by the difference in the Ni content between the (Cu1- x Ni x )6Sn5 layer on the Ni side and the (Cu1- y Ni y )6Sn5 layer on the Cu side. As the consequence of the coupling, the growth rate of the (Cu1- x Ni x )6 Sn5 layer on the Ni side was rapidly accelerated by decreasing Sn layer thickness and increasing aging temperature. Owing to the cross-interaction with the top Ni layer, the growth rate of the (Cu1- y Ni y )6Sn5 layer on the Cu side was accelerated at 150C and 180C but was retarded at 200C, while the growth rate of the Cu3Sn layer was always retarded. The growth kinetic model proposed in an attempt to interpret the experimental results was able to reproduce qualitatively all of the important experimental observations pertaining to the growth of the IMC layers in the Ni/Sn/Cu diffusion couple.

Hong, K. K.; Ryu, J. B.; Park, C. Y.; Huh, J. Y.

2008-01-01

250

Coffin-Manson equation of Sn4.0Ag0.5Cu solder joint  

Microsoft Academic Search

Purpose The purpose of this paper is to fit Coffin-Manson equation of Sn-4.0Ag-0.5Cu lead free solder joint by using results of solders joint reliability test and finite element analysis. Also to present a novel device for solder joint reliability test. Design\\/methodology\\/approach Two-points bending test of Sn-4.0Ag-0.5Cu lead free solder joint was carried out at three deflection levels by

S. Chen; P. Sun; X. C. Wei; Z. N. Cheng; J. Liu

2009-01-01

251

Spectroscopy of microcrystals in the CuI-AgI system  

SciTech Connect

Using comparative analysis of the absorption and luminescence spectra of samples with different compositions, we studied the effect of the preparation procedure on the structure of composite CuI-AgI microcrystals formed in the gelatin matrix. The resonance character of excitation and its localization at the substrate/epitax interface were established. The most probable composition of the thermally stable photolytic centers as a function of the relative content of Cu and Ag was discussed.

Voll, V.A.; Barmasov, A.V.; Struts, A.V. [St. Petersburg State Univ., Petrodvorets (Russian Federation)

1994-06-01

252

Flow stress behavior and processing map of Al-Cu-Mg-Ag alloy during hot compression  

Microsoft Academic Search

The hot deformation behavior of Al-Cu-Mg-Ag was studied by isothermal hot compression tests in the temperature range of 573773\\u000a K and strain rate range of 0.0011 s?1 on a Gleeble 1500 D thermal mechanical simulator. The results show the flow stress of Al-Cu-Mg-Ag alloy increases with strain\\u000a rate and decreases after a peak value, indicating dynamic recovery and recrystallization. A

Sheng Yang; Danqing Yi; Hong Zhang; Sujuan Yao

2008-01-01

253

EPIDEMIOLOGICAL STUDY ON SN-AG-CU SOLDER: BENCHMARKING RESULTS FROM ACCELERATED LIFE TESTING  

Microsoft Academic Search

This paper will present the results of a comprehensive overview of accelerated life testing (ALT) of components assembled with SnAgCu solder. Over 100 private documents and published articles were assessed for data on SnAgCu performance under temperature cycling. Data on test parameters, component materials and design, and interconnect dimensions were acquired and results were grouped by attach geometry, including leadless

Craig Hillman; Nathan Blattau; Ed Dodd; Joelle Arnold

254

Nanoindentation on SnAgCu lead-free solder and analysis  

Microsoft Academic Search

To improve the measurement accuracy of hardness and modulus results of lead-free SnAgCu from nanoindentation experiments, evaluation of the creep effect on measured result and was reported. For SnAgCu solder in this study, it was found that penetration continues with a very long time and the penetration depth could increase extra 1000 nm when the load was held constant. Thus

Luhua Xu; J. H. L. Pang

2005-01-01

255

Accommodation of the misfit strain surrounding (III) precipitates [omega] in Al-Cu-Mg-(Ag)  

SciTech Connect

In this paper, [omega] phase in Al-Cu-Mg and Al-Cu-Mg-Ag is examined to determine the influence of silver addition on the [omega] precipitate structure and the effect of the large misfit normal to the [omega] plate habit plane on the interfacila structure. Using electron diffraction and HREM, no difference in [omega] structure could be discerned between the two alloys with and without Ag additions.

Fonda, R.W.; Shiflet, G.J. (Virginia Univ., Charlottesville, VA (United States). Dept. of Materials Science); Cassada, W.A. (Reynolds Metals Co., Richmond, VA (United States))

1992-10-01

256

Precipitation hardening of a Cu-free AuAgPdIn dental alloy  

Microsoft Academic Search

The hardening mechanism and related microstructural changes of the Cu-free dental casting alloy composed of AuAgPdIn was examined by means of hardness test, X-ray diffraction (XRD), scanning electron microscopic (SEM) observations and electron probe microanalysis (EPMA). The AuAgPdIn alloy showed apparent age-hardenability. In the SEM photograph, three phases were observed in the solution-treated specimen, that is, the AuAg based phase

Hyo-Joung Seol; Kuk-Hyeon Son; Chin-Ho Yu; Yong Hoon Kwon; Hyung-Il Kim

2005-01-01

257

Growth, thermal stability and oxidation of Ag/Fe and Ni/Fe bilayers  

NASA Astrophysics Data System (ADS)

A study of the growth, thermal stability and oxidation of Ag/Fe and Ni/Fe on MgO(100) is presented. The layers were found to grow epitaxially. The Ag layer grows as an (001) single crystal layer on the epitaxial Fe(001) layer. The Ni layer grows as a (011) layer with a fine structure of domains. Upon annealing of the Ag/Fe bilayers at /200C and /320C, round holes were formed in the top layer of Ag. After exposure to O2 at pressures of 0.1-30 mbar and at /200C and /320C a rough layer of Fe-oxide is formed on top of the still epitaxial Ag layer. The speed of oxidation is not impeded by the Ag cap layer. A model to explain these observations is presented. The thermal stability and the resistance against oxidation of the Ni/Fe bilayers was found to be much better. Some Ni/Fe interdiffusion was observed after annealing in vacuum for 30h. After oxidation in 10-6 mbar O2 at /200C for 40h and subsequent air exposure only a thin Fe-hydroxide layer was observed. The results obtained can be of interest to judge the stability of magnetic multilayers.

Mijiritskii, A. V.; Boerma, D. O.

2001-06-01

258

Effect of plant-based phenol derivatives on the formation of Cu and Ag nanoparticles.  

PubMed

The complexes formed on the reaction of various metal ions viz., Cu(II) and Cu(I) with phenol derivatives viz. catechol, chlorogenic acid (CGA), hydroquinone and n-propyl gallate (nPG) were established by UV-visible spectroscopy. The metal/ligand complexing ratio and complexation constants have been determined. Further, we showed that nanoparticles of Cu can be prepared from metal-phenol complexes in the presence of a protein (gelatin) by ?-irradiation showing that the reduction is metal ion centered. Formation of Ag nanoparticles was also observed on photo-irradiation with xenon lamp in the presence of dihydroxy benzene. The Ag and Cu nanoparticles were characterized by transmission electron microscopy (TEM) and UV-visible absorption spectroscopy. TEM technique showed the presence of Cu and Ag nanoparticles with average size of 20 and 30 nm, respectively. PMID:21621984

Jacob, Jasmine A; Biswas, Nandita; Mukherjee, Tulsi; Kapoor, Sudhir

2011-05-07

259

Adsorption characteristics of Cu and Ni on Irish peat moss  

Microsoft Academic Search

Peat has been widely used as a low cost adsorbent to remove a variety of materials including organic compounds and heavy metals from water. Various functional groups in lignin allow such compounds to bind on active sites of peat. The adsorption of Cu2+ and Ni2+ from aqueous solutions on Irish peat moss was studied both as a pure ion and

B. Sen Gupta; M. Curran; Shameem Hasan; T. K. Ghosh

2009-01-01

260

Study on Cu-Al-Ni Shape Memory Alloys.  

National Technical Information Service (NTIS)

Due to the lower cost and simple fabricating technology, copper based shape memory alloys are drawing scientists' attention day by day. Though the study on Cu-Al-Ni shape memory alloys still remains insufficient, it has been found that its properties are ...

X. Zhou X. Liu Y. Zheng J. Mu Y. Ning

1992-01-01

261

Photoemission study of AgTO2 delafossites (T=Fe, Co, Ni)  

NASA Astrophysics Data System (ADS)

The electronic structures of the AgTO2 delafossites (T = Fe, Co, Ni) have been investigated using photoemission spectroscopy. T 2p spectra exhibit satellite structures around 6 eV below main peaks, reflecting the strong on-site 3d Coulomb interaction. T 2p spectra of AgTO2 (T=Fe, Co, Ni) are similar to those of ?-Fe2O3, CoO, and NiO, respectively, suggesting the strong covalent bonding in AgTO2. The valence-band spectrum of Ag0.75CoO2 shows negligible spectral weight near EF, consistent with its semiconducting behavior. The extracted Ag 4d and Co 3d partial spectral weight (PSW) distributions of Ag0.75CoO2 reveal a small overlap between these two states, while the O 2p PSW shows a significant overlap with the Co 3d PSW. Such trends in the PSWs are consistent with those in the calculated partial densities of states of AgCoO2.

Kang, J.-S.; Kwak, J. H.; Shin, Y. J.; Han, S. W.; Kim, K. H.; Min, B. I.

2000-04-01

262

Mechanical Properties and Electrochemical Corrosion Behavior of Al/Sn-9Zn- xAg/Cu Joints  

NASA Astrophysics Data System (ADS)

The effect of Ag content on the wetting behavior of Sn-9Zn- xAg on aluminum and copper substrates during soldering, as well as the mechanical properties and electrochemical corrosion behavior of Al/Sn-9Zn- xAg/Cu solder joints, were investigated in the present work. Tiny Zn and coarsened dendritic AgZn3 regions were distributed in the Sn matrix in the bulk Sn-9Zn- xAg solders, and the amount of Zn decreased while that of AgZn3 increased with increasing Ag content. The wettability of Sn-9Zn-1.5Ag solder on Cu substrate was better than those of the other Sn-9Zn- xAg solders but worse than that of Sn-9Zn solder. The wettability of Sn-9Zn-1.5Ag on the Al substrate was also better than those of the other Sn-9Zn- xAg solders, and even better than that of Sn-9Zn solder. The Al/Sn-9Zn/Cu joint had the highest shear strength, and the shear strength of the Al/Sn-9Zn- xAg/Cu ( x = 0 wt.% to 3 wt.%) joints gradually decreased with increasing Ag content. The corrosion resistance of the Sn-9Zn- xAg solders in Al/Sn-9Zn- xAg/Cu joints in 5% NaCl solution was improved compared with that of Sn-9Zn. The corrosion potential of Sn-9Zn- xAg solders continuously increased with increasing Ag content from 0 wt.% to 2 wt.% but then decreased for Sn-9Zn-3Ag. The addition of Ag resulted in the formation of the AgZn3 phase and in a reduction of the amount of the eutectic Zn phase in the solder matrix; therefore, the corrosion resistance of the Al/Sn-9Zn- xAg/Cu joints was improved.

Huang, M. L.; Huang, Y. Z.; Ma, H. T.; Zhao, J.

2011-03-01

263

Corrosion Behavior of Pb-Free Sn-1Ag-0.5Cu- XNi Solder Alloys in 3.5% NaCl Solution  

NASA Astrophysics Data System (ADS)

Potentiodynamic polarization techniques were employed in the present study to investigate the corrosion behavior of Pb-free Sn-1Ag-0.5Cu- XNi solder alloys in 3.5% NaCl solution. Polarization studies indicated that an increase in Ni content from 0.05 wt.% to 1 wt.% in the solder alloy shifted the corrosion potential ( E corr) towards more negative values and increased the linear polarization resistance. Increased addition of Ni to 1 wt.% resulted in significant increase in the concentration of both Sn and Ni oxides on the outer surface. Secondary-ion mass spectrometry and Auger depth profile analysis revealed that oxides of tin contributed primarily towards the formation of the passive film on the surface of the solder alloys containing 0.05 wt.% and 1 wt.% Ni. Scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDX) established the formation of a Sn whisker near the passive region of the solder alloy obtained from the polarization curves. The formation of Sn whiskers was due to the buildup of compressive stress generated by the increase in the volume of the oxides of Sn and Ni formed on the outer surface. The presence of Cl- was responsible for the breakdown of the passive film, and significant pitting corrosion in the form of distinct pits was noticed in Sn-1Ag-0.5Cu-0.5Ni solder alloy after the polarization experiment.

Mohanty, Udit Surya; Lin, Kwang-Lung

2013-04-01

264

Structure and electrical conductivity of ultrathin Ni-Cu films  

SciTech Connect

The structure, phase composition, morphology, and electrical conductivity of Ni-Cu alloy ultrathin films having a thickness of d = 1-10 nm and a Cu concentration of 10-95 at % have been studied. All films are shown to be fcc Ni-Cu alloys; they have an island structure with an island size of 1.5-2 nm in the as-deposited films and of about 20 nm in the films annealed to 700 K. The electrical conductivity of the films depends on their thickness and morphology. For films with d {approx} 1 nm, the electrical conductivity is thermally activated with an activation energy E{sub a} {approx} 0.086-0.095 eV. Films with d > 3 nm exhibit the metallic temperature dependence of electrical conductivity with a positive temperature coefficient of resistivity.

Loboda, V. B., E-mail: loboda@sspu.sumy.ua; Khursenko, S. N. [Sumy State Pedagogical University (Ukraine)

2006-11-15

265

Nanoscale duplex oxide growth during early stages of oxidation of Cu-Ni(100)  

SciTech Connect

A combination of real-time in situ synchrotron x-ray diffraction and ex situ transmission electron microscopy is utilized to investigate the early stages of oxidation of Cu-Ni(100). Sequential formation of NiO and Cu{sub 2}O oxides was observed by increasing oxygen partial pressure, and the Cu{sub 2}O phase was identified to form preferentially on top of NiO nanoislands. The origin of this unexpected phenomenon is attributed to localized enrichment of Cu atoms accompanied with NiO growth, which thermodynamically drives the nanoscale Cu{sub 2}O/NiO duplex oxide growth.

Zhou Guangwen [Department of Mechanical Engineering and Multidisciplinary Program in Materials Science and Engineering, State University of New York, Binghamton, New York 13902 (United States); Fong, Dillon D.; Fuoss, Paul H.; Baldo, Peter M.; Thompson, Loren J.; Eastman, Jeffrey A. [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Wang Liang [Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States)

2009-10-01

266

Fabrication of Cu-Ag core-shell bimetallic superfine powders by eco-friendly reagents and structures characterization  

NASA Astrophysics Data System (ADS)

Superfine bimetallic Cu-Ag core-shell powders were synthesized by reduction of copper sulfate pentahydrate and silver nitrate with eco-friendly ascorbic acid as a reducing agent and cyclodextrins as a protective agent in an aqueous system. The influence of Ag/Cu ratio on coatings was investigated. Ag was homogeneously distributed on the surface of Cu particles at a mole ratio of Ag/Cu=1. FE-SEM showed an uniformity of Ag coatings on Cu particles. Antioxidation of Cu particles was improved by increasing Ag/Cu ratio. TEM-EDX and UV-vis spectra also revealed that Cu cores were covered by Ag nanoshells on the whole. The surface composition analysis by XPS indicated that only small parts of Cu atoms in the surface were oxidized. It was noted that the hindrance of cyclodextrins chemisorbed on particles plays an important role in forming high quality and good dispersity Cu-Ag (Cu@Ag) core-shell powders.

Zhao, Jun; Zhang, Dongming; Zhao, Jie

2011-09-01

267

Interactions of Oxygen and Ethylene with Submonolayer Ag Films Supported on Ni(111)  

SciTech Connect

We investigate the oxidation of, and the reaction of ethylene with, Ni(111) with and without sub-monolayer Ag adlayers as a function of temperature. The addition of Ag to Ni(111) is shown to enhance the activity towards the ethylene epoxidation reaction, and increase the temperature at which ethylene oxide is stable on the surface. We present a systematic study of the formation of chemisorbed oxygen on the Ag-Ni(111) surfaces and correlate the presence and absence of O{sup 1-} and O{sup 2-} surface species with the reactivity towards ethylene. By characterizing the samples with low-energy electron microscopy (LEEM) in combination with X-ray photoelectron spectroscopy (XPS), we have identified specific growth of silver on step-edge sites and successfully increased the temperature at which the produced ethylene oxide remains stable, a trait which is desirable for catalysis.

Alamgir, F.M.; Senanayake, S.; Rettew, R.E.; Meyer, A.; Chen, T.-L.; Petersburg, C.; Flege, J.I.; Falta, J.

2011-06-01

268

Interactions of oxygen and ethylene with submonolayer Ag films supported on Ni(111).  

PubMed

We investigate the oxidation of, and the reaction of ethylene with, Ni(111) with and without sub-monolayer Ag adlayers as a function of temperature. The addition of Ag to Ni(111) is shown to enhance the activity towards the ethylene epoxidation reaction, and increase the temperature at which ethylene oxide is stable on the surface. We present a systematic study of the formation of chemisorbed oxygen on the Ag-Ni(111) surfaces and correlate the presence and absence of O(1-) and O(2-) surface species with the reactivity towards ethylene. By characterizing the samples with low-energy electron microscopy (LEEM) in combination with X-ray photoelectron spectroscopy (XPS), we have identified specific growth of silver on step-edge sites and successfully increased the temperature at which the produced ethylene oxide remains stable, a trait which is desirable for catalysis. PMID:21556442

Rettew, Robert E; Meyer, Axel; Senanayake, Sanjaya D; Chen, Tsung-Liang; Petersburg, Cole; Ingo Flege, J; Falta, Jens; Alamgir, Faisal M

2011-05-10

269

Interactions of Oxygen and Ethylene with Submonolayer Ag Films Supported on Ni(111)  

SciTech Connect

We investigate the oxidation of, and the reaction of ethylene with, Ni(111) with and without sub-monolayer Ag adlayers as a function of temperature. The addition of Ag to Ni(111) is shown to enhance the activity towards the ethylene epoxidation reaction, and increase the temperature at which ethylene oxide is stable on the surface. We present a systematic study of the formation of chemisorbed oxygen on the Ag-Ni(111) surfaces and correlate the presence and absence of O{sup 1-} and O{sup 2-} surface species with the reactivity towards ethylene. By characterizing the samples with low-energy electron microscopy (LEEM) in combination with X-ray photoelectron spectroscopy (XPS), we have identified specific growth of silver on step-edge sites and successfully increased the temperature at which the produced ethylene oxide remains stable, a trait which is desirable for catalysis.

R Rettew; A Meyer; S Senanayake; T Chen; C Petersburg; J Flege; J Falta; F Alamgir

2011-12-31

270

Interactions of oxygen and ethylenewith submonolayer Ag filmssupported on Ni(111)  

SciTech Connect

We investigate the oxidation of, and the reaction of ethylene with, Ni(111) with and without sub-monolayer Ag adlayers as a function of temperature. The addition of Ag to Ni(111) is shown to enhance the activity towards the ethylene epoxidation reaction, and increase the temperature at which ethylene oxide is stable on the surface. We present a systematic study of the formation of chemisorbed oxygen on the Ag Ni(111) surfaces and correlate the presence and absence of O1 and O2 surface species with the reactivity towards ethylene. By characterizing the samples with low-energy electron microscopy (LEEM) in combination with X-ray photoelectron spectroscopy (XPS), we have identified specific growth of silver on step-edge sites and successfully increased the temperature at which the produced ethylene oxide remains stable, a trait which is desirable for catalysis.

Rettew, Robert [Georgia Institute of Technology; Meyer, Axel [ORNL; Senanayake, Sanjaya D [ORNL; Chen, Tsung-Liang [ORNL; Petersburg, Cole [Georgia Institute of Technology; Flege, J. Ingo [University of Bremen, Bremen, Germany; Falta, Jens [University of Bremen, Bremen, Germany; Alamgir, Faisal [ORNL

2011-01-01

271

Anodic vacuum arc developed nanocrystalline CuNi and FeNi thin film thermocouples  

Microsoft Academic Search

This paper deals with the development of nanocrystalline CuNi and FeNi thin film thermocouples (TFTCs) by using ion-assisted anodic vacuum arc deposition technique. The crystallographic structure and surface morphology of individual layer films have been studied by x-ray diffraction and scanning electron microscopy, respectively. The resistivity, temperature coefficient of resistance, and thermoelectric power of as deposited and annealed films have

S. K. Mukherjee; M. K. Sinha; B. Pathak; S. K. Rout; P. K. Barhai

2009-01-01

272

Anodic vacuum arc developed nanocrystalline Cu-Ni and Fe-Ni thin film thermocouples  

Microsoft Academic Search

This paper deals with the development of nanocrystalline Cu-Ni and Fe-Ni thin film thermocouples (TFTCs) by using ion-assisted anodic vacuum arc deposition technique. The crystallographic structure and surface morphology of individual layer films have been studied by x-ray diffraction and scanning electron microscopy, respectively. The resistivity, temperature coefficient of resistance, and thermoelectric power of as deposited and annealed films have

S. K. Mukherjee; M. K. Sinha; B. Pathak; S. K. Rout; P. K. Barhai

2009-01-01

273

Impact of Electrical Current on the Long-Term Reliability of Fine-Pitch Ball Grid Array Packages with Sn-Ag-Cu Solder Interconnects  

NASA Astrophysics Data System (ADS)

The interaction between electrical current and the long-term reliability of fine-pitch ball grid array packages with Sn-3.0Ag-0.5Cu (wt.%) solder ball interconnects is investigated. In this study, 0.4-mm fine-pitch packages with 300- ?m-diameter Sn-Ag-Cu solder balls are used. Electrical current was applied under various conditions to two different package substrate surface finishes to compare the effects of chemically unmixed and mixed joint structures: a Cu/SAC305/Cu structure and a NiAu/SAC305/Cu structure, respectively. To study the thermal impact on the thermal fatigue performance and long-term reliability, the samples were thermally cycled from 0C to 100C with and without current stressing. Based on Weibull plots, the characteristic lifetime was degraded for the mixed joint structure, but little degradation was observed for the unmixed joint structure. The microstructure evolution was observed during constant current stressing and current stressing during thermal cycling. Accelerated intermetallic precipitation depletion at the package-side interface was observed in NiAu/SAC305/Cu structures due to current stressing, which was identified as the potential reason for the degradation in the thermal cycling performance.

Lee, Tae-Kyu

2013-04-01

274

Temperature-dependence of interlayer exchange bias coupling in NiO/Cu/NiFe  

SciTech Connect

The trilayers 10 nm NiO(AF)/X Cu/10 nm NiFe(FM) were prepared for the study on the temperature effect in interlayer exchange bias coupling. The characteristic behavior of the interlayer exchange bias coupling as a function the spacer thickness was shown to strongly depend on the temperature. A monotonic decrease of the exchange bias field with increasing Cu spacer layer was observed at low temperature around 20 K. At higher temperatures (about 145 K), a clear oscillatory evolution of the exchange bias field with the Cu thickness was found even without background subtraction. The temperature-dependent feature of the interlayer exchange bias coupling was also found to vary significantly with different Cu thickness. {copyright} 2001 American Institute of Physics.

Lin, Minn-Tsong; Ho, C. H.; Chang, Ching-Ray; Yao, Y. D.

2001-06-01

275

Phase Transitions of AgI-CuI Nanosystem in the Aniya-Ichihara Theory  

NASA Astrophysics Data System (ADS)

AgI-CuI `solid-solution' nanoparticles prepared by mechanochemical reaction at ambient temperature show a progressive linear increase in the zincblende-bcc phase transition temperature upon increase of Cu concentration. Aniya-Ichihara model has been invoked to qualitatively account for the experimental observations adopting the linear model for the concentration dependence of defect-defect interaction. The specific role played by Cu namely occupation of lattice Ag+ sites and depletion of Frenkel defects probably justifies the use of the linear model.

Mohan, D. Bharathi; Sunandana, C. S.

2011-07-01

276

Alloy Catalyst in a Reactive Environment: The Example of Ag-Cu Particles for Ethylene Epoxidation  

SciTech Connect

Combining first-principles calculations and in situ photoelectron spectroscopy, we show how the composition and structure of the surface of an alloy catalyst is affected by the temperature and pressure of the reagents. The Ag-Cu alloy, recently proposed as an improved catalyst for ethylene epoxidation, forms a thin Cu-O surface oxide, while a Ag-Cu surface alloy is found not to be stable. Several possible surface structures are identified, among which the catalyst surface is likely to dynamically evolve under reaction conditions.

Piccinin, Simone [School of Physics, University of Sydney, Sydney, New South Wales 2006 (Australia); CNR-INFM DEMOCRITOS National Simulation Center, Theory-Elettra Group, Trieste (Italy); Zafeiratos, Spiros [Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin (Germany); LMSPC-UMR 7515 du CNRS, Strasbourg (France); Stampfl, Catherine [School of Physics, University of Sydney, Sydney, New South Wales 2006 (Australia); Hansen, Thomas W.; Haevecker, Michael; Teschner, Detre; Girgsdies, Frank; Knop-Gericke, Axel; Schloegl, Robert; Scheffler, Matthias [Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin (Germany); Bukhtiyarov, Valerii I. [Boreskov Institute of Catalysis, SB RAS, Novosibirsk 630090 (Russian Federation)

2010-01-22

277

Novel PdAgCu ternary alloy: Hydrogen permeation and surface properties  

NASA Astrophysics Data System (ADS)

Dense PdAgCu ternary alloy composite membranes were synthesized by the sequential electroless plating of Pd, Ag and Cu on top of both disk and tubular porous stainless steel substrates. X-ray diffraction and scanning electron microscopy were employed to study the structure and morphology of the tested samples. The hydrogen permeation performance of these membranes was investigated over a 350-450 C temperature range and a trans-membrane pressure up to 100 kPa. After annealing at 500 C in hydrogen stream followed by permeation experiments, the alloy layer presented a FCC crystalline phase with a bulk concentration of 68% Pd, 7% Ag and 25% Cu as revealed by EDS. The PdAgCu tubular membrane was found to be stable during more than 300 h on hydrogen stream. The permeabilities of the PdAgCu ternary alloy samples were higher than the permeabilities of the PdCu alloy membranes with a FCC phase. The co-segregation of silver and copper to the membrane surface was observed after hydrogen permeation experiments at high temperature as determined by XPS.

Tarditi, Ana M.; Braun, Fernando; Cornaglia, Laura M.

2011-05-01

278

Mechanical strength of thermally aged Sn3.5Ag\\/NiP solder joints  

Microsoft Academic Search

This work presents an investigation on the influence of the solder\\/under bump metallization (UBM) interfacial reaction to\\u000a the tensile strength and fracture behavior of Sn-3.5Ag\\/Ni-P solder joints under different thermal aging conditions. The tensile\\u000a strength of Sn-3.5Ag\\/Ni-P solder joints decreases with aging temperature and duration. Four types of failure modes have been\\u000a identified. The failure modes shift from the bulk

Min He; Zhong Chen; Guojun Qi

2005-01-01

279

Theoretical study of LaOXS X=Cu, Ag layered oxide sulphides  

NASA Astrophysics Data System (ADS)

The ternary oxides, owing to the mismatch between the energy levels of the transition metal d-orbitals and the deep oxygen p-orbitals, typically show a limited dispersivity of the valence band maxima (VBM) and relatively heavy masses that make them not favorable in applications as p-type transparent conducting oxides (TCOs). In a hope to increase the p-d hybridization and preserve large band gaps in oxides with the addition of sulphur atoms, we studied the reported layered quarternary oxysulphides (LaCuOS, LaAgOS) using density functional theory with G0W0 self energy corrections. We confirmed that the VBM is mainly contributed by the antibonding state of Cu/Ag-d and S-p and the hole effective mass increases upon Cu substitution by Ag, which has a deeper d level than the Cu d one.

Lam, Kanber; Trimarchi, Giancarlo; Freeman, Arthur J.

2013-03-01

280

Formation of CuCl and AgCl nanoclusters by sequential implantation  

NASA Astrophysics Data System (ADS)

Copper chloride (CuCl) and silver chloride (AgCl) nanoclusters are successfully formed by sequential implantation. Chlorine ions were firstly implanted into Al2O3 substrates to doses of the order 1017/cm2, and copper or silver ions were implanted subsequently. The energies of Cl+ (140 keV), Cu+ (240 keV) and Ag+ (360 keV) ions were chosen to produce overlapping concentration profiles in the matrix. It was found that CuCl and AgCl crystallites with 7-35 nm in diameter were formed without any thermal treatments subsequent to ion implantation. The optical absorption measurement reveals confinement of excitons in the CuCl nanoclusters.

Takahiro, Katsumi; Kawatsura, Kiyoshi; Nagata, Shinji; Yamamoto, Shunya; Naramoto, Hiroshi; Sasase, Masato; Ito, Yoshifumi

2003-05-01

281

Phase Relations in the LaNi/sub 5-x/Cu/sub x/, LaNi/sub x/ and Related Systems.  

National Technical Information Service (NTIS)

The Ni in LaNi sub 5 can be partially replaced by other elements. Limits of solid solubility were determined in the La(Mn,Ni) sub 5 , La(Fe,Ni) sub 5 , La(Ni,Al) sub 5 and La(Ni,Cu) sub 5 systems. Sections of the quaternary La(Mn,Ni,Al) sub 5 , La(Ni,Cu,A...

A. E. Dwight

1977-01-01

282

Cu cap layer on Ni8/Cu(001): reorientation and TC-shift  

NASA Astrophysics Data System (ADS)

Adding a non-magnetic Cu overlayer on Ni8/Cu(001) is known to induce the reorientation of the magnetic easy axis from in-plane to out-of-plane and to reduce the Curie temperature. In this paper both effects are described on the same footing using an effective Heisenberg trilayer. The model takes into account thermal fluctuations of the magnetization and allows to separate explicitly between two possible mechanisms behind the experimental observations, namely between a reduction of the magnetic moment by hybridization and a lattice relaxation at the Ni/Cu interface. Ferromagnetic resonance data for the reorientation and the decreased Curie temperature due to the Cu cap layer are best reproduced by assuming a reduction of the magnetic moment at the interface by ?1/3.

Krmann, F.; Kienert, J.; Schwieger, S.; Nolting, W.

2008-10-01

283

L10-ordered FeNi film grown on Cu-Ni binary buffer layer  

NASA Astrophysics Data System (ADS)

An FeNi film with a metastable L10-ordered phase was fabricated by an alternate monatomic layer deposition. An Fe monolayer and a Ni monolayer were alternately grown on a Cu0.6Ni0.4 binary buffer layer. A (001) L10-FeNi superlattice peak, which indicates the formation of a L10 phase, was clearly observed by an X-ray diffraction. A long-range order parameter S of L10-FeNi was estimated to be 0.5 0.1. It was found that the film has a uniaxial magnetic anisotropy along c-axis by magnetization measurement. The uniaxial magnetic anisotropy energy Ku was evaluated to be (5.0 0.1) 106 erg/cc.

Kojima, T.; Mizuguchi, M.; Takanashi, K.

2011-01-01

284

Comparison of partial structures of melts of superionic AgI and CuI and non-superionic AgCl.  

PubMed

Neutron and high-energy x-ray diffraction analyses of molten AgI have been performed and the partial structures are discussed in detail with the aid of the structural modelling procedure of the reverse Monte Carlo (RMC) technique by comparison with those of molten CuI and AgCl. It is well known that AgI and CuI have a superionic solid phase below the melting point, in which the cations favour a tetrahedral configuration, while solid AgCl has a rock-salt structure with an octahedral environment around both Ag and Cl atoms. Even in the molten states, there is a significant difference between superionic and non-superionic melts. The cation is located on the triangular plain formed by three iodine ions in molten AgCl and CuI, while molten AgCl favours a 90 Cl-Ag-Cl bond angle, which is understood to maintain a similar local environment to that in the solid state. The atomic configurations of the RMC model suggest that the cation distributions in superionic melts of CuI and AgI exhibit large fluctuations, while Ag ions in the non-superionic melts of AgCl are distributed much more uniformly. PMID:21694124

Kawakita, Yukinobu; Tahara, Shuta; Fujii, Hiroyuki; Kohara, Shinji; Takeda, Shin'ichi

2007-07-04

285

Dissolutive wetting of Ag on Cu : a molecular dynamics simulation study.  

SciTech Connect

Reactive wetting in the eutectic AgCu system is studied with molecular dynamics simulations. As Ag(l) spreads on the Cu surface, Cu dissolves into the liquid. The results for reactive wetting are compared to simulations in which no mixing is permitted, demonstrating that wetting kinetics are enhanced by dissolution reactions. The time dependent radius of the droplet R(t) is used to quantify kinetics for the wetting geometry of an infinitely long cylinder spreading on a substrate. Data show that, when dissolution is dominant, spreading is well described by R(t){approx}(R{sub 0}t){sup 1/2}, where R{sub 0} is the starting cylinder radius. Contact angle {theta}(t) data were calculated via a method that accounts for structure near the contact region and compared to data obtained using circular fits to the droplet profile. Significant differences were observed due to molecular scale structure that rapidly evolves near the contact line. This structure exhibits markedly lower {theta} than what is predicted from droplet profile data and it is proposed to exist throughout most stages of dissolutive wetting. Simulations of AgCu binary liquids spreading on Cu demonstrate that wetting kinetics decrease with increasing Cu in the liquid, further emphasizing that wetting kinetics are intrinsically linked to dissolution kinetics. After dissolution is complete, a Ag-rich monolayer of atoms advances diffusively across the Cu surface.

Webb, Edmund Blackburn, III; Hoyt, Jeffrey John; Grest, Gary Stephen; Heine, David R.

2004-06-01

286

Dilute Cu Alloying for Sn-Cu Bumping by Annealing Electroplated Cu\\/Sn Stacks on Ti\\/Ni\\/Pd UBM  

Microsoft Academic Search

Sn-Cu bumping has been demonstrated to employ sequential electroplating of Cu and Sn, followed by alloying the Cu\\/Sn stacks during reflow. Alloying behavior of the Cu\\/Sn stacks has been investigated with varying the underlying Cu thickness. The Cu6Sn5 based compounds were observed at the interface between a sputter deposited Ti\\/Ni\\/Pd under bump metallization and the Cu\\/Sn plated stack The underlying

H. Ezawa; K. Higuchi; M. Seto; M. Uchida; T. Togasaki

2006-01-01

287

Periplasmic domain of CusA in an Escherichia coli Cu + \\/Ag + transporter has metal binding sites  

Microsoft Academic Search

The resistance nodulation division (RND)-type efflux systems are utilized in Gram-negative bacteria to export a variety of\\u000a substrates. The CusCFBA system is the Cu+ and Ag+ efflux system in Escherichia coli, conferring resistance to lethal concentrations of Cu+ and Ag+. The periplasmic component, CusB, which is essential for the assembly of the protein complex, has Cu+ or Ag+ binding sites.

Bo-Young Yun; Yongbin Xu; Shunfu Piao; Nahee Kim; Jeong-Hyun Yoon; Hyun-Soo Cho; Kangseok Lee; Nam-Chul Ha

2010-01-01

288

Perpendicular magnetic anisotropy and structural properties of NiCu\\/Cu multilayers  

Microsoft Academic Search

Perpendicular magnetic anisotropy (PMA) was studied at low temperature (T=30 K) in dc-magnetron sputtered Ni60Cu40\\/Cu multilayers. PMA has been observed in many multilayer structures for ferromagnetic layer thicknesses less than a certain thickness t?. In general cases t? is less than a few nanometers, making such structures unsuitable for low-cost fabrication techniques. Our results show a strong perpendicular easy direction

A. Ruotolo; C. Bell; C. W. Leung; M. G. Blamire

2004-01-01

289

Giant magnetoresistance peaks in CoNiCu\\/Cu multilayers grown by electrodeposition  

Microsoft Academic Search

Giant magnetoresistance (GMR) of CoNiCu\\/Cu multilayers grown by electrodeposition was measured as a function of the copper layer thickness and effects of the order of 14% were obtained. The copper layer thickness ranged from 0.7 to 3.5 nm. Two peaks in the magnetoresistance were observed. One was centered at a copper thickness of approximately 1.0 nm and the second was

S. Z. Hua; D. S. Lashmore; L. Salamanca-Riba; W. Schwarzacher; L. J. Swartzenruber; R. D. McMichael; L. H. Bennett; R. Hart

1994-01-01

290

Transport properties and lithium insertion study in the p-type semi-conductors AgCuO2 and AgCu0.5Mn0.5O2  

NASA Astrophysics Data System (ADS)

The transport properties and lithium insertion mechanism into the first mixed valence silver-copper oxide AgCuO2 and the B-site mixed magnetic delafossite AgCu0.5Mn0.5O2 were investigated by means of four probes DC measurements combined with thermopower measurements and in situ XRD investigations. AgCuO2 and AgCu0.5Mn0.5O2 display p-type conductivity with Seebeck coefficient of Q=+2.46 and +78.83 ?V/K and conductivity values of ?=3.210-1 and 1.810-4 S/cm, respectively. The high conductivity together with the low Seebeck coefficient of AgCuO2 is explained as a result of the mixed valence state between Ag and Cu sites. The electrochemically assisted lithium insertion into AgCuO2 shows a solid solution domain between x=0 and 0.8Li+ followed by a plateau nearby 1.7 V (vs. Li+/Li) entailing the reduction of silver to silver metal accordingly to a displacement reaction. During the solid solution, a rapid structure amorphization was observed. The delafossite AgCu0.5Mn0.5O2 also exhibits Li+/Ag+ displacement reaction in a comparable potential range than AgCuO2; however, with a prior narrow solid solution domain and a less rapid amorphization process. AgCuO2 and AgCu0.5Mn0.5O2 provide a discharge gravimetric capacity of 265 and 230 mA h/g above 1.5 V (vs. Li+/Li), respectively, with no evidence of a new defined phases.

Sauvage, F.; Muoz-Rojas, D.; Poeppelmeier, K. R.; Casa-Pastor, N.

2009-02-01

291

Pd-cu2 o and ag-cu2 o hybrid concave nanomaterials for an effective synergistic catalyst.  

PubMed

Palladium and silver salts were combined with Cu2 O octadecahedra in concave heterostructures. The formation of concave faces involved selective oxidative etching of Cu2 O on the {100} faces and in situ growth of Pd/Ag on different sites. The structures showed superior catalytic activities to both single domains and their mixtures in a model Sonogashira-type organic reaction. PMID:24038721

Li, Lingling; Chen, Xiaobin; Wu, Yuen; Wang, Dingsheng; Peng, Qing; Zhou, Gang; Li, Yadong

2013-08-26

292

High-temperature internal oxidation of Ag/1.2at.% Mg and Ag/0.25at.% Mg-0.25at.% Ni.  

SciTech Connect

High-temperature oxygen diffusion and internal oxidation in Ag, Ag/1.2 at.% Mg (Ag-Mg), and Ag/0.25 at.% Mg-0.25 at.% Ni (Ag-Mg-Ni) have been studied, mostly in air and 8% O{sub 2}, at 450-835 C. The focus of the studies was on thermogravimetric analysis, microhardness tests, and optical and electron microscopy observations of grain growth and its inhibition by oxidation. The internal oxidation of both alloys exhibited nearly identical activation energies (0.81 eV for Ag-Mg and 0.83 eV for Ag-Mg-Ni) and rate constants. The maximum O content of both alloys was superstoichiometric (e.g., O/Mg > 1.0) and the maximum O/Mg ratios were higher at lower temperatures than at higher temperatures (e.g., 1.25 at 500 C and 1.05 at 800 C). Diffusion of O in pure Ag was {approx}60 times faster at 825 C and {approx}400 times faster at 500 C than internal oxidation of either of the Ag alloys. Grain growth of both alloys and of the Ag was quantified between 450-800 C and related to internal oxidation.

Balachandran, U.; Goretta, K. C.; McNallan, M. J.; Park, J.-H.; Prorok, B. C.

1999-09-08

293

Fracture of Sn-Ag-Cu Solder Joints on Cu Substrates. II: Fracture Mechanism Map  

NASA Astrophysics Data System (ADS)

A methodology to construct fracture mechanism maps for Sn-3.8%Ag-0.7%Cu (SAC387) solder joints attached to Cu substrates has been developed. The map, which delineates the operative mechanisms of fracture along with corresponding joint fracture toughness values, is plotted in a space described by two microstructure-dependent parameters, with the abscissa describing the interfacial intermetallic compound (IMC) and the ordinate representing the strain-rate-dependent solder yield strength. The plot space encompasses the three major mechanisms by which joints fail, namely (i) cohesive fracture of solder, (ii) cleavage fracture of interfacial intermetallic compounds (IMC), and (iii) fracture of the solder-IMC interface. Line contours of constant fracture toughness values, as well as constant fraction of each of the above mechanisms, are indicated on the plots. The plots are generated by experimentally quantifying the dependence of the operative fracture mechanism(s) on the two microstructure-dependent parameters (IMC geometry and solder yield strength) as functions of strain rate, reflow parameters, and post-reflow aging. Separate maps are presented for nominally mode I and equi-mixed mode loading conditions (loading angle ? = 0 and 45, respectively). The maps allow rapid assessment of the operative fracture mechanism(s) along with estimation of the expected joint fracture toughness value for a given loading condition (strain rate and loading angle) and joint microstructure without conducting actual tests, and may serve as a tool for both prediction and microstructure design.

Kumar, P.; Huang, Z.; Dutta, I.; Sidhu, R.; Renavikar, M.; Mahajan, R.

2012-02-01

294

Evaluation of thermal fatigue life and failure mechanisms of Sn-Ag-Cu solder joints with reduced Ag contents  

Microsoft Academic Search

The electronic industry is making substantial progress toward a full transition to Pb-free soldering in the near future. At present, the leading candidate Pb-free solders are near-ternary eutectic Sn-Ag-Cu alloys. The electronic industry has begun to study both the processing behaviors and the thermomechanical fatigue properties of these alloys in detail in order to understand their applicability in context of

Sung K. Kang; Paul Lauro; Da-Yuan Shih; Donald W. Henderson; Timothy Gosselin; Jay Bartelo; Steve R. Cain; Charles Goldsmith; Karl J. Puttlitz; Tae-Kyung Hwang

2004-01-01

295

Wetting and interface integrity of Sn-Ag-Bi solder/Fe-42 percent Ni alloy system  

SciTech Connect

The wetting and interfacial integrity of lead-free Sn-Ag and Sn-Ag-Bi solders with 42 alloy (Fe-42wt percent Ni) were investigated. A tin-iron intermetallic layer formed at the interface and, during cooling, Ni3Sn4 platelets precipitated in the solder. After bonding, the Sn-3Ag joints have a eutectic microstructure, with a fine network of Ag3Sn particles surrounding large primary -Sn grains. Bismuth addition to Sn-3Ag improved wettability, but decreased the joint strength, owing to Bi segregation to the interface.

Hwang, C.-W.; Suganuma, K.; Saiz, E.; Tomsia, A.P.

2002-01-15

296

Power consumption reduction scheme of magnetic microactuation using electroplated Cu-Ni nanocomposite  

NASA Astrophysics Data System (ADS)

This letter presents a power consumption reduction scheme of magnetic microactuation using Cu-Ni nanocomposite film which is electroplated in alkaline noncyanide based Ni colloidal copper plating solution at 40 C. The superconducting quantum interference device magnetometer measurements show that Cu film is modified from diamagnetism to ferromagnetism via the incorporation of Ni ferromagnetic nanoparticles into itself to form a Cu-Ni nanocomposite film. A magnetic microactuator made of the nanocomposite can have about 9% performance improvement in terms of actuation enlargement. In other words, the coil made of the Cu-Ni nanocomposite can exhibit better power efficiency for the same output displacement.

Huang, Yu Wen; Chao, Tzu-Yuan; Chen, C. C.; Cheng, Y. T.

2007-06-01

297

Preparation and optical properties of silica Ag-Cu alloy core-shell composite colloids  

SciTech Connect

The silica Ag-Cu alloy core-shell composite colloids have been successfully synthesized by an electroless plating approach to explore the possibility of modifying the plasmon resonance at the nanoshell surface by varying the metal nanoshell composition for the first time. The surface plasmon resonance of the composite colloids increases in intensity and shifts towards longer, then shorter wavelengths as the Cu/Ag ratio in the alloy shell is increased. The variations in intensity of the surface plasmon resonance with the Cu/Ag ratio obviously affect the Raman bands of the silica colloid core. The report here may supply a new technique to effectively modify the surface plasmon resonance. - Graphical abstract: The silica Ag-Cu alloy core-shell colloids have been successfully synthesized to explore the possibility of modifying the surface plasmon resonance (SPR) by varying the metal nanoshell composition for the first time. Varying the Cu/Ag ratio of the alloy nanoshell has obvious influences on the SPR of the composite colloids and the Raman bands of the amorphous silica core.

Zhang Jianhui [National Laboratory of Solid State Microstructures, Department of Physics, Nanjing University, Nanjing 210093 (China)], E-mail: zhangjh@nju.edu.cn; Liu Huaiyong [National Laboratory of Solid State Microstructures, Department of Physics, Nanjing University, Nanjing 210093 (China); Wang Zhenlin [National Laboratory of Solid State Microstructures, Department of Physics, Nanjing University, Nanjing 210093 (China); Ming Naiben [National Laboratory of Solid State Microstructures, Department of Physics, Nanjing University, Nanjing 210093 (China)

2007-04-15

298

Phase-Field Modeling and Experimental Observation of Microstructures in Solidifying Sn-Ag-Cu Solders  

NASA Astrophysics Data System (ADS)

A multiphase-field model coupled to a thermodynamic database has been successfully applied to model the microstructure evolution during solidification of ternary Sn-Ag-Cu solders, revealing up to five different phases. Simulations were performed in two dimensions (2D) in the bulk volume of the solder as well as at the interface with a copper substrate, addressing the length scales of both dendritic and eutectic structures. Primary dendrite spacing and secondary arm spacing of Sn dendrites in the bulk solder volume match well with experimental observations. The eutectic spacing of Ag3Sn lamellae and their thickness also match experimental data, while the thickness of the Cu6Sn5 lamellae is slightly larger than found by experiment. Nucleation and growth of Cu6Sn5 on a Cu substrate lead to superficial dissolution and roughening of the substrate, with the size of the Cu6Sn5 largely determined by its nucleation conditions.

Schmitz, G. J.; Zhou, B.; Bttger, B.; Klima, S.; Villain, J.

2013-08-01

299

On the Role of Ni in Cu Precipitation in Multicomponent Steels  

NASA Astrophysics Data System (ADS)

The nature of Cu precipitation in quench-tempered multicomponent high-strength low-alloy steels is characterized by atom probe tomography. The detected nanometer sized Ni-rich clusters act as preferential nucleation sites for Cu-rich clusters, and Ni segregation at the Cu-rich precipitate/matrix heterophase interface contribute to fast growth of Cu precipitates. Molecular dynamics simulation indicates that local Ni clustering at atomic scale significantly quickens the solute diffusion. The initial Ni composition has a profound effect on the nature of Cu precipitation.

Liu, Qingdong; Gu, Jianfeng; Liu, Wenqing

2013-10-01

300

Aging characteristics of thermomechanically processed Cu-9Ni-6Sn alloy  

SciTech Connect

Cu-Ni-Sn alloys have gathered a considerable amount of interests over the past 20 years, since the strength level of Cu-Ni-Sn alloys with a proper thermomechanical processing equals to those obtained by high-strength, precipitation-hardened Cu-Be alloys. In the present study, aging characteristics of heavily swaged Cu-9Ni-6Sn alloy, the composition of which is known to have the best combination of mechanical and physical properties, were examined. The hardening behaviors of cu-9Ni-6Sn alloys, either solutionized and aged or directly aged, are discussed with SEM fractographic studies and TEM micrographic observations.

Kim, S.S.; Rhu, J.C. [Gyeongsang National Univ., Chinju (Korea, Republic of). Div. of Materials Science and Engineering; Jung, Y.C.; Han, S.Z.; Kim, C.J. [Korea Inst. of Machinery and Materials, Changwon (Korea, Republic of). Materials Engineering Dept.

1998-12-04

301

Magnetostructural transition in NiCuCoMnGa alloys  

NASA Astrophysics Data System (ADS)

The effects of the addition of Co on the martensitic transformation and Curie transition temperatures of polycrystalline Ni46?xCu4CoxMn33.5Ga16.5 (x = 0, 1, 3, 5) alloys are investigated. An abrupt decrease in the martensitic transformation temperature and an obvious increase in the Curie transition temperature of austenite (TCA) are observed when Co is doped in the NiCuMnGa alloy. As a result, the composition range for obtaining the magnetostructural transition is extended. Furthermore, the effect of a strong magnetic field on the magnetostructural transition is analyzed. This study offers a possible method to extend the composition range for obtaining magnetostructural transition in Heusler alloys.

Li, Pan-Pan; Wang, Jing-Min; Jiang, Cheng-Bao

2013-08-01

302

Reduction of charge fluctuation energies in ultrathin NiO films on Ag(001)  

NASA Astrophysics Data System (ADS)

As the film becomes atomically thin, the on-site Coulomb interaction energy between two 3p holes of the NiO films on Ag(001) U (Ni 3p) significantly decreases as revealed by both X-ray photoelectron and Auger electron spectroscopies. The reduction of U (Ni 3p) for the ultrathin films is well accounted for by varied image potentials and polarization energies in the films from their bulk values. The present results confirm a previous model predicting the reduction of charge fluctuation energies in ultrathin oxide films on highly polarizable substrates due to the extra-atomic relaxations.

Yang, Seolun; Park, H.-K.; Kim, J.-S.; Phark, S.-H.; Chang, Young Jun; Noh, T. W.; Hwang, H.-N.; Hwang, C.-C.; Kim, H.-D.

2013-10-01

303

Rapid dechlorination of chlorophenols in aqueous solution by [Ni|Cu] microcell.  

PubMed

The [Ni|Cu] microcell was prepared by mixing the Ni(0) and Cu(0) particles. The composition and crystal form were characterized by X-ray diffraction (XRD) and scanning electron microscope. The results evidenced the zero-valence metals Ni and Cu were exposed on the surface of particles mixture. The [Ni|Cu] microcell was employed to decompose chlorophenols in aqueous solution by reductive dechlorination. The dechlorination rates of chlorophenols by [Ni|Cu] were >10 times faster than those by [Fe|Cu], [Zn|Cu], [Sn|Cu], and [Fe|Ni] mixtures under the same conditions. [Ni|Cu] is different from other zero valent metals (ZVMs) in that it performed the best at neutral pH. The main products of chlorophenol dechlorination were cyclohexanol and cyclohexanone. The reduction kinetics was between pseudo zero-order and first-order, depending on the pH, concentration, and temperature. These results, combined with electrochemical analysis, suggested that Ni(0) acted as a reductant and catalyst in dechlorination reaction. The H* corridor mechanism from Ni(0) to Cu(0) was also proposed based on hydrogen spillover. The inhibition on the release of Ni(2+) by adding natural organic matters and adjusting pH was investigated. PMID:22305601

Yin, Lifeng; Dai, Yunrong; Niu, Junfeng; Bao, Yueping; Shen, Zhenyao

2012-01-23

304

Giant magnetoresistance in spinodally decomposed CuNiFe films  

Microsoft Academic Search

We report the observation of the GMR effect in spinodally decomposed Cu20Ni20Fe thin films. A ?R\\/R value as high as 6.5% was observed at room temperature. In contrast to the commonly observed temperature-dependent behavior of ?R\\/R increasing at low temperature; thin film shows a decrease in ?R\\/R at 4.2 K. The dependence of the GMR effect on various deposition parameters,

L. H. Chen; S. Jin; T. H. Tiefel; T. C. Wu

1994-01-01

305

Wear resistance of CuNiMo austempered ductile iron  

Microsoft Academic Search

A series of ductile iron samples alloyed with 0.66% Cu, 1.02% Ni, and 0.26% Mo were austempered at 315 and 370C for 5240min and then tested for wear strength. A block-on-ring wear testing machine was used for this purpose. The wear samples were tested under a load of 45N and a displacement speed of 2.40m\\/s. The experimental outcome indicates that

M. J. Prez; M. M. Cisneros; H. F. Lpez

2006-01-01

306

Preparation and Structure of FeNi nanoparticles coated with Ag and its Microwave-Absorption Properties  

Microsoft Academic Search

Microwave-absorption materials that have a good magnetic permeability and electrical conductivity are attracting more attentions in the EMI shielding field. This manuscript reported a kind of microwave-absorption FeNi@Ag nanoparticles fabricated through silver mirror reaction, i.e. silver was coated onto the surface of FeNi nanoparticles. The results showed that monodisperse spherical FeNi@Ag nanoparticles had been successfully prepared and exhibited ferromagnetic behavior

Shaofeng Zhou; Qiaoxin Zhang; Jingsong Zhou; Guojin Shen; Jin Huang

2012-01-01

307

Effect of a Pd sacrifice layer on the interfacial reaction in Sn-3.5Ag/Pd/Cu  

NASA Astrophysics Data System (ADS)

The effect of a Pd layer on the interfacial reaction in Sn-3.5Ag/Pd/Cu was studied by varying the thickness of the Pd layer. The formation of PdSn4, (Pd1- x Cu x )Sn4, and (Cu1- y Pd y )6Sn5 intermetallic compounds (IMCs), along with CuSn IMCs, was observed. The Sn-3.5Ag/Pd/Cu structure did not suppress the growth of the (Cu1- y Pd y )6Sn5 IMCs, but the growth of Cu3Sn IMCs was inhibited by the presence of a 200- to 600-nm-thick Pd layer.

Na, Seong-Hun; Kim, Jin-Soo; Lim, Seung-Kyu; Suh, Su-Jeong

2012-10-01

308

Magnetization-orientation dependence of the superconducting transition temperature in the ferromagnet-superconductor-ferromagnet system: CuNi/Nb/CuNi.  

PubMed

The superconducting critical temperature (T(c)) of ferromagnet-superconductor-ferromagnet systems has been predicted to exhibit a dependence on the magnetization orientation of the ferromagnetic layers such that T(AP)(c)>T(P)(c) for parallel (P) and antiparallel (AP) configurations of the two ferromagnetic layers. We have grown CuNi/Nb/CuNi films via magnetron sputtering and confirmed the theoretical prediction by measuring the resistance of the system as a function of temperature and magnetic field. We find an approximately 25% resistance drop occurs near T(c) in Cu0.47Ni0.53(5 nm)/Nb(18)/CuNi(5) when the two CuNi layers change their magnetization directions from parallel to antiparallel, whereas there is no corresponding resistance change in the normal state. PMID:12484851

Gu, J Y; You, C-Y; Jiang, J S; Pearson, J; Bazaliy, Ya B; Bader, S D

2002-12-09

309

Industrial Cu-Ni alloys for HTS coated conductor tape  

NASA Astrophysics Data System (ADS)

Copper rich Cu-Ni alloys have been textured with the RABiTS method in order to get non-magnetic and cost efficient substrates for coated conductor wires. The study is focused on two industrial compositions: Cu55Ni45 (Constantan) and Cu70Ni30. Studies on surface roughness have been done. The effects of annealing conditions (temperature and atmosphere) on the grain boundaries deepness were analyzed. Electrolytic polishing was also applied to improve the surface quality. RX pole figures and micro hardness measurements have been achieved on samples annealed up to 950C. Attention has been paid to the rolling texture and to the annealing processes. The rolling texture has been found to be mainly copper-type (C, S and B contributions). Beginning of recrystallization occurred between 400C and 600C and stabilized between 900C to 950C, depending on the nickel content of the alloy. Finally both samples, rolled and annealed under the appropriate conditions, have been characterized. Pole figure measurements gave the global in plane and out of plane disorientations of our samples which are in-plane 7.4 and out-plane (RD) 4.3 for both samples. EBSD maps have shown the details of the distribution and have allowed us to quantify the ratio between cubic {100}<001> and twined {122}<21-2> orientations.

Girard, A.; Bruzek, C. E.; Jorda, J. L.; Ortega, L.; Soubeyroux, J. L.

2006-06-01

310

NiZnCu ferrite applied for LTCC microinductor  

NASA Astrophysics Data System (ADS)

This paper describes the fabrication of thin magnetic layers for an LTCC planar-type inductor with a 0.11 mm thickness. The thin ferrite layers were fabricated by tape casting method. Synthesis conditions and X-ray analysis (300 K) of the Ni0.3Zn0.62Cu0.08Fe2O4 ferrite are presented. A pure cubic, Fd 3m crystal structure was observed for the Ni0.3Zn0.62Cu0.08Fe2O4 ferrite. The complex impedance and dielectric permittivity of Ni0.3Zn0.62Cu0.08Fe2O4 ferrite were determined as a function of temperature (from -55 to 170 C) and frequency (from 10 Hz to 2 MHz). Dc resistivity was measured in a temperature range from -55 to 170 C. Magnetization and magnetic hysteresis were measured by a vibrating sample magnetometer (VSM) in an applied magnetic field up to 60 kOe. The inductance and quality factor were measured in a frequency range 0.1-120 MHz. With the help of finite elements method (FEM) simulation it is possible to calculate the elements electrical parameters and optimize the design. This paper presents a magnetic field modelling of an inductor structure.

Guzdek, P.; Kulawik, J.; Zaraska, K.; Bie?kowski, A.

2010-10-01

311

Electromigration Behavior in Sn-37Pb and Sn-3.0Ag-0.5Cu Flip-Chip Solder Joints under High Current Density  

NASA Astrophysics Data System (ADS)

The electromigration of conventional Sn-37Pb and Pb-free Sn-3.0Ag-0.5Cu (in wt.%) solder bumps was investigated with a high current density of 2.5 104 A/cm2 at 423 K using flip-chip specimens comprised of an upper Si chip and a lower bismaleimide triazine (BT) substrate. Electromigration failure of the Sn-37Pb and Sn-3.0Ag-0.5Cu solder bumps occurred with complete consumption of electroless Ni immersion Au (ENIG) underbump metallization (UBM) and void formation at the cathode side of the solder bump. Finite element analysis and computational simulations indicated high current crowding of electrons in the patterned Cu on the Si chip side, whereas the solder bumps and Cu line of the BT substrate had a relatively low density of flowing electrons. These findings were confirmed by the experimental results. The electromigration reliability of the Sn-3.0Ag-0.5Cu solder joint was superior to that of Sn-37Pb.

Ha, Sang-Su; Kim, Jong-Woong; Yoon, Jeong-Won; Ha, Sang-Ok; Jung, Seung-Boo

2009-01-01

312

Mechanism of Ag and Al on improving the glass forming ability of CuZr-based alloys  

NASA Astrophysics Data System (ADS)

By a mean field theoretical computation, the equilibrium distributions of additional Ag and Al in the crystalline phase of CuZr-based alloys were determined to occupy the two sublattices of the B2 structure randomly. With the molecular dynamics technique, the effects of Ag and Al on the enthalpy difference (? H) between the supercooled melt and the crystalline phase were evaluated. The improved glass forming ability of Cu45Zr45Al10 and Cu45Zr45Ag10 can be attributed to their remarkably smaller ? H than that of CuZr. The calculated diffusion coefficients are more sensitive to the atomic weight of the component atoms than to their interaction strength. As the component atom with the largest mass, the additional Ag increases the viscosity of the supercooled melt significantly and the experimentally stronger glass formation ability of Cu45Zr45Ag10 than Cu45Zr45Al10 can be well understood.

Ni, Xiao-Dong; Wang, Zheng; Sun, Xiang; Shen, Jiang; Chen, Nan-Xian

2011-08-01

313

Effects of Cu contents in Pb-free solder alloys on interfacial reactions and bump reliability of Pb-free solder bumps on electroless NiP under-bump metallurgy  

Microsoft Academic Search

Using the screen-printed solder-bumping technique on the electroless plated Ni-P under-bump metallurgy (UBM) is potentially\\u000a a good method because of cost effectiveness. As SnAgCu Pb-free solders become popular, demands for understanding of interfacial\\u000a reactions between electroless Ni-P UBMs and Cu-containing Pb-free solder bumps are increasing. It was found that typical Ni-Sn\\u000a reactions between the electroless Ni-P UBM and Sn-based solders

Young-Doo Jeon; Kyung-Wook Paik; Adreas Ostmann; Herbert Reichl

2005-01-01

314

Improvement on the microstructure stability, mechanical and wetting properties of SnAgCu lead-free solder with the addition of rare earth elements  

Microsoft Academic Search

Ternary lead-free solder alloys SnAgCu were considered as the potential alternatives to leadtin alloys comparing with other solders. In this paper, microstructure and mechanical properties of Sn2.5Ag0.7Cu, Sn3.5Ag0.7Cu, Sn3.5Ag0.7Cu0.1RE, and Sn3.5Ag0.7Cu0.25RE alloys were researched. Coarse ?-Sn grains were formed in Sn2.5Ag0.7Cu and Sn3.5Ag0.7Cu alloys and bulky Ag3Sn intermetallics were found in Sn3.5Ag0.7Cu alloy. With the addition of trace rare earth

D. Q Yu; J Zhao; L Wang

2004-01-01

315

Perpendicular magnetic anisotropy and structural properties of NiCu/Cu multilayers  

NASA Astrophysics Data System (ADS)

Perpendicular magnetic anisotropy (PMA) was studied at low temperature (T=30 K) in dc-magnetron sputtered Ni60Cu40/Cu multilayers. PMA has been observed in many multilayer structures for ferromagnetic layer thicknesses less than a certain thickness t?. In general cases t? is less than a few nanometers, making such structures unsuitable for low-cost fabrication techniques. Our results show a strong perpendicular easy direction of magnetization for NiCu layer thickness between 4.2 nm and 34 nm. The thickness t? at which the multilayers change the preferential orientation from perpendicular to in-plane is estimated to be 55 nm. Structural studies show that the low magnetostatic energy density is likely to be the main reason for the large t? value obtained in this system.

Ruotolo, A.; Bell, C.; Leung, C. W.; Blamire, M. G.

2004-07-01

316

Compression StressStrain Behavior of Sn-Ag-Cu Solders  

Microsoft Academic Search

New Pb-free alloys that are variations of the Sn-Ag-Cu (SAC) ternary system, having reduced Ag content, are being developed\\u000a to address the poor shock load survivability of current SAC305, SAC396, and SAC405 compositions. However, the thermal mechanical\\u000a fatigue properties must be determined for the new alloys in order to develop constitutive models for predicting solder joint\\u000a fatigue. A long-term study

Edwin P. Lopez; Paul T. Vianco; Jerome A. Rejent; Carly George; Alice Kilgo

2010-01-01

317

Microwave-absorbing characteristics of epoxy resin composites containing nanoparticles of NiZn- and NiCuZn-ferrites  

NASA Astrophysics Data System (ADS)

NiZn- and NiCuZn-ferrite nanoparticles (50-70 nm) with the chemical formula Ni0.5 Zn0.5Fe2O4 (NiZn) and Ni0.35Cu0.15Zn0.5Fe2O4 (NiCuZn) were synthesized by a combustion synthesis method. The nanocrystallite of these materials was characterized by structural and magnetic methods. Saturation magnetization increases from 83 emu/g (NiZn) to 91 emu/g (NiCuZn). Magnetic permeability and dielectric permittivity were measured on sintered samples (pellets and toroids) in the frequency range of 1 MHz-1.8 GHz. Reflection losses (RL) for both samples were calculated from complex permeability and permittivity. Cu substitution in NiZn-ferrite enhances permeability and RL. In order to explore microwave-absorbing properties in X-band, magnetic nanoparticles were mixed with an epoxy resin to be converted into a microwave-absorbing composite and microwave behaviors of both materials were studied using a microwave vector network analyzer from 7.5 to 13.5 GHz. Cu substitution diminishes absorption intensity in the range 11.5-12.5 GHz.

Aphesteguy, J. C.; Damiani, Abel; Digiovanni, Dalmas; Jacobo, S. E.

2009-10-01

318

Diffusion bonding of electroless Ni plated WC composite to Cu and AISI 316 stainless steel  

Microsoft Academic Search

In this study, a composite containing WC (Tungsten Carbide) and Ni was produced by two different processing routes. Electroless\\u000a Ni coated WC powders were consolidated and sintered at 1200 C. Diffusion bonding couples of WC(Ni)-electrolytic Cu, WC(Ni)-AISI\\u000a 316 stainless steel and WC(Ni)-WC(Ni) were manufactured by using a preloaded compression system under Ar atmosphere. Diffusion\\u000a bonding was carried out at varying

Ahmet Ynetken; Mehmet akmakkaya; Ayhan Erol; ?kr Tala?

2011-01-01

319

Synthesis of Ni-Cu Nanoparticles by Pulsed Wire Discharge and their Compositional Distribution  

NASA Astrophysics Data System (ADS)

Ni-Cu nanopowders were successfully synthesized from Cu and Ni wires using pulsed wire discharge. The powders were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDS). XRD confirmed that the nanopowder produced from Ni and Cu stranded wire was of Ni-Cu alloy. The composition of the nanopowders was controlled by varying the ratio of Ni to Cu wire diameter. TEM showed that the size of the prepared particles was less than 100 nm. EDS results revealed that the compositions of single nanoparticles in the nanopowder were different from each other. The composition distribution indicated that most compositions of nanoparticles agreed with that of the stranded wire. Submicron-sized particles consisting of Ni- or Cu-rich compositions were also found in the sample.

Suwa, Koji; Nakayama, Tadachika; Suzuki, Tsuneo; Suematsu, Hisayuki; Jiang, Weihua; Niihara, Koichi

2008-01-01

320

Nearly Constant Electrical Resistance over Large Temperature Range in Cu3NMx (M = Cu, Ag, Au) Compounds  

PubMed Central

Electrical resistance is a material property that usually varies enormously with temperature. Constant electrical resistivity over large temperature range has been rarely measured in a single solid. Here we report the growth of Cu3NMx (M = Cu, Ag, Au) compound films by magnetron sputtering, aiming at obtaining single solids of nearly constant electrical resistance in some temperature ranges. The increasing interstitial doping of cubic Cu3N lattice by extra metal atoms induces the semiconductor-to-metal transition in all the three systems. Nearly constant electrical resistance over 200?K, from room temperature downward, was measured in some semimetallic Cu3NMx samples, resulting from opposite temperature dependence of carrier density and carrier mobility, as revealed by Hall measurement. Cu3NAgx samples have the best performance with regard to the range of both temperature and doping level wherein a nearly constant electrical resistance can be realized. This work can inspire the search of other materials of such a quality.

Lu, Nianpeng; Ji, Ailing; Cao, Zexian

2013-01-01

321

Thermal cycling aging effects on SnAgCu solder joint microstructure, IMC and strength  

Microsoft Academic Search

Thermal cycling aging studies on a lead-free 95.5Sn3.8Ag0.7Cu solder joint were investigated. Soldered lap joint specimens were fabricated by a solder reflow process using a 95.5Sn3.8Ag0.7Cu solder sphere, no-clean flux on FR4 substrate parts. Characterization of the solder joint microstructure, intermetallic compound (IMC) and shear strength was conducted. Studies on the effects of thermal aging on IMC thickness and residual

John H. L. Pang; T. H. Low; B. S. Xiong; Xu Luhua; C. C. Neo

2004-01-01

322

Cluster reaction of [Ag8]?/[Cu8]? with chlorine: Evidence for the harpoon mechanism?  

NASA Astrophysics Data System (ADS)

To examine the question whether the harpoon mechanism can account for the reactive behavior of microscopic charged systems, we have investigated the reactivity of coinage metal clusters in gas phase. Our studies reveal that the reactivity between [Cu8]?/[Ag8]? and chlorine gas is consistent with the harpoon mechanism. An increased reactive cross section is noted through our theoretical estimation based on two methods, ascribed to a long-range transfer of valence electrons from the [Cu8]?/[Ag8]? cluster to chlorine. Insights into this reactivity will be of interest to other researchers working on obtaining a better understanding of the reaction mechanisms of such superatomic species.

Luo, Zhixun; Berkdemir, Cneyt; Smith, Jordan C.; Castleman, A. W.

2013-09-01

323

Degenerated mixed cation effect in CuIAgIAs 2Se 3 glasses: 64Cu and 110Ag tracer diffusion studies  

Microsoft Academic Search

In contrast to the usual behaviour of mixed cation glasses (large deviations from additivity with a pronounced minimum at the conductivity isotherms and a diffusivity crossover when guest cations reduce the mobility of ions coming from the host material), the CuIAgIAs2Se3 glassy system exhibits remarkable differences in the transport properties. First, the ionic conductivity increases monotonically by four orders of

A Bolotov; E Bychkov; Yu Gavrilov; Yu Grushko; A Pradel; M Ribes; V Tsegelnik; Yu Vlasov

1998-01-01

324

Coupling a proton and a neutron to the semidoubly magic nucleus 68 Ni : A study of 70 Cu via the beta decay of 70 Ni and 70 Cu  

Microsoft Academic Search

The 70 Ni nucleus has been produced at the LISOL facility and its beta decay to 70 Cu has been observed. In parallel, the 70 Cu nucleus has been produced at the ISOLDE facility. A new third beta -decaying isomeric state in 70 Cu has been identified, partly with the aid of the in-source laser spectroscopy method. Its measured half-life

J. van Roosbroeck; H. de Witte; M. Gorska; M. Huyse; K. Kruglov; K. van de Vel; P. van Duppen; S. Franchoo; J. Cederkall; V. N. Fedoseyev; H. Fynbo; U. Georg; O. Jonsson; U. Kster; L. Weissman; W. F. Mueller; V. I. Mishin; D. Fedorov; W. B. Walters; N. A. Smirnova; A. van Dyck; A. de Maesschalck; K. Heyde

2004-01-01

325

Relationships between mechanical strength and electrical conductivity for Cu Ag filamentary microcomposites  

NASA Astrophysics Data System (ADS)

Cu Ag filamentary microcomposites with various Ag contents, alloying additions and ingot annealing processes were prepared by vacuum casting and cold drawing. The strength and conductivity were measured at different drawing strain degrees. High conductivity tends to connect to low strength for the microcomposites with different Ag content, alloying addition and annealing process. Increasing Ag concentration, adding constituents Zr and Cr, or using low ingot annealing temperature can improve the strength but impair the conductivity. Alloying additions or ingot annealing processes affect the relationships between the strength and conductivity more significantly than that of Ag concentration. The strengthening benefit is mainly from interface obstacle and dispersive precipitation while conducting loss is mainly from lattice distortion and interface scattering. An approximate expression to predict the relationships between the strength and conductivity is deduced from the interface strengthening and scattering model.

Liu, J. B.; Zhang, L.; Meng, L.

2007-03-01

326

Room temperature solid-state transformation from Ag{sub 2}Cu{sub 2}O{sub 3} to Ag{sub 2}Cu{sub 2}O{sub 4} by ozone oxidation  

SciTech Connect

The mixed silver-copper oxide, Ag{sub 2}Cu{sub 2}O{sub 4} has been previously synthesized by electrochemical oxidation of suspensions of the precursor Ag{sub 2}Cu{sub 2}O{sub 3} and also by direct oxidation/coprecipitation of soluble salts. This work shows how the transformation from Ag{sub 2}Cu{sub 2}O{sub 3} to Ag{sub 2}Cu{sub 2}O{sub 4} can take place in solid state at room temperature by ozonization of the precursor. The final phase is overstoichiometric in oxygen but shows the same structural features of the firstly described phase Ag{sub 2}Cu{sub 2}O{sub 4}. The maximum content of oxygen achieved is 4.34 per unit formula.

Munoz-Rojas, D. [Institut de Ciencia de Materials (CSIC), Campus UAB, Bellaterra 08193 (Spain); Fraxedas, J. [Institut de Ciencia de Materials (CSIC), Campus UAB, Bellaterra 08193 (Spain); Gomez-Romero, P. [Institut de Ciencia de Materials (CSIC), Campus UAB, Bellaterra 08193 (Spain); Casan-Pastor, N. [Institut de Ciencia de Materials (CSIC), Campus UAB, Bellaterra 08193 (Spain)]. E-mail: nieves@icmab.es

2005-01-15

327

Giant Magnetoresistance In Ni/Cu Multilayers Fabricated By Electron-Beam Evaporation  

NASA Astrophysics Data System (ADS)

Electron beam evaporation technique has been used to deposit the multilayers of Ni-Cu, represented by Si[BLt/[Ni(tFM)/Cu(tNM)]n] where Si is used as a substrate and BL is buffer layer, n is the number of bilayers, t, tFM and tNM are thicknesses of buffer layer, ferromagnetic (Ni) and nonmagnetic (Cu) layers, respectively. We characterize the multilayers using M-H curves, magnetoresistance measurement (at room temperature).

Vikram, V.; Rahman, Md. Rizwanur; Katiyar, Monica

2008-04-01

328

Elastic Property Dependence on Layer Periodicity in Cu\\/Ni Superlattices  

Microsoft Academic Search

Cu\\/Ni superlattices are prepared by magnetron sputter deposition and structurally characterized with X-ray diffraction measurement. A 1.2 4.5 nm range of layer pair spacings is produced in a series of 1 2-m-thick films which have a [111] textured growth. Uniaxial tensile testing is used to produce load-displacement curves from free-standing Cu\\/Ni films and calibration standards of Cu and Ni films.

Alan F. Jankowski; Edward M. Sedillo; Jeffrey P. Hayes

1994-01-01

329

Preparation of homogeneous Mn-X-Bi (X=Cu, Ni) thin films by rf sputtering  

Microsoft Academic Search

The conditions (annealing temperature and chemical composition) for preparing Mn-X-Bi (X=Cu, Ni) thin films with good homogeneity have been investigated. The films were made by annealing two-layered films of Mn-Cu (or Mn-Ni) and Bi deposited by rf sputtering. The annealing temperature to crystallize the Mn-Cu-Bi(Mn-Ni-Bi) films was above 245 C (?195 C). The optimum compositions for getting good homogeneity of

Manabu Gomi; Makoto Kajima; Masanori Abe

1984-01-01

330

Experimental study and modeling of the thermodynamic properties of Cu-Fe-Ni melts  

Microsoft Academic Search

The partial mixing enthalpy of nickel in ternary liquid Cu-Fe-Ni alloys is studied at 1873 K along sections characterized by ratios x Cu: x Fe = 3, 1, and 1\\/3 at x Ni = 0-0.55. The investigations are undertaken using a high-temperature isoperibolic calorimeter. The temperature and composition dependence of the excess mixing Gibbs energy of liquid Cu-Fe-Ni alloys are

L. A. Dreval; A. R. Abdulov; P. G. Agraval; M. A. Turchanin

2010-01-01

331

Synthesis of CuNi Alloy Powder Directly from Metal Salts Solution  

Microsoft Academic Search

CuNi alloy powders were synthesized directly from metal nitrate solution. Combustion, ultrasonic mist combustion and ultrasonic pyrolysis processes were applied and CuNi alloy powder was successfully synthesized by mist combustion and ultrasonic pyrolysis of nitrate salts in a reducing atmosphere. X-ray diffraction data showed that the copper and the nickel atoms were completely mixed. For CuNi alloy powder prepared by

Choong-Hwan Jung; Hee-Gyoun Lee; Chan-Joong Kim; S. B. Bhaduri

2003-01-01

332

Annealing effect on magnetoresistance in NiO-Co-Cu based spin valves  

Microsoft Academic Search

We have fabricated two sets of NiO-Co-Cu based spin valves by the magnetosputtering technique with different deposition parameters. Magnetoresistance (MR) measurements show that the MR value for the NiO layer under the bottom of Co\\/Cu\\/Co spin valve (BSV) is larger than that for the NiO layer at the top of Co\\/Cu\\/Co (TSV). The MR value of BSV decreases with increasing

A. M. Zhang; X. S. Wu; L. Sun; Y. X. Wang; M. Lu; A. Hu; S. S. Jiang; Z. J. Chen; X. Chen; M. H. Sun; Z. H. Wu

2005-01-01

333

Holding temperature dependent variation of damping capacity in a MnCuNiFe damping alloy  

Microsoft Academic Search

A Ni-added MnCuNiFe damping alloy is observed to show a smaller damping capacity degradation than other MnCu alloys during holding at room temperature. A step-increase mode of damping capacity appears in the MnCuNiFe alloy during holding at a higher temperature above Tt=350K, the phase transformation temperature of the alloy. The critical holding time corresponding to the onset of the step-increase

Takuya Sakaguchi; Fuxing Yin

2006-01-01

334

Reflow behavior of Mo nanoparticle added Sn3.8Ag0.7 Cu solder  

Microsoft Academic Search

Summary form only given. This work investigates the reflow behavior of lead-free Sn-3.8Ag-0.7Cu solder on Cu substrate in the presence of Mo nanoparticles up to 0.1 wt%. Solders were reflowed in a reflow oven up to six times. The melting behavior of the composite solder was investigated by differential scanning calorimeter. The spreading rate and wetting angle were evaluated to

M. M. Arafat; A. S. M. A. Haseeb; M. R. Johan

2010-01-01

335

Rupture time analyses of the Sn3.5Ag solder alloys containing Cu or Bi  

Microsoft Academic Search

The creep rupture properties of Sn3.5Ag based ternary alloys with varying amounts of Cu or Bi were investigated using rolled and heat-treated bulk specimens. Nominal compositions of the third element were 0% (Base), 0.5, 0.75, 1.0 and 1.5% Cu and 2.5, 4.8, 7.5 and 10% wt% Bi, respectively. The alloys generally showed the secondary and tertiary creep characteristics only, and

Jin Yu; D. K Joo; S. W Shin

2002-01-01

336

Thermodynamic modeling of liquid Fe-Ni-Cu-Co-S mattes  

NASA Astrophysics Data System (ADS)

The modified quasichemical model for short-range ordering is described for liquid metal-sulfur solutions. Available thermodynamic data for molten Fe-S, Ni-S, Cu-S, and Co-S solutions are collected, critically evaluated, and optimized by means of the model. Very good descriptions of the thermodynamic properties are obtained with few parameters. Using only these binary parameters, the model predicts the thermodynamic properties of Fe-Ni-S, Fe-Cu-S, Ni-Cu-S, and Fe-Ni-Cu-S mattes over a wide range of composition and temperature within experimental error limits.

Kongoli, Florian; Pelton, Arthur D.; Dessureault, Yves

1998-06-01

337

Effect of Cu on Ni nanoparticles used for the generation of carbon nanotubes by catalytic cracking of methane  

Microsoft Academic Search

In this study, a simple method for the addition of Cu to unsupported nickel nanoparticles is employed to investigate the promotion effect of copper during the nickel-catalyzed decomposition of methane into carbon nanotubes. Bulk nickel and copper acetates were mixed by grinding the parent salts in a mortar, to obtain samples with selected Ni\\/Cu atomic ratios (NiCu0.03, NiCu0.07 and NiCu0.16)

Ismael Gonzlez; Juan Carlos De Jesus; Caribay Urbina de Navarro; Miguel Garca

2010-01-01

338

Interfacial reaction of Pb-Sn solder and SnAg solder with electroless Ni deposit during reflow  

Microsoft Academic Search

The interfaces between electroless Ni-P deposit and Pb-Sn solder and Sn-Ag solder were formed by reflowing for different time\\u000a periods to examine their microstructures and microchemistry. It was found that the Pb-Sn solder interface is more stable than\\u000a the Sn-Ag solder interface. Sn-Ag solder reacts quickly with the electroless Ni-P deposit and forms nonadherent Ni-Sn intermetallic\\u000a compounds (IMCs). Pb-Sn solder

M. O. Alam; Y. C. Chan; K. C. Hung

2002-01-01

339

Sensitive and selective detection of Hg2+ and Cu2+ ions by fluorescent Ag nanoclusters synthesized via a hydrothermal method  

NASA Astrophysics Data System (ADS)

An easily prepared fluorescent Ag nanoclusters (Ag NCs) probe for the sensitive and selective detection of Hg2+ and Cu2+ ions was developed here. The Ag NCs were synthesized by using polymethacrylic acid sodium salt as a template via a convenient hydrothermal process. The as-prepared fluorescent Ag NCs were monodispersed, uniform and less than 2 nm in diameter, and can be quenched in the presence of mercury (Hg2+) or copper (Cu2+) ions. Excellent linear relationships existed between the quenching degree of the Ag NCs and the concentrations of Hg2+ or Cu2+ ions in the range of 10 nM to 20 ?M or 10 nM to 30 ?M, respectively. By using ethylenediaminetetraacetate (EDTA) as the masking agent of Cu2+, Hg2+ was exclusively detected in coexistence with Cu2+ with high sensitivity (LOD = 10 nM), which also provided a reusable detection method for Cu2+. Furthermore, the different quenching phenomena caused by the two metals ions such as changes in visible colour, shifts of UV absorbance peaks and changes in size of Ag NCs make it easy to distinguish between them. Therefore the easily synthesized fluorescent Ag NCs may have great potential as Hg2+ and Cu2+ ions sensors.An easily prepared fluorescent Ag nanoclusters (Ag NCs) probe for the sensitive and selective detection of Hg2+ and Cu2+ ions was developed here. The Ag NCs were synthesized by using polymethacrylic acid sodium salt as a template via a convenient hydrothermal process. The as-prepared fluorescent Ag NCs were monodispersed, uniform and less than 2 nm in diameter, and can be quenched in the presence of mercury (Hg2+) or copper (Cu2+) ions. Excellent linear relationships existed between the quenching degree of the Ag NCs and the concentrations of Hg2+ or Cu2+ ions in the range of 10 nM to 20 ?M or 10 nM to 30 ?M, respectively. By using ethylenediaminetetraacetate (EDTA) as the masking agent of Cu2+, Hg2+ was exclusively detected in coexistence with Cu2+ with high sensitivity (LOD = 10 nM), which also provided a reusable detection method for Cu2+. Furthermore, the different quenching phenomena caused by the two metals ions such as changes in visible colour, shifts of UV absorbance peaks and changes in size of Ag NCs make it easy to distinguish between them. Therefore the easily synthesized fluorescent Ag NCs may have great potential as Hg2+ and Cu2+ ions sensors. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr03329e

Liu, Jing; Ren, Xiangling; Meng, Xianwei; Fang, Zheng; Tang, Fangqiong

2013-09-01

340

Compositional characterization of Cu-rich phase particles present in as-cast Al-Cu-Mg(-Li) alloys containing Ag  

SciTech Connect

The effects of small additions of Ag on the aging of wrought Al-Cu-Mg(-Li) alloys, involving widespread nucleation of Cu-rich {Omega} (and T{sub 1}) phase precipitates, are known. This article examines the influence of small additions of Ag on the nature of Cu-rich {theta}-Al{sub 2}Cu, S-Al{sub 2}CuMg, and T{sub 1}-Al{sub 2}CuLi phases present in appropriate as-cast Al-Cu, Al-Cu-Mg, and Al-Cu-Li-Mg alloys. Using a combination of light microscopy, scanning electron microscopy (SEM), and electron probe microanalysis (EPMA), it is shown that neither independent nor combined additions of Ag and Mg to the binary Al-Cu alloy after the composition of the {theta} phase; however, there are differences in the ways the {theta} phase is evolved in Al-Cu-Mg alloys with and without Ag. Ag additions to the Al-Cu-Mg alloy result in the formation of an Al-Cu-Mg-based ternary phase, having a Cu content similar to that of the {theta} phase and containing small amounts of Mg; rapid rates of cooling cause the retention of this phase in the as-cast alloy. Relatively large amounts of both Ag and Mg are always located in the peripheral regions of such a phase. This phase is readily replaced by {theta} phase upon annealing at 450 C. The S phase of the ternary Al-Cu-Mg system is identified in this alloy and is found to dissolve small amounts of Ag. In the case of the Al-Cu-Li-Mg-Ag alloy, two major changes are observed; both Ag and Mg are always present in relatively large amounts in the peripheral regions of the T{sub 1} phase, and the S-phase particles are once again found to dissolve small amounts of Ag. These results are discussed in light of the known compositional features of the precipitates formed in the artificially aged Al-Cu-Mg(-Li)-Ag alloys, to reveal that examination of phases present in the as-cast microstructure is a contributory step toward determining the locations of trace alloy additions in the phase precipitates of interest.

Mukhopadhyay, A.K. [Defence Metallurgical Research Lab., Hyderabad (India)

1999-07-01

341

Nature of the superionic transition in Ag+ and Cu+ halides  

Microsoft Academic Search

Silver and copper halides generally display an abrupt (first-order) transition to the superionic state. However, powder diffraction studies and molecular dynamics (MD) simulations of AgI under hydrostatic pressure both indicate that a continuous superionic transition occurs on heating. The gradual onset of the highly conducting state is accompanied by an increasing fraction of dynamic Frenkel defects, a peak in the

D. A. Keen; S. Hull; A. C. Barnes; P. Berastegui; W. A. Crichton; P. A. Madden; M. G. Tucker; M. Wilson

2003-01-01

342

Magnetic anisotropy in epitaxial Py/FeMn/Cu(001) and Py/FeMn/Ni/Cu(001) films  

NASA Astrophysics Data System (ADS)

Py/FeMn/Cu(001) and Py/FeMn/Ni/Cu(001) films were grown and studied as a function of both the FeMn and the Ni thicknesses using rotating magneto-optic Kerr effect and x-ray magnetic circular dichroism. For Py/FeMn/Cu(001), we find that the FeMn antiferromagnetic order switches the sign of the Py fourfold magnetic anisotropy but has little effect on the step-induced uniaxial magnetic anisotropy. For Py/FeMn/Ni/Cu(001), we find that out-of-plane Ni magnetization has little effect on the Py magnetic anisotropy, but in-plane Ni magnetization enhances the Py magnetic anisotropy in the region just above antiferromagnetic transition thickness. The underlying mechanism could be attributed to the FeMn 3Q spin structure.

Tan, A.; Li, J.; Jenkins, C. A.; Arenholz, E.; Scholl, A.; Hwang, C.; Qiu, Z. Q.

2013-09-01

343

Dynamic solidification mechanism of ternary Ag-Cu-Ge eutectic alloy under ultrasonic condition  

NASA Astrophysics Data System (ADS)

The dynamic solidification of ternary Ag38.5Cu33.4Ge28.1 eutectic alloy within a 35 kHz ultrasonic field is investigated and compared with both its equilibrium solidification by DSC method and its rapid solidification in drop tube. The volume fractions of the primary (Ge) phase and pseudobinary (Ag+ ? 2) eutectic solidified within ultrasonic field are larger than those formed under equilibrium state, whereas that of ternary (Ag+ ? 2+Ge) eutectic exhibits the reverse trend. During rapid solidification, the liquid alloy droplet directly solidifies into ternary (Ag+ ? 2+Ge) eutectic if its diameter is smaller than 350 ?m. The ultrasound stimulates the nucleation of alloy melt and prevents the bulk undercooling. With the increase of sound intensity, the primary (Ge) phase transfers from faceted dendrites to nonfaceted blocks with blunt edges, and its grain size is remarkably reduced. Both pseudobinary (Ag+ ? 2) and ternary (Ag+ ? 2+Ge) eutectics experience a morphological transition from regular to anomalous structures. This indicates that their cooperative growth mode is replaced by independent growth of eutectic phases under the combined effects of cavitation and acoustic streaming. The ultrasound also shows a prominent coarsening effect to the pseudobinary (Ag+ ? 2) and ternary (Ag+ ? 2 +Ge) eutectics.

Zhai, Wei; Hong, ZhenYu; Mei, CeXiang; Wang, WeiLi; Wei, BingBo

2013-02-01

344

On the discontinuous precipitation reaction and solute redistribution in a Cu-15%Ni-8%Sn alloy  

SciTech Connect

Optical and transmission electron microscopy studies have been undertaken in order to clarify some morphological aspects of the discontinuous precipitation (DP) reaction in a Cu-15Ni-8Sn (wt.%) alloy in the temperature range 800-950 K. The DP reaction proceeds in the ternary Cu-Ni-Sn system relatively fast (in binary Cu-Ni alloy is not present) with typical morphological features like change of growth direction, appearance and disappearance of solute-rich {gamma} lamellae. A fine continuous precipitation of single Ni and Sn-rich phase was also evidenced within the solute-depleted {alpha} lamellae. An energy-dispersive X-ray analysis showed the level of partitioning of the alloying elements. Most of the Ni and Sn is located in the {gamma} lamellae. However, the formula of the {gamma} lamellae is still close to (Cu{sub 3}Sn), which indicates that some Cu atoms are replaced by Ni.

Alili, B.; Bradai, D. [Houari Boumediene University of Sciences and Technology, BP 32 El-Alia, Algiers (Algeria); Zieba, P. [Houari Boumediene University of Sciences and Technology, BP 32 El-Alia, Algiers (Algeria)], E-mail: nmzieba@imim-pan.krakow.pl

2008-10-15

345

Barrierless Cu-Ni-Mo Interconnect Films with High Thermal Stability Against Silicide Formation  

NASA Astrophysics Data System (ADS)

Cu-Ni-Mo alloys were investigated to increase thermal stability against silicide formation. The alloy compositions were chosen such that an insoluble element (Mo) solute was dissolved into Cu via a third element Ni which is soluble in both Cu and Ni. Thin-film Cu-Ni-Mo alloys were prepared by magnetron sputtering. The films with Mo/Ni ratio of 1/12 exhibited low electrical resistivities in combination with high thermal stabilities against silicide formation, in support of a tentative "cluster-plus-glue-atom" model for stable solid solutions. In particular, a (Mo1/13Ni12/13)0.3Cu99.7 sample reached a minimum resistivity of 2.6 ?? cm after 400C/1 h annealing and remained highly conductive with resistivities below 3 ?? cm even after 400C/40 h annealing. These alloys are promising candidates for future interconnect materials.

Li, X. N.; Liu, L. J.; Zhang, X. Y.; Chu, J. P.; Wang, Q.; Dong, C.

2012-12-01

346

Electrochemical and histomorphometric evaluation of the TiNiCu shape memory alloy.  

PubMed

By means of electrochemical and quantitative histomorphometric methods, the corrosion resistance and tissue biocompatibility of Ti50Ni50 and Ti50Ni50-xCux (x = 1, 2, 4, 6, 8) were investigated. It is discovered that the repassivation potential of Ti50Ni50-xCux (x = 2, 4, 6, 8) alloys is about 200 mV higher than that of Ti50Ni50 alloy. Namely, the addition of Cu raises the repassivation potential of TiNi shape memory alloys and improves their corrosion resistance. Pitting potentials of Ti50Ni50 and Ti50Ni50-xCux (x = 1, 2, 4, 6, 8) alloys increase with solution pH value, but the repassivation potentials keep constant. The adding of Cu has no obvious influence on pitting potential (Epit) of TiNi alloys, meanwhile, the corrosion potential and corrosion rate of Ti50Ni50-xCux (x = 1, 2, 4, 6, 8) alloys are irrelevant to its Cu content and the values are almost the same as those of TiNi alloys. The connective tissue layer covering the plates is statistically significantly thicker for Ti50Ni42Cu8 plates (p < 0.05) than that of Ti50Ni50, Ti50Ni48Cu2, Ti50Ni44Cu6 plates after one month. The numbers of connective tissue cells, polynucleated cells, macrophages and round cells are higher for Ti50Ni42Cu8 plates than those of the other three types of plates, but no statistically significant differences are detected. There are no significant differences on tissue reaction parameters after two and three months among four alloys. After one, two and three months implantation, no corrosion is observed on the plates surfaces. A preliminary conclusion can be drawn that Ti50Ni50-xCux (x = 2, 6, 8) shape memory alloys have good biocompatibility. PMID:9171899

Wen, X; Zhang, N; Li, X; Cao, Z

1997-01-01

347

Microstructure, Melting and Wetting Properties of Pd-Ag-CuO Air Braze on Alumina  

SciTech Connect

A reactive air brazing (RAB) technique utilizing silver-copper oxide (Ag-CuO) alloys has previously been developed for joining ceramics components used in high temperature devices ranging from oxygen separation membranes, gas turbines and combustion engines. The application of the Ag-CuO system as a brazing material is limited by its solidus and liquidus temperatures, which are known to be in the range of 935 C and 967 C. Some joined ceramic components may be used in devices, which require further processing steps, or may be used in applications, that exceed these temperatures. It has been found that the addition of palladium to the silver copper oxide system will increase solidus and liquidus temperatures of the resulting alloy. In our work, we are studying the effects of palladium addition on the wetting properties of Ag-CuO braze system on alumina. Quality of brazing is evaluated through microstructural analysis and bending strength of brazed joints created with alumina. The presentation will include processing, and characterization of Ag-CuO brazed system with and without palladium addition on alumina.

Darsell, Jens T.; Hardy, John S.; Kim, Jin Yong Y.; Weil, K. Scott

2005-03-19

348

THE TWO-DIMENSIONAL VALENCE ELECTRONIC STRUCTURE OF A MONOLYAER OF Ag ON Cu(00l)  

SciTech Connect

The metal overlayer system c(10x2)Ag/Cu(001) was studied at coverages near one monolayer with angle-resolved photoemission. The observed spectroscopic features indicate a two-dimensional d-band electronic structure that can be interpreted using a model with planar, hexagonal symmetry in which crystal field effects dominate over spin-orbit effects.

Tobin, J.G.; Robey, S.W.; Shirley, D.A.

1985-05-01

349

Ablation characteristics of Au, Ag, and Cu metals using a femtosecond Ti:sapphire laser  

Microsoft Academic Search

Femtosecond laser ablation of metallic bulk crystals of Au, Ag and Cu was experimentally studied with laser pulse widths ranging from 120 fs through 800 fs at a center wavelength of 780 nm for micro-machining applications. Two different ablation regimes were found in terms of the laser fluence. The characteristic length of different ablation regimes was explained in terms of

K. Furusawa; K. Takahashi; H. Kumagai; K. Midorikawa; M. Obara

1999-01-01

350

Sm(Co, Cu, Ni) thin films with giant coercivity  

NASA Astrophysics Data System (ADS)

Nanostructured Sm(Co, Ni, Cu) thin films have been obtained by heat treating as-deposited sputtered amorphous films. The room-temperature coercivity increases from less than 100 Oe in the amorphous state to 42 kOe in a SmCo2Cu3 sample annealed 30 min at 550 C. Structural data in the optimum samples suggest a particle size around 10 mn. Magnetic viscosity measurements indicated that the switching volume is of the same order as the crystallite size. Remanence measurements showed that interparticulate interactions are magnetizing and rather independent of the crystallization stage. These data indicate that the huge coercivity enhancement is due to domain-wall pinning at high anisotropy Sm-Co precipitates.

Prados, C.; Hadjipanayis, G. C.

1999-01-01

351

Effect of the Cu capping thickness on the magnetic properties of thin Ni/Cu(001) films  

NASA Astrophysics Data System (ADS)

We have studied the effect of the Cu capping thickness (in the range 20<=tCu <=180) on the magnetic and structural properties of ultrathin FCC 40 Ni/Cu(001) films by means of magneto-optic Kerr effect (MOKE) magnetometry, polarised neutron reflection (PNR) and grazing incidence X-ray surface diffraction (GID) measurements. MOKE measurements show that perpendicular magnetic anisotropy (PMA) is observed for the whole of the Cu thickness range studied, while an increase of the coercive field with tCu is found. The variation of the in-plane strain in the Ni film is shown to increase monotonously between 20 and 90 Cu capping thickness from -1.60+/-0.03% to -1.86+/-0.07% as revealed by GID, while PNR measurements show a marked decrease in the Ni magnetic moment per atom with increasing Cu capping layer thickness, from 0.54+/-0.03?B for tCu=50 to 0.45+/-0.03?B for tCu=180. These results clearly show that a strain-induced reduction in the Ni magnetic moment per atom occurs. The increase in the coercive field is also attributed to the increase in the strain of the Ni film.

Vaz, C. A. F.; Lauhoff, G.; Bland, J. A. C.; Fulthorpe, B. D.; Hase, T. P. A.; Tanner, B. K.; Langridge, S.; Penfold, J.

2001-05-01

352

Effect of tensile misfit dislocation on diffusion of Ni adatom on Ni/Cu(111): a Molecular Dynamics study  

NASA Astrophysics Data System (ADS)

We apply molecular dynamics and molecular static methods to calculate the effect of tensile misfit dislocation on Ni adatom diffusion for Ni/Cu(111) system and compare the results with those calculated previously for Cu adatom on the Cu/Ni(111) system [1] which has compressive dislocation. Our Ni/Cu(111) substrate model system consists of 5 layers of Ni on top of a 7-layer Cu(111) slab which after energy minimization displays an isolated misfit dislocation buried at the Cu-Ni interface, causing the Ni film to be under tensile stress. In contrast to the isotropic trajectory that emerges on a defect-free surface, in this tensile stressed system we find that presence of the defect under the surface strongly affects the adatom trajectory, introducing anisotropy in atomic diffusion similar to compressive system, but with the difference: tensile misfit dislocation enhances diffusion in the direction perpendicular to the misfit dislocation line and decreases it in the direction parallel to it, whereas compressive dislocation induces the opposite behavior. We present the calculated energy barriers for the adatom and compare them with adatom diffusion on defect -- free and on the surface containing compressive dislocation. [4pt] [1] M. Aminpour, O. Trushin, and T. S. Rahman, Physical Review B, 84, 035455 (2011).

Trushin, Oleg; Aminpour, Maral; Rahman, Talat S.

2012-02-01

353

63,65Cu NQR study of Zn and Ni doped YBa 2Cu 3O 7  

Microsoft Academic Search

63,65Cu NQR measurements have been performed on Zn and Ni doped YBCO (YBa2Cu3?xMxO7, M?Zn or Ni, x=0.0 ? 0.09). Distinctive differences due to the nonmagnetic Zn and the magnetic Ni dopants substituted for copper are compared microscopically based on the plane and the chain 63,65Cu NQR data. Both spin-lattice and spin-spin relaxation rates decrease for Zn doped YBCO whereas they

K. S. Han; B. J. Mean; K. H. Lee; D. H. Kim; S. W. Seo; Moohee Lee; W. C. Lee; J. S. Cho

2000-01-01

354

Magnetic anisotropy and layer-selective magnetometry of Cu/Co/Ni/Cu/Si (0 0 1)  

NASA Astrophysics Data System (ADS)

Perpendicular magnetic anisotropy (PMA) up to 6.15+/-1.25 Co thickness is found for ferromagnetically coupled epitaxial Co/60 Ni/Cu/Si(0 0 1) structures. Polarized neutron reflection measurements on a Cu/9 Co/Ni/Cu(0 0 1) structure yield almost bulk like magnetic moments at room-temperature of 1.70+/-0.20 ?B and 0.57+/-0.05 ?B for Co and Ni, respectively. Magneto-optic Kerr effect measurements show that the uniaxial Co volume anisotropy is entirely attributed to the Co shape anisotropy due to an absence of strain in the Co film.

Lauhoff, G.; Lee, J.; Bland, J. A. C.; Langridge, S.; Penfold, J.

1999-06-01

355

Microstructure analysis of the ferromagnetic Ag-Ni system synthesized by pulsed electrodeposition  

NASA Astrophysics Data System (ADS)

Nanocrystalline silver-nickel deposits were prepared by pulsed electrolysis at different current densities from nontoxic complex electrolytes of two compositions containing silver nitrate and nickel sulphate. The structural and magnetic properties of these deposits have been analyzed in comparison with those of pure Ag and pure Ni deposited under similar conditions. The morphological and the microstructural studies have been carried out for these samples using SEM and HRTEM. The results suggest that the as deposited materials consist of Ag-Ni in the metastable alloy form. Heating the sample beyond Curie temperature leads to grain growth and long range ordering. The hysteresis curves and the magneto-thermograms reveal that the deposits exhibit room temperature ferromagnetism.

Santhi, Kalavathy; Karthick, S. N.; Kim, Hee-Je; Nidhin, Marimuthu; Narayanan, V.; Stephen, A.

2012-01-01

356

Elevated temperature fracture toughness of Al-Cu-Mg-Ag sheet: Characterization and modeling  

SciTech Connect

The plane-strain initiation fracture toughness (K{sub JlCi}) and plane-stress crack growth resistance of two Al-Cu-Mg-Ag alloy sheets are characterized as a function of temperature by a J-integral method. For AA2519 + Mg + Ag, K{sub JlCi} decreases from 32.5 MPa {radical}m at 250 C to 28.5 MPa {radical}m at 175 C, while K{sub JlCi} for a lower Cu variant increases from 34.2 MPa {radical}m at 25 C to 36.0 Mpa {radical}m at 150 C. Crack-tip damage in AA2519 + Mg + Ag evolves by nucleation and growth of voids from large undissolved Al{sub 2}Cu particles, but fracture resistance is controlled by void sheeting coalescence associated with dispersoids. Quantitative fractography, three-dimensional (3-D) reconstruction of fracture surfaces, and metallographic crack profiles indicate that void sheeting is retarded as temperature increases from 25 C to 150 C, consistent with a rising fracture resistance. Primary microvoids nucleate from smaller constituent particles in the low Cu alloy, and fracture strain increases. A strain-controlled micromechanical model accurately predicts K{sub JlCi} as a function of temperature, but includes a critical distance parameter (l*) that is not definable a priori. Nearly constant initiation toughness for AA2519 + Mg + Ag is due to rising fracture strain with temperature, which balances the effects of decreasing flow strength, work hardening, and elastic modulus on the crack-tip strain distribution. Ambient temperature toughnesses of the low Cu variant are comparable to those of AA2519 + Mg + Ag, despite increased fracture strain, because of reduced constituent spacing and l*.

Haynes, M.J.; Gangloff, R.P. [Univ. of Virginia, Charlottesville, VA (United States). Dept. of Materials Science and Engineering

1997-09-01

357

Elevated temperature fracture toughness of Al-Cu-Mg-Ag sheet: Characterization and modeling  

NASA Astrophysics Data System (ADS)

The plane-strain initiation fracture toughness ( K JICi ) and plane-stress crack growth resistance of two Al-Cu-Mg-Ag alloy sheets are characterized as a function of temperature by a J-integral method. For AA2519 +Mg+Ag, K JICi decreases from 32.5 MPa?m at 25 C to 28.5 MPa?m at 175 C, while K JICi for a lower Cu variant increases from 34.2 MPa?m at 25 C to 36.0 MPa?m at 150 C. Crack-tip damage in AA2519+Mg+Ag evolves by nucleation and growth of voids from large undissolved Al2Cu particles, but fracture resistance is controlled by void sheeting coalescence associated with dispersoids. Quantitative fractography, three-dimensional (3-D) reconstruction of fracture surfaces, and metallographic crack profiles indicate that void sheeting is retarded as temperature increases from 25 C to 150C, consistent with a rising fracture resistance. Primary microvoids nucleate from smaller constituent particles in the low Cu alloy, and fracture strain increases. A strain-controlled micromechanical model accurately predicts K JICi as a function of temperature, but includes a critical distance parameter ( l*) that is not definable a priori. Nearly constant initiation toughness for AA2519+Mg+Ag is due to rising fracture strain with temperature, which balances the effects of decreasing flow strength, work hardening, and elastic modulus on the crack-tip strain distribution. Ambient temperature toughnesses of the low Cu variant are comparable to those of AA2519+Mg+Ag, despite increased fracture strain, because of reduced constituent spacing and l*.

Haynes, Michael J.; Gangloff, Richard P.

1997-09-01

358

Microstructures and degradation of heat sink very-thin quad flat package no-leads Pb-free Sn-Ag-Cu solder joints after thermal aging  

NASA Astrophysics Data System (ADS)

Heat sink very-thin quad flat package no-leads (HVQFN) packages soldered with Sn-3.8Ag-0.7Cu on metallized laminate substrates have been put to thermal aging. Temperatures from 140C to 200C for times up to 30 weeks were applied. The solder joint microstructure develops intermetallic compound layers and voids within the solder. Due to this, the mechanical reliability of the HVQFN inner lead solder joints is degraded. The intermetallic layers are of the type (Cu, Y)6Sn5, with Y=Ni, Au or Ni+Au, as well as Cu3Sn, and follow a power law with aging time: X=Ctn, where n=0.4 to 1.9 depending on temperature. The voids within the solder are attributed to Sn depletion of the solder in favor of the growth of (Cu,Ni)6Sn5. They are more pronounced the less the solder volume is in proportion to the intermetallic diffusion area. The amount of voids is quantified as a percentage of the residual solder. The time to reach the failure criterion of 50%, i.e., t50%, is related to the absolute temperature according to an Arrhenius equation with an activation energy Ea=0.95 eV. This equation is used for determination of the maximum allowable temperature at a certain required operating lifetime.

Fredriksz, W.

2005-09-01

359

Valence and spin states in delafossite AgNiO2 and the frustrated Jahn-Teller system ANiO2 (A=Li,Na)  

NASA Astrophysics Data System (ADS)

Electronic structures of delafossite oxides AgNi1-xCoxO2 and the frustrated Jahn-Teller (JT) system ANiO2 (A=Li,Na) have been investigated by employing soft x-ray absorption spectroscopy and photoemission spectroscopy (PES). It is found that Ni ions are in the Ni2+-Ni3+ mixed-valent states and that the low-spin (LS) Ni3+ component increases from LiNiO2 to AgNiO2 and NaNiO2 , in agreement with the presence of the JT transition in NaNiO2 and the absence of the JT transition in LiNiO2 and AgNiO2 . In AgNi1-xCoxO2 , the Ni3+ component increases with x , while Co ions are in the LS Co3+ states for all x , which is consistent with the metallic nature for low values of x . A good agreement is found between the measured PES spectra and the calculated local spin density approximation (LSDA) electronic structures of AgNiO2 and AgCoO2 , but the pseudogap feature in PES of AgNiO2 is not described by the LSDA.

Kang, J.-S.; Lee, S. S.; Kim, G.; Lee, H. J.; Song, H. K.; Shin, Y. J.; Han, S. W.; Hwang, C.; Jung, M. C.; Shin, H. J.; Kim, B. H.; Kwon, S. K.; Min, B. I.

2007-11-01

360

Thermoelectric properties of molten Bi2Te3, CuI, and AgI  

NASA Astrophysics Data System (ADS)

To achieve large figure of merit (ZT) and superior thermal durability at high temperatures, we have investigated thermoelectric properties of molten Bi2Te3, CuI, and AgI up to 1173 K. Molten Bi2Te3 was found to have large electrical conductivity between 1800 and 2000 (? . cm)-1. Molten CuI and AgI, however, exhibited small electrical conductivity less than 1 (? . cm)-1, nevertheless they show very large Seebeck coefficients over 800 ?V/K. We estimated thermal conductivity using Wiedemann Franz law and the model established by Regel et al. [Phys. Status Solidi A 5, 13 (1971)]. The evaluated ZT for CuI is over 0.1.

Nishikawa, Kazutaka; Takeda, Yasuhiko; Motohiro, Tomoyoshi

2013-01-01

361

Syntheses and catalytic performances of AgNi bi-metals  

Microsoft Academic Search

AgNi bi-metal nanocrystals were prepared by a novel solution method, in which ethanol was first taken as a green solvent with no use of any external toxic reducing agents. The as-prepared bi-metal nanocrystals were spherical and constructed by an aggregation of tiny crystals with particle size of about 12nm. Infrared data indicated that the surfaces of the as-prepared nanocrystals were

Changlin Tang; Liping Li; Hongbo Gao; Guangshe Li; Xiaoqing Qiu; Jiang Liu

2009-01-01

362

Electromigration Study on Sn(Cu) Solder/Ni(P) Joint Interfaces  

NASA Astrophysics Data System (ADS)

This study investigates the electromigration (EM) effect under a high current density (104 A/cm2) on the different interfacial compound phases at Sn(Cu) solder/electroless nickel immersion gold (ENIG) interfaces. The interfacial Ni3Sn4 phase at the Sn-0.7 wt.%Cu/ENIG joint interface was quickly depleted after a short period (50 h) of current stressing. The inference drawn is that the Ni atoms in the Ni3Sn4 phase at the joint interface are likely forced out under current stressing; however, the ternary (Cu,Ni)6Sn5 compound effectively reduces the EM-driven Ni flux into the Sn bump; thus, a significantly lower Ni(P) consumption was observed at the Sn-1 wt.%Cu/ENIG interface. The EM-induced Ni(P) dissolution rates in the Sn-0.2 wt.%Cu/ENIG and Sn-1 wt.%Cu/ENIG cases were calculated to be 0.028 ?m/h and 0.018 ?m/h, respectively. In addition, significant EM-assisted Ni3P formation was observed for the current-stressed Sn-0.2 wt.%Cu/ENIG and Sn-0.7 wt.%Cu/ENIG cases; however, for the Sn-1 wt.%Cu/ENIG case, formation of a Ni3P layer was scarcely observed. Moreover, the initial (Cu,Ni)6Sn5 that formed at the interface appeared compact with a layer-type structure, which reduced the EM-driven Ni diffusion.

Wu, S. H.; Hu, Y. J.; Lu, C. T.; Huang, T. S.; Chang, Y. H.; Liu, C. Y.

2012-12-01

363

Application of Auger Electron Spectroscopy in Studies About Diffusion of Cu in Thin Ni Films.  

National Technical Information Service (NTIS)

The diffusion coefficient of Cu in thin Ni films (350A) at low temperatures is determined by using Auger electron spectroscopy and timepermeation technic. A grain-boundary mechanism is proposed for the diffusion of Cu in Ni. The activation energy is deter...

C. A. Achete W. H. P. Losch

1980-01-01

364

Selective recovery of Cu, Zn, and Ni from acid mine drainage.  

PubMed

In Korea, the heavy metal pollution from about 1,000 abandoned mines has been a serious environmental issue. Especially, the surface waters, groundwaters, and soils around mines have been contaminated by heavy metals originating from acid mine drainage (AMD) and mine tailings. So far, AMD was considered as a waste stream to be treated to prevent environmental pollutions; however, the stream contains mainly Fe and Al and valuable metals such as Ni, Zn, and Cu. In this study, Visual MINTEQ simulation was carried out to investigate the speciation of heavy metals as functions of pH and neutralizing agents. Based on the simulation, selective pH values were determined to form hydroxide or carbonate precipitates of Cu, Zn, and Ni. Experiments based on the simulation results show that the recovery yield of Zn and Cu were 91 and 94%, respectively, in a binary mixture of Cu and Zn, while 95% of Cu and 94% of Ni were recovered in a binary mixture of Cu and Ni. However, the recovery yield and purity of Zn and Ni were very low because of similar characteristics of Zn and Ni. Therefore, the mixture of Cu and Zn or Cu and Ni could be recovered by selective precipitation via pH adjustment; however, it is impossible to recover selectively Zn and Ni in the mixture of them. PMID:23754100

Park, Sang-Min; Yoo, Jong-Chan; Ji, Sang-Woo; Yang, Jung-Seok; Baek, Kitae

2013-06-11

365

Three-dimensionally ordered macroporous Cu2O/Ni inverse opal electrodes for electrochemical supercapacitors.  

PubMed

With an ordered polystyrene (PS) template-assisted electrochemical approach we synthesized three-dimensional ordered macroporous (3DOM) Cu2O/Ni inverse opals as electrodes for supercapacitors. The 3DOM Cu2O/Ni electrodes display superior kinetic performance, and satisfactory rate capability and cycling performance. PMID:23608896

Deng, Ming-Jay; Song, Cheng-Zhao; Ho, Pei-Jung; Wang, Cheng-Chia; Chen, Jin-Ming; Lu, Kueih-Tzu

2013-04-22

366

Couplings and interface effects on magnetic and electronic properties in binary Ni/Cu superlattices  

NASA Astrophysics Data System (ADS)

Self-consistent ab initio calculations, based on DFT (Density Functional Theory) approach and using FLAPW (Full potential Linear Augmented Plane Wave) method, are performed to investigate both electronic and magnetic properties of the Ni/Cu superlattices. Polarized spin and spinorbit coupling are included in calculations within the framework of the ferromagnetic state between two adjacent Ni/Cu superlattices.

Bahmad, L.; Masrour, R.; Hlil, E. K.; Hamedoun, M.; Benyoussef, A.

2013-11-01

367

Sensitive and selective detection of Hg(2+) and Cu(2+) ions by fluorescent Ag nanoclusters synthesized via a hydrothermal method.  

PubMed

An easily prepared fluorescent Ag nanoclusters (Ag NCs) probe for the sensitive and selective detection of Hg(2+) and Cu(2+) ions was developed here. The Ag NCs were synthesized by using polymethacrylic acid sodium salt as a template via a convenient hydrothermal process. The as-prepared fluorescent Ag NCs were monodispersed, uniform and less than 2 nm in diameter, and can be quenched in the presence of mercury (Hg(2+)) or copper (Cu(2+)) ions. Excellent linear relationships existed between the quenching degree of the Ag NCs and the concentrations of Hg(2+) or Cu(2+) ions in the range of 10 nM to 20 ?M or 10 nM to 30 ?M, respectively. By using ethylenediaminetetraacetate (EDTA) as the masking agent of Cu(2+), Hg(2+) was exclusively detected in coexistence with Cu(2+) with high sensitivity (LOD = 10 nM), which also provided a reusable detection method for Cu(2+). Furthermore, the different quenching phenomena caused by the two metals ions such as changes in visible colour, shifts of UV absorbance peaks and changes in size of Ag NCs make it easy to distinguish between them. Therefore the easily synthesized fluorescent Ag NCs may have great potential as Hg(2+) and Cu(2+) ions sensors. PMID:24056730

Liu, Jing; Ren, Xiangling; Meng, Xianwei; Fang, Zheng; Tang, Fangqiong

2013-09-26

368

Adaptive composites with embedded NiTiCu wires  

NASA Astrophysics Data System (ADS)

Adaptive composites have been produced by embedding prestrained shape memory alloy (SMA) wires into an epoxy matrix, reinforced with aramid fibers. These materials demonstrate attractive effects such as shape change or a shift in the vibration frequency upon activation. When heated above their transformation temperature, the wires' strain recovery is confined, and recovery stresses are generated. As a result, if the wires are placed along the neutral axis of a composite beam, a shift in resonance vibration frequency can be observed. To optimize the design of such composites, the matrix - SMA wire interfacial shear strength has been analyzed with the pull out testing technique. It is shown that the nature of the wire surface influences the interfacial shear strength, and that satisfactory results are obtained for SMA wires with a thin oxide layer. Composite samples consisting of two different types of pre- strained NiTiCu wires embedded in either pure epoxy matrix or Kevlar-epoxy matrix were produced. The recovery force and vibration response of composites were measured in a clamped-clamped configuration, to assess the effect of wire type and volume fraction. The results are highly reproducible in all cases with a narrow hysteresis loop, which makes NiTiCu wires good candidates for adaptive composites. The recovery forces increase with the volume fraction of the embedded wires, are higher when the wires are embedded in a low CTE matrix and, at a given temperature, are higher when the wire transformation temperature is lower.

Balta, J. Antonio; Michaud, Veronique; Parlinska, Magdelena; Gotthardt, Rolf; Manson, J.-A. E.

2001-07-01

369

Performance of ethanol electro-oxidation on Ni Cu alloy nanowires through composition modulation  

NASA Astrophysics Data System (ADS)

To reduce the cost of the catalyst for direct ethanol fuel cells and improve its catalytic activity, highly ordered Ni-Cu alloy nanowire arrays have been fabricated successfully by differential pulse current electro-deposition into the pores of a porous anodic alumina membrane (AAMs). The energy dispersion spectrum, scanning and transmission electron microscopy were utilized to characterize the composition and morphology of the Ni-Cu alloy nanowire arrays. The results reveal that the nanowires in the array are uniform, well isolated and parallel to each other. The catalytic activity of the nanowire electrode arrays for ethanol oxidation was tested and the binary alloy nanowire array possesses good catalytic activity for the electro-oxidation of ethanol. The performance of ethanol electro-oxidation was controlled by varying the Cu content in the Ni-Cu alloy and the Ni-Cu alloy nanowire electrode shows much better stability than the pure Ni one.

Tian, Xi-ke; Zhao, Xiao-yu; Zhang, Li-de; Yang, Chao; Pi, Zhen-bang; Zhang, Su-xin

2008-05-01

370

New cross-sections and intercomparison of proton monitor reactions on Ti, Ni and Cu  

Microsoft Academic Search

The excitation functions of proton induced reactions on Ti, Ni and Cu were studied using activation method on stacks made of thin metallic foil targets with natural isotopic composition. Since titanium, nickel and copper are ideal target material with respect to their availability, physical, mechanical and chemical properties the use of the natTi(p,x)48V, natNi(p,x)57Ni, natCu(p,x)62Zn, natCu(p,x)63Zn and natCu(p,x)65Zn processes are

S. Takcs; F. Trknyi; M. Sonck; A. Hermanne

2002-01-01

371

Effects of Cu, Ag and Sb on the creep-rupture strength of lead-free solder alloys  

Microsoft Academic Search

The materials used in the present research are pure Sn metal and Sn-0.5% Cu, Sn-3.5%Ag, Sn-0.3%Sb, and Sn-3.5%Ag-0.5%Cu alloys.\\u000a Effects of Cu, Ag and Sb on the creep-rupture strength of lead-free solder alloys have been investigated. Creep tests are\\u000a performed at the stress and temperature range of 3 to 12 MPa and 378 to 403 K, respectively. A 3.5% addition

Noboru Wade; Kepeng Wu; Johji Kunii; Seiji Yamada; Kazuya Miyahara

2001-01-01

372

Misfit dislocation network in Cu\\/Ni multilayers and its behaviors during scratching  

Microsoft Academic Search

The structure and distribution of misfit dislocations at CuNi interfaces and their effects on the tribological behavior of a Ni film are investigated with 3D Molecular Dynamic Simulations. The structure of misfit dislocation network at a CuNi interface differs according to different crystallographic orientations of the film relative to the substrate: a triangle and square type of misfit dislocation network

Dong Cheng; Zhi Jun Yan; L. Yan

2007-01-01

373

NiFe\\/INSULATOR\\/Cu Composite Wires and Their Giant Magneto-Impedance Effects  

Microsoft Academic Search

In this work, two types of electrodeposited Ni-Fe\\/insulator\\/Cu composite wires, namely Ni-Fe\\/seed layer\\/glass coated copper wire (Composite Wire A), and Ni-Fe\\/seed layer\\/sputtered SiO2\\/Cu (Composite Wire B), have been fabricated and their giant magneto-impedance effects have been investigated. With different implementations of the insulator layer, the magneto-impedance effect of Composite Wire A, whose insulator layer is cast from the melt Pyrex,

N. Ning; J. Fan; J. Wu; H. Chiriac; X. P. Li

2010-01-01

374

Giant magnetoresistance in NiFe\\/Cu multilayers formed by ion beam sputtering  

Microsoft Academic Search

In Ni-Fe\\/Cu multilayers formed by ion beam sputtering, oscillatory magnetoresistance changes with copper thickness have been observed at room temperature. As the thickness of the Ni-Fe layer increased, the magnetoresistance ratio increased, reached a maximum value at 1.0-1.1 nm, and decreased slightly above 1.1 nm. The maximum magnetoresistance ratio was 19% for the Ni-Fe (1.0 nm)\\/Cu(1.0 nm) multilayer at room

Ryoichi Nakatani; Toshiyuki Dei; Toshio Kobayashi; Yutaka Sugita

1992-01-01

375

Scale-dependent fracture mode in CuNi laminate composites  

Microsoft Academic Search

Fracture behavior of CuNi laminate composites has been investigated by tensile testing. It was found that as the individual layer thickness decreases from 100 to 20 nm, the resultant fracture angle of the CuNi laminate changes from 72 to 50. Cross-sectional observations reveal that the fracture of the Ni layers transforms from opening to shear mode as the layer thickness

X. F. Zhu; G. P. Zhang; C. Yan; S. J. Zhu; J. Sun

2010-01-01

376

The types and the formation mechanisms of AgNi contact morphology due to breaking arc erosion  

Microsoft Academic Search

By means of breaking tests on different Ni content for AgNi contact materials in a CKS contact material machine, an attempt was made to elucidate the formation mechanisms of the various surface morphologies after the arc erosion process as caused by the break arc. We first investigated the morphology of the anode and cathode surface that was eroded by a

Zheng Xinjian; Wang Qiping

1993-01-01

377

Mixed-sputter deposition of Ni-Ti-Cu shape memory films  

Microsoft Academic Search

Ni-Ti-Cu shape memory films were mixed-sputter deposited from separate nickel, titanium, and copper targets, providing increased compositional flexibility. Shape memory characteristics, examined for films with 7 at.% Cu and 4151 at.% Ti, were determined with temperature-controlled substrate-curvature measurements, and the microstructure was studied with transmission electron microscopy. The Ni-Ti-Cu films were found to have shape memory properties comparable with bulk

P. Krulevitch; P. B. Ramsey; D. M. Makowiecki; A. P. Lee; M. A. Northrup; G. C. Johnson

1996-01-01

378

Fabrication of biaxially textured Cu-Ni alloy tapes for YBCO coated conductor  

NASA Astrophysics Data System (ADS)

Nickel is well suited as a substrate material for YBa2Cu3O7-x coated conductors. However, nickel's ferromagnetism leads to AC losses when it is used in AC applications. In this paper, Cu-Ni non-magnetic tapes were made for YBa2Cu3O7-x film deposition. The biaxially textured Cu-Ni alloy tapes were formed through heavy cold rolling followed by recrystallization heat treatment. Cu-Ni alloy tapes with sharp cube texture, full width at half maximum (FWHM) less than 9 for X-ray (111) ?-scan, were obtained. The NiO(200) buffer layer was formed on Cu-Ni alloy tapes by using surface-oxidation epitaxy method. The textures of the substrate and the NiO(200) buffer layer were characterized by X-ray diffraction ?-2?-scan, ?-scan and pole figures. The surface morphology of NiO buffer layer on the Cu-Ni alloy tapes was observed by scanning electron microscope.

Shi, K.; Zhou, Y.; Meng, J.; Yang, J.; Hu, G. Y.; Gu, H. W.; Yuan, G. S.

2003-04-01

379

The effects of alloying and pressing routes in equal channel angular pressing of Cu-Fe-Cr and Cu-Fe-Cr-Ag composites  

Microsoft Academic Search

Equal channel angular pressing (ECAP) was carried out on Cu-Fe-Cr and Cu-Fe-Cr-Ag composites at room temperature. ECAPed Cu-Fe-Cr\\u000a and Cu-Fe-Cr-Ag exhibited ultrafine-grained microstructures with the shape and distribution of Fe-Cr phase were dependent\\u000a on the processing routes. In route A, the initial dendrites of Fe-Cr phase were elongated along the shear direction and developed\\u000a into filaments, whereas in route Bc

Young Chul Choi; Hyoung Seop Kim; Sun Ig Hong

2009-01-01

380

Tensile strength and creep resistance in nanocrystalline Cu, Pd and Ag  

SciTech Connect

Measurements of tensile strength and creep resistance have been made on bulk samples of nanocrystalline Cu, Pd and Ag consolidated from powders by cold compaction. Samples of Cu-Cu{sub 2}O have also been tested. Yield strength for samples with mean grains sizes of 5-80 nm and bulk densities on the order of 95% of theoretical density are increased 2--5 times over that measured in pure, annealed samples of the same composition with micrometer grain sizes. Ductility in the nanocrystalline Cu has exceeded 6% true strain, however, nanocrystalline Pd samples were much less ductile. Constant load creep tests performed at room temperature at stresses of >100 MPa indicate logarithmic creep. The mechanical properties results are interpreted to be due to grain size-related strengthening and processing flaw-related weakening. 26 refs., 2 figs.

Nieman, G.W.; Weertman, J.R. (Northwestern Univ., Evanston, IL (USA). Dept. of Materials Science and Engineering); Siegel, R.W. (Argonne National Lab., IL (USA))

1990-12-01

381

A cervelleite-like mineral and other Ag-Cu-Te-S minerals [Ag 2 CuTeS and (Ag,Cu) 2 TeS] in gold-bearing veins in metamorphic rocks of the Cycladic Blueschist Unit, Kallianou, Evia Island, Greece  

Microsoft Academic Search

A cervelleite-like mineral, two unnamed silver sulfotellurides in the system Ag-Cu-Te-S [Ag2CuTeS, (Ag,Cu)2TeS], Te-rich polybasite and cadmian tetrahedrite occur in gold-bearing quartz veins in metapelites and faults within brecciated\\u000a marbles of the Cycladic Blueschist Unit in the Kallianou area (southern Evia Island, Greece). The quartz veins and faults\\u000a are discordant to syn-metamorphic structures and formed during ductile to brittle deformation

Panagiotis Christos Voudouris; Paul G. Spry; Gregory Aarne Sakellaris; Constantinos Mavrogonatos

2011-01-01

382

Template-grown NiFe/Cu/NiFe nanowires for spin transfer devices.  

PubMed

We have developed a new reliable method combining template synthesis and nanolithography-based contacting technique to elaborate current perpendicular-to-plane giant magnetoresistance spin valve nanowires, which are very promising for the exploration of electrical spin transfer phenomena. The method allows the electrical connection of one single nanowire in a large assembly of wires embedded in anodic porous alumina supported on Si substrate with diameters and periodicities to be controllable to a large extent. Both magnetic excitations and switching phenomena driven by a spin-polarized current were clearly demonstrated in our electrodeposited NiFe/Cu/ NiFe trilayer nanowires. This novel approach promises to be of strong interest for subsequent fabrication of phase-locked arrays of spin transfer nano-oscillators with increased output power for microwave applications. PMID:17715984

Piraux, Luc; Renard, Krystel; Guillemet, Raphael; Matfi-Tempfli, Stefan; Matfi-Tempfli, Maria; Antohe, Vlad Andrei; Fusil, Stphane; Bouzehouane, Karim; Cros, Vincent

2007-08-23

383

Specific heat of dilute CuCr and AgCr alloys  

NASA Astrophysics Data System (ADS)

The impurity contribution ?C to the specific heat of dilute (c = 5, 31 and 106 ppm) CuCr alloys shows single impurity behaviour: ?C/c = f(T). The Kondo temperature TK = 2.1 K. In 340 and 1010 ppm alloys the scaling law ?C/c = f(T/c) for RKKY interactions is obeyed. In AgCr interactions are seen in an alloy with a Cr concentration of only 11 ppm. A 7 ppm alloy shows single impurity behaviour. The Kondo temperature is about 10 times smaller than for CuCr.

Impens, G.; Dupr, A.

1980-01-01

384

A viable tin-lead solder substitute: Sn-Ag-Cu  

NASA Astrophysics Data System (ADS)

Rising concern over the use of lead in industry provides a driving force for the development of improved lead-free industrial materials. Therefore, a new lead-free base solder alloy Sn-4.7Agl.7Cu (wt.%) has been developed upon which a family of lead-free solders can be based. This solder alloy exhibits a ternary eutectic reaction at 216.8 1C (L ? ? + ? + ?-Sn; ? = Cu6Sn5, ? = Ag3Sn). Preliminary tests of solderability demonstrate intermetallic phase formation on model solder joint interfaces and good wettability in a fluxed condition suggest technological viability and motivates much more extensive study of this solder alloy.

Miller, Chad M.; Anderson, Iver E.; Smith, Jack F.

1994-07-01

385

Creep rupture of lead-free Sn3.5Ag-Cu solders  

Microsoft Academic Search

Creep-rupture properties of lead-free Sn-3.5Ag-based alloys with varying amount of Cu were investigated using rolled and heat-treated\\u000a dog-bone-shaped specimens. Nominal compositions of added copper were 0 wt.%, 0.5 wt.%, 0.75 wt.%, 1.0 wt.%, and 1.5 wt.%.\\u000a During creep tests, the matrix hardness dropped significantly, and the minimum strain rates (\\u000a $$\\\\dot \\\\varepsilon _{min} $$\\u000a ) were lowest for the 0.75Cu

D. K. Joo; Jin Yu; S. W. Shin

2003-01-01

386

Constitutive Behavior of Sn3.8Ag0.7Cu and Sn1.0Ag0.5Cu Alloys at Creep and Low Strain Rate Regimes  

Microsoft Academic Search

Constitutive models for SnAgCu solder alloys are of great interest at the present. Commonly, constitutive models that have been successfully used in the past for Sn-Pb solders are used to describe the behavior of SnAgCu solder alloys. Two issues in the modeling of lead-free solders demand careful attention: 1) Lead-free solders show significantly different creep strain evolution with time, stress

Dhruv Bhate; Dennis Chan; Ganesh Subbarayan; Tz Cheng Chiu; Vikas Gupta; Darvin R. Edwards

2008-01-01

387

Effects of Dwell Time on the Fatigue Life of Sn3.8Ag0.7Cu and Sn3.0Ag0.5Cu Solder Joints During Simulated Power Cycling  

Microsoft Academic Search

Compared to Sn-Pb solder joints, our understanding of the fatigue of SnAgCu solder joints is far from complete. The challenges to achieving a complete understanding of SnAgCu solder joint fatigue arise partly from their significantly different creep behavior and vulnerability to micro structure evolution (aging). In this paper, we present results from thermal fatigue tests carried out with the help

D. Chan; D. Bhate; G. Subbarayan; D. Love; R. Sullivan

2007-01-01

388

Interfacial Reactions in Sn-Co-(Cu)/Ni Couples With/Without Current Stressing  

NASA Astrophysics Data System (ADS)

Sn-Co and Sn-Co-Cu show promise as Pb-free solders. Interfacial reactions in Sn-Co-(Cu)/Ni couples reacted at 180C and 210C, with and without current stressing, were examined. In both the Sn-0.05 wt.%Co/Ni and Sn-0.5 wt.%Co/Ni couples without current stressing, the (Ni,Co)Sn4 phase and the Ni3Sn4 phase were formed at the interface. After passing an electrical current of 500 A/cm2 through the sample, the growth rates of both the (Ni,Co)Sn4 and the Ni3Sn4 phase were enhanced at the cathode side and retarded at the anode side. With longer reaction time and current stressing, the (Ni,Co)Sn4 phase was not found along the interface at the anode side. If the presence of (Ni,Co)Sn4 phase is ignored, the results are similar to those for the Sn/Ni couples. Surprisingly, it was found that the effective charge of Co should be negative, which is different from the value found in the literature. In the Sn-0.7 wt.%Cu-0.05 wt.%Co/Ni and Sn-0.7 wt.%Cu-0.5 wt.%Co/Ni couples, the reaction product was the Cu6Sn5 phase in the early stage, and the Ni3Sn4 phase was formed after longer reaction time. After stressing with a 500 A/cm2 electrical current, growth of Cu6Sn5 was enhanced at the cathode and retarded at the anode. These results are similar to those for Sn-0.7 wt.%Cu/Ni couples. However, the growth of the Ni3Sn4 phase is retarded at the cathode side and nearly unaffected at the anode. The differences in the growth rates of Ni3Sn4 in the Sn-Co-Cu/Ni couples with 500 A/cm2 current stressing are caused by the competitive formation of Cu6Sn5, which is a secondary effect of electromigration.

Chen, Chih-ming; Hsu, Chia-ming; Chen, Sinn-wen

2012-11-01

389

Elevated Temperature Creep Properties of Conventional 50Au-50Cu and 47Au 50Cu-3Ni Braze Alloys.  

National Technical Information Service (NTIS)

The elevated temperature creep properties of the 50Au-50Cu wt% and 47Au-50Cu-3Ni braze alloys have been evaluated over the temperature range 250-850 C. At elevated temperatures, i.e., 450-850 C, both alloys were tested in the annealed condition (2 hrs. 75...

Stephens Schmale

2000-01-01

390

Transport properties and lithium insertion study in the p-type semi-conductors AgCuO{sub 2} and AgCu{sub 0.5}Mn{sub 0.5}O{sub 2}  

SciTech Connect

The transport properties and lithium insertion mechanism into the first mixed valence silver-copper oxide AgCuO{sub 2} and the B-site mixed magnetic delafossite AgCu{sub 0.5}Mn{sub 0.5}O{sub 2} were investigated by means of four probes DC measurements combined with thermopower measurements and in situ XRD investigations. AgCuO{sub 2} and AgCu{sub 0.5}Mn{sub 0.5}O{sub 2} display p-type conductivity with Seebeck coefficient of Q=+2.46 and +78.83 {mu}V/K and conductivity values of {sigma}=3.2x10{sup -1} and 1.8x10{sup -4} S/cm, respectively. The high conductivity together with the low Seebeck coefficient of AgCuO{sub 2} is explained as a result of the mixed valence state between Ag and Cu sites. The electrochemically assisted lithium insertion into AgCuO{sub 2} shows a solid solution domain between x=0 and 0.8Li{sup +} followed by a plateau nearby 1.7 V (vs. Li{sup +}/Li) entailing the reduction of silver to silver metal accordingly to a displacement reaction. During the solid solution, a rapid structure amorphization was observed. The delafossite AgCu{sub 0.5}Mn{sub 0.5}O{sub 2} also exhibits Li{sup +}/Ag{sup +} displacement reaction in a comparable potential range than AgCuO{sub 2}; however, with a prior narrow solid solution domain and a less rapid amorphization process. AgCuO{sub 2} and AgCu{sub 0.5}Mn{sub 0.5}O{sub 2} provide a discharge gravimetric capacity of 265 and 230 mA h/g above 1.5 V (vs. Li{sup +}/Li), respectively, with no evidence of a new defined phases. - Graphical abstract: Investigation on the transport properties of AgCuO{sub 2} and the new B-site mixed Delafossite AgCu{sub 0.5}Mn{sub 0.5}O{sub 2} shows a p-type conductivity of {sigma}=3.2x10{sup -1} and 1.8x10{sup -4} S/cm, respectively. The high conductivity, as a result from a high charge carrier density in AgCuO{sub 2} supports the existence of a mixed valence state between silver and copper. A particular emphasis is also placed on the electrochemical lithium insertion properties into these two materials by in situ XRD measurements to better insight on the Li{sup +} insertion mechanism and also scrutinize possible new compounds electrochemically accessible in the Li-Ag-Cu system.

Sauvage, F. [Department of Chemistry and Materials Research Center, Northwestern University, Evanston, IL 60208-3113 (United States)], E-mail: frederic.sauvage@u-picardie.fr; Munoz-Rojas, D. [Instituto de Ciencia de Materiales de Barcelona, CSIC, Campus UAB, 08193 Bellaterra, Barcelona (Spain)], E-mail: davidmunozrojas@gmail.com; Poeppelmeier, K.R. [Department of Chemistry and Materials Research Center, Northwestern University, Evanston, IL 60208-3113 (United States); Casan-Pastor, N. [Instituto de Ciencia de Materiales de Barcelona, CSIC, Campus UAB, 08193 Bellaterra, Barcelona (Spain)

2009-02-15

391

Self-organized Cu--Ag nanocomposites synthesized by intermediate temperature ion-beam mixing  

SciTech Connect

We perform an investigation of ion-beam mixing in the immiscible system Ag--Cu based on cross-sectional transmission electron microscopy. Multilayered samples consisting of ten periods of (6.7 nm Cu/11.2 nm Ag) are irradiated at temperatures ranging from 25 to 225 C with normally incident 1 MeV Kr ions to doses in the range 1--2 x 10{sup 16} ion/cm{sup 2}, enough to reach a nonequilibrium dynamical steady state. Regardless of the irradiation temperature, extensive grain growth takes place. At intermediate temperatures, competition between thermal decomposition and irradiation mixing results in a nanometer-scale phase separation. This spontaneous decomposition demonstrates that ion-beam mixing can be used as a processing tool to synthesize nanocomposite materials.

Enrique, Raul A.; Bellon, Pascal

2001-06-25

392

Self-organized Cu{endash}Ag nanocomposites synthesized by intermediate temperature ion-beam mixing  

SciTech Connect

We perform an investigation of ion-beam mixing in the immiscible system Ag{endash}Cu based on cross-sectional transmission electron microscopy. Multilayered samples consisting of ten periods of (6.7 nm Cu/11.2 nm Ag) are irradiated at temperatures ranging from 25 to 225{degree}C with normally incident 1 MeV Kr ions to doses in the range 1{endash}2{times}10{sup 16}ion/cm{sup 2}, enough to reach a nonequilibrium dynamical steady state. Regardless of the irradiation temperature, extensive grain growth takes place. At intermediate temperatures, competition between thermal decomposition and irradiation mixing results in a nanometer-scale phase separation. This spontaneous decomposition demonstrates that ion-beam mixing can be used as a processing tool to synthesize nanocomposite materials. {copyright} 2001 American Institute of Physics.

Enrique, Raul A.; Bellon, Pascal

2001-06-25

393

Possible Mesozoic age of Ellenville Zn-Pb-Cu(Ag) deposit, Shawangunk Mountains, New York  

USGS Publications Warehouse

Ore textures, epithermal open-space filling of Permian structures of the Alleghanian orogeny, and largely postorogenic mineralization of the Ellenville, New York, composite Zn-Pb-Cu(Ag) vein system, provide permissive evidence for post-Permian mineralization. Isochron ages determined by 40Ar/39Ar laser-fusion techniques for K-bearing liquid inclusions in main-stage quartz from the Ellenville deposit additionally suggest a Mesozoic time of mineralization, associated with extensional formation of the Newark basin. The best 40Ar/39Ar total-fusion age range is 165 ?? 30 to 193 ?? 35 Ma. The Mesozoic 40Ar/39Ar age agrees with that of many other dated northern Appalachian Zn-Pb-Cu(Ag) deposits with near-matching lead isotope ratios, and adds new evidence of Jurassic tectonism and mineralization as an overprint to Late Paleozoic tectonism at least as far north as Ellenville (lat. 41??43???N). ?? 1994 Springer-Verlag.

Friedman, J. D.; Conrad, J. E.; McKee, E. H.; Mutschler, F. E.; Zartman, R. E.

1994-01-01

394

Nonlinear Viscoelastic Characteristics of Sn-Ag-Cu Solder Pastes Used in Electronics Assembly Applications  

NASA Astrophysics Data System (ADS)

Sn-Ag-Cu solder pastes are widely used as the joining material in the electronic assembly process. The aim of this work was to evaluate the nonlinear viscoelastic behaviors of three different Sn-Ag-Cu solder pastes. Three novel rheological test methods were developed for this purpose. These include viscosity, thixotropic loop, and oscillatory amplitude sweep tests. The nonlinear flow curves obtained from the viscosity tests revealed the "shear-thinning" behavior of solder paste samples. Thixotropic loop test results explain the time-dependent structural breakdown and recovery of solder pastes. The viscoelastic properties of solder pastes were interpreted through oscillatory test parameters: storage modulus ( G'), loss modulus ( G?), and phase angle (?). The discrepancies observed in the rheological behaviors of the paste samples were found to be related with flux composition (liquid phase in the solder paste) and particle size distribution.

Mallik, Sabuj; Chan, Erica Hiu Laam; Ekere, Ndy

2013-04-01

395

Microstructural evolution and mechanical properties of SnAgCu alloys  

NASA Astrophysics Data System (ADS)

Lead containing solder paste is now considered as an environmental threat. In order to eliminate this undesirable environmental impact associated to their production, a family of lead-free solder joint, Sn-3.8Ag-0.7Cu, is proposed. Microstructural and mechanical data of this solder joint have been acquired and compared with the most common used SnPb solder paste. The evolution of the microstructure as well as the failure mode and the mechanical properties of SnAgCu solder joint are discussed as a function of strain rate, annealing treatments, and testing temperature. Tensile tests have been performed, at temperatures ranging from -50 to +150 C, on bulk samples. Changes of the mechanical properties of bulk tested samples are actually correlated with microstructural changes, as shown by transmission electronic microscopy investigations.

Fouassier, O.; Heintz, J.-M.; Chazelas, J.; Geffroy, P.-M.; Silvain, J.-F.

2006-08-01

396

[Dissolution of silver and copper from Ag-Cu binary alloys under dynamic conditions].  

PubMed

Ag-Cu binary alloys containing 5-30% copper were subjected to dynamic extraction at 200 rpm and 37 degrees C to simulate the functional movement in the oral environment. Extraction was carried out in Eagle's minimum essential medium every two weeks for 18 weeks. The corrosion products were examined by the separation of extracts with a 0.22 micron filter. Significant dissolution of copper occurred with increasing copper content, but the increase in silver dissolution was slight. The amount of copper in the filtrate was the same as that in the extract, but no silver was detected in the filtrate. Therefore, dynamic extraction accelerated the dissolution of copper from the Ag-Cu binary alloys and thus lowered the corrosion resistance. PMID:2134821

Takeda, S; Sano, Y; Takimoto, T; Tsutsumi, N; Nakamura, M

1990-07-01

397

Linear and nonlinear optical properties of metal nanocluster-silica composites formed by sequential implantation of Ag and Cu  

SciTech Connect

Nanometer dimension metal colloids were formed in silica by sequential implantation of Ag and Cu ions. The Ag and Cu were implanted with relative ratios of Ag to Cu of 9:3, 6:6, and 3:9. The total nominal dose was 12 {times} 10{sup 16} ions/cm{sup 2}. TEM techniques were used to examine colloid size and size distributions. The linear optical response was measured from 200 to 900 nm. The nonlinear optical properties were measured using the z-scan technique at a wavelength of 570 nm. The linear and nonlinear optical properties were found to be dependent upon the relative ratio of sequentially implanted Ag to Cu. The results are consistent with effective medium theory.

Zuhr, R.A. [Oak Ridge National Lab., TN (United States); Magruder, R.H. III; Anderson, T.A.; Osborne, D.O. Jr. [Vanderbilt Univ., Nashville, TN (United States)

1994-12-01

398

Possible Mesozoic age of Ellenville Zn-Pb-Cu(Ag) deposit, Shawangunk Mountains, New York  

Microsoft Academic Search

Ore textures, epithermal open-space filling of Permian structures of the Alleghanian orogeny, and largely postorogenic mineralization of the Ellenville, New York, composite Zn-Pb-Cu(Ag) vein system, provide permissive evidence for post-Permian mineralization. Isochron ages determined by 40Ar\\/39Ar laser-fusion techniques for K-bearing liquid inclusions in main-stage quartz from the Ellenville deposit additionally suggest a Mesozoic time of mineralization, associated with extensional formation

J. D. Friedman; J. E. Conrad; E. H. McKee; F. E. Mutschler; R. E. Zartman

1994-01-01

399

Enhanced mechanical properties in an AlCuMgAg alloy by duplex aging  

Microsoft Academic Search

A type of duplex aging heat treatment was developed to improve the mechanical properties at room temperature and elevated temperatures in a pre-strained AlCuMgAg alloy. In contrast to the conventional T8 temper at 165C and 200C, the hardening response of the alloy to aging was increased by duplex aging treatment, the ultimate tensile strength and yield strength of duplex aging

Yao Li; Zhiyi Liu; Song Bai; Xuanwei Zhou; Heng Wang; Sumin Zeng

2011-01-01

400

Unified viscoplastic constitutive model for Sn3.8Ag0.7Cu solder  

Microsoft Academic Search

The time-independent plastic and time-dependent creep deformations of Sn3.8Ag0.7Cu solder are considered in a unified framework by using a state variable approach. A new viscoplastic constitutive model that includes the kinematic hardening behavior of solder is proposed in this paper. Back stress, which is used for characterizing the kinematic hardening behavior, is selected as the state variable for the proposed

H.-C. Yang; T.-C. Chiu

2010-01-01

401

Rate-dependent properties of Sn-Ag-Cu based lead free solder joints  

Microsoft Academic Search

The increasing demand for portable electronics has led to the shrinking in size of electronic components and solder joint dimensions. The industry also made a transition towards the adoption of lead-free solder alloys, commonly based around the Sn-Ag-Cu alloys. As knowledge of the processes and operational reliability of these lead-free solder joints (used especially in advanced packages) is limited, it

Yong'An Su; Long Bin Tan; V. B. C. Tan; Tong Yan Tee

2009-01-01

402

Submonolayer growth of Ag on Cu(111) studied by proton induced Auger electron spectroscopy  

Microsoft Academic Search

We studied the growth of Ag on Cu(111) by electron- and proton-induced Auger electron spectroscopy. The Auger signal versus coverage plots indicate a growth in a monolayer-by-monolayer fashion. In case of grazingly incident protons, additional information on the real mesoscopic structure in the submonolayer coverage range could be obtained by comparison of the experimental results with computer simulations. We found

R. Pfandzelter; J. Landskron

1996-01-01

403

Jumps and concerted moves in Cu, Ag, and Au(110) adatom self-diffusion  

Microsoft Academic Search

We present a molecular-dynamics simulation of self-diffusion on the (110) surfaces of Cu, Ag, and Au. The metals are modeled by semiempirical potentials developed in the framework of the second-moment approximation to the tight-binding model. The energy barriers for the relevant diffusion processes are calculated by quenched molecular dynamics and compared with the available data in literature, obtaining a good

F. Montalenti; R. Ferrando

1999-01-01

404

Dielectric properties of the system AgI-CuI-CsI  

Microsoft Academic Search

The dielectric properties of the system AgI-CuI-CsI with four molar ratios namely 90-05-05, 70-15-15, 50-25-25 and 30-35-35 have been measured and the results discussed. The relaxational frequencies have been calculated and the activation energies obtained suggest the conduction to be mainly due to silver ions only. The conduction mechanism has been observed to be due to a hopping mechanism of

B. Nalini; S. Selvaskarapandian

1997-01-01

405

Precipitation sequence in an Al-Cu-Mg-Ag-Zn alloy  

Microsoft Academic Search

The precipitation sequence at 190C in a complex A1-4Cu-035Mg-07Ag-12Zn foundry alloy belonging to the commercial AVIOR composition has been investigated by means of differential scanning calorimetry and transmission electron microscopy, and a comparison with a Zn-free alloy has been made in order to evaluate the influence of Zn on the precipitation sequence. It is found that Zn modifies the sequence

G. Riontino; P. Mengucci; S. Abis

1995-01-01

406

Electronic structure and conductivity of nanocomposite metal (Au,Ag,Cu,Mo)-containing amorphous carbon films  

Microsoft Academic Search

In this work, we study the influence of the incorporation of different metals (Me = Au, Ag, Cu, Mo) on the electronic structure of amorphous carbon (a-C:Me) films. The films were produced at room temperature using a novel pulsed dual-cathode arc deposition technique. Compositional analysis was performed with secondary neutral mass spectroscopy whereas X-ray diffraction was used to identify the

Jose L. Endrino; David Horwat; Raul Gago; Joakim Andersson; Y. S. Liu; Jinghua Guo; Andre Anders

2008-01-01

407

Electronic structure and conductivity of nanocomposite metal (Au, Ag, Cu, Mo)-containing amorphous carbon films  

Microsoft Academic Search

In this work, we study the influence of the incorporation of different metals (Me=Au, Ag, Cu, Mo) on the electronic structure of amorphous carbon (a-C:Me) films. The films were produced at room temperature using a species selective bias pulsed dual-cathode arc deposition technique. Compositional analysis was performed with secondary neutral mass spectroscopy whereas X-ray diffraction was used to identify the

J. L. Endrino; D. Horwat; R. Gago; J. Andersson; Y. S. Liu; J. Guo; A. Anders

2009-01-01

408

Tensile deformation behavior of nano-sized Mo particles reinforced SnAgCu solders  

Microsoft Academic Search

In this work, tensile deformation of Sn3.8Ag0.7Cu (SAC387) solder and composite of SAC387 reinforced with nano-sized Mo particles have been studied with strain rates from 10?5 to 10?1s?1 and temperatures of 25, 75 and 125C. It is found that the yield strength (?Y.S) and strain hardening exponent (n) are increased with the strain rate, but the n values decrease with

B. S. S. Chandra Rao; K. Mohan Kumar; V. Kripesh; K. Y. Zeng

2011-01-01

409

Combined thermal and electromigration exposure effect on SnAgCu BGA solder joint reliability  

Microsoft Academic Search

Research of thermal, mechanical and electrical effect on lead free solder joints is very important for understanding the reliability of electronic package like BGA assemblies. Combined thermal and electromigration (EM) exposure on SnAgCu BGA solder joint reliability were reported. PBGA assemblies which were soldered on PCB board experienced thermal aging and Thermal-EM combined aging with current density of 103 to

Luhua Xu; John H. L. Pang

2006-01-01

410

Effect of PWB Plating on the Microstructure and Reliability of SnAgCu Solder Joints  

Microsoft Academic Search

This paper describes the interaction of the NEMI recommended lead-free solder for reflow assembly (Sn3.8Ag0.7Cu) with different commercial printed wiring board (PWB) platings. It also discusses the effects of plating type and manufacturer on the strength of the lead-free solder joints. PWBs from two different manufacturers with the same four types of plating were examined. The platings were organic solderability

Y. Zheng; C. Hillman; P. McCluskey

411

Intermetallic growth on PWBs soldered with Sn3.8Ag0.7Cu  

Microsoft Academic Search

This paper describes the nature of the intermetallic phases observed at the interface and in the bulk of Sn3.8Ag0.7Cu solder immediately after reflow on PWBs coated with a variety of commercial plating systems. It also discusses the growth of these intermetallic phases after aging at homologous temperatures of 0.8Tm, 0.85Tm and 0.9Tm for 10, 100 and 1000 hours. The following

Y. Zheng; C. Hillman; P. McCluskey

2002-01-01

412

Structural simulation of super-cooled liquid AuCu, AuAg alloys  

Microsoft Academic Search

The structure and thermodynamics of liquid AuCu and AuAg alloys have been simulated using molecular dynamics method based upon the EAM interatomic potential to reveal influence of the mismatch in atomic size on the glass-forming ability. Under the cooling rate in the range of 41012 to 11011K\\/s, the system undergoes the liquid, super-cooled liquid and solid state. Liquid Au and

Li Wang; Yanning Zhang; Hua Yang; Ying Chen

2003-01-01

413

Short-Range and Medium-Range Order in Liquid Cu-Ni Alloy  

NASA Astrophysics Data System (ADS)

The liquid structure of the Cu70Ni30 alloy has been investigated using a ?-? high-temperature x-ray diffractometer. At all temperatures above its liquidus, a distinct pre-peak has been found around a scattering vector magnitude of 13.5nm-1. The height of the pre-peak decreases gradually with increasing temperature but it clearly exists up to a temperature of 1400C. This behaviour indicates that stable medium-range order atomic clusters exist in the melt. It is concluded that the short-range order atomic clusters of the liquid Cu70Ni30 alloy mainly consist of Cu atoms with centred Ni atoms. The appearance of the pre-peak in the structure factor of the liquid Cu70Ni30 alloy is caused by the interaction between centred Ni atoms locating in the neighbouring atomic clusters.

Wang, Huan-Rong; Tian, Xue-Lei; Teng, Xin-Ying; Shi, Zhi-Qiang; Ye, Yi-Fu; Min, Guang-Hui; QIN, Jing-Yu

2002-02-01

414

Composition pathway in Fe-Cu-Ni alloy during coarsening  

NASA Astrophysics Data System (ADS)

In this work the microstructure evolution for a two phase Fe-Cu-Ni ternary alloy is studied in order to understand the kinetic composition paths during coarsening of precipitates. We have employed a quantitative phase-field model utilizing the CALPHAD database to simulate the temporal evolution of a multi-particle system in a two-dimensional domain. The paths for the far-field matrix and for precipitate average compositions obtained from simulation are found to be rectilinear. The trends are compared with the corresponding sharp interface theory, in the context of an additional degree of freedom for determining the interface compositions due to the Gibbs-Thomson effect in a ternary alloy.

Mukherjee, Rajdip; Choudhury, Abhik; Nestler, Britta

2013-10-01

415

Characteristic of TiNi(Cu) shape memory thin film based on micropump  

NASA Astrophysics Data System (ADS)

Shape memory thin films offer a unique combination of novel properties and have the potential to become a primary actuating mechanism for micropumps. In this study, a micropump driven by TiNiCu shape memory thin film is designed and fabricated. The micropump is composed of a TiNiCu/Si bimorph driving membrane, a pump chamber and two inlet and outlet check valves. The property of TiNiCu films and driving capacity of TiNiCu/Si bimorph driving membrane are investigated. By using the recoverable force of TiNiCu thin film and biasing force of silicon membrane, the actuation diaphragm realizes reciprocating motion effectively. Experimental results show that the film surface appears a smooth and featureless morphology without any cracks, and the hysteresis width ?T of TiNiCu film is about 2-3C, the micropump driving by TiNiCu film has good performance, such as high pumping yield, high working frequency, stable driving capacity, and long fatigue life time.

Zhang, Huijun; Qiu, Chengjun

2009-07-01

416

Nearly Constant Electrical Resistance over Large Temperature Range in Cu3NMx (M = Cu, Ag, Au) Compounds.  

PubMed

Electrical resistance is a material property that usually varies enormously with temperature. Constant electrical resistivity over large temperature range has been rarely measured in a single solid. Here we report the growth of Cu3NMx (M = Cu, Ag, Au) compound films by magnetron sputtering, aiming at obtaining single solids of nearly constant electrical resistance in some temperature ranges. The increasing interstitial doping of cubic Cu3N lattice by extra metal atoms induces the semiconductor-to-metal transition in all the three systems. Nearly constant electrical resistance over 200?K, from room temperature downward, was measured in some semimetallic Cu3NMx samples, resulting from opposite temperature dependence of carrier density and carrier mobility, as revealed by Hall measurement. Cu3NAgx samples have the best performance with regard to the range of both temperature and doping level wherein a nearly constant electrical resistance can be realized. This work can inspire the search of other materials of such a quality. PMID:24169599

Lu, Nianpeng; Ji, Ailing; Cao, Zexian

2013-10-30

417

Effect of microstructure on thermal conductivity of Cu, Ag thin films.  

PubMed

Thin film type materials are widely used in modern industries, such as semiconductor devices, functional superconductors, machining tools, and so on. The thermal properties of material in semiconductor are very important factors for stable operation because the heat generated during device operation may increase clock frequency. Even though thermal properties of thin films may play a major role in assessing reliability of parts, the measurement methods of thin film thermal properties are generally known to be complex to devise. In this study, a temperature distribution method was applied for the measurement of thermal conductivity of Cu and Ag thin film on borosilicate glass substrate. Cu and Ag thin films were deposited on borosilicate glass using thermal evaporation processes. To measure the thermal conductivity changes according to the microstructure of metallic thin film, the processing variables for the Cu and Ag thin film deposition were changed. To minimize the effect of film thickness, the film thickness was fixed to the thickness of approximately 500 nm throughout experiments. The thermal conductivities of thin films were measured to be much lower than those of bulk materials. Thin film with larger grain size showed higher thermal conductivity probably due to the lower number density of grain boundary. Weidman-Franz law could be applied to thin films produced in this study. Thermal conductivity was also estimated from the resistivity of thin film and Lorenz number of bulk material. PMID:20358967

Ryu, Sang; Juhng, Woonam; Kim, Youngman

2010-05-01

418

Investigation of Pd-Modified Ag-CuO Air Braze Filler Metals  

SciTech Connect

This paper reports on the effects of palladium on the liquidus/solidus temperatures and wetting behavior of a series of Ag-CuOx air braze filler metals. Currently, the maximum operating temperature of the Ag-CuOx system is limited by its eutectic temperature of ~935C. One strategy to increase the maximum operational temperature of this family of filler metals is to add a higher melting noble alloying element. In the current study, we examined the effects of palladium additions on the melting characteristics of the Ag-CuO materials and the wetting properties of the resulting air braze filler metals with respect to alumina. It was found that while the addition of Pd causes the anticipated increase in the melting temperature, it does so at a sacrifice in wetting properties. The extent of both effects and therefore the opportunity to trade-off the two properties in order to develop an optimized higher temperature air braze depends on concentrations of both the palladium and copper oxide.

Weil, K. Scott; Kim, Jin Yong; Hardy, John S.; Darsell, Jens T.

2006-01-01

419

Enzymatic assay of acid phosphatase and microanalysis of Cu 2+ and Ag + with a SAW-impedance sensor  

Microsoft Academic Search

Using adenosine-5?-monophosphate (5?-AMP) as a substrate, the surface acoustic wave (SAW)-impedance sensor has been successfully applied to detection of acid phosphatase and microanalysis of Cu2+ and Ag+. The assay of acid phosphatase is based on the change in conductance of the solution caused by enzymatic reaction between 5?-AMP and acid phosphatase. The microanalysis of Cu2+ and Ag+ is based on

Ronghui Wang; Qingyun Cai; Defang Tong; Lihua Nie; Shouzhuo Yao

1998-01-01

420

The effect of Sn grain number and orientation on the shear fatigue life of SnAgCu solder joints  

Microsoft Academic Search

A study of the dependence of room temperature shear fatigue lifetime of SnAgCu solder joints on Sn grain number and orientation was conducted. Both essentially single Sn grain and multi (two or three) Sn grain samples are found in many SnAgCu solder joints in the field, and these Sn grain morphologies were examined here. The mean fatigue lifetime was found

B. Arfaei; Y. Xing; J. Woods; J. Wolcott; P. Tumne; P. Borgesen; E. Cotts

2008-01-01

421

A comparative study of the microstructures and optical properties of Cu and Ag-doped ZnO thin films  

Microsoft Academic Search

Cu- and Ag-doped ZnO films were deposited by direct current co-reactive magnetron sputtering technique. The microstructure, the chemical states of the oxygen, zinc, copper and silver and the optical properties in doped ZnO films were investigated by X-ray diffraction spectroscopy (XRD), X-ray photoelectron spectroscopy (XPS) and UV-Visible spectroscopy. XRD analysis revealed that both of Cu- and Ag-doped ZnO films consist

Y. Chen; X. L. Xu; G. H. Zhang; H. Xue; S. Y. Ma

2009-01-01

422

A comparative study of the microstructures and optical properties of Cu and Ag-doped ZnO thin films  

Microsoft Academic Search

Cu- and Ag-doped ZnO films were deposited by direct current co-reactive magnetron sputtering technique. The microstructure, the chemical states of the oxygen, zinc, copper and silver and the optical properties in doped ZnO films were investigated by X-ray diffraction spectroscopy (XRD), X-ray photoelectron spectroscopy (XPS) and UVVisible spectroscopy. XRD analysis revealed that both of Cu- and Ag-doped ZnO films consist

Y. Chen; X. L. Xu; G. H. Zhang; H. Xue; S. Y. Ma

2009-01-01

423

Nanoporous PtAg and PtCu alloys with hollow ligaments for enhanced electrocatalysis and glucose biosensing  

Microsoft Academic Search

Nanoporous silver (NPS) and copper (NPC) obtained by dealloying AgAl and CuAl alloys, respectively, were used as both three-dimensional templates and reducing agents for the fabrication of nanoporous PtAg (NPS-Pt) and PtCu (NPC-Pt) alloys with hollow ligaments by a simple galvanic replacement reaction with H2PtCl6. Electron microscopy and X-ray diffraction characterizations demonstrate that NPS and NPC with similar ligament sizes

Caixia Xu; Yunqing Liu; Fa Su; Aihua Liu; Huajun Qiu

2011-01-01

424

Flip chip reliability: comparative characterization of lead free (Sn\\/Ag\\/Cu) and 63Sn\\/Pb eutectic solder  

Microsoft Academic Search

The reliability of a ternary Sn\\/Ag\\/Cu alloy for flip chip solder joints will be reported in this paper. Dominant failure mechanisms for given thermal stress regimes are well defined for 63Sn\\/Pb eutectic solder. Characterizing Sn\\/Ag\\/Cu solder reliability in comparison to 63Sn\\/Pb solder provides a true baseline for these thermal stress regimes and still allows for a broad search of mechanisms

Haluk Balkan; Deborah Patterson; Guy Burgess; Craig Carlson; Peter Elenius; Michael Johnson; Brian Rooney; Joseph Sanchez; David Stepniak; Jim Wood

2002-01-01

425

A Study on the Breakdown Mechanism of an Electroless-Plated Ni(P) Diffusion Barrier for Cu/Sn/Cu 3D Interconnect Bonding Structures  

NASA Astrophysics Data System (ADS)

This study examined the thermal stability of an electroless-plated Ni(P) barrier layer inserted between Sn and Cu in the bonding structure of Cu/Sn/Cu for three-dimensional (3D) interconnect applications. A combination of transmission electron microscopy (TEM) and scanning electron microscopy allowed us to fully characterize the bonding morphology of the Cu/Ni(P)/Sn/Ni(P)/Cu joints bonded at various temperatures. The barrier suppressed Cu and Sn interdiffusion very effectively up to 300C; however, an interfacial reaction between Ni(P) and Sn led to gradual decomposition into Ni3P and Ni3Sn4. Upon 350C bonding, the interfacial reaction brought about complete disintegration of the barrier in local areas, which allowed unhindered interdiffusion between Cu and Sn.

Lee, Byunghoon; Jeon, Haseok; Jeon, Seong-Jae; Kwon, Kee-Won; Lee, Hoo-Jeong

2012-01-01

426

Oxidation resistance of graphene-coated Cu and Cu/Ni alloy.  

PubMed

The ability to protect refined metals from reactive environments is vital to many industrial and academic applications. Current solutions, however, typically introduce several negative effects, including increased thickness and changes in the metal physical properties. In this paper, we demonstrate for the first time the ability of graphene films grown by chemical vapor deposition to protect the surface of the metallic growth substrates of Cu and Cu/Ni alloy from air oxidation. In particular, graphene prevents the formation of any oxide on the protected metal surfaces, thus allowing pure metal surfaces only one atom away from reactive environments. SEM, Raman spectroscopy, and XPS studies show that the metal surface is well protected from oxidation even after heating at 200 C in air for up to 4 h. Our work further shows that graphene provides effective resistance against hydrogen peroxide. This protection method offers significant advantages and can be used on any metal that catalyzes graphene growth. PMID:21275384

Chen, Shanshan; Brown, Lola; Levendorf, Mark; Cai, Weiwei; Ju, Sang-Yong; Edgeworth, Jonathan; Li, Xuesong; Magnuson, Carl W; Velamakanni, Aruna; Piner, Richard D; Kang, Junyong; Park, Jiwoong; Ruoff, Rodney S

2011-01-28

427

Microwave sintering of W-18Cu and W-7Ni-3Cu alloys.  

PubMed

Microwave processing is emerging as an innovative and highly effective material processing method offering many advantages over conventional methods, especially for sintering applications. It is recognized for its various advantages, such as: time and energy saving, rapid heating rates, considerably reduced processing cycle time and temperature, fine microstructures and improved mechanical properties which lead to better product performance. Major constraints in conventional sintering of refractory material such as tungsten and its alloys are high sintering temperatures and long soaking times which cause abnormal grain growth and lead to poor mechanical properties. They get further aggravated at smaller (submicron and nano) tungsten powder sizes. This study describes recent research findings; W-18Cu and W-7Ni-3Cu alloys have been successfully consolidated using microwave heating which resulted in an overall reduction of sintering time of up to 80%. The microwave sintered samples exhibited finer microstructure and superior mechanical properties when compared with the conventional samples. PMID:21384717

Mondal, Avijit; Upadhyaya, Anish; Agrawal, Dinesh

2009-01-01

428

Creep rupture of lead-free Sn3.5Ag and Sn3.5Ag0.5Cu solders  

Microsoft Academic Search

The aim of this study is to investigate the creep rupture behavior of lead-free Sn-3.5Ag and Sn-3.5Ag-0.5Cu solders at three temperatures ranging from room temperature (RT) to 90 C, under a tensile stress range of s\\/E=10-4 to 10-3. The ultimate tensile strength (UTS) and creep resistance were found to be decreased with increasing temperature for each given lead-free solder. Both

Chih-Kuang Lin; De-You Chu

2005-01-01

429

Structure and mechanism of Cu- and Ni-substituted analogs of metallo-?-lactamase L1  

PubMed Central

In an effort to further probe metal binding to metallo-?-lactamase L1 (m?l L1), Cu- (Cu-L1) and Ni-substituted (Ni-L1) L1 were prepared and characterized by kinetic and spectroscopic studies. Cu-L1 bound 1.7 equivalents of Cu and small amounts of Zn(II) and Fe. The EPR spectrum of Cu-L1 exhibited two overlapping, axial signals, indicative of type 2 sites with distinct affinities for Cu(II). Both signals indicated multiple nitrogen ligands. Despite the expected proximity of the Cu(II) ions, however, only indirect evidence was found for spin-spin coupling. Cu-L1 exhibited higher kcat (96 s?1) and Km (224 ?M) values, as compared to the values of dinuclear Zn(II)-containing L1, when nitrocefin was used as substrate. The Ni-L1 bound 1 equivalent of Ni and 0.3 equivalents of Zn(II). Ni-L1 was EPR-silent, suggesting that the oxidation state of nickel was +2; this suggestion was confirmed by 1H NMR spectra, which showed relatively sharp proton resonances. Stopped-flow kinetic studies showed that ZnNi-L1 stabilized significant amounts of the nitrocefin-derived intermediate and that the decay of intermediate is rate-limiting. 1H NMR spectra demonstrate that Ni(II) binds in the Zn2 site and that the ring-opened product coordinates Ni(II). Both Cu-L1 and ZnNi-L1 hydrolyze cephalosporins and carbapenems, but not penicillins, suggesting that the Zn2 site modulates substrate preference in m?1 L1. These studies demonstrate that the Zn2 site in L1 is very flexible and can accommodate a number of different transition metal ions; this flexibility could possibly offer an organism that produces L1 an evolutionary advantage when challenged with ?-lactam containing antibiotics.

Hu, Zhenxin; Spadafora, Lauren J.; Hajdin, Christine E.; Bennett, Brian; Crowder, Michael W.

2009-01-01

430

Effects of Surface Finishes and Current Stressing on Interfacial Reaction Characteristics of Sn-3.0Ag-0.5Cu Solder Bumps  

NASA Astrophysics Data System (ADS)

The effects of surface finishes on the in situ interfacial reaction characteristics of ball grid array (BGA) Sn-3.0Ag-0.5Cu lead-free solder bumps were investigated under annealing and electromigration (EM) test conditions of 130C to 175C with 5.0 103 A/cm2. During reflow and annealing, (Cu,Ni)6Sn5 intermetallic compound (IMC) formed at the interface of electroless nickel immersion gold (ENIG) finish. In the case of both immersion Sn and organic solderability preservative (OSP) finishes, Cu6Sn5 and Cu3Sn IMCs formed. Overall, the IMC growth velocity of ENIG was much lower than that of the other finishes. The activation energies of total IMCs were found to be 0.52 eV for ENIG, 0.78 eV for immersion Sn, and 0.72 eV for OSP. The ENIG finish appeared to present an effective diffusion barrier between the Cu substrate and the solder, which leads to better EM reliability in comparison with Cu-based pad systems. The failure mechanisms were explored in detail via in situ EM tests.

Kim, Jae-Myeong; Jeong, Myeong-Hyeok; Yoo, Sehoon; Park, Young-Bae

2012-04-01

431

Surface and interfacial tension of the Ni-Fe-S, Ni-Cu-S, and fayalite slag systems  

Microsoft Academic Search

The surface tensions of the Ni-Fe-S system together with the Ni-Cu-S and fayalite-type slag systems were measured using the\\u000a sessile drop technique. Drop images were obtained by X-ray radiography. For the Ni3S2-FeS pseudo-binary system, the surface tension of the matte increased with matte grade and showed a positive deviation from\\u000a ideality with matte grade. This suggests that Ni3S2 dominates in

S. W. Ip; J. M. Toguri

1993-01-01

432

Silver sheathed superconducting tapes made from the bi-system oxide powders mixed with metal Ag or Cu powders  

Microsoft Academic Search

Properties of Ag sheathed tapes of the 2212-phase Bi system were investigated. Prior to the packing into a Ag tube, calcined powders were mixed with metal powders of Ag and\\/or Cu by using an attrition-type mill and further heat-treated in vacuum. By this fabrication method, the crystal growth of the 2212 phase of the Bi system and superconducting properties were

T. Asano; Y. Tanaka; M. Fukutomi; K. Komori; K. Inoue; H. Maeda; M. Yoshikawa; M. Naitoh

1992-01-01

433

Eutectic crystallization behavior of new Zr48Cu36Al8Ag8 alloy with high glass-forming ability  

NASA Astrophysics Data System (ADS)

A water quenching method is used to produce as-cast Zr48Cu36Al8Ag8 rods with diameters from 20 mm to 25 mm. The microstructures of the as-cast samples were investigated by X-ray diffraction, optical microscopy and scanning electron microscopy. Furthermore, the crystallization behavior of the Zr48Cu36Al8Ag8 glassy alloy was examined by XRD and transmission electron microscopy. Based on the results obtained one can assume that the simultaneous precipitation of the Zr2Cu+AlCu2Zr eutectic phases is the possible reason for the high stabilization of the quaternary Zr48Cu36Al8Ag8 supercooled liquid.

Zhang, Q. S.; Zhang, W.; Xie, G. Q.; Inoue, A.

2009-01-01

434

Element-specific study of epitaxial NiO/Ag/CoO/Fe films grown on vicinal Ag(001) using photoemission electron microscopy  

SciTech Connect

NiO/Ag/CoO/Fe single crystalline films are grown epitaxially on a vicinal Ag(001) substrate using molecular beam epitaxy and investigated by photoemission electron microscopy. We find that after zero-field cooling, the in-plane Fe magnetization switches from parallel to perpendicular direction of the atomic steps of the vicinal surface at thinner CoO thickness but remains in its original direction parallel to the steps at thicker CoO thickness. CoO and NiO domain imaging result shows that both CoO/Fe and NiO/CoO spins are perpendicularly coupled, suggesting that the Fe magnetization switching may be associated with the rotatable-frozen spin transition of the CoO film.

Meng, Y.; Li, J.; Tan, A.; Jin, E.; Son, J.; Park, J. S.; Doran, A.; Young, A. T.; Scholl, A.; Arenholz, E.; Wu, J.; Hwang, C.; Zhao, H. W.; Qiu, Z. Q.

2011-01-10

435

Cu-Ni composition gradient for the catalytic synthesis of vertically aligned carbon nanofibers  

SciTech Connect

The influence of catalyst alloy composition on the growth of vertically aligned carbon nanofibers was studied using Cu-Ni thin films. Metals were co-sputtered onto a substrate to form a thin film alloy with a wide compositional gradient, as determined by Auger analysis. Carbon nanofibers were then grown from the gradient catalyst film by plasma enhanced chemical vapor deposition. The alloy composition produced substantial differences in the resulting nanofibers, which varied from branched structures at 81%Ni-19%Cu to high aspect ratio nanocones at 80%Cu-20%Ni. Electron microscopy and spectroscopy techniques also revealed segregation of the initial alloy catalyst particles at certain concentrations.

Klein, Kate L [ORNL; Melechko, Anatoli Vasilievich [ORNL; Rack, Philip D [ORNL; Fowlkes, Jason Davidson [ORNL; Meyer III, Harry M [ORNL; Simpson, Michael L [ORNL

2005-01-01

436

Formation of quasicrystals in bulk glass forming Zr-Cu-Ni-Al alloys  

Microsoft Academic Search

Zr65Cu17.5Ni10Al7.5 as well as Zr69.5Cu12Ni11Al7.5 belong to the best glass forming alloys known. Transmission electron microscopy (TEM) and X-ray analysis of samples annealed above the glass transition temperature exhibit the formation of quasicrystalline microstructures. The metastable icosahedral phase is primitive with a quasilattice constant a = 0.253 nm; its composition is close to Zr69.5Cu12Ni11Al7.5. The growth of spherical shaped quasicrystals

U. Kster; J. Meinhardt; S. Roos; R. Busch

1997-01-01

437

Experimental study and modeling of the thermodynamic properties of Cu-Fe-Ni melts  

Microsoft Academic Search

The partial mixing enthalpy of nickel in ternary liquid Cu-Fe-Ni alloys is studied at 1873 K along sections characterized\\u000a by ratios x\\u000a Cu: x\\u000a Fe = 3, 1, and 1\\/3 at x\\u000a Ni = 00.55. The investigations are undertaken using a high-temperature isoperibolic calorimeter. The temperature and composition\\u000a dependence of the excess mixing Gibbs energy of liquid Cu-Fe-Ni alloys are

L. A. Dreval; A. R. Abdulov; P. G. Agraval; M. A. Turchanin

2010-01-01

438

The microstructure of eutectic Au-Sn solder bumps on Cu\\/electroless Ni\\/Au  

Microsoft Academic Search

In this work we studied the initial microstructure and microstructural evolution of eutectic Au-Sn solder bumps on Cu\\/electroless\\u000a Ni\\/Au. The solder bumps were 150160 m in diameter and 4550 m tall, reflowed on Cu\\/electroless Ni\\/Au, and then aged at 200C\\u000a for up to 365 days. In addition, Au-Ni-Sn-alloys were made and analyzed to help identify the phases that appear at

H. G. Song; J. P. Ahn

2001-01-01

439

Martensitic transformation in Cu-doped NiMnGa magnetic shape memory alloys  

NASA Astrophysics Data System (ADS)

This paper studies the martensitic transformation in the Cu-doped NiMnGa alloys. The orthorhombic martensite transforms to L21 cubic austenite by Cu substituting for Ni in the Ni50-xCuxMn31Ga19 (x=2-10) alloys, the martensitic transformation temperature decreases significantly with the rate of 40 K per Cu atom addition. The variation of the Fermi sphere radius (kF) is applied to evaluate the change of the martensitic transformation temperature. The increase of kF leads to the increase of the martensitic transformation temperature.

Li, Pan-Pan; Wang, Jing-Min; Jiang, Cheng-Bao

2011-02-01

440

Formation of TiZrCuNiSnSi bulk metallic glasses with good plasticity  

Microsoft Academic Search

Formation and mechanical properties of TiZrCuNiSnSi glassy alloys consisting of dissimilar and similar elements are studied. Ti45.8Zr6.2Cu39.9Ni5.1Sn2Si1 glassy alloy can be prepared in a bulk glassy rod form of 4mm in diameter and exhibits strength of 2100MPa and a plastic strain of ?5% prior to failure in compression. The plasticity of the Ti45.8Zr6.2Cu39.9Ni5.1Sn2Si1 bulk metallic glass is attributed to the

Enhuai Yin; Min Zhang; Shujie Pang; Xiangjin Zhao; Tao Zhang

2010-01-01

441

Giant Magnetoresistance In Ni/Cu Multilayers Fabricated By Electron-Beam Evaporation  

SciTech Connect

Electron beam evaporation technique has been used to deposit the multilayers of Ni-Cu, represented by Si[BL{sub t}/[Ni(t{sub FM})/Cu(t{sub NM})]xn] where Si is used as a substrate and BL is buffer layer, n is the number of bilayers, t, t{sub FM} and t{sub NM} are thicknesses of buffer layer, ferromagnetic (Ni) and nonmagnetic (Cu) layers, respectively. We characterize the multilayers using M-H curves, magnetoresistance measurement (at room temperature)

Vikram, V.; Rahman, Md. Rizwanur; Katiyar, Monica [Department of Materials and Metallurgical Engineering Indian Institute of Technology Kanpur, Uttar Pradesh, 208016 (India)

2008-04-24

442

Nanocrystalline Sm-(Co,Cu,Ni) Films with Giant Coercivity  

NASA Astrophysics Data System (ADS)

The drive for higher density recording media calls for new materials with smaller grain size (<100 ; and higher coercivity, in the range of 3-4 kOe. Rare earth intermetallic compounds appear to be suitable for this application. Several studies have already been reported in Sm-Co thin films. In this work, we have studied the magnetic and structural properties of sputtered Sm-(Co,Cu,Ni)/Cr bilayers. The as-deposited films were amorphous and relatively soft with a coercivity around 100 Oe. A nanocrystalline structure was developed after annealing giving rise to a huge enhancement in coercivity. The maximum coercivity of 42 kOe was obtained in a SmCo_2Cu3 sample annealed for 30 min. at 550^circ C . Magnetic viscosity measurements showed that the switching volume is of the same order as the crystallite size. Remanence measurements showed that interparticulate interactions are magnetizing and rather independent of the crystallization stage. These data indicate that the huge coercivity enhancement is due to the domain walls pinning at the high anisotropy Sm-Co precipitates. The possibility of tuning the coercivity more than two orders of magnitude by varying the annealing conditions makes this type of thin films suitable for a wide variety of applications, from longitudinal recording media to thin film permanent magnets.

Hadjipanayis, G. C.; Prados, Celso

1998-03-01

443

Oxidation of carbon monoxide over Cu- and Ag-NaY catalysts with aqueous hydrogen peroxide  

SciTech Connect

A novel oxidation reaction of CO with aqueous H{sub 2}O{sub 2} over Cu-NaY (2-15 wt%) and Ag-NaY (5-15 wt%) catalysts has been achieved at low temperatures (55-70 deg. C) using a flow mode system. The employed catalysts were prepared by the incipient wetness impregnation of NaY zeolite (Si/Al = 5.6, surface area = 910 m{sup 2}/g) with an aqueous solution of known concentrations of copper acetate and silver nitrate. Solids were subjected to thermal treatment at 300-450 deg. C prior to catalytic measurements unless subjected to subsequent reduction with hydrogen at 350 deg. C. The physicochemical characterization of the catalysts was probed using X-ray diffraction (XRD), FT-IR and combined thermal analyses TGA-DrTGA. The XRD data indicated that, the Ag particles have an ordered location in the sodalite cavity and the center of a single six-ring. The FT-IR data also proved the presence of a new peak at 1385 cm{sup -1} that is assigned to Ag-coordinated with the framework. A slow induced oxidation of CO (induction period, t{sub ind}) took place at the initial stage of the CO oxidation reaction after which the reaction obeyed first-order kinetics. The utilized metal ions are proposed to be reduced to lower oxidation states such as Cu{sup +} and Ag{sup 0} during the first period of reaction, t{sub ind}, where the reaction proceeded favorably on such sites. Such argument was evidenced by carrying out the oxidation reaction over H{sub 2}-reduced Cu10-NaY and Ag10-NaY catalysts. The reduction caused a decrease in the t{sub ind}, giving an evidence that the lower oxidation states Cu{sup +} and Ag{sup 0} are the active sites in the studied oxidation reaction. The enhancement in catalytic activity was interpreted in terms of the facile adsorption of CO on the low oxidation state species.

El-Bahy, Zeinhom Mohamed [Chemistry Department, Faculty of Science, Al-Azhar University, Nasr City, 11884 Cairo (Egypt)], E-mail: zeinelbahy2020@yahoo.com

2007-12-04

444

Phase evolution of 17(Cu10Ni)-(NiFe 2O 4-10NiO) cermet inert anode during aluminum electrolysis  

Microsoft Academic Search

17(Cu-10Ni)-(NiFe2O4-10NiO) cermets were prepared by cold pressing and sintering in nitrogen atmosphere, and tested as inert anode for aluminum electrolysis at 960 C for 10 and 40 h, respectively. Microstructures and phase compositions of the as-sintered and post-electrolyzed samples were investigated. The impurity contents in the electrolyte and the cathode metal were detected in order to investigate the corrosion characteristic

Jian-yuan LIU; Zhi-you LI; Yu-qiang TAO; Dou ZHANG; Ke-chao ZHOU

2011-01-01

445

Gain lifetime measurement of a Ni-like Ag soft X-ray laser.  

PubMed

Experimental results of a two-stage Ni-like Ag soft X-ray laser operated in a seed-amplifier configuration are presented. Both targets were pumped applying the double-pulse grazing incidence technique with intrinsic travelling wave excitation. The injection of the seed X-ray laser into the amplifier target was realized by a spherical mirror. The results show amplification of the seed X-ray laser and allow for a direct measurement of the gain lifetime. The experimental configuration is suitable for providing valuable input for computational simulations. PMID:23187356

Ecker, B; Oliva, E; Aurand, B; Hochhaus, D C; Neumayer, P; Zhao, H; Zielbauer, B; Cassou, K; Daboussi, S; Guilbaud, O; Kazamias, S; Le, T T T; Ros, D; Zeitoun, P; Kuehl, T

2012-11-01

446

The Influence of Sn Orientation on Intermetallic Compound Evolution in Idealized Sn-Ag-Cu 305 Interconnects: an Electron Backscatter Diffraction Study of Electromigration  

NASA Astrophysics Data System (ADS)

Previous research showed the relationship between Sn grain orientation and the intermetallic growth rate in Sn-Ag-Cu (SAC)305 interconnects. Samples with the Sn c-axis aligned parallel to the current flow have an intermetallic compound growth rate significantly faster than samples with the c-axis perpendicular to the current flow. This study continues the previous research by investigating intermetallic growth in polygranular joints and in joints that have a thin Ni layer at the cathodic or anodic interface of the interconnect. Planar SAC305 interconnects were sandwiched between two Cu pads (sometimes incorporating a thin Ni layer at the interface) and subjected to uniaxial current. The crystallographic orientation of Sn in these samples was characterized with electron backscatter diffraction before and after electromigration testing. The results show that polycrystalline joints have relatively slow intermetallic growth rates, close to those found in single-crystal joints with the c-axis perpendicular to the current. When a Ni layer was present on the anode side, the intermetallic grew at a rate comparable to that in samples without a Ni layer. However, when the Ni layer was on the cathode side, the intermetallic growth was significantly retarded. The measured growth rates of the intermetallic, combined with literature values for the diffusion of Cu in Sn, were used to calculate values for the effective charge, z *, which is significantly smaller for samples with current parallel to the c-axis than for either polycrystalline samples or samples with the c-axis perpendicular to the electron flow.

Linares, Xioranny; Kinney, Chris; Lee, Kyu-Oh; Morris, J. W.

2013-10-01

447

Momentum-resolved electron dynamics of image-potential states on Cu and Ag surfaces  

NASA Astrophysics Data System (ADS)

The dependence of the inelastic lifetime of electrons in the first n=1 image-potential state of clean and rare-gas covered Ag(111), Cu(111), and Cu(100) surfaces on their momentum parallel to the surface has been studied experimentally by means of time- and angle-resolved two-photon photoemission spectroscopy (2PPE) and theoretically by calculations based on the many-body theory within the self-energy formalism. Similar to the previously studied clean Cu(100) surface, the theoretical results are in excellent agreement with the experiment findings for Cu(111). For Ag(111), the theory overestimates the decay rate and its momentum dependence, which is attributed to the neglect of surface plasmon excitations. With increasing parallel momentum, the n=1 state shifts out of the projected bulk band gap on both surfaces and turns into an image-potential resonance. This opens an additional decay channel by resonant electron transfer into the bulk, which is theoretically treated by the application of the wave packet propagation approach. The expected stronger increase of the decay rate upon crossing the edge of the band gap, however, is not observed in the experiment. The decoupling of the image-potential states from the metal surface upon adsorption of rare-gas layers results in a decrease of the decay rate as well as of its momentum dependence by a similar factor, which can be successfully explained by the change of interband and intraband contributions to the total decay rate.

Schubert, K.; Damm, A.; Eremeev, S. V.; Marks, M.; Shibuta, M.; Berthold, W.; Gdde, J.; Borisov, A. G.; Tsirkin, S. S.; Chulkov, E. V.; Hfer, U.

2012-05-01

448

Magnetic structure of the metallic triangular antiferromagnet Ag2NiO2.  

PubMed

The magnetic structure of the metallic antiferromagnet Ag2NiO2 with the Nel temperature TN=56K has been investigated by means of a neutron diffraction technique using a powder sample in the temperature range between 5 and 65K. The antiferromagnetic (AF) diffraction peaks are clearly observed below TN and can be indexed with the propagation vector [Formula: see text]. Based on the results of both a representational analysis and a Rietveld refinement of the magnetic peaks, the AF spin structure is determined as an A-type AF structure with ml=m0cos(2?k ?l), where ml is the moment at the lth Ni(3+) site and m0=(0.31,0,0.65)?B at 5K. PMID:23793164

Nozaki, Hiroshi; Mnsson, Martin; Roessli, Bertrand; Pomjakushin, Vladimir; Kamazawa, Kazuya; Ikedo, Yutaka; Fischer, Henry E; Hansen, Thomas C; Yoshida, Hiroyuki; Hiroi, Zenji; Sugiyama, Jun

2013-06-21

449

Demonstration and Characterization of Sn3.0Ag0.5Cu\\/Sn57Bi1Ag Combination Solder for 3-D Multistack Packaging  

Microsoft Academic Search

A combination solder of Sn-3.0Ag-0.5Cu (numbers are all in weight percent unless specified otherwise) wrapped by Sn-57Bi-1Ag\\u000a was tested for application to three-dimensional (3-D) multistack packaging. The experimental variables controlled were the\\u000a reflow peak temperatures (170, 185, 200, and 230C), the reflow cycles (up to four times), and the mask which controls the\\u000a amount of Sn-57Bi-1Ag solder paste (two sizes).

Yun-Hwan Jo; Joo Won Lee; Sun-Kyoung Seo; Hyuck Mo Lee; Hun Han; Dong Chun Lee

2008-01-01

450

Impact of Isothermal Aging on Long-Term Reliability of Fine-Pitch Ball Grid Array Packages with Sn-Ag-Cu Solder Interconnects: Surface Finish Effects  

NASA Astrophysics Data System (ADS)

The interaction between isothermal aging and the long-term reliability of fine-pitch ball grid array (BGA) packages with Sn-3.0Ag-0.5Cu (wt.%) solder ball interconnects was investigated. In this study, 0.4-mm fine-pitch packages with 300- ?m-diameter Sn-Ag-Cu solder balls were used. Two different package substrate surface finishes were selected to compare their effects on the final solder composition, especially the effect of Ni, during thermal cycling. To study the impact on thermal performance and long-term reliability, samples were isothermally aged and thermally cycled from 0C to 100C with 10 min dwell time. Based on Weibull plots for each aging condition, package lifetime was reduced by approximately 44% by aging at 150C. Aging at 100C showed a smaller impact but similar trend. The microstructure evolution was observed during thermal aging and thermal cycling with different phase microstructure transformations between electrolytic Ni/Au and organic solderability preservative (OSP) surface finishes, focusing on the microstructure evolution near the package-side interface. Different mechanisms after aging at various conditions were observed, and their impacts on the fatigue lifetime of solder joints are discussed.

Lee, Tae-Kyu; Ma, Hongtao; Liu, Kuo-Chuan; Xue, Jie

2010-12-01

451

Exploring highly correlated materials via electron pair emission: the case of NiO/Ag(100).  

PubMed

Metal oxides like NiO are usually termed 'highly correlated', because the material properties are decisively determined by the electron-electron interaction. This makes them interesting candidates for electron pair spectroscopy which is particularly sensitive to the electron correlation. We have prepared ultrathin NiO/Ag(100) films and studied the electron pair emission upon electron impact. Compared to the metal substrate we observe an increase of the coincidence intensity by a factor of 8 for NiO. Thickness dependent measurements prove that this enhancement is an intrinsic effect rather than due to a mean free path increase of the oxide. The Nel temperature T(N) of NiO films displays a thickness dependence which allows us to tune T(N). We performed temperature dependent measurements and observed no temperature dependence of the coincidence spectra. This proves that the electron pair emission probes the local correlation rather than long range order. An enhanced coincidence intensity was also found for other oxide phases compared to their corresponding metal phases. PMID:23399964

Schumann, F O; Behnke, L; Li, C H; Kirschner, J

2013-02-12

452

Intermetallic Compounds Formed in In-3Ag Solder BGA Packages with ENIG and ImAg Surface Finishes  

NASA Astrophysics Data System (ADS)

During the reflow process of In-3Ag solder ball grid array (BGA) packages with electroless nickel immersion gold (ENIG) and immersion silver (ImAg) surface finishes, continuous (Au0.9Ni0.1)In2 and scallop-shaped (Ag0.9Cu0.1)In2 intermetallic layers form at the interfaces of In-3Ag solder with Au/Ni/Cu and Ag/Cu pads, respectively. The (Au0.9Ni0.1)In2 layer breaks into clusters with increases in the aging time and temperature. Aging at 115 C results in the formation of an additional continuous Ni10In27 layer on the Ni/Cu pads and the migration of (Au0.9Ni0.1)In2 intermetallic clusters into the solder matrix. In contrast, the (Ag0.9Cu0.1)In2 scallops grow into a continuous layer after aging treatment. Accompanying the interfacial reactions, AgIn2 precipitates in the interior of In-3Ag solder balls and coarsens during aging, causing the ball shear strengths of reflown ENIG (1.18 N) and ImAg (1.11 N)-surface-finished solder joints to decrease gradually. However, the migration of (Au0.9Ni0.1)In2 clusters into the solder matrix of ENIG-surface-finished In-3Ag packages leads to an increase in their ball shear strengths after aging at 115 C over 300 h. Both the ENIG- and ImAg-surface-finished In-3Ag solder joints, after ball shear tests, have fractured across the solder balls with ductile characteristics.

Chuang, T. H.; Jain, C. C.; Wang, S. S.

2009-11-01

453

Giant magnetoimpedance effect in electroplated CoNiFe\\/Cu wires with varying Ni, Fe and Co content  

Microsoft Academic Search

Giant magnetoimpedance (GMI) behaviour has been studied for wires consisting of an 8.8213.75?m thick magnetic layer containing either Co20.77Ni61.74Fe17.49, Co18.21Ni41.20Fe40.59, Co18.97Ni49.60Fe31.43, Co46.01Ni39.87Fe14.12 or Co33.67Ni51.44Fe14.89. These magnetic layers were electroplated onto a 50?m diameter Cu non-magnetic wire. A large and sensitive GMI effect (about a 257% magnetoimpedance ratio) with nearly no hysteresis has been found in Co18.97Ni49.60Fe31.43 wire at a 90kHz

F. E. Atalay; H. Kaya; S. Atalay

2006-01-01

454

Electromigration-induced cracks in Cu/Sn3.5Ag/Cu solder reaction couple at room temperature  

NASA Astrophysics Data System (ADS)

Electromigration (EM) behavior of Cu/Sn3.5Ag/Cu solder reaction couple was investigated with a high current density of 5 103 A/cm2 at room temperature. One dimensional structure, copper wire/solder ball/copper wire SRC was designed and fabricated to dissipate the Joule heating induced by the current flow. In addition, thermomigration effect was excluded due to the symmetrical structure of the SRC. The experimental results indicated that micro-cracks initially appeared near the cathode interface between solder matrix and copper substrate after 474 h current stressing. With current stressing time increased, the cracks propagated and extended along the cathode interface. It should be noted that the continuous Cu6Sn5 intermetallic compounds (IMCs) layer both at the anode and at the cathode remained their sizes. Interestingly, tiny cracks appeared at the root of some long column-type Cu6Sn5 at the cathode interface due to the thermal stress.

Hongwen, He; Guangchen, Xu; Fu, Guo

2009-03-01

455

Phenomenological equation transport model of the stability of p-type (Cu,Ag)Se as a thermoelectric material  

Microsoft Academic Search

To aid in understanding the behavior of (Cu,Ag)Se thermoelectric generators, a set of phenomenological equations, which account for thermal fluxes, currents, and copper fluxes (particularly as a neutral species), was developed. A thermodynamic data base for describing copper chemical potentials across the phase existence range of Cu\\/sub (2-x)\\/Se is presented. 6 refs.

J. H. Norman; J. Chin; N. B. Elsner

1981-01-01

456

Mechanism of the Delayed Growth of Intermetallic Compound at the Interface between Sn?4.0Ag?0.5Cu and Cu?Zn Substrate  

Microsoft Academic Search

A Cu?Zn wetting layer was very effective to depress the excessive growth of intermetallic compound (IMC). The effect of Zn\\u000a addition to the Cu layer on the IMC growth and microvoid formation in the solder interface was similar to the effect of Zn\\u000a addition into the Sn-Ag-Cu (SAC) solders. In this study, the mechanism of slow IMC growth at the

Young Min Kim; Kyoung-Moo Harr; Young-Ho Kim

2010-01-01

457