• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.643-645
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• 2008

Stainless steel 304 and 316 plates were deposited with the multi-layered coatings of titanium film (0.1um) and gold film (1-2um) by an electron beam evaporation method. The XRD patterns of the stainless steel plates modified with the multi-layered coatings showed the crystalline phases of the external gold film and the stainless steel substrate. Surface microstructural morphologies of the stainless steel bipolar plates modified with multi-layered coatings were observed by AFM and FE-SEM images. The external gold films formed on the stainless steel plates showed microstructure of grains of about 100nm diameter. The grain size of the external surface of the stainless steel plates increased with the gold film thickness. The electrical resistance and water contact angle of the stainless steel bipolar plates covered with multi-layered coatings were examined with the thickness of the external gold film.

• Journal of Conservation Science
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• v.1 no.1 s.1
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• pp.60-79
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• 1992

In relation to the scientific conservation treatment of ancient gilt bronze, the gold film coated on the bronze excavated from Hwangnam Great Tomb of Old Silla Kingdom(A. D. 5C) was studied in the view of coating technology and metallurgy of bronze. The uniform and dense gold film containing $2.44\sim12.40%$ of Hg with the thickness of $5.99\sim12.97{\mu}m$ was found to be coated on the bronze objects by amalgam coating method. On silver objects, the film with the thickness of $19.96{\mu}m$ was coated also continously and uniformly with gold by the same method. The bronze objects was fabricated by forging technique and contained almost $4.7\sim11.5%$ of Pb. Its microstructure was $\alpha-phase$ solid solution including Pb segregation in the matrix. The amount of $0.4\sim2.0%$ Zn was added in the bronze for the purpose of easy fabricating of Cu alloy. Based on the data studied, the gold film on bronze sample was reproduced by amalgam coating method and compared with the ancient gold film.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.1
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• pp.156-160
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• 2007

Surface plasmon resonance(SPR) has been widely studied for biological and chemical sensing applications. The present study conducts numerical simulation for the single and bimetallic layer SPR configurations by using the multiple beam interference matrix(MBIM) method to investigate the influence of wave interference and complex refractive indices of materials on optical characteristics such as reflectance and optical phase shift which are used for sensing. First, calculated reflectances are compared with experimental data for validation. In addition, in the single film structures this study finds out the appropriate film thicknesses with minimum reflectance for cases of gold film and silver film. For a bimetallic silver-gold film structure, in particular, the bimetallic film thicknesses that has the minimum reflectance are found 36 nm for silver and 5 nm for gold. From the results, the use of phase shift would be useful compared to reflectance in determining the SPR configuration because the phase shift becomes more sensitive than reflectance.

• Journal of the Korean Ceramic Society
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• v.45 no.8
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• pp.472-476
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• 2008

The surface region of commercial stainless steel 304 and 316 plates has been modified through deposition of the multi-layered coatings composed of titanium film ($0.1{\mu}m$) and gold film ($1-2{\mu}m$) by an electron beam evaporation method. XRD patterns of the stainless steel plates deposited with conductive metal films showed the peaks of the external gold film and the stainless steel substrate. Surface microstructural morphologies of the stainless steel bipolar plates modified with multi-layered coatings were observed by AFM and FE-SEM images. The stainless steel plates modified with $0.1{\mu}m$ titanium film and $1{\mu}m$ gold film showed microstructure of grains of under 100 nm diameter. The external surface of the stainless steel plates deposited with $0.1{\mu}m$ titanium film and $2{\mu}m$ gold film represented somewhat grain growth of Au grains in FE-SEM image. The electrical resistance and water contact angle of the stainless steel bipolar plates modified with multi-layered coatings were examined with the thickness of the gold film.

• Journal of the Korean institute of surface engineering
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• v.55 no.2
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• pp.102-119
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• 2022

Gold plating is used as a coating of connecter in printed circuit boards, ceramic integrated circuit packages, semiconductor devices and so on, because the film has excellent electric conductivity, solderability and chemical properties such as durability to acid and other chemicals. As increasing the demand for miniaturization of printed circuit boards and downsizing of electronic devices, several types of electroless gold plating solutions have been developed. Most of these conventional gold plating solutions contain cyanide compounds as a complexing agent. The gold film obtained from such baths usually satisfies the requirements for electronic parts mentioned above. However, cyanide bath is highly toxic and it always has some possibility to cause serious problems in working environment or other administrative aspects. The object of this investigation was to develop a cyanide-free electroless gold plating process that assures the high stability of the solution and gives the excellent solderability of the deposited film. The investigation reported herein is intended to establish plating bath composition and plating conditions for electroless gold plating, with thiomalic acid as a complexing agent. At the same time, we have investigated the solution stability against nickel ion and pull strength of solder ball. Furthermore, by examining the characteristics of the plated Au plating film, the problems of the newly developed electroless Au plating solution were improved and the applicability to various industrial fields was examined. New type electroless gold-plating bath which containing thiomalic acid as a complexing agent showing so good solution stability and film properties as cyanide bath. And this bath shows the excellent stability even if the dissolved nickel ion was added from under coated nickel film, which can be used at the neutral pH range.

• Rapid Communication in Photoscience
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• v.2 no.3
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• pp.79-81
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• 2013

A novel method of fabricating polythiophene-gold nanoparticle composite film electrodes for photoelectric conversion is demonstrated. The method includes electrodeposition of gold and electropolymerization of 2,2'-bithiophene onto an indium-tin-oxide (ITO) electrode. First, electrodeposition of gold onto the ITO electrode was carried out with various repetition times of pulsed applied potential (0.25 s at -2.0 V vs. Ag/AgCl) in an aqueous solution of $HAuCl_4$. Significant progress of the number density of deposited gold nanoparticles was confirmed from scanning electron micrographs, from 4 (1 time) to 25% (15 times). Next, electropolymerization of 2,2'-bithiophene onto the above ITO electrode was performed under controlled charge condition (+1.4 V vs. Ag wire, 15 $mC/cm^2$). Structural characterization of as-fabricated films were carried out by spectroscopic and electron micrographic methods. Photocurrent responses from the sample film electrodes were investigated in the presence of electron acceptors (methyl viologen and oxygen). Photocurrent intensities increased with increasing the density of deposited gold nanoparticles up to ~10%, and tended to decrease above it. It suggests that the surplus gold nanoparticles exhibit quenching effects rather than enhancement effects based on localized electric fields induced by surface plasmon resonance of the deposited gold nanoparticles.

• Journal of the Korean institute of surface engineering
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• v.25 no.6
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• pp.309-317
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• 1992

Evaluation of electroplated gold has been carried out to obtain the data base for electrical, mechanical and environmental properties for telecommunication component applications. Gold plating was performed to a various thickness of $0.1\mu\textrm{m}$ to 1.$25\mu\textrm{m}$ after Ni plating of $3\mu\textrm{m}$ on C52100 bronze. Electrical properties were evaluated by measuring contact resistance using 4-wire method under static contact and dynamic contact during wear. Reciprocating wear test was performed to study the wear behavior as well as failure of gold contacts. Environmental characteristics were evaluated by using salt spray testing and SO2 test. Hardness of soft gold film was measured to be 53KHN under 5g load. Friction coefficient was initially obtained to be 0.15 and 0.25 under 100g and 200g loads respectively, and then raised up to 0.8 with increasing reciprocating wear cycles. Static contact resistance was 2 to 3m$\Omega$ regardless of gold film thickness while drastic changes of contact resistance were occured upon stripping of the gold film during wear. The lifetime of contact wear showing stable contact resistance increased up to 6 times for $1\mu\textrm{m}$ thickness compared to that of$ 0.1\mu\textrm{m}$ thickness under 100g load. All gold plating appeared to be stable under salt atmosphere while only the gold plating over 1$\mu\textrm{m}$ was stable under SO2 atmosphere.

• Journal of the Korean institute of surface engineering
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• v.25 no.3
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• pp.107-116
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• 1992

The optimum thickness of Pd-Ni plated layers used as an electrical contact film was investigated by evaluating mechanical, thermal and environmental characteristics. The variations of morphologies and chemical compositions were studied by using SEM, EDS and ESCA. As a result of wear test, the wear resistance behavior of the gold plated layers was not changed with the sliding velocity changes. The palladium-nickel plated layer showed better wear resistance than the gold plated layer at low sliding velocity, but it showed poor wear resistance at high sliding velocity. Under the thermal condition of $400^{\circ}C$ in air, the gold thickness of $2\mu\textrm{m}$ without underplate on phosphorous bronze formed copper oxide on the surface layer by rapid diffusion of copper whereas the gold thickness of $0.8\mu\textrm{m}$ deposited on nickel and palladium-nickel underplate was stable at $400^{\circ}C$. Under the sulfur dioxide environments, the gold thickness of $0.3\mu\textrm{m}$ deposited on the nickel thickness of$ 3\mu\textrm{m}$ and the palladium-nickel thickness of $2\mu\textrm{m}$ underplate was more corrosion-resistant than the gold thickness of $2\mu\textrm{m}$ without underplate on phosphorous bronze. Under the nitric acid vapor environment, corrosion resistance of the gold film was superior to an equivalent thickness of the palladium-nickel film.

• Transactions of the Korean hydrogen and new energy society
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• v.22 no.2
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• pp.199-205
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• 2011

Stainless steel 304 and 316 plates were deposited with the multi-layered coatings of titanium film (0.1 um) and gold film (1-2 um) by an electron beam evaporation method. The XRD patterns of the stainless steel plates modified with the multi-layered coatings showed the crystalline phases of the external gold film and the stainless steel substrate. Surface microstructural morphologies of the stainless steel bipolar plates modified with multi-layered coatings were observed by AFM and FE-SEM images. The external gold films formed on the stainless steel plates showed micro structure of grains of about 100 nm diameter. The grain size of the external surface of the stainless steel plates increased with the gold film thickness. The electrical resistance and water contact angle of the stainless steel bipolar plates covered with multi-layered coatings were examined with the thickness of the external gold film.

• Proceedings of the Korean Society of Laser Processing Conference
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• 2006.06a
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• pp.108-111
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• 2006

Recently, mobile information devices, such as cellular phone, PDA(Personal Digital Assistant, PDA) are getting smaller and thinner. Accordingly, ultra precision welding technology is required to manufacture the high performance system for use in the telecommunication industry. In this study, we propose the laser micro welding process. Using ytterbium fiber laser, a wide range of experiments have been carried out for the gold wire-to-gold thin film welding.