• Journal of the Microelectronics and Packaging Society
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• v.8 no.3
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• pp.55-62
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• 2001

With a spread of BGA, CSP and fine pitch devices, the need of flatter surface finish in bare board is becoming more critical in solderability. The electroless Ni/Au plating has a solution of these needs and also has being spread to apply to surface finish for bare board in many electronic goods. But, the electroless Ni/Au plating had several issues such as Ni oxidation and phosphorous contents. Before this study, we studied on the effect of BGA solderability in electroless Ni/Au plating and chose some major factors such as the oxidation property of NiP plating and warpage of board. Firstly, we made test board with various plating conditions and improved the plating property through the improvement of NiP oxidation reducing P content. Also, we minimized the warpage of board with the improvement of inner layer structure and the analysis of warpage. For the evaluation of solderability, we analyzed the warpage of board and the plating property after mounting BGA on the board with optimizing conditions. The solder joint of BGA is investigated by SEM(Scanning Electronic Microscope) and OM(Optical Microscope). The composition of joint is used by EDS(Energy Dispersive Spectroscopy). We analyzed the fracture strength and mode by ball shear teser.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.251-254
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• 2002

The technique of high speed machining is widely studied in machining field. In this study, TiAIN single-layered and TiAIN/TiN double-layered coatings were applied to end-mill by an arc ion plating technique. Their performances were comparatively studied about cutting force, tool wear, tool life and surface roughness of workpiece under high speed cutting conditions. The TiAIN single-layer coated tool showed higher wear-resistance due to its higher hardness, while the TiAIN/TiN double-layer coated tool showed better performance for high metal removal, i.e., high fled per tooth condition due to its higher toughness. The surface roughness of the workpiece was not influenced by the wear amount of coated tools.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1998.11a
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• pp.240-244
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• 1998

This study was carried out to investigate the efficiency of steel mill slag and sludge in removing heavy metals and cyanide in metal plating wastewater. Laboratory experiments were peformed with jar tester, The tests were peformed at ambient temperature. The results of tests showed that overall rates metals removed were greater than 90 %. Metals were removed from solution as the combined effects of adsorption and precipitation in alkaline condition. The removal efficiency of cyanide by steel mill wastes was above 90 % at optimum conditions. In view of the test results and other engineering characteristics of steel mill slag and sludge, these industrial by-products from steel industry have a high potential to be used in metal plating wastewater treament and were particularly beneficial.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.697-703
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• 1996

Fatigue strength of high strengthsteels are variable with many different surface treatment. It is well known that residual compressive stress retard fatigue crack growth rate(or arrest crack). High strngth steels are manufactured by following process. Heat treatment, shot peening and chromium plating process. High strength steel(HRC40 or above) which are subjected to fatigue load and dynamic load, chromium plated parts shall be peened in accordance with requirements and baked after plating. The purpose of this paper is to compare and discuss the influence of surface treatment and hydrogen embrittlement on fatigue strength of high strength steel. Therefore, fatigue test was performed to investigate influence of surface treatment. The results shows that shot peening is very effect method in creasing fatigue life and after plating, baking process is essential to prevent hydogen failure. In this paper, the experimental investigation is made to clarify the influence of shot peening conditions and baking process on fatigue strength of high strength steel.

• Journal of the Korean Ceramic Society
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• v.46 no.5
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• pp.497-504
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• 2009

DLC is considered as the candidate material for application of moving parts in automotive components relatively in high pressure and temperature operating conditions for its high hardness with self lubrication and chemical inertness. Different deposition method such as arc plating, ion gun plating and PECVD were used for comparing mechanical and tribological properties of each DLCs deposited on stainless steel with 1 um thick respectively. Among these 3 types of DLCs, the arc plated DLC film showed highest value for wear resistance in dry condition. From the results of analysis for physical properties of DLC films, it seems that the adhesion force and crack initiation modes were more important factors than intrinsic mechanical properties such as hardness, elastic modulus and/or roughness to the wear resistance of DLC films. Raman spectroscopy was used for understanding chemical bonding natures of each type of DLC films. Typical D and G peaks were identified based on the deposition method. Hardness of the coating layers were identified by nanoindentation method and the adhesions were checked by scratch method.

• Journal of the Korean institute of surface engineering
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• v.32 no.3
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• pp.265-275
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• 1999

Titanium nitride and related overlayers produced by arc ion plating (AIP) are applied as commercial coatings in world-wide scale since the middle of 80s. Due to the achievements of low temperature deposition (LTD), they begin now to be used as wear and corrosion-resistant coatings for machine parts, besides applications on cemented carbide and high speed steel cutting tools. On the other side, TiN can be now applied successfully to brass, Al-alloy, ZnAl alloy articles as decorative coating through LTD. Various nitrides, carbonitrides, borides and other refractory compounds, such as (Ti, Al)N, TiCN, CrN, are used as the coatings for special heavy-duty working conditions instead of TiN since 90s. More and more multilayer coatings are applied now substituting single layer ones. Duplex processes are under development.

• Journal of the Korean Society for Heat Treatment
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• v.34 no.6
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• pp.281-286
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• 2021

Arc ion plating (AIP), laser cladding, and nitriding are methods that can prevent mold damage or repair and create cracks and breakages on the die surface. The dissolution and soldering behavior of coated SKD61 by using arc ion plating, laser cladding, and nitriding was investigated. The structure of the coating was investigated as a function of deposition conditions by X-ray diffraction and the crystallographic orientation was determined using the texture factor. The TiAlN film deposited with AIP showed excellent corrosion resistance in the molten aluminum alloy at 680℃. In this paper, we have detailed the corrosion and mass loss phenomena associated with these steel-cast metal interactions.

• Journal of the Korea Convergence Society
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• v.9 no.10
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• pp.271-276
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• 2018

In the industry, Zn galvanizing on the steel using the principle of sacrificial anode is used. The steel have some problem, specially corrosion problem. To solve corrosion problem, Zn-Mn alloy plating has been studied as one of the measures to increase the corrosion resistance rather than pure zinc plating. It is possible to be applied to automotive parts requiring high corrosion resistance even though the plating cost is high. In this study, Zn-Mn alloys were electrodeposited from an acidic chloride bath. The influence of the electrolytic conditions on the composition of the alloy plating in the chloride bath was investigated. As the current density of the cathode increases, Zn content of electrodeposit decrease and Mn content of electrodeposit increase. As the temperature of the electrolyte increases, Zn content of electrodeposit decrease and Mn content of electrodeposit increase. The results are explained by the cathode overvoltage curve of Mn and Zn.

• Journal of the Korean Vacuum Society
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• v.9 no.3
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• pp.207-215
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• 2000

Al films on cold-rolled steel sheet have been prepared by vacuum evaporation and arc-induced ion plating, respectively, and the evaporation rate and vapor distribution (thickness distribution over the substrate) have been investigated according to deposition conditions. The arc-induced ion plating (AIIP) method have been employed, which makes use of arc-like discharge current induced by ionization electrode located near the evaporation source. The AIIP takes advantage of high ionization rate compared with conventional ion plating, and can be carried out at low pressure of less than $10^{-4}$ torr. Very high evaporation rate of more than 2.0 mu\textrm{m}$/min could be achieved for Al evaporation using alumina liner by electron beam evaporation. The geometry factor n for the $cos^{n/\phi}$ vapor distribution, which affects the thickness distribution of films at the substrate turned out to be around 1 for vacuum evaporation, while it features around 2 or higher for ion plating. For the ion plated films, it has been found that the ionization condition and substrate bias are the main parameters to affect the thickness distribution of the films.

• Journal of Plant Biotechnology
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• v.49 no.4
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• pp.331-338
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• 2022

Sunflower (Helianthus annuus L.) protoplasts were isolated from seven-day-old etiolated hypocotyls of 10 A line and four-week-old fully expanded young leaves of PI 441983 line in vitro seedlings using an enzymatic method. Purified protoplasts were collected by filtration and floatation in sucrose solution. Semi-solid protoplast culture was performed using the L4 regeneration protocol with various culture media and plating densities to achieve the highest efficiencies for protoplast culture of hypocotyl and mesophyll protoplasts of 10 A and PI 441983 lines, respectively. The concentrations in liquid L'4M medium and different plating densities were evaluated in two types of cytokinins, the adenine-type 6-benzyladenine (BA) and the phenylurea-type thidiazuron (TDZ). The highest colony formation was achieved in both sunflower lines when 0.5 mgL^-1 BA and 0.5 mgL^-1 TDZ were applied with a high plating density (3 × 10⁵ protoplasts mL^-1). These conditions led to 38.45% and 39.40% colony formation for hypocotyl protoplasts of the 10 A line and mesophyll protoplasts of the PI 441983 line, respectively. Moreover, many hypocotyl protoplast-derived colonies developed into micro-calli. In addition, superior development of both sunflower protoplasts was observed with all plating densities when BA was used in combination with TDZ. This finding will be applicable to future sunflower hybrid production via somatic hybridization.