• 한국표면공학회:학술대회논문집
• /
• 한국표면공학회 1999년도 춘계학술발표회 초록집
• /
• pp.111-111
• /
• 1999

• 공업화학
• /
• 제17권5호
• /
• pp.532-538
• /
• 2006

탄화 및 활성화 조건을 매개체로 여러 등급의 Polyacrylonitrile (PAN)계 ACF (ACF : Activated Carbon Fiber)를 제조하여 최적의 비표면적을 나타내는 활성화 공정을 알아보았고, 가장 큰 비표면적을 갖는 PAN계 ACF에 대한 표면특성 및 독성가스 등에 대한 흡착특성을 분석하였다. 시험결과 활성화 온도가 증가할수록 비표면적이 증가하고 탄화 온도가 감소할수록 비표면적이 감소하였고, $900^{\circ}C$로 15 min간 탄화한 후 $900^{\circ}C$로 30 min간 활성화 공정을 거친 ACF가 $1204m^2/g$의 가장 높은 비표면적을 나타내었고 요오드 및 테러용 독성가스에 대한 흡착 성능시험 결과 기존의 흡착제보다 우수하였다. 또한 선택적 흡착을 위한 기능성을 부여하기 위하여 기존의 금속염을 침적하는 방법을 대체하여 비교적 안정화된 금속나노입자(Ag, Pt, Cu, Pd)를 제조하여 첨착하였고 이에 대한 표면특성 및 $SO_{2}$에 대한 흡착특성을 분석하였다. 금속나노입자 첨착 ACF에 대한 $SO_{2}$ 흡착성능 시험결과 Ag, Pt, Cu 나노입자를 첨착한 ACF는 무첨착 ACF의 파과시간(326 sec)과 비교 할 때 크게 변함이 없었으나 Pd 나노입자를 첨착한 ACF는 파과시간이 925 sec로 $SO_{2}$ 흡착성능이 매우 우수함을 알 수 있었다.

• 한국연초학회지
• /
• 제30권1호
• /
• pp.8-13
• /
• 2008

Several activated carbon in different specific surface area was prepared by steam and chemical activation of coconut shell. Products were characterized by BET ($N_2$) at 77K, and probed to be highly specific surface area of $1580m^2/g$ and pore volume that had increased with activating conditions. And also we have analyzed the adsorption efficiency of vapor phase components in cigarette mainstream smoke in order to evaluate the relationship between thesmoke components and the physicochemical properties of activated carbons. As a result of this study, the delivery of mainstream smoke was directly affected by the specific surface area and the pore size of activated carbon. The activated carbon prepared by steam activation exhibited better adsorption efficiency on the vapor phase components in mainstream smoke compared with activated carbon prepared by $ZnCl_2$, due to the higher micro-pore area of 66%. But the adsorption efficiency of semi-volatile matters such as phenolic components in a main stream smoke by the activated mesoporous carbon prepared by $ZnCl_2$ is more effective. From the these results, we can conclude that specific surface area by the micropore area increased the adsorption efficiency of activated carbon on vapour phase components, but semi-volatiles or particulate matter was affected by the ratio of mesopore area in total specific surface area.

• Transactions on Electrical and Electronic Materials
• /
• 제1권4호
• /
• pp.1-6
• /
• 2000

The mechanical strength of silicon carbide dose nor permit the use of diffusion as a means to achieve selective doping as required by most electronic devices. While epitaxial layers may be doped during growth, ion implantation is needed to define such regions as drain and source wells, junction isolation regions, and so on. Ion activation without an annealing cap results in serious crystal damage as these activation processes must be carried out at temperatures on the order of 1600$^{\circ}C$. Ion implanted silicon carbide that is annealed in either a vacuum or argon environment usually results in a surface morphology that is highly irregular due to the out diffusion of Si atoms. We have developed and report a successful process of using silicon overpressure, provided by silane in a CAD reactor during the anneal, to prevent the destruction of the silicon carbide surface, This process has proved to be robust and has resulted in ion activation at a annealing temperature of 1600$^{\circ}C$ without degradation of the crystal surface as determined by AFM and RBS. In addition XPS was used to look at the surface and near surface chemical states for annealing temperatures of up to 1700$^{\circ}C$. The surface and near surface regions to approximately 6 nm in depth was observed to contain no free silicon or other impurities thus indicating that the process developed results in an atomically clean SiC surface and near surface region within the detection limits of the instrument(${\pm}$1 at %).

• 한국표면공학회:학술대회논문집
• /
• 한국표면공학회 2013년도 춘계학술대회 논문집
• /
• pp.81-82
• /
• 2013

In this study, precipitation behaviors of hydroxyapatite on highly ordered nanotubular Ti-35Ta-xNb alloy surface were researched. Ta and Nb additions to Ti increased corrosion resistance. The surface characteristics of anodized alloy depended on the nanotube formed voltage and alloy element. The HA precipitation morphology was influenced by nanorubular structure of alloys.

• 한국표면공학회지
• /
• 제28권1호
• /
• pp.23-33
• /
• 1995

AISI 304 stainless steel has high resistance to corrosion due to the presence of a self-healing chromium oxide film on the surface, which also accounts for the difficulty in plating. Surface cleaning of this alloy is of fundamental importance in gold plating since its effectiveness puts an upper limit on the quality of the final coating. The cleaning of AISI 304 stainless steel was investigated with elimination of artificial passive oxide film and degreasing of remaining buffing wax as stearic acid. The familiar cleaning methods i.e. ultrasonic cleaning, electro-cleaning and activation treatment were fabricated in this study. Activation treatment showed best cleaning efficiency for elimination of passive oxide film among these methods, which was also confirmed by AES (Auger electron spectrometer) analysis. However, the best condition of cleaning was obtained by combining these methods. Electrocleaning time, for degreasing the stearic acid layer, was decreased with increasing amount of added KCN.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 1995년도 제8회 학술발표회 논문개요집
• /
• pp.113-113
• /
• 1995

The adsorpption and decompposition of NO on a stepped ppt(111) surface have been studied using thermal desorpption sppectroscoppy and Auger electron sppectroscoppy. NO adsorbs molecularly in two different states of the terrace and the stepp, which are distinguishable in thermal desorpption sppectra. NO dissociates via a bent sppecies at the stepp sites on the basis of vibrational sppectrum data repported ppreviously. The dissociation of NO is activation pprocess : the activation energy is estimated to be about 2 kcal/mol. Increase in the NO dissociation with adsorpption tempperature is expplained by a pprocess controlled by different of the dissociated atomic nitrogen from the stepp to the terrace of the surface. In addition to No and N2, the desorpption ppeak of N2O is observed. We conclude that the formation of N2O is attributed to surface reaction of No and N adsorbed on the surface.

• Bulletin of the Korean Chemical Society
• /
• 제16권2호
• /
• pp.157-163
• /
• 1995

The adsorption and decomposition of NO on a stepped Pt(111) surface have been studied using thermal desorption spectroscopy and Auger electron spectroscopy. NO adsorbs molecularly in two different states of the terrace and the step, which are distinguishable in thermal desorption spectra. NO dissociates via a bent species at the step sites on the basis of vibrational spectrum data reported previously. The dissociation of NO is an activation process : the activation energy is estimated to be about 2 kcal/mol. Increase in the NO dissociation with adsorption temperature is explained by a process controlled by diffusion of the dissociated atomic nitrogen from the step to the terrace of the surface. In addition to NO and N2, the desorption peak of N2O is observed. We conclude that the formation of N2O is attributed to surface reaction of NO and N adsorbed on the surface.

• 한국표면공학회지
• /
• 제41권4호
• /
• pp.163-168
• /
• 2008

The dental orthodontic bracket requires good mechanical properties, such as elastic strength and frictional resistance, combined with a high resistance to corrosion. The objective of this study was to investigate the effects of TiN and ZrN coating on corrosion resistance of orthodontic brackets using various electrochemical methods. Brackets manufactured by Ormco Co. were used, respectively, for experiment. Ion plating was carried out for coatings of bracket using Ti and Zr coating materials with nitrogen gas. Ion plated surface of each specimen was observed with field emission scanning electron microscopy(FE-SEM), energy dispersive Xray spectroscopy(EDS) and electrochemical tester. The corrosion potential of the TiN and ZrN coated bracket was comparatively high. The current density of TiN and ZrN coated bracket was smaller than that of non-coated bracket in 0.9% NaCl solution. Pit nucleated at angle of bracket slot.

• 한국수소및신에너지학회논문집
• /
• 제8권4호
• /
• pp.161-171
• /
• 1997

$AB_2$ type Zr-based Laves phase alloys have been studied for potential application as negative electrode in Ni/MH batteries. However, They have a serious disadvantage of poor activation behavior in KOH solution. In this work, a new method of alloy design method was tried for improving Zr-based alloy activation. this method has focused on phase controlling to make multi-phase microstructure. In the case of multi-phase Zr-V-Mn-Ni shows good performance in activation, but activation mechanism has not been known. So, we were in search of elucidating this mechanism, Using morphological and electrochemical analysis, we could find that surface morphology and electocatalytic activity of the alloy change during immersion in KOH solution. V-rich second phases are selectively corroded and dissolved and then become Ni-rich phases. Resulting from these surface reaction in KOH solution, self-hydrogen charging occurs through Ni-rich phase. However, the alloy has poor cyclic durability because of such a corrosion mechanism. Therefore, finally we developed durable alloys by substitution of other alloying element.