• KSTLE International Journal
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• 제3권1호
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• pp.43-48
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• 2002

Dry sliding wear and friction test of CrN coaling on two types of aluminum alloy substrates,6061 Al and 7075 Al deposited by arc ion plating, was peformed with a ball-on-disk tribometer. The effects of normal Bead and the mechanical properties of substrate on the friction coefficient and wear-resistance of CrN coating were investigated. The worn surfaces were observed by SEM. The results show that surface micro-hardness of CrN- coated 7075 Al is higher than that of CrN-coated 6061 Al. With an increase in normal lead, wear volume increases, while the friction coefficient decreases. The friction coefficient of CrN-coated 6061 Al is higher than that of CrN-coated 7075 Al, while the wear-resistance of CrN-coated 6061 Al is lower than the CrN-coated 7075 Al's, which indicates that the substrate mechanical properties have strong inf1uences on the friction coefficient and wear of CrN coating. The main wear mechanism was fragments of CrN coating, which were caused by apparent plastic deformation of substrate during wear test.

• 한국전자파학회논문지
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• 제19권2호
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• pp.257-262
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• 2008

본 논문에서는 열전도도가 우수한 AIN 기판에 $CO_2$ Laser 장비 를 이용하여 Thru-hole과 scribing line을 형성하기 위해 $CO_2$ laser의 파라미터(촛점 거리, 공기량, 레이저 빔 시간, 펄스 개수)를 실험하고, 자체 정렬 마스킹 기법을 이용한 5 um 두께의 Cu 도금으로 AIN 기판에 전송 선로와 나선형 평면 인덕터를 제작하였다. AIN 기판에서의 마이크로스트립 라인의 전송 손실은 10 GHz에서 0.1 dB/mm, 6 nH 나선형 평면 인덕터는 1 GHz에서 56의 품질 계수를 얻었고, 이를 통해 열전도도가 우수한 AIN 기판의 고전력 RF 응용이 가능할 것으로 기대한다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.472-477
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• 2001

Spent catalysts containing platinum were generated in petroleum refinery and other chemical industries. The reclamation of precious metals from such wastes has long been attempted in view of their rare, expensive and indispensable nature. In this study, the recovery of platinum from petroleum catalysts was attempted by a method consisting mainly of dissolving alumina substrate with sulfuric acid thereby concentrating insoluble platinum. Also, platinum dissolved partially in sulfuric acid was recovered by a cementation method using aluminum metal as a reductive agent. The effect of temperature, time, concentration of sulfuric acid. and pulp density on the dissolution of substrate was investigated. When the substrate of platinum catalyst was ${\gamma}$-AI$_2$O$_3$ about 95% alumina was dissolved in 6.0M sulfuric acid at 10$0^{\circ}C$ for 2 hours. When the substrate was the mixture of ${\gamma}$-A1$_2$O$_3$and $\alpha$-A1$_2$O$_3$about 92% was dissolved after 4 hours. As a result, more than 99% of platinum could be recovered by this method and aluminum sulfate was obtained as byproduct.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.99-100
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• 2006

Cold gas dynamic spray or cold-spray is a deposition process, which causes deformation of a thin substrate. The deformation is usually convex to the deposited side. In this research, the main cause of the deformation was investigated using 6061-T6 aluminum alloy. The effects or anisotropic coefficient or thermal expansion (CTE) or the deposited layer by cold-spray and residual stress were studied by experiments and finite element analysis. The Hole Drilling method was applied to measure residual stress in the cold-spray layer and substrate. The data obtained by the experiments were used for the analysis of substrate deformation. From the result of the analysis, it was concluded that compressive residual stress was the main reason of substrate deformation while CTE had little effect.

• 전기화학회지
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• 제3권3호
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• pp.136-140
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• 2000

용융탄산염 연료전지의 분리판 재료로 사용되는 스테인레스 스틸은 고온 용융탄산염 분위기에서 부식이 심각하여 일반적으로 표면에 알루미늄 확산막을 코팅함으로써 내식성을 향상시켜 사용하고 있다. 본 연구에서는 기존 방법에 비해 보다 경제적인 슬러리 페인팅 및 열처리에 의한 알루미늄 확산막 형성 방법을 고안하여, 스테인레스 스틸 시편 표면에 알루미늄 확산막을 코팅하고, 산화 분위기의 용융탄산염에서 부식 실험을 수행하였다. $650\~800^{\circ}C$에서 제작된 알루미늄 확산막의 두께는 $25\~80{\mu}m$였으며, 열처리 온도가 높고 열처리 시간이 증가할 수록 알루미늄 확산막의 두께가 증가하였다. 부식 실험 결과 스테인레스 스틸 316L의 용융탄산염에 대한 내식성은 알루미늄 확산막을 표면에 형성시킴으로써 크게 향상되었음을 확인하였다. 또한 분극 실험 결과 슬러리 페인팅 및 열처리 방법에 의하여 알루미늄 확산막이 형성된 시편은 기존의 IVD 및 열처리 방법에 의해 알루미늄 확산막이 제작된 시편과 유사하게 안정한 부동태 피막을 형성함으로써 스테인레스 스틸 316L의 부식을 효과적으로 억제시킴을 알 수 있었다.

• International Journal of Ocean System Engineering
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• 제2권2호
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• pp.106-115
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• 2012

In the present study, TiN and CrN films were coated by arc ion plating equipment onto aluminum alloy substrate, A2024. The film thickness was about 4.65 ${\mu}m$. TiN and CrN films were analyzed by X-ray diffraction and energy dispersive X-ray equipments. The Young's modulus and the micro-Vickers hardness of aluminum substrate were modified by the ceramic film coatings. The difference in Young's modulus between substrate and coating film would affect on the wear resistance. The critical load, Lc, was 75.8 N for TiN and 85.5 N for CrN. It indicated from the observation of optical micrographs for TiN and CrN films that lots of cracks widely propagated toward the both sides of scratch track in the early stage of MODE I. TiN film began to delaminate completely at MODE II stage. The substrate was finally glittered at MODE III stage. For CrN film, a few crack can be observed at MODE I stage. The delamination of film was not still occurred at MODE II and then was happened at MODE III. This agrees with critical load measurement which the adhesive strength was greater for CrN film than for TiN film. Consequently, it was difficult for CrN to delaminate because the adhesive strength was excellent against Al substrate. The wear process, which the film adheres and the ball transfers, could be enhanced because of the increase in loading. The wear weight of ball was less for CrN than for TiN. This means that the wear damage of ball was greater for TiN than for CrN film. It is also obvious that it was difficult to delaminate because the CrN coating film has high toughness. The coefficient of friction was less for CrN coating film than for TiN film.

• 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.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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• pp.746-749
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• 2002

Aluminum oxide thin films were grown on a poly ethylene naphthalate (PEN) substrate at the temperature of 100$^{\circ}C$ using atomic layer deposition method. The film showed very flat morphology and good adhesion to the substrate. The visible spectrum showed higher transmittance in the range from 400 nm to 800 nm than that of PEN. The water vapor transmission value measured with MOCON for 230nm oxide-deposited PEN was 0.62g/$m^2$/day @ 38$^{\circ}C$, while that of PEN substrate was 1.4g/$m^2$/day @ 38$^{\circ}C$.

• 한국전자파학회논문지
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• 제22권12호
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• pp.1069-1077
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• 2011

본 논문에서는 선택적 산화 알루미늄(SAAO: Selectively Anodized Aluminum Oxide) 기판을 이용하여 2.5 GHz 8 W급 소형 GaN HEMT 전력 증폭기 모듈을 설계, 제작하였다. SAAO 기판 공정은 최근 Wavenics사에서 제안한 특허 기술로서, 알루미늄을 웨이퍼로 이용한다. 본 연구에 사용된 능동 소자는 최근 발표된 TriQuint사의 칩 형태 의 GaN HEMT이다. 최적의 임피던스는 수동 조정 소자가 내장된 지그를 사용하여 실험적으로 결정하였다. 결정된 임피던스를 이용하여, 입 출력 임피던스 정합 회로를 EM co-시뮬레이션을 이용하여 F급으로 설계를 수행하였으며, SAAO 기판에 구현하였다. 이때, 소형의 패키지(모듈)에 집적하기 위하여 인덕터와 커패시터는 각각 spiral inductor, single layer capacitor를 사용하였다. 소형으로($4.4{\times}4.4\;mm^2$) 패키지된 전력 증폭기 모듈의 경우, 출력은 8 W, 효율은 40 % 그리고 2차 및 3차 고조파에 대한 고조파 억제는 30 dBc 이상의 특성을 보였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 C
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• pp.1216-1218
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• 1997

Hydrolysis of BTDA-ODA: MPDA, PMDA-ODA, PIQ polyimides were investigated by FT-IR. The results showed that hydrolysis depends on structure of polyimide and that polyimide obtains hydrolytic stability by curing. Polyimide-aluminum interfaces were characterized by RAIR. It was concluded that imidization of the polyamic acid to polyimde was inhibited by interaction of acid groups with substrate to form aluminum carboxylate.