• Proceedings of the International Microelectronics And Packaging Society Conference
• /
• 2002.05a
• /
• pp.183-188
• /
• 2002

With the contact pad consisted of $0.5{\mu}{\textrm}{m}$ $Au/5{\mu}{\textrm}{m}$ Ni/Cu layers on a conventional ball grid array(BGA) substrate, metallurgical reaction properties between the pad and In-15(wt.%)Pb-5Ag solder alloy were studied after reflow and solid aging. In as-reflow condition, thin AuIn$_2$or Ni$_{28}$In$_{72}$ intermetallic layer was formed at the solder/pad interface according to reflow time. Dissolution of the Au layer into the molten solder was remarkably limited in comparison with eutectic Sn-37Pb alloy. After solid aging of 300 hrs, thickness of In-Ni layer increased to about $2{\mu}{\textrm}{m}$ in the both as-reflow case. It was observed that In atoms diffuse through the AuIn$_2$phase to react with underlaying Ni layer. The metallurgical reaction properties between In-l5Pb-7Ag alloy and Au/Ni surface finish were analysed to result in suppression of Au-embrittlement in the solder joints.

• Journal of the Korean Ceramic Society
• /
• v.36 no.8
• /
• pp.835-842
• /
• 1999

Si3N4 -Si3N4 joints were made using Ag-Cu-Ti and Ag-Cu-In-Ti via brazing method and the change in joint strength was investigated after heat treatment at $400^{\circ}C$ or $650^{\circ}C$ for up to 2000h. The initial strength of as-brazed joints with Ag-Cu-In-Ti was lower but the reduction of the strength was less dramatic than that with Ag-Cu-Ti. The joints made of a new brazing alloy Au-Ni-Cr-Mo-Fe which is developed for high temperature applications were heat-treated at $650^{\circ}C$ for 1000h. As the heat treatment time increased the bond strength increased. The results of the joining system with Mo or Cu interlayer showed that the strength of the joint with Mo interlayer was higher but the system incurred problems in joint production Also it was found from oxidation experiment that Ti and In affected the oxidation resistance of brazing alloy.

• Transactions of the Korean hydrogen and new energy society
• /
• v.19 no.1
• /
• pp.35-40
• /
• 2008

Ni-based amorphous alloy ribbon was prepared by a single-roller melt-spinning technique. Palladium coating was found to enhance significantly the absorption/desorption behavior of hydrogen in amorphous alloy. The hydrogen permeability of a Pd-coated $(Ni_{60}Nb_{40}){_{100-X}}$TaX(x=5, 10) amorphous alloy was examined in the temperature range of $623{\sim}773K$, comparable with those of $Pd_{60}-Cu_{40}$ alloys. The permeated hydrogen flux was increased with increasing the temperature and the difference of hydrogen pressure between the feed side and permeates side of the membrane. The Ni-based amorphous alloys were characterized by X-ray diffractometry(XRD) and differential scanning calorimetry(DSC). The morphology of surface and roughness was observed by using scanning electron microscopy(SEM) and atomic force microscopy(AFM).

• Corrosion Science and Technology
• /
• v.6 no.3
• /
• pp.133-139
• /
• 2007

Nickel powder was coated with aluminum nitrate solution to increase the thermal stability of a porous nickel support and control the nickel content in the Pd-Cu-Ni ternary alloyed membrane. Raw nickel powder and alumina coated nickel powder were uniaxialy pressed by home made press with metal cylindrical mold. Though the used nickel powder prepared by pulsed wire evaporation (PWE) method has a good thermal stability, the porous nickel support was too much sintered and the pores of porous nickel support was plugged at high temperature (over $800^{\circ}C$) making it not suitable for the porous support of a palladium based composite membrane. In order to overcome this problem, the nickel powder was coated by alumina and alumina modified porous nickel support resists up to $1000^{\circ}C$ without pore destruction. Furthermore, the compositions of Pd-Cu-Ni ternary alloy membrane prepared by magnetron sputtering and Cu-reflow could be controlled by not only Cu-reflow temperature but also alumina coating amount. SEM analysis and mercury porosimeter analysis evidenced that the alumina coated on the surface of nickel powder interrupted nickel sintering.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.7 no.1
• /
• pp.47-58
• /
• 2004

Loss factors of A356, Mn-Cu alloy and aluminum matrix composites reinforced with $SiC_p$ and Ni-coated graphite particles at various contents have been investigated using clamped-free cantilever beam method. The loss factors of half-power bandwidth of the specimens were measured over a wide range of frequencies from 50 to 3300Hz. Among the specimens, Al-10%$SiC_p$-10%$C_p$ showed the highest loss factor at the mode I, while Mn-Cu alloy showed the highest loss factors at the modes II and III. Consequently, at the mode I the Al-10%$SiC_p$--10%$C_p$ showed the loss factor of 0.00093, which is 2.64 and 1.58 times higher than those of A356 and Mn-Cu alloy, respectively.

• Proceedings of the Korean Powder Metallurgy Institute Conference
• /
• 2006.09b
• /
• pp.1057-1058
• /
• 2006

The preparation of $Ti_{50}Cu_{28}Ni_{15}Sn_7$ metallic glass composite powders was accomplished by the mechanical alloying of a pure Ti, Cu, Ni, Sn and carbon nanotube (CNT) powder mixture after 8 h milling. In the ball-milled composites, the initial CNT particles were dissolved in the Ti-based alloy glassy matrix. The bulk metallic glass composite was successfully prepared by vacuum hot pressing the as-milled CNT/$Ti_{50}Cu_{28}Ni_{15}Sn_7$ metallic glass composite powders. A significant hardness increase with the CNT additions was observed for the consolidated composite compacts.

• Journal of the Korean Society of Safety
• /
• v.24 no.1
• /
• pp.26-30
• /
• 2009

Shape memory recoverable stress and strain of Ti-42.5at%Ni-10at%Cu alloys were measured by means of constant temperature tensile tests. The alloys' transformation behavior is B2 - B19 by DSC result. The strain by tensile stress were perfectly recovered by heating at any testing conditions but shape memory recoverable stress increased to 66MPa and then slightly decreased. Transformation temperatures from thermal cycling under constant uniaxial applied tensile loads linearly increased by increasing tensile load and their thermal hysteresis are about 110K and their maximum recoverable strain is 6.5% at 100MPa condition.

• Resources Recycling
• /
• v.24 no.1
• /
• pp.35-42
• /
• 2015

To obtain the fundamental information on the dissolution of nickel into the slag in the pyrometallurgical processes for treatment of wasted PCB, the distribution ratios of nickel between CaO-$SiO_2-Al_2O_3$-MgO slag and copper-5 wt%Ni alloy were measured at 1623 K to 1823 K under a controlled $CO_2$-CO atmosphere. The distribution ratio of Ni increased linearly with increasing oxygen partial pressure. Therefore, the dissolution reaction of nickel into the slags could be described by the following equation; $$Ni(l)_{metal}+\frac{1}{2}O_2(g)NiO(l)_{slag}$$ The distribution ratio of Ni increased linearly with increasing content of basic oxides(CaO and MgO) in slag. However, the distribution ratio of Ni decreased linearly with increasing temperature. From these results, the empirical equation of distribution ratio of Ni was obtained by the following equation from the analysis of experimental conditions by multiple regression. $${\log}L_{Ni}=0.4000{\log}P_{O2}-5.1{\times}10^{-4}T+0.3375\(\frac{X_{CaO}+X_{MgO}}{X_{SiO2}}\)$$

• Proceedings of the Korean Vacuum Society Conference
• /
• 1994.02a
• /
• pp.35-35
• /
• 1994

The surface segragation of NiZr, CuZr alloy has been studied wi th X-ray Imotoelectron spectroscopy(XPS), Auger electron spectroscopy(AES) and low energy ion scattering(LEIS). The composition of outmost atomic layer has been determinded by the use of LEIS at several incident energies using Ar+ ion. In the LEIS analysis, the effect of charge exchange has been estimated by a novel measurment of the charge exchange parameters while simul taneous determining the relative concentrations of Ni and Zr and the complementary information obtained will be described. The composition of the clean annealed surface, measured with AES only, will be contrasted wi th the surface concentration of the preferentially sputtered surface. The experimental results has been clearly demonstrated that when the NiZr ruld CuZr alloys are exposed to continuous Ar+ ion bombardment the outermost atomic layer is Zr rich due to preferential sputtering of Ni atoms. where Ni is preferentially sputtered, but the difference in sputtering yields is not sufficient to explain the observed composition. Therefore, it is necessary to consider other processes such as Radiation Induced Segregation(RIS). The surface composition of the heated sample surface predicts that Zr should surface segregate which futher supports the view that part of the Zr enrichment is due to RIS.to RIS.

• Journal of Korea Foundry Society
• /
• v.23 no.1
• /
• pp.30-39
• /
• 2003

Porous hybrid preforms were fabricated by reactive sintering using the compacts consisting of SiC particles, Fe and Al powders. Squeeze casting processing was employed to produce the composite in which the matrix phase is Al-Si7Mg. The microstructural change and wear resistance of the composites were investigated in terms of an amount of SiC particles. The wear loss was increased with increasing the contact pressure in the alloy containing SiC particles coated with Cu. The most drastic change was found to the specimen tested at 2.5 MPa of contact pressure. Concerning the alloys containing SiC particles coated with Ni-P, a drastic increase in the wear loss exhibited at 2 MPa of contact pressure in those alloys containing 4 and 8 wt. % of SiC particles coated with Ni-P. In the alloy containing 16 wt. % a proportional increase in wear loss was observed to the change of contact pressure. With respecting to the sliding velocity, the wear loss of the alloy containing SiC particles coated with Cu increased at the initial stage of wear process and then decreased. Similar result was found in the alloys containing SiC particles coated with Ni-P. On the basis of the present results obtained, it was found that wear resistance of the alloys tested was improved to show in the order of the alloy reinforced by coated SiC particles > by uncoated SiC particles > by intermetallic compound without SiC particles.