• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2015.11a
• /
• pp.334-335
• /
• 2015

알루미늄 양극산화 피막의 내마모성 향상 및 염료 침지의 봉인을 위해 다양한 봉공처리법이 개발되고 상용되어왔다. 현재, 주로 사용되는 방법들은 에너지 소비량이 많고, 유독성의 용액을 사용해야하며 봉공처리의 품질 자체가 좋지 못하다는 단점이 있다. 이에 저에너지 소비 및 친환경적이고 무독성의 용액을 사용하는 봉공처리를 고안하고자 한다.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.36 no.10
• /
• pp.1019-1023
• /
• 2012

In this research, a novel direct-aluminum-heating-induced crystallization method was developed for the purpose of application to solar cells. By applying a constant current of 3 A to an aluminum thin film, a 200-nm-thick amorphous silicon (a-Si) thin film with a size of $1cm{\times}1cm$ can be crystallized into a polycrystalline silicon (poly-Si) thin film within a few tens of seconds. The Raman spectrum analysis shows a peak of 520 $cm^{-1}$, which verifies the presence of poly-Si. After removing the aluminum layer, the poly-Si thin film was found to be porous. SIMS analysis showed that the porous poly-Si thin film was heavily p-doped with a doping concentration of $10^{21}cm^{-3}$. Thermal imaging shows that the crystallization from a-Si to poly-Si occurred at a temperature of around 820 K.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.14 no.4
• /
• pp.923-928
• /
• 2010

Anodic aluminum oxide (AAO) nanotemplates for nano electronic device applications have been attracting increasing interest because of ease of fabrication, low cost process, and possible fabrication in large area. The size and density of the nanostructured materials can be controlled by changing the pore diameter and the pole density of AAO nanotemplate. In this paper, nano porous alumina films AAO nanotemplate was fabricated by second anodization method using sputterd Al films. In addition, effects of electrolyte temperature and anodization voltate on the microstructure of porous alumina films were investigated. As the electrolyte temperature was increased from $8^{\circ}C$ to $20^{\circ}C$, the growth rate of nanoporous alumina films was increased from 86.2 nm/min to 179.5 nm/min. The AAO nanotemplate fabricated with optimal condition had the mean pore diameter of 70 nm and the pore depth of $1\;{\mu}m$.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2008.04a
• /
• pp.848-851
• /
• 2008

유리섬유 및 폴리에스테르와 같은 섬유질 흡음재의 단점을 보완하기 위하여 다공성 알루미늄과 같은 강체 흡음재가 개발되고 있다. 본 연구에서는 스테인리스 스틸을 이용한 다공성 강체에 대하여 수직입사 흡음성능을 조사하였다. 밀도, 두께, 세부 프로파일 등에 따른 성능비교를 위하여 서로 다른 9개의 시험편의 성능을 측정하였다. 측정결과 밀도가 낮고 두께가 두꺼운 다공성 강체의 흡음성능이 다소 높은 것으로 나타났으며, 두께의 증가에 따라 중저주파수 대역의 흡음특성이 증가되었다. 배후 공기층이 형성되는 경우 중 저주파수 대역의 흡음성능이 매우 향상되는 것으로 나타났다. 또한 접착제가 사용된 실험편에 배후공기층이 형성되는 경우 전주파수 대역에서 매우 평탄한 수직입사 흡음특성을 갖는 것으로 나타났다. 향후 스테인리스 스틸 다공성 강체가 방음시설물, 흡음.확산용 내장재 등으로 사용될 수 있을 것으로 판단된다.

• Journal of the Korean Solar Energy Society
• /
• v.23 no.2
• /
• pp.91-98
• /
• 2003

Experimental study for a porous aluminum heat dissipator/or heat sink made by casting method is conducted to evaluate the performance of the porous aluminum heat sinks. The parameters applied for the present study are the manufacturing method. various bonding materials for the bottom plate of heat sink, and their different material, pore size, etc.. The casting method for porous aluminum heat sink is suggested for the best performance of heat dissipation in this experiment. The bottom plate applied by melting aluminum is introduced and proved their excellent characteristics compared with brazing, soldering, and bonding methods. In the present experiment, aluminum with different conductivities, such as AC8A and pure aluminum, are tested and the pure aluminums with the higher conductivity than AC8A shows their improvement of the performance. And the proper dimensions related to the pore size and the height of porous aluminum heat sinks are proposed in the present study.

• Journal of the Korean Magnetics Society
• /
• v.18 no.2
• /
• pp.79-83
• /
• 2008

We have investigated the effect of the formation of an initial oxide layer on the fabrication of the porous aluminium oxide. The porous aluminium oxide was fabricated by two-step anodization process with a electropolished aluminium foil. Before the first anodization step, the initial oxide layer with thickness of 10 nm was formed under the applied voltage of 1 V and later the anodization was continued under 40 V using oxalic acid solution. With the formation of the initial oxide layer, the anodization process was stable and the anodization current was constant throughout the process. In case of the absence of the initial oxide layer, the anodization was very unstable and the continuous increase in the anodization current was observed. This indicates the formation of the initial oxide layer on the aluminium surface prevents the burning of the surface due to the nonuniform distribution of the applied electric field, and allows the stable anodization process required for the porous aluminium oxide.

• Journal of Energy Engineering
• /
• v.18 no.2
• /
• pp.108-113
• /
• 2009

An experimental study of jet impingement on aluminum foam mounted on the surface with constant heat flux is conducted with the presentation of the heat transfer rate measured when jet impinges normally to a flat plate. Effects of pore density, foam thickness and Reynolds number on the heat transfer are analyzed. Experimental results show that the significant enhancement in Nu is obtained when the aluminum foam is mounted on the heated plate and that the increase in the heat transfer due to the porous material insertion is dominated by both the increase in the heat transfer area and the decrease in the momentum flux resulted from the pressure drop.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2008.02a
• /
• pp.334-334
• /
• 2008

• Resources Recycling
• /
• v.14 no.2
• /
• pp.19-27
• /
• 2005

The recycling possibility of aluminum waste dross(AWD) as a ceramic raw material of porous light-weight material was examined. A aluminum waste dross was washed 4-7 consecutive times and roasted at 900$^{\circ}% for 1hour as pre-treatments. The properties of the pre-treatment of aluminum waste dross was investigated. It was conformed by XRD result that the spinel crystalline was grown in AWD, after roasting. After the roasted AWD was ground in aqueous state, the sodium hexaphosphate(SHP) as a dispersant which is used for stabilizing the concentrated slurry was added to the AWD slurry. The porous material was prepared by slurry foaming method with surfactant at room temperature. The foamed slurry volumes were 2 and 3 times of the original slurry volume. The properties of porous material with extended volume of 3 times was following: the porosity was about 84%, bulk density was 0.59 g/cm$^3$, the range of pore was from 50 ${\mu}m$ to 500 ${\mu}m$ and mean pore size was about 200 ${\mu}m$. AWD porous material was sintered at 1150$^{\circ}C-1250$^{\circ}C. It was colcluded that AWD was sintered well at 1200$^{\circ}C from material surface observation by SEM.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.5
• /
• pp.2002-2008
• /
• 2012

In recent years, while the importance of thermal management has been emphasized due to smaller electronic products, various materials have been used as heat sink. In this study, porous ceramic heat sink was developed with SiC, successfully separated from the slurry of SiC occurring in solar energy materials industry and the thermal performance of porous SiC heat sink has been compared with those of aluminum heat sink and pure SiC heat sink through experiment. From the experimental results, it was verified that porous recycled SiC heat sink has better thermal performance than aluminum heat sink since its micropores increase the heat transfer area. In addition, the effect of the micropores on thermal performance has been quantified by increasing convective heat transfer coefficient with numerical analysis.