• Journal of the Korean institute of surface engineering
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• v.5 no.2
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• pp.1-4
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• 1972

We have studied about the optimum chemical etching and sensitizing conditions of the plating on plastics. As specimen 'Mitzubishi Nobren MM2A' was used. The results were as follow. 1) The optimum chemical etching conditions. Etched the specimens for $10{\sim}40$ minutes at $70{\sim}80^{\circ}C$ with the etching solution of table 1, and for $10{\sim}15$ minutes at $65{\sim}70^{\circ}C$ with the etching solution of table 2 Table 1. Etching solution (I) Composition : $H_2SO_4(95%)-Component : 250 ml, Composition : $H_3PO_4(85%)$ - Component : 75ml, Composition : $K_2Cr_2O_7$ - Component : 12.5g, 2) The optimum sensitizing conditions. Sensitized the specimens for $60{\sim}90$ seconds at $25^{\circ}C$ with the sensitizing solution of table 3 Table 2. Etching solution (II) Composition : $H_2SO_4(95%)$ - Component : 22.5ml, Composition : $H_3PO_4(85%)$ - Component : 15ml, Composition : $CrO_3$ - Component : 105g, Composition : Water - Component : 150 ml, Table 3. Sensitizing solution Composition : $SnCl_2$ - Component : 9g, Composition : HCl(35%) - Component : 36ml, Composition : Water - Component : 300 ml

• 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.

• Korean Journal of Materials Research
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• v.11 no.10
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• pp.820-832
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• 2001

In order to obtain the basic data on the optimum conditions of electroforming process for fabricating the micro wiring pattern for plate type micro- motor core, characteristics of plating bath and properties of deposits were studied with various copper plating baths which contain sulfate, fluoborate, pyrophosphate and cyanide salt, respectively. Cathodic polarization, throwing power, internal stress, texture and surface morphology of deposits were observed. Throwing power of plating solution is deeply related to the polarization curves and the values are in the range of +20∼20%. The order of values ate as follows- pyrophosphate, cyanide, sulfate and fluoborate bath. Internal stresses of deposits are tensile in all of the copper plating bath. Thickness of the deposits plated at the center of holes has the highest value in the pyrophosphate bath and K factor, ratio of height and width of deposit, is 1.44. It was confirmed that the pyrophosphate bath was the best one for the electroforming of wire pattern.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.12
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• pp.1297-1303
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• 2015

The internal chromium plating of a long-axis tube is widely used in military and industrial application, with the thick hard plating formed using a mixed solution of Chromium acid and catalytic $H_2SO_4$. A large-caliber gun can endure a high explosive force as a result of the increased stiffness and wear resistance provided by this internal hard chromium surface. The internal chromium layer of a tube is prone to exfoliation caused by the high kinetic energy of the projectile and high pressure of the explosion. Therefore, we reviewed the plating process. Chromium plating comprises many steps, including the removal of Grease, water cleaning, electrolytic abrasion, etching, plating, water cleaning, and hydrogen brittleness removal. The exfoliated chromium plating layer is affected by the adhesion property of the plating. In particular, the Fe concentration of the electrolyte affects the adhesion property. The optimum Fe concentration for effectively suppressing the exfoliation of the plating layer was established by using a scanning electron microscope to determine the surface roughness, and the effectiveness was proved in an adhesion test, etc.

• Journal of Powder Materials
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• v.15 no.3
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• pp.221-226
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• 2008

Silver coated copper composite powders were prepared by electroless plating method by controlling the activation and deposition process variables such as feeding rate of silver ions solution, concentration of reductant and molar ratio of activation solution $(NH_4OH/(NH_4)_2SO_4)$ at room temperature. The characteristics of the product were verified by using a scanning electron microscopy (SEM), X-ray diffraction (XRD) and atomic absorption (A.A.). It is noted that completely cleansing the copper oxide layers and protecting the copper particles surface from hydrolysis were important to obtain high quality Ag-Cu composite powders. The optimum conditions of Ag-Cu composite powder synthesis were $NH_4OH/(NH_4)_2SO_4$ molar ratio 4, concentration of reductant 15g/l and feeding rate of silver ions solution 2 ml/min.

• International Journal of Precision Engineering and Manufacturing
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• v.9 no.2
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• pp.75-80
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• 2008

The fabrication of complex three-dimensional electrodes for micro electrical discharge machining (micro-EDM) is an important issue in the field of micromachining Localized electrochemical deposition (LECD) is a simple and inexpensive technique for fabricating micro-EDM electrodes. This study presents a new process for manufacturing electrodes with complex cross-sections using masks of different shapes, In this process, a non-conductive mask is placed between an anode and cathode that are immersed in a plating solution of acidified copper sulfate. The LECD is achieved by applying a pulsed voltage between the anode and cathode, which are separated by a small distance. In this setup, the cathode is placed above the anode and the mask, so that the deposited electrode can be used directly for EDM without changing the tool orientation. We found that the microstructure of the deposited electrode is influenced by the concentration of the plating solution and organic additives. Moreover, the values of the voltage, frequency, and duty cycle of the pulsed input have significant effects on the microstructure of the fabricated electrode. Finally, the optimum values of the voltage, frequency, and duty cycle were determined for the most effective fabrication of complex-shaped electrodes.

• Journal of Electrochemical Science and Technology
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• v.8 no.2
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• pp.146-154
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• 2017

In this study, copper (II) oxide was prepared for use in a copper electroplating solution. Copper chloride powder and copper (II) oxide are widely used as raw materials for electroplating. Copper (II) oxide was synthesized in this study using a two-step chemical reaction. Herein, we developed a method for the preparation of copper (II) oxide without the use of sintering. In the first step, copper carbonate was prepared without sintering, and then copper (II) oxide was synthesized without sintering using sodium hydroxide. The optimum amount of sodium hydroxide used for this process was 120 g and the optimum reaction temperature was $120^{\circ}C$ regardless of the starting material.

• Proceedings of the Materials Research Society of Korea Conference
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• 1992.05b
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• pp.26-27
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• 1992

The effect of activation and electroless nickel plating conditions on contact properties were investigated for selective electroless nickel plating of Si farers in order to obtain an optimum condition of contact hole filling. According to RCA prosess, p-type si 1 icon (100) surface was cleaned out and activated. The effects of temperture, DMAB concentration, time, and stirring iwere investigated for activation of p-type Si(100) surface. The optimal activation condition obtained was 0.5M HF, 1mM PdCl$_2$, 2mM EDTA, 7$0^{\circ}C$, 90sec under ultrasonic vibration. In electroless nickel plating, the effect of temperature, DMAB concentration, pH, and plating ti me were studied. The optimal plating condition found was 0. 10M NiS0$_4$.$H_2O$, 0.lIM Citrate, pH 6.8, 6$0^{\circ}C$, 30 minutes. The contact resistence of fi]ms wascomparatively low. It took 30 minutes to obtain 1$\mu$m thick film with 8$\mu$M DMAB concentration. The film surface roughness was improved with increasing temperature and decreasing pH of the plating solution. The best quality of the film was obtained with the condition of temperature 6$0^{\circ}C$ and pH 6.8. The micro-victors hardness of film was about 600Hv and was decreased wi th increasing particle size of plating layer.

• Journal of the Korean institute of surface engineering
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• v.10 no.3
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• pp.3-11
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• 1977

The trivalent choromium plating process have been studied by serveral group of orkers in the recent years. In the plating process, Alecra 3 process is the most familiar one. Potassium formate and potassium chloride of the bath compositions in the above process, are exchanged for sodium formate and sodium chloride, and then they have been examined characteristics of the electrodeposition using above bath solution and a few optimum conditions. The results are as follows, (1) The characteristics of the electrodeposition ; that is, throwing power, covering power, appearance, and deposition rate are most satisfied when concentration of $CrCl_3{\cdot}6H_2O$ is 0.4 mol/l, and mol ratio of HCOONa to Chromium(III); HCOONa/$Cr^{3+}$, is 2 to 3. (2) Throwing power, covering power, color and deposit rate show a similiar tendency to Alecra 3 process.

• Journal of the Korean institute of surface engineering
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• v.19 no.4
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• pp.140-148
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• 1986

Using sodium pyrophoshate as complexing agent, the characteristics and the magnetic properties of the films deposited from electroless cobalt plating bath have been studied. The result obtained are as following; 1. It was found that the optimum bath compositions consisted of 0.1M cobalt sulfate, 0.2M sodium hypophosphite as reducing agent, 0.4M sodium pyrophosphate as complexing agent and 0.5M ammonium sulfate as buffer agent, whereas good operating conditions were the bath of pH 10.5 adjusted with ammonia and 70$^{\circ}C$ of bath temperature, respectively. 2. The coercive force and the squareness of magnetic films were increased with deposition from the low temperature bath. 3. The phosphorous content in Co-P films deposited from these bath was relatively higher than that from Brenner bath. It was assumed to be due to codeposition of phosphorous from the pyrophosphate anion in the solution.