• Transactions of the Korean hydrogen and new energy society
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• v.9 no.2
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• pp.65-75
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• 1998

Five different processes were selected and tested to find an useful method of manufacturing Fe-Ti type electrode. Initially, FeTi alloy was prepared by melting in plasma arc furnace and then powdered for shaping. Electroless Ni plating on these powder particles before shaping improved the discharge characteristics. The effects of heat-treatments on the electrode characteristics were also investigated. The discharge capacities of electrods were increased with the increasing heat-treatment temperatures. When heat treated at $1000^{\circ}C$ after shaping, the best results were acquired in the discharge capacity and cycle life. Both electroless Ni plating and heat-treatment were appeared to be crucial for the performance improvement of FeTi type electrode. Fe-Ti -Mn electrodes were prepared according to the process suggested in this study and tested to verify the promising effects of that.

• Journal of the Korean institute of surface engineering
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• v.19 no.3
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• pp.83-91
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• 1986

Codeposited of boron nitride(BN) particle dispersed into electroless nickel-phosphours (Ni-P) and nickel-boron(Ni-B) platings were studied for the purpose of developing the wear resistance and lubricity. BN can be codeposited from electroless nickel plating bath with $NaH_2PO_2$ and $NaBH_4$ as the reducing agents. Most dispersolids were distributed uniformly in the Ni-P and Ni-B matrix. Abrasion loss decreased with increasing amount of codeposits and reached a constant value 2.4 percent by volume percent of BN particle. The wear resistance and the friction coefficient of the heat treated BN composite coatings were improved about three times than that of as-coatings. The BN composite coatings were more wear resistance than hard chromium. Ni-B-BN composite coatings showed lower wear resistance and friction coefficient than Ni-P-BN. The BN content of the deposite was found to be 2.4 v/o for these optium conditions.

• Journal of the Microelectronics and Packaging Society
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• v.11 no.3 s.32
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• pp.37-45
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• 2004

Electroless Ni(P) has been widely used for under bump metallization (UBM) of flip chip and surface finish layer in microelectronic packaging because of its excellent solderability, corrosion resistance, uniformity, selective deposition without photo-lithography, and also good diffusion barrier. However, the brittle fracture at solder joints and the spatting of intermetallic compound (IMC) associated with electroless Ni(P) are critical issues for its successful applications. In the present study, the mechanism of IMC spatting and microstructure change of the Ni(P) film were investigated with varying P content in the Ni(P) film (4.6,9, and $13 wt.\%$P). A reaction between Sn penetrated through the channels among $Ni_3Sn_4$ IMCs and the P-rich layer ($Ni_3P$) of the Ni(P) film formed a $Ni_3SnP$ layer. Thickening of the $Ni_3SnP$ layer led to $Ni_3Sn_4$ spatting. After $Ni_3Sn_4$ spatting, the Ni(P) film directly contacted the molten solder and the $Ni_3P$ phase further transformed into a $Ni_2P$ phase. During the crystallization process, some cracks formed in the Ni(P) film to release tensile stress accumulated from volume shrinkage of the film.

• Korean Journal of Materials Research
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• v.5 no.8
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• pp.1013-1019
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• 1995

The thin plate of Co-Ni-P was deposited on the polyester film by the electroless plating method. Through present experiments, deposition rates and metal compositions of the plates were determined according to compositions of solution, pH and temperature. Also, magnetic properties of plates were examined according to metal compositions. Considering magnetic properties and deposition rates of electroless plating, the best condition was obtained as pH of 8.5 and 90℃. It was observed that metal compositions were evidently varied by the pH of solutions and the concentration of complex agents. However. they were not affected by other factors. At the optimum condition, the composition of the plate was Co(78%), Ni(16%), and P(6%). Also, it was found that the coercive force was 370 Oe, and squareness was 0.65 at this condition. Magnetic properties (hard or soft) of thin plates were determined by metal compositions. Therefore. the plate became soft magnetic plate as the composition of nickel increased over 30 per cents. The crystal structure of the soft magnetic plate was found to be amorphous in which it was strongly oriented to the (111)phahe of nickel. On the ohter hand, the hard magnetic place was found to be hcp crystalline of α-cobalt which was oriented to the (101)phase of cobalt and the (100)phase of cobalt.

• Journal of the Korean institute of surface engineering
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• v.22 no.2
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• pp.69-77
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• 1989

Codeposion of inert particles particles in a metallic mateix by electroless plating process involves two phenomena. Firstly, the adsorption of inercles and secondly, the adsorption of inert particles on the cathode. In the present paper the first adsorption phenomenon and in the next paper the second ane are studied in greaterdetail for the Ni-SiCc, Ni-Al2AO3 and Ni-WC systems. Measurements of the Zeta potentials for the SiC and Al2AO3 particles have been in different electrolyte solutions and the ionic species adsorbed on the Particles studied. The addition of sodium acetate, trisodium citrate and sodium phosphinate to nikel sulface sruomotes the zeta potential of SiC and Al2O3 particles, but zeta phosphinate to nickel is more positive than Al2O3 particles although the amount of nickel ion adsorbrd on the Al2O3 particles become greater than that of SiC particles. It is suggested that this is due to adsortion of Na ion onto the surface SiC particles.

• Korean Journal of Materials Research
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• v.6 no.7
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• pp.700-708
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• 1996

Electroless plating technique was utilized to flip chip bonding to improve surface mount characteristics. Each step of plating procedure was studied in terms pf pH, plating temperature and plating time. Al patterned 4 inch Si wafers were used as substrstes and zincate was used as an activation solution. Heat treatment was carried out for all the specimens in the temperature range from room temperature to $400^{\circ}C$ for $30^{\circ}C$ minutes in a vacuum furnace. Homogeneous distribution of Zn particles of size was obtained by the zincate treatment with pH 13 ~ 13.5, solution concentration of 15 ~ 25% at room temperature. The plating rates for both Ni-P and Au electroless plating steps increased with increasing the plating temperature and pH. The main crystallization planes of the plated Au were found to be (111) a pH 7 and (200) and (111) at pH 9 independent of the annealing temperature.

• Polymer(Korea)
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• v.37 no.4
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• pp.449-454
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• 2013

In this work, the effect of electroless Ni-plating of multi-walled carbon nanotubes (MWCNTs) on thermal conductivity and fracture toughness properties of MWCNTs/$Al_2O_3$/epoxy composites was investigated. The surface properties of the Ni-plated MWCNTs were determined by scanning electron microscopy (SEM), X-ray photoelectron spectrometry (XPS), and X-ray diffraction (XRD) analyses. Thermal conductivity was tested using a thermal conductivity measuring system. The fracture toughness of the composites was carried out through the critical stress intensity factor ($K_{IC}$) measurement. As a result, the electroless Ni-plated MWCNTs led to a significant change of surface characteristics of the MWCNTs. Thermal conductivity and fracture toughness of the MWCNTs/$Al_2O_3$/epoxy composites were greater than those of non-treated ones. These results were probably due to the improvement of intermolecular interaction between the Ni-MWCNTs and the matrix resins.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.434-435
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• 2009

The crystalline silicon solar cell where the solar cell market grows rapidly is occupying of about 85% or more. high-efficiency and low cost endeavors many crystalline silicon solar cells. the fabrication processes of high-efficiency crystalline silicon solar cells necessitate complicated fabrication processes and Ti/Pd/Ag contact, however, this contact formation processed by expensive materials. Ni/Cu contact formation is good alternative. in this paper, according to temperature Ni silicide makes, produced Ni/Cu contact solar cell and measured conversion efficiency.

• Journal of the Korean institute of surface engineering
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• v.45 no.4
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• pp.162-167
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• 2012

Ni-P/C multi-layer was synthesized by electroless plating and paste coating for better corrosion and surface conductance as a metallic bipolar plate. The Ni-P layer could be synthesized with the range of 2.6~22.4 at.% P contents and it's surface morphology and corrosion resistance depend on content of P. Corrosion resistance of the Ni-P layer in sulfuric acid by electrochemical test is similar with pure Ni. Surface resistance of pure Ni after corrosion was increased about 8% compared to pure Ni. On the other hand, that of the Ni-P/C composite with 20% carbon content was increased only 1%.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2003.10a
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• pp.11-11
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• 2003

Electroplated hexavalent chromium coatings have been used in many technical applications since it was invented by G.J. Sargent in 1920. Because of the environmental problems and health risks associated with the use of hexavalent chromium, there has been an extensive search for alternative coatings with properties such as corrosion resistance and wear resistance, at a reasonable cost. However there is no single substitute that meets all the desirable performance characteristics of chromium. Advanced techniques, such as alloy plating, electroless plating, trivalent chromium plating, plasma and thermal spray coating, PVD and ion implantation, have been applied for replacing hexavalent chromium plating.