觸媒粒子 內에서 細孔擴散이 選擇度에 미치는 影響

孫太源,廉聖培 弘益大學校 1983 弘大論叢 Vol.15 No.2

The in fluence of pore diffusion on the yield and selectivity has been studied for a chemical reaction occuring in a catalyst particle. When a consecutive reaction (A???→R???→S) proceeds, mathematical formulation is performed by introducing Wheeler's classical work. Also the variation of the yield of intermediate product R due to conversion of reactant A was considered incase of plug flow reactor. By computations, favorable conditions to increase yield of desired product R with various values of parameters were obtained. The present results show that it is favorable when the reaction rate constant k₁is larger than k₂. And as a whole, the values of lower Thiele modulus for a nonporous catalyst and of higher effective diffusivity ratio tend to increase the yield of intermediate product.

전기도금에 의한 알루미늄의 박막 제조 및 그 특성에 관한 연구

孫太源,趙漢相 弘益大學校 科學技術硏究所 2000 科學技術硏究論文集 Vol.11 No.-

용융탄산염 연료전지(Molten Carbonate Fuel Cell ; MCFC)는 최근 10년간 제 3세대 연료전지로써 활발한 개발 중에 있다. MCFC는 고온에서 작동하므로 반응속도가 빨라 고가의 촉매가 필요 없으며 다량의 폐열회수가 가능하지만, 고온에서 작동되므로 전극재료의 부식문제나 기계적 안정성, 전해질의 관리문제 등의 문제점등이 대두되고 있다. MCFC의 스테인레스강으로 된 분리판의 부식문제 해결은 현재도 많은 관심사가 되고 있다. 특히 wet seal부위에 대한 부식을 방지하기 위하여 주로 스테인레스강에 알루미늄 박막을 코팅하는 기술이 요구되고 있으며, 그 방법으로는 용융도금, Plasma spray, PVD, DVD, 전기도금 등이 있다. 이 방법들 중 용융염 전기도금의 경우, 적절한 알루미늄의 전기도금을 위해 알맞은 전해질을 선택하는 것이 중요하다. 본 연구에서는 aluminum-chloride-alkali melt 전해질과 유기용매를 제조하여 각 전해질의 전기화학적 특성에 대해 실험을 하였다. 선형전류전압법을 사용하여 알루미늄 환원 기작을 연구하였고 용융염 전해질에서 stainless steel으로 알루미늄의 확산계수가 D_(0)=2.98×10^(-10) ㎠/sec, 유기용매 전해질에서 D_(0)=6.41×10^(-9) ㎠/sec 임을 알수 있었다. 또한 10mA/㎠의 전류 밀도로 전기도금을 시행한 결과 알루미늄 도금층을 확인할 수 있었다. The molten carbonate fuel cell(MCFC) has been under intensive development during the last decade as second generation fuel cell. It has high reaction rate, need not expensive catalyst and, can recover heat of large quantity. But high operating temperature results in many troubles such as corrosion of electrode material, maintenance of electrolytes, etc. Corrosion of wet seal area that made of stainless steel is very important. For the corrosion protection of wet seal area, techniques that coating stainless steel with aluminum film are required. These coating techniques are molten plating, plasma spray, physical vapor deposition, chemical vapor deposition and electrodeposition(electroplating), etc. In case of molten salt electroplating among these techniques, suitable electrolyte is selected for pertinent electroplating of aluminum. In this study, we prepared aluminum chloride-alkali chloride melt electrolyte and organic electrolyte. We proceeded to experiment using them for electrochemical characterist of each electrolyte. A detail study of the aluminum reduction mechanism was carried out using the electrochemical methods of linear sweep voltammetry. The solid state diffusion coefficient of aluminum into the stainless steel was evaluated and found to be D_(0)=2.98 x 10^(-10) ㎠/sec in molten salt electrolyte and D_(0)=6.41 x 10^(-9) ㎠/sec in organic electrolyte. In addition, electroplating reaction using galvanostatic method progressed toward cathodic direction(10 mA/㎠) and aluminum plating layer was observed.

공장에서의 금속 부식에 대한 문제점과 그 대책

손병청,손태원,임병오 弘益大學校 1980 弘大論叢 Vol.12 No.-

It must be obvious that the corrosion has been treated rightly and overlooked because of its long history and ever-slow taking process. Also it is difficult to find its nature and anti-corrosion scheme, since the theory of corrosion is a complex mixture of a variety of natural sciences with electrochemisty as the sheet anchor. Further, it must be again obvious that the working engineer generally has neither the time, nor the training, to comprehend the whole theory. Most companies have no corrosion engineer and simply exchange corroded parts without trying any other anti-corrosion method. Some of them have been depend upon the foreign companies associated with them. A few companies are begining to tackle their corrosion problem by the cooperation with the domestic corrosion engnieers and researchers. It has been a consequence of the complexity of corrosion nature that, over the years, an uncomplicated common-sense approach to anticorrosion methods has been developed. This anti-corrosion methods may help to enable an engineer to tackle his corrosion problems with confidence.

RuxIr₁xO₂/Ti mesh 촉매전극에 의한 페놀의 전기화학적 산화특성에 관한 연구

孫太源,李相雄 弘益大學校 科學基術硏究所 1999 科學技術硏究論文集 Vol.10 No.2

One of the best ways of turning the characteristics of aromatic compounds the major anti-degradable compounds, into the one of bio-degradable is electrochemical oxidation. Among the aromatic compounds chlorine group on phenol has been chosen and the probabilities of electrochemical oxidation was researched by measuring Cyclic voltammogram(CV) and Tafel polarization curve for RUx.rxO₂/Ti mesh catalytic electrode. The value of HPP using Ru/Ir 7:3 electrode was smaller and i?? was larges than using Ru/Ir 3:7 electrode. Ru/Ir 7:3 electrode was better than Ru/Ir 3:7 electrode on the electrochemical oxidation of phenol.

용융탄산염 내에서의 Stainless steel의 부식특성에 관한 연구

孫太源,金俊亨,金炳天 弘益大學校 科學技術硏究所 1997 科學技術硏究論文集 Vol.8 No.-

The effect of oxidant gas on corrosion behavior of separator material for molten carbonate fuel cell, the AISI 316L stainless steel in the molten carbonates was investigated by using the electrochemical techniques. The composition of electrolyte used in this study were 62mol% Li₂CO₃ and 38mol% K₂CO₃. The concentration of oxidant gases CO₂, O₂ were varied from 5vol% to 50vol% respectively. it had been found the increase of oxidant gas concentration proportionally enhanced the corrosion rate of AlSl 316L stainlees steel. From the result, we obtained to the relation between Ecorr, Icorr and CO₂ gas partial pressure and also O₂ gas partial pressure. Therefore it is suggested Ecorr ∝ P(o₂)??, Icorr ∝ P(o₂)?? and Ecorr ∝ P(co₂)?? , Icorr ∝ P(co₂)??.

3.5% NaC1 溶液에서 銅, 低炭素鋼, 스테인레스綱에 對한 腐蝕抑制劑의 影響에 關한 硏究

孫太源,金基溶 弘益大學校 1985 弘大論叢 Vol.17 No.2

Experiments were conducted to study on the inhibiting effect of monoethanolamine, ethylenediamine, thiourea, and benzotriazole for copper, low carbon steel, and stainless steel in 3.5% NaCl solution. Corrosion rates were calculated by anodic and cathodic polarization curves using the potentiostat. For all cases of three kinds of metals used in this experiment, inhibitive efficiency of corrosion decreased in the following order: benzotriazole>ethylenediamine>monoethanolamine>thiourea. Especially benzotriazole, for the whole three kinds of metals was represented a very high inhibitive efficiency from 92% to 82%. The number of nitrogen atoms in the inhibitor's molecule was found to have an important roll on corrosion rate. As the number of nitrogen atoms increased, the inhibitive efficiency was improved for all inhibitors except thiourea. For stainless steel, all inhibitors, specially amine group, raised pitting potential and improved inhibiting effect on pitting. In 3.5% NaCl solution without inhibitor, the corrosion rates of metal decreased in the following order: low carbon steel>copper>stainless steel

양이온의 층간 반응에 의한 텅스텐 산화막과 전해질 계면에서의 전기화학적 특성에 관한 수치해석

孫太源,趙成鎭 弘益大學校 科學技術硏究所 1998 科學技術硏究論文集 Vol.9 No.2

In this study, optical density for tungsten oxide film is investigated by equation of diffusion derived for cation diffusion into film. Current is calculated for one case; reversible case that reaction rate is very fast. Dimensionless parameter ξ, ratio of diffusion coefficient in electrolyte and inside of film, and ζ, include exchange current density, are defined. Optical density is calculated with distribution of cation concentration that is calculated for dimensionless parameters in film. In reversible case, concentration of interfacial of electrolyte and film is very high and it takes long time to distribute uniformly. Change of optical density is great for change of diffusion coefficient.

텅스텐 산화 피막을 입힌 NO₂수정 압전 가스센서의 감응성에 관한 연구

손태원,민태엽 弘益大學校 科學技術硏究所 1995 科學技術硏究論文集 Vol.6 No.-

This experiment carried out sensing property of tungsten trioxide with QCM (quartz crystal microbalace) device. The stability, sensitivity and selectivity of dip-coated tungsten trioxide (WO₃) films gas sensing applications have been examined. In this experiment, the WO₃ film sensing properties, such as adsorption, desorption and reversivity for NO₂ gas, Measured. The WO₃ films are exposed to NO₂ gas and are found to be very sensitive to NO₂.

무시안 알칼리 아연 도금을 위한 Hull cell Test

孫太源 弘益大學校 科學技術硏究所 2005 科學技術硏究論文集 Vol.16 No.-

Noncyanide alkaline plating process on zinc was studied by analysing the process technology through efficiency test, analysis of fluid composition, and physical property research on existing oversea manufactures. Also it was compared suggested solution's standard composition with manufactures' one under plating conditions and changes of solution composition, consumption, impurity effect. It was examined electrochemical characteristics of agents such as complexing agent, conductivity reinforcing agent and stability. Zinc plating characters such as uniformity, brightness using Hull cell test. Electrochemical quality of zinc plating solution was studied by searching current density, current efficiency and cyclic voltammeter. Suggested product's plating characteristics such as agent's quantity, current density and relation with plating temperature are composed with existing cyanide plating process and oversea products through Hull cell test. Suggested product showed superior qualities in most of aspects such as uniformity, brightness, and leveling. Even comparing to cyanide alkaline plating, sample showed superiority in every aspect except plating rate. However, at high current region, brightness bounds became narrowed compare to oversea product.

3.5% NaCl 溶液에서 炭素鋼의 Ethylendiamine에 대한 腐蝕 抑制 Mechanism에 關한 硏究

孫太源,閔丙喆 弘益大學校 1990 弘大論叢 Vol.22 No.2

The inhibitive effect of carbon steel S.S 41 in the 3.5% NaCl solution has been studied using polarization test method. A significant retardation of corrosion rate was observed in the NaCl solution containing the inhibitor. The rate of corrosion was depended on the nature of the inhibitor and its concentration and tempratures of the environment. The results obtained from polarization test method were revealed that ethylendiamine performed a dual function in corrosion inhibition of carbon steel; one was a neutralization of the solution and the other was the adsortion of ethylendiamine on the metal surface. Using Bockris-Swinkels adsorption isotherm, the expected value of n and the heat of adsorption for ethylendiamine on carbon steel surface were estimated to 5, 57.38Kcal/mole, respectively. The activation energy in the uninhibitive and inhibitive NaCl solution were observed as a value characteristic of diffusion process.