• 대한치과기공학회지
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• 제23권2호
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• pp.161-170
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• 2002

The Purpose of this study was to investigate the chemically improvement of metal-ceramics bond strength in the course of recasting Ni-Cr metal composite system with 10wt.%, 20wt.% and 30wt.% aluminum respectively. We have tested the bond strength, micro-structure, chemical composition of each metal composites and metal- ceramic bond interfaces by 3-point bending strength tester, SEM and EDS. We have made the conclusions through this study as follow: 1. The most suitable amount of aluminum to the Ni-Cr metal composite recasting is 20wt. % for improving metal-ceramics bond strength with debonding strength value of 49.54 kgf/mm2. 2. The aluminum must be changed to small spread alumina like phases and second aluminum-metal composites phases in the morphology of Ni-Cr metal composite system by adding during it's casting. These second phases have inclined functional oxide phases mixed with metal elements and they must take roll to improvement of metal-ceramics bond strength. 3. In the case of 30wt.% aluminum appended to Ni-Cr metal composite system, an excess of second inclined functional oxide phases produce cracks and spalling of them apart from it's base material. It must be a important factor of reduction of metal-ceramics bond strength.

• 공업화학
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• 제17권4호
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• pp.335-342
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• 2006

금속 알루미늄의 낮은 환원전위는 전기화학적 산화반응을 통하여 알루미늄과 그 표면에 존재하는 산화막의 구조 및 성질의 변화를 일으킨다. 산성용액에서 알루미늄을 전기화학적으로 에칭하여 표면적을 확대시키고 중성의 용액에서 알루미늄 표면에 치밀한 유전체 산화막을 형성시켜 커패시터의 전극으로 이용하고 있다. 저온의 산성용액에서는 양극산화시 나노크기의 다공층 산화막이 형성되며, 나노구조체의 템플레이트로 사용되고 있다. 이와같은 알루미늄의 전기화학적 특성은 알루미늄을 새로운 기능성을 가진 재료로 변화시킴으로서 다양한 분야에서 응용될 것으로 기대된다.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.714-715
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• 2006

The Application of powder metallurgy (PM) aluminum structural parts is at its early growing stage, despite of some automotive applications. The market potential for PM aluminum, however, is large. Growth is expected from the market expansion of the existing applications and new applications, including the replacements of aluminum and zinc based castings and some ferrous PM automotive parts by PM aluminum. Compared to castings, PM is an efficient mass production technology. The PM aluminum is more competitive than die casting for some automotive applications. Besides weight saving leading to performance improvement, the total cost increase for aluminum PM parts is less than 15% compared to ferrous PM automotive parts. The future is promising for PM aluminum.

• 한국생산제조학회지
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• 제21권3호
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• pp.493-501
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• 2012

A rotational force generator for molten metal is developed using a linear motor design technology. Also, the developed device is applied to reproduce aluminum scraps and easy to control the rotate, stop, and forward and reverse rotation of molten metal. In addition, the developed device improves the melting speed and reproduction rate about 250 (%) and 96-99 (%), respectively, compared to the conventional handmade methods. Because it generates almost no dusts, it can improve working environments in a factory. Also, it has no losses in energy because it directly melts scraps. The device generates small amounts of the loss in refractory materials and aluminum caused by its oxidation because the molten metal is continuously rotated in which the loss and oxidized aluminum are the problems in the conventional melting and holding furnaces. Thus, it is possible to extend the life of furnaces and to produce high quality aluminum products.

• 설비공학논문집
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• 제11권2호
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• pp.185-192
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• 1999

Effective thermal conductivities and pressure-drop-related properties of aluminum foam metals have been measured. The effects of porosity and cell size in the aluminum foam metal are investigated in detail. The porosity of the foam metal, considered in the present study, varies from 0.89 to 0.96 and the cell size from 0.65㎜ to 2.5㎜. The effective thermal conductivity is evaluated by comparing the temperature gradient of the foam metal with that of the thermal conductivity-known material. The pressure drop in the foam metal is measured by a highly precise electric manometer while air is flowing through the aluminum foam metal in the channel. The results obtained indicate that the effective thermal conductivities are found to be increased with a decrease in the porosity while the effective thermal conductivities ire little affected by the cell size at a fixed porosity. However, the pressure drop is strongly affected by the cell size as well as the porosity. It is seen that the pressure drop is increased as the cell size becomes smaller, as expected. The minimum pressure drop is obtained in the porosity 0.94 at a fixed cell size. A new correlation of the pressure drop is proposed based on the permeability and Ergun's coefficient for the aluminum foam metal.

• 자원리싸이클링
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• 제28권2호
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• pp.3-13
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• 2019

알루미늄은 지각 구성 원소 중 실리콘에 이어 두 번째로 풍부한 금속원소이다. 알루미늄은 가볍고, 전기전도도가 우수하고, 내식성이 우수하지만 산소와의 친화력이 강한 특성을 가지고 있다. 그러나 알루미늄의 1차 지금을 제조하기 위해서는 다량의 에너지를 소비한다. 한편 알루미늄 스크랩을 리사이클링하면 1차 지금 생산과 비교하여 에너지 및 환경부하를 저감할 수 있다. 그러나 알루미늄 스크랩 중의 불순물 제거가 곤란하여 재생되는 양은 한정되어 있다. 본 논문에서는 알루미나의 제조부터 스크랩 처리 및 용융까지의 알루미늄 생산 및 리사이클링 공정에 대하여 고찰하였다.

• 대한치과교정학회지
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• 제44권3호
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• pp.105-112
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• 2014

Objective: The purpose of this study was to evaluate the effects of three different surface conditioning methods on the shear bond strength (SBS) of metal brackets bonded directly to gold alloy with chemically cured resin. Methods: Two hundred ten type III gold alloy specimens were randomly divided into six groups according to the combination of three different surface conditioning methods (aluminum oxide sandblasting only, application of a metal primer after aluminum oxide sandblasting, silica coating and silanation) and thermocycling (with thermocycling, without thermocycling). After performing surface conditioning of specimens in accordance with each experimental condition, metal brackets were bonded to all specimens using a chemically cured resin. The SBS was measured at the moment of bracket debonding, and the resin remnants on the specimen surface were evaluated using the adhesive remnant index. Results: Application of metal primer after aluminum oxide sandblasting yielded a higher bond strength than that with aluminum oxide sandblasting alone (p < 0.001), and silica coating and silanation yielded a higher bond strength than that with metal primer after aluminum oxide sandblasting (p < 0.001). There was no significant change in SBS after thermocycling in all groups. Conclusions: With silica coating and silanation, clinically satisfactory bond strength can be attained when metal brackets are directly bonded to gold alloys using a chemically cured resin.

• 한국환경과학회지
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• 제19권12호
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• pp.1355-1359
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• 2010

The application of metal caps has been continuously increased as real life are extended. Metal caps is usually made of aluminum and polyethylene(PE) as packing. Since metal caps contain 75% aluminum on a weight basis, metal caps may be a valuable source when these were properly recovered. The recovery methods of metal caps have mechanical peeling and incineration. However these are either hard to apply in some case or environmentally unacceptable. So in this investigation, recovery method of aluminum from metal caps was investigated using pyrolysis. The result shows that pyrolysis temperature and pyrolysis time was $450^{\circ}C$ and 120min. respectively. Also 100% of aluminum was recovered from metal caps. Heat content of recovered oil was high enough to use as a fuel representing 7,425.0, 7,793.1, 7,583.2, 7,726.2(cal/g). Heavy metal contens in the oil were under regulatory limit indicating.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 추계학술대회 논문집 Vol.18
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• pp.86-87
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• 2005

Aluminum(Al) sputtering is best known method to form Al film for the Si wafer in the process of 180nm and above. In the Al metal line process, one of the frequently founded and well-known defect was metal depression. In this paper, several experiments were performed such as temperature, Ar gas flow rate, thickness change in other to reduce the metal depression and find the origination of metal depression. Through experiments, it is found that metal depression was significantly related to the temperature. And the Ar gas flow rate did not influence to the creation of depression. The off status ESC also showed stable metal film without depression by same mechanism of temperature decrease. Also, thickness is strongly influence to the metal depression.

• 한국공작기계학회논문집
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• 제17권1호
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• pp.1-6
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• 2008

There are some methods that have been used to manage a degasing process in recent years, such as an injection method that uses aluminum molten metal powder and chemicals supplier and input method that supplies argon and nitrogen, or chlorine gas by using a gas blow-tube. However, these methods show some problems, and it shows that it is a difficult process to handle, pollution due to producing a lot of toxic gases like chlorine and fluoride gas, irregular effects, and lowering work efficiency due to the excessive processing time. The problems that are the most fatal are the producing a lot of sludge due to the reaction of aluminum molten metal with chemicals, loss of metals, and decreasing the life of refractory materials. In order to solve these problems, this paper develops a technology that is related to aluminum continuous casting molten metal and monolithic degasing apparatus. A degasing apparatus developed in this study improved the existing methods and prevented environmental pollution with smokeless, odorless, and harmlessness by using a new method that applies argon and nitrogen gas in which the methods used in the West and Japan are eliminated. The method developed in this study decreases the molten metal processing and settling time compared to the existing methods and improves the workers' health, safety, and environment because there is no pollution in processes.