• 한국수소및신에너지학회논문집
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• 제20권4호
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• pp.291-299
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• 2009

Ni-plated polytetrafluoroethylene(Ni-PTFE) particles($25{\mu}m$, $500{\mu}m$) were prepared by using nickel electroless plating. The Ni content in Ni-PTFE particles increased with increasing the amount of reduction agent. At about 53 wt% Ni content, $25{\mu}m$ Ni-PTFE particles showed conductivity of 320S/m. The Ni-PTFE particles were formed into the Ni-PTFE plate using heat treatment at $350^{\circ}C$ under $10{\sim}1000kg/cm^2$. The Ni-PTFE plate displayed the high conductivity of 5100S/m due to the formation of 3-dimentional Ni network. The plate was used as an electrode in an alkaline fuel cell(AFC). In terms of the current density, the Ni-PTFE electrode having higher Ni content(53 wt%) showed improved performance.

• 한국결정성장학회지
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• 제23권5호
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• pp.218-223
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• 2013

본 연구에서는 LCD 또는 LED를 이용한 디스플레이 장치의 BLU 반사판으로 사용할 목적으로 무전해도금에 의하여 플라스틱 기판위에 성장되어진 은 나노코팅의 반사율 특성을 조사하였다. 은 나노코팅의 미세구조는 아주 미세한 나노크기의 은 결정들로 이루어진 다결정 나노코팅인 것을 확인할 수 있었으며 코팅 층의 두께가 증가함에 따라 환원, 석출된 은 나노결정입자의 크기도 비례하여 증가되었다. 은 나노코팅의 두께가 증가함에 따라 가시광선 영역의 반사율이 감소하였으며 파장이 짧을수록 반사율의 감소가 더 심하였다. 나노코팅의 두께 증가에 따른 반사율의 감소는 환원 석출된 은나노결정의 크기와 밀접하게 관련된 것으로 은 결정입자가 클수록 요철의 정도가 심하여 반사율이 감소하는 것으로 생각되어진다. 그래서 가능한 미세한 은 나노결정을 환원, 석출시키고 코팅두께를 얇게 하는 것이 반사율 관점에서 바람직한 것으로 판단되어진다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 추계학술대회논문집
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• pp.119-123
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• 2006

The ionic-polymer-metal-composite actuators have the best merit for bio-mimetic locomotion because of their large bending performance. Especially, they have the advantage for mimicking a fish-like motion because IPMCs are useful to be actuated in water. So we have developed IPMC actuators with multiple electrodes for realization of biomimetic motion. Generally, the IPMC actuator has been fabricated in electroless plating technique, while it needs very long fabrication time and shows poor repeatability in the actuation performance owing to the variables in chemical fabrication process. Therefore, the novel fabrication methods were investigated by combining electroless plating and electroplating techniques capable of patterning precisely. On the whole, two different methods were compared and analyzed with similar thickness level of Platinum electrodes. Present results show that mixing chemical reduction and electroplating can be a promising candidate for electrode patterning.

• 한국표면공학회지
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• 제22권4호
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• pp.161-167
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• 1989

Effects of bath composition on electroless deposition of Ni-W-B from sulphate solution were invesrigated in terms of deposition kinetics, electro resistivity and composition of deposit film. The microstruigated and crystataine structure of the films were also studied using a scanning electron microscope and X-ray diffractometer. The deposition rate increased linearly with increasing the concentration of nickel sulphate in bath solution, wheras the rate decreasing with sodium citrate. The rate was also affected by sodium tungstate, which was maaximum at the concentration of 0.06 M/1 in sodium tungstate, The content of W in the deposit increased with increased with increasing the sodium citrate had on opposite effect on the composition of W and B in the deposit. The crystal change film from armorphous to cryatallicne nature by heat treatments was proved by the reduction of specific resistance and X-ray diffration.

• 폴리머
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• 제33권1호
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• pp.33-38
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• 2009

은 카바메이트 착체 화합물의 환원에 의한 무전해 도금법으로 은/폴리스티렌 비드를 제조하기 위하여 폴리스티렌 및 아민 관능기를 가지는 공중합체 비드를 제조하였다. 스티렌, divinylbenzene(DVB) 그리고 2-(N,N-dimethylamino)ethyl methacrylate (DAEMA) 단량체들을 poly(vinyl alcohol) 존재 하에서 물/메탄올을 용매로 사용하여 무유화중합을 진행하였다. 30/0$\sim$1.5/0$\sim$3 wt%의 단량체 조성을 가지는 poly(styrene/DVB/DAEMA) 비드는 구형으로 1 ${\mu}m$의 일정한 크기를 가지고 있었다. 아민 기능기를 가지는 폴리스티렌 비드의 무전해 도금은 비드의 전처리 없이 silver 2-ethylhexylcarbamate (Ag-EHCB) 복합체와 히드라진 환원제를 사용하여 메탄올 용액에서 진행하였다. 제조된 비드와 도금된 비드 표면의 형태를 SEM으로 관찰하였으며 은 도금된 비드를 분산시켜 자외선 흡수 변화 그리고 도금된 은의 성분을 XRD로 분석하였다.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2009년도 춘계학술발표대회 논문집
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• pp.230-234
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• 2009

It is significant technique to increase competitiveness that solar cells have a high energy conversion efficiency and cost effectiveness. When making high efficiency crystalline Si solar cells, evaporated Ti/Pd/Ag contact system is widely used in order to reduce the electrical resistance of the contact fingers. However, the evaporation process is no applicable to mass production because high vacuum is needed. Furthermore, those metals are too expensive to be applied for terrestrial applications. Ni/Cu/Ag contact system of silicon solar cells offers a relatively inexpensive method of making electrical contact. Ni silicide formation is one of the indispensable techniques for Ni/Cu/Ag contact sytem. Ni was electroless plated on the front grid pattern, After Ni electroless plating, the cells were annealed by RTP(Rapid Thermal Process). Ni silicide(NiSi) has certain advantages over Ti silicide($TiSi_2$), lower temperature anneal, one step anneal, low resistivity, low silicon consumption, low film stress, absence of reaction between the annealing ambient. Ni/Cu/Ag metallization scheme is an important process in the direction of cost reduction for solar cells of high efficiency. In this article we shall report an investigation of rapid thermal silicidation of nickel on silngle crystalline silicon wafers in the annealing range of $350-390^{\circ}C$. The samples annealed at temperatures from 350 to $390^{\circ}C$ have been analyzed by SEM(Scanning Electron Microscopy).

• Korean Chemical Engineering Research
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• 제46권5호
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• pp.863-867
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• 2008

피치계 활성탄소섬유가 납사분해 잔사유를 개질하여 용융 방사하고, 산화, 탄화 및 스팀으로 활성화하여 제조되었다. 활성탄소섬유의 표면은 주석-팔라듐을 사용하여 단일 스텝에 의해 예민화 과정을 거쳤다. 예민화된 활성탄소섬유 표면에 무전해도금법을 사용하여 구리를 골고루 담지하였다. 도금시간을 증가시켜서 구리의 담지량을 변화시키고, BET, SEM, XRD 및 ICP를 이용하여 촉매 특성 변화에 미치는 영향을 관찰하였다. 도금시간에 따라 부가된 구리의 양은 증가하나, 기공부피와 비표면적은 감소하였다. 또한 반응 온도가 증가함에 따라 NO 제거 성능이 증가하였다. $300^{\circ}C$ 이상의 반응 온도에서 부가된 구리의 양이 증가하면 표면적의 감소와 구리 분산도의 감소 때문에 NO 제거 성능은 감소하는 결과를 얻었다.

• 마이크로전자및패키징학회지
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• 제6권2호
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• pp.13-21
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• 1999

Flip chip assembly directly on organic boards offers miniaturization of package size as well as reduction in interconnection distances resulting in a high performance and cost-competitive Packaging method. This paper describes the investigation of alternative low cost flip-chip mounting processes using electroless Ni/Au bump and anisotropic conductive adhesives/films as an interconnection material on organic boards such as FR-4. As bumps for flip chip, electroless Ni/Au plating was performed and characterized in mechanical and metallurgical point of view. Effect of annealing on Ni bump characteristics informed that the formation of crystalline nickel with $Ni_3$P precipitation above $300^{\circ}C$ causes an increase of hardness and an increase of the intrinsic stress resulting in a reliability limitation. As an interconnection material, modified ACFs composed of nickel conductive fillers for electrical conductor and non-conductive inorganic fillers for modification of film properties such as coefficient of thermal expansion(CTE) and tensile strength were formulated for improved electrical and mechanical properties of ACF interconnection. The thermal fatigue life of ACA/F flip chip on organic board limited by the thermal expansion mismatch between the chip and the board could be increased by a modified ACA/F. Three ACF materials with different CTE values were prepared and bonded between Si chip and FR-4 board for the thermal strain measurement using moire interferometry. The thermal strain of ACF interconnection layer induced by temperature excursion of $80^{\circ}C$ was decreased with decreasing CTEs of ACF materials.

• 한국표면공학회지
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• 제32권3호
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• pp.447-451
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• 1999

Silver has the highest electrical conductivity of all metals and consequently this property is an attractive feature which makes it a leading candidate for use in electronic devices. The research conducted was focused primarily on the development of a process for obtaining a deposited silver-coating onto alumina, for applications related to electrical-conducting devices and, ancillarily, catalysts. Alumina balls and plane substrates were utilized for the investigation. The coating process employed an aqueous ammoniacal silver-nitrate electrolytes with a formaldehyde solution as the reductant. Modifying additives-an activator which would be expected to promote good deposition-characteristics onto the (dielectric) substrate and an inhibitor which would obviate homogeneous reduction (precipitation) of silver was observed when the activator-containing silver-electrolyte reductant constituents were combined. However, the silver-electrolyte/reductant system with inhibitor could be employed (at 8$0^{\circ}C$) to achieve a viable (subject to future research optimization) coating on alumina. The influence of the processing temperature on the deposition process was delineated during the course of the research. The morphology of the deposited-silver on the alumina balls was assessed by SEM imaging. A tape-peel test was employed, with the plane substrates, to semi-quantitatively characterize the adhesion to the alumina.

• 한국재료학회지
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• 제31권11호
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• pp.626-634
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• 2021

Cu matrix composites reinforced with chopped carbon fiber (CF), which is cost effective and can be well dispersed, are fabricated using electroless plating and hot pressing, and the effects of content and alignment of CF on the thermal properties of CF/Cu composites are studied. Thermal conductivity of CF/Cu composite increases with CF content in the in-plane direction, but it decreases above 10% CF; this is due to reduction of thermal diffusivity related with phonon scattering by agglomeration of CF. The coefficient of thermal expansion decreases in the in-plane direction and increases in the through-plane direction as the CF content increases. This is because the coefficient of thermal expansion of the long axis of CF is smaller than that of the Cu matrix, and the coefficient of thermal expansion of its short axis is larger than that of the Cu matrix. The thermal conductivity is greatly influenced by the agglomeration of CF in the CF/Cu composite, whereas the coefficient of thermal expansion is more influenced by the alignment of CF than the aggregation of CF.