• Journal of Surface Science and Engineering
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• v.32 no.6
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• pp.709-716
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• 1999

Ceramic is select for an alternative substrate material for high-speed circuits due to its low-thermal expansion. As, in this study, ceramic was prepared by ISG (interlayer sol-gel) process using metal salts and a metal alkoxide as the starting materials. Generally ceramic substrate is used electroless copper plating for the metallization. But it has been indicate weakely the adhesion strength between the substrate and copper layer. Therefore, this research, using the ISG process on the preparation of homogeneous and possible preparation at law temperature fabricated sol solution. Using of the dip coating method was coated for the purpose of giving the anchoring effect on the coating layer and enhancing the adhesion strength between the $Al_2$O$_3$ substrate and copper layer. This study examined primary the characteristic of the sol making condition and differential thermal analysis (DTA) X-ray diffraction (XRD) were mearsured to identify the crystal phase of heat treatment specimens. The morphology of the coated films were studied by scanning electron microscopy(SEM). As a resurt, XRD analysis was obtained patterns of $\alpha$-cordierite after heat-treatment about 2 hours at $1000^{\circ}C$. SEM analysis could have seen a large number of voids on coated film. The more contants of$ Al_2$$O_3$ Wt% was increased the more voids was advanced. Peel adhesion strength has a maximum in the contants of the TEOS:ANE of 1:0.7 mole%. In this case, adhesion strength has been measured 1150gf, peel adhesion strength were about 10 times more than uncoated of the ceramics film.

• Journal of Surface Science and Engineering
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• v.33 no.5
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• pp.319-328
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• 2000

Silver is known to have such characteristics as low shear strength, good transfer-film forming tendency, and good corrosion resistance. Silver thin films have been prepared by ion plating of physical vapour deposition (PVD) using both argon gas pressure and bias voltage of processing condition. After the silver films were prepared, the properties in them were examined by gas pressure and bias voltage of substrate. Their morphology and crystal orientation were investigated by scanning electron microscopy (SEM) and X-ray diffractor. The properties of film were, also, studied to relate with morphology, X-ray diffraction pattern, and friction coefficient at vacuum ambient. The friction coefficient was stabilized remarkably on deposited films with increasing argon pressure for deposition. Also, the effect of increasing of the bias voltage for deposition resulted in lower friction coefficient and stability in $1.7$\times$10^{-4}$ torr. On the contrary, behavior of friction coefficient was stabilized on deposited films with decreasing the bias voltage in $1.7$\times$10^{-5}$ torr for deposition.

• Journal of Surface Science and Engineering
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• v.33 no.4
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• pp.222-228
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• 2000

The life time of cutting tool was studied in the relation with the properties of TiN coating tools. The purpose of this study is to compare the cutting conditions of the TiN coated tools with those of the non-coated tools and to find out the optimal cutting condition of the TiN coated tool. The coated tools were prepared by the sputtering process at $4$\times$10^{-3}$Torr. When the cutting speed is increased 22.2% from 90m/min, the limited life of coating bite was decreased by 60.61%, but non-coating bite was decreased by 64.05%. In the tool lifetime equation of the coated tools "a"(exponent of feed rate) was not much changed in comparison with that of the non-coated tools but "n" (exponent of tool′s life) was increased by 9.3% and "b" (exponent of cutting depth) was increased by 2.4%. It was thought to be that TiN coated tools was used for higher cutting speed than non-coated tools to improve the lifetime of the coated tools.

• Journal of Surface Science and Engineering
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• v.57 no.4
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• pp.274-284
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• 2024

In this study, copper foil was electroplated under high current density conditions. We used Polyethylene Glycol (PEG), known for its thermal stability and low decomposition rate, as an inhibitor to form a stable and smooth copper layer on the titanium cathode. The electrolyte was composed of 50 g/L CuSO₄ and 100 g/L H₂SO₄, MPSA as an accelerator, JGB as a leveler, and PEG as a suppressor, and HCl was added as chloride ions for improving plating efficiency. The copper foil electroplated in the electrolyte added PEG which induced to inhibit the growth of rough crystals. As a result, the surface roughness value was reduced, and a uniform surface was formed over a large area. Moreover, the addition of PEG led to priority growth to the (111) plane and the formation of polygonal crystals through horizontal and vertical growth of crystals onto the cathode. In addition, the grains became fine when more than 30 ppm of PEG was added. As the microcrystalline structure changed, mechanical and electrical properties were altered. With the addition of PEG, the tensile strength increased due to grain refinement, and the elongation was improved due to the uniform surface. However, as the amount of PEG added increased, the corrosion rate and resistivity increased due to grain refinement. Finally, it was possible to manufacture a copper foil with excellent electrical and mechanical properties and the best surface properties when electroplating was carried out under the condition of additives with Cl-20 ppm, MPSA 10 ppm, JGB 5 ppm, and PEG 10 ppm.

• Journal of Advanced Marine Engineering and Technology
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• v.20 no.5
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• pp.103-113
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• 1996

The properties of the deposited film depend on the deposition condition and these, in turn depend critically on the morphology and crystal orientation of the films. Therefore, it is important to clarify the nucleation occurrence and growth stage of the morphology and orientation of the film affected by deposition parameters, e.g. the gas pressure and bias voltage etc. In this work, magnesium thin flims were prepared on cold-rolled steel substrates by a thermo-eletron activation ion plating technique. The influence of nitrogen gas pressure and substrate bias voltage on their crystal orientation and morphology of the coated films were investigated by scanning electron microscopy (SEM) and X-ray diffraction, respectively. The diffraction peaks of magnesium film became less sharp and broadened with the increase of nitrogen gas pressure. With an increase in nitrogen gas pressure, flim morphology changed from colum nar to granular structure, and surface crystal grain-size decreased. The morphology of films depended not only on gas pressure but also on bias voltage, i.e., the effect of increasing bias voltage was similar to that of decreasing gas pressure. The effect of crystal orientation and morphology of magnesium films on corrosion behaviors was estimated by measuring anodic polarization curves in deaerated 3%NaCl solution. Magnesium, in general, has not a good corrosion resistance in all environments. However, these magnesium films prepared by changing nitrogen gas pressure showed good corrosion resistance. Among the films, magnesium films which exhibited granular structure had the highest corrosion resistance. The above phenomena can be explained by applying the effects of adsorption, occlusion and ion sputter of nitrogen gas.

• Journal of the Korean Electrochemical Society
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• v.16 no.1
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• pp.46-51
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• 2013

In order to monitor in situ electrochemical reaction we prepared the gold microshells on silica microspheres of $2{\mu}m$ in diameter which were able to not only work as electrodes but also surface enhanced Raman scattering (SERS) active substrates. Previously reported gold microshell using polystyrene as core material have a few serious problems, mostly coming from solubility in organic solvent, nonuniform distribution in size and toxicity of the polystyrene. Here we prepared silica core-gold microshell to obtain a strong SERS active platform benefitting from the physicochemical stability, uniformity and non-toxicity of silica. Varying the concentration of 3-aminopropyl triethoxysilane (APTES), the surfaces of silica beads were modified and the optimal condition was determined to be 1% APTES that made the SERS activity of gold microshell strongest. The gold microshells as made were characterized by homemade Micro-Raman system spectrometer, Field-Emission Scanning Electron Microscope.

• Journal of Powder Materials
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• v.22 no.6
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• pp.432-437
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• 2015

The en-riched $^{58}Ni$ powders are dissolved in acid solution and coated on a Cu target for proton irradiation at cyclotron to produce $^{57}Co$ radioisotope. The condition of the plating bath and the coating process are determined using the en-riched powders. To establish the coating conditions for $^{57}Co$, non-radioactive Co ions are dissolved in an acid solution and electroplated on to a rhodium plate. The thermal diffusion of electroplated Co into a rhodium matrix was studied to apply a $^{57}Co$ Mssbauer source. The diffusion depth from surface to matrix of Co is depended on the annealing temperature and time. The deposited Co atoms diffuse completely into a rhodium (Rh) matrix without substantial loss at an annealing temperature of 1200 for 4 hours.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.3
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• pp.223-229
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• 2015

Surface modification is a technology to form a new surface layer and overcome the intrinsic properties of the base material by applying thermal energy or stress onto the surface of the material. The purpose of this technique is to achieve anti-corrosion, beautiful appearance, wear resistance, insulation and conductance for base materials. Surface modification techniques may include plating, chemical conversion treatment, painting, lining and surface hardening. Among which, a surface modification process using electrolytes has been investigated for a long time in connection with research on its industrial application. The technology is highly favoured by various fields because it provides not only high productivity and cost reduction opportunities, but also application availability for components with complex geometry. In this study, an electrochemical experiment was performed on the surface of 5083-O Al alloy to determine an optimal electrolyte temperature, which produces surface with excellent corrosion resistance under marine environment than the initial surface. The experiment result, the modified surface presented a significantly lower corrosion current density with increasing electrolyte temperature, except for $5^{\circ}C$ of electrolyte temperature at which premature pores was created.

• Journal of the Korean Society for Heat Treatment
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• v.25 no.1
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• pp.6-13
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• 2012

HVOF thermal spray coating of 80%WC-CoFe powder is one of the most promising candidate for the replacement of the traditional hard chrome plating and hard ceramics coating because of the environmental problem of the very toxic $Cr^{6+}$ known as carcinogen by chrome plating and the brittleness of ceramics coatings. 80%WC-CoFe powder was coated by HVOF thermal spraying for the study of durability improvement of the high speed spindle such as air bearing spindle. The coating procedure was designed by the Taguchi program, including 4 parameters of hydrogen and oxygen flow rates, powder feed rate and spray distance. The surface properties of the 80%WC-CoFe powder coating were investigated roughness, hardness and porosity. The optimal condition for thermal spray has been ensured by the relationship between the spary parameters and the hardness of the coatings. The optimal coating process obtained by Taguchi program is the process of oxygen flow rate 34 FRM, hydrogen flow rate 57 FRM, powder feed rate 35 g/min and spray distance 8 inch. The coating cross-sectional structure was observed scanning electron microscope before chemical etching. Estimation of coating porosity was performed using metallugical image analysis. The Friction and wear behaviors of HVOF WC-CoFe coating prepared by OCP are investigated by reciprocating sliding wear test at $25^{\circ}C$ and $450^{\circ}C$. Friction coefficients (FC) of coating decreases as sliding surface temperature increases from $25^{\circ}C$ to $450^{\circ}C$.

• Korean Journal of Optics and Photonics
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• v.18 no.5
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• pp.362-366
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• 2007

In this research, the optimal grinding condition has been obtained by design of experiment (DOE) fur the development of aspheric lens for the 3 Mega Pixel, 2.5x optical zoom camera-phone module. Also, the tungsten carbide (WC) mold was processed by the method of ultra precision grinding under this optimal grinding condition. The influence of diamond-liked carbon (DLC) coating on form accuracy (PV) and surface roughness (Ra) of the mold was evaluated through measurements after DCL coating using ion plating on the ground mold. Also, aspheric glass lenses were molded, some before DLC coating of the mold and some after the DLC coating. The optical characteristics of each sample, molded by the different molds, were compared with each other.