• 한국세라믹학회지
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• 제40권9호
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• pp.897-901
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• 2003

황산암모늄에 의한 석탄회의 황산화반응 및 반응생성물로부터 황산에 의한 알루미늄이온의 마이크로파 추출에 관하여 검토하였다. 석탄회와 황산암모늄의 반응생성물인(NH$_4$)$_3$Al(SO$_4$)$_3$는 35$0^{\circ}C$ 이상에서 NH$_4$Al(SO$_4$)$_2$로 분해하였다. 황산화반응생성물(40$0^{\circ}C$, 120분)로부터 마이크로파 열원을 이용한 알루미뉴이온의 최대 추출율은 84%(석탄회중의 Al 함량을 기준)이었으나, 재래식 가열시는 동일한 반응조건(1 M, H$_2$SO$_4$, 9$0^{\circ}C$, 240분)에서 77%이었다.

• 한국진공학회지
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• 제6권4호
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• pp.293-297
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• 1997

점성진공계(spinning rotor gauge, SRG)는 고진공영역인 1${\times}$10-5∼100Pa에서 전달표 준기(transfer standard gauge)로 사용되고 있는 진공게이지이다. 제조회사가 각각 Leybold-Heraeus와 MKS회사인 두 개의 SRG에 대해서 질소가스를 사용하여 장기안정성과 적응계수(accommodation coefficient, $sigma$)결정에 영향을 미치는 변수들인 측정압력, 온도, 최 대도달압력(base pressure), 신호분산(signal scattering), 영점(offset)변화에 대한 특성을 10 개월에 걸쳐 조사하였다. 이 결과 장기안정특성 및 입력변수들에 의한 영향이 SRG 고유오 차인 $pm$1.0% 이내에 있음을 확인하였다.

• 한국표면공학회지
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• 제50권4호
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• pp.231-236
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• 2017

The present work addresses how to measure the amount of dissolved aluminum in phosphoric acid, based on volumetric and gravimetric measurements of the precipitates formed by reaction between the $H_3PO_4$ solution containing dissolved aluminum ions and 10 % KF solution. The volume of the precipitates increased with dilution of the dissolved aluminum-containing $H_3PO_4$ solution up to 1/4 dilution above which it decreased with further dilution. The lowered amounts of the precipitates at low dilution less than 1/4 and high dilution more than 1/4 are attributed to high acidity of the solution and decreased amount of dissolved aluminum in the solution, respectively. Volumetric measurement of the amount of precipitates was found not to be very reliable with the experiments, while weight measurement of the precipitates after drying for 80 min at $60^{\circ}C$ appeared to be very reproducible. In the present work, it is suggested that the amount of Al dissolved in 85 % $H_3PO_4$ solution can be calculated by multiplying 50 to the weight of precipitate obtained by reacting 8 ml of 1/4 diluted $H_3PO_4$ solution containing dissolved aluminum ions with 6 ml of 10 % KF solution.

• 한국표면공학회지
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• 제34권1호
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• pp.56-61
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• 2001

In this work, the surface treatment of aluminum/composites (graphite-epoxy composites) was investigated. The surface of composites was treated by $Ar^{+}$ ion beam under oxygen environment. The surface of aluminum was treated by DC plasma. The optimal condition of surface treatment for the composites was determined by measuring the contact angle as a function of ion dose. The optimal treatment condition of the aluminum was determined by measuring the contact angle and T-peel strength as a function of mixture ratio of acetylene gas to nitrogen gas. The mixture ratios used were 1:9, 3:7, 5:5, 7:3, and 9:1. The results showed that the contact angle of composites decreased from$ 81^{\circ}$ to $8^{\circ}$ as the ion dose increased from zero to $1$\times$10^{17}$ions/$\textrm{cm}^2$. The optimal condition of ion dose was $1$\times$10^{16}$ions/$\textrm{cm}^2$. The results also showed that the contact angle of aluminum was a minimum for the mixture ratio of 5:5. Similarly, the T-peel strength was a maximum for the mixture ratio of 5:5, which indicates that the optimal condition of mixture ratio of acetylene gas to nitrogen gas is 5:5.

• Corrosion Science and Technology
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• 제19권6호
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• pp.281-287
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• 2020

Chloride ion is one of the most important corrosive agents in atmospheric corrosion, especially in marine environments. It has high adsorption rate and increases the conductivity of electrolytes. Since chloride ions affect the protective properties and the surface composition of the corrosion product, they increase the corrosion rate. A low level of chloride ions leads to uniform corrosion, whereas a high level of chloride ions may induce localized corrosion. However, higher solution temperatures tend to increase the corrosion rate by enhancing the migration of oxygen in the solution. This work focused on the effect of NaCl concentration and temperature on galvanic corrosion between A516Gr.55 carbon steel and AA7075T6 aluminum alloys. When AA7075T6 aluminum alloy was galvanically coupled to A516Gr.55 carbon steel, AA7075T6 was severely corroded regardless of NaCl concentration and solution temperature, unlike the corrosion properties of single specimen. The combined effect of surface treatment involving carbon steel and aluminum alloy on corrosion behavior was also discussed.

• 상하수도학회지
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• 제9권3호
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• pp.88-98
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• 1995

Several kinds of coagulants such as aluminum sulfate, PAC, PASS are being used to treat drinking water resulting in residual aluminum ions in the water. Recently, it has been reported that high intake of aluminum ion may cause neurological dieseases such as Alzheimer's diesease and presenile dementia. Because of the possible adverse effect, WHO and EEC recommand to regulate residual aluminum. The autorities in Korea also has plan of regulating residual alunimum from 1995. But there is not enough information about the range of residual aluminum ion concentration when the aluminum sulfate, PAC or PASS has been used as a coagulant. Therefore the study has been conducted to find out the range of residual aluminum ion concentration after using aluminum sulfate, PAC, and PASS. Furthermore the effect of turbidity and alkalinity have been investigated. The experimental results are summarized as; 1. Most of the residual aluminum ion concentrations were within $10^{-6}$ and $10^{-5}mole/l$. Three coagulants have not showed any considerable difference in the residual aluminum concentration up to 50 NTU. However PAC has showed the least residual aluminum in high turbidity water over 100 NTU. 2. The low alkalinity water having 25mg/l as $CaCO_3$ has showed less residual aluminum than the water having 50mg/l alkalinity. However, the difference was not significcant. 3. Even the lowest residual aluminum concentration was over 0.05mg/l. Therefore the process to reduce residual aluminum would be necessary in water treatment plants.

• 한국막학회:학술대회논문집
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• 한국막학회 1994년도 추계 총회 및 학술발표회
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• pp.8-11
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• 1994

Disposal of hazardous ions in the aqueous streams is a significant industrial waste problem.. Waste streams from electronics, electroplating, and photographic industries contain metal ions such as copper, nickel, zinc, chromium(IV), cadmium, aluminum, silver, and gold, amongst others in various aqueous solutions such as sulfates, chlorides, fluorocarbons, and cyanides. Typical plating solutions having similar compositions are listed in Table 1. Spent process streams in catalyst manufacturing facilities also contain precious metals such as Ag, Pt, and Pd. Developing an effective recovery process of these metal ions for reuse is important.

• 청정기술
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• 제20권1호
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• pp.51-56
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• 2014

본 연구에서는 폴리술폰(polysulfone, PSf)으로 알루미늄 수산화물(aluminum hydroxide, $Al(OH)_3$)을 고정화한 PSf-$Al(OH)_3$ 비드를 제조하였다. 제조한 PSf-$Al(OH)_3$ 비드에 의한 불소 이온 제거실험은 회분식으로 수행하였으며, pH, 초기농도, 공존이온과 같은 변수들의 영향을 살펴보았다. Langmuir 등온식으로 구한 불소 이온의 최대 제거량은 52.4 mg/g이었으며, 최적 pH 범위는 4~10이었다. PSf-$Al(OH)_3$ 비드에 의한 불소 이온의 제거과정은 전 단계에서 외부물질전달이 나중 단계에서 내부확산이 지배인 것을 알 수 있었다. 또한 PSf-$Al(OH)_3$에 의한 불소 이온의 제거에서 $HCO_3{^-}$, $SO{_4}^{2-}$, $NO_3{^-}$, $Cl^-$와 같은 공존 음이온들은 불소 이온의 제거에 방해를 하는 것으로 나타났다.

• 한국세라믹학회지
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• 제31권5호
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• pp.485-490
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• 1994

The reactive ion etching characteristics of aluminum oxide films, prepared by PECVD, were investigated in the CCl4 plasma. The atomic chlorine concentration and the DC self bias were determined at various etching conditions, and their effects on the etch rate of aluminum oxide film were studied. The bombarding energy of incident particles was found to play the more important role in determining the etch rate of aluminum oxide rather than the atomic chlorine concentration. It is considered to be because the bombardment of ions or neutral atoms breaks the strong Al-O bonds of aluminum oxide to help activate the formation reaction of AlCl3 which is the volatile etch product.

• 한국세라믹학회지
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• 제29권12호
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• pp.956-962
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• 1992

The predominant sintering mechanisms of low firing temperature ceramic substrate which consists of borosilicate glass containing alumina as a filler are the rearrangement of alumina particles and the viscous flow of glass powders. In this system, sintering condition depends on the volume ratio of alumina to glass and on the particle size. When the substrate contains about 35 vol% alumina filler and the average alumina particle size is 4 $\mu\textrm{m}$, the best firing condition is obtained at the temperature range of 900∼1000$^{\circ}C$. The extensive rearrangement behavior occurs at these conditions, and the optimum sintering condition is attained by smaller size of glass particles, too. The formation of cristobalite during sintering causes the difference of thermal expansion coefficient between the substrate and Si chip. This phenomenon degradates the capacity of Si chip. Therefore, the crystallization should be prevented. In the alumina filled borosilicate glass system, the crystallization does not occur. This effect may have some relation with aluminum ions in alumina. For aluminum ions diffuse into glass matrix during sintering, functiong as network former.