• 한국수소및신에너지학회논문집
• /
• 제21권5호
• /
• pp.383-389
• /
• 2010

Co-B, Co-P-B, Co-Ni-B and Co-Ni-P-B catalysts supported on Ni foam were prepared using electroless plating in the present study. The surface morphology of the catalysts/Ni foam was observed using SEM and EDS analysis. The Co-Ni-P-B/Ni foam catalyst showed the superior performance on hydrogen generation due to the uniform formation of catalyst particles on the Ni foam surface. The characteristics of hydrogen generation with Co-Ni-P-B/Ni foam catalyst was investigated at the variety of $NaBH_4$ and NaOH concentrations. Durability test was performed, resulting in the stable hydrogen generation for 6 hours.

• 한국재료학회지
• /
• 제27권8호
• /
• pp.397-402
• /
• 2017

We used an etching process to control the line-width of screen printed Ag paste patterns. Ag paste was printed on anodized Al substrate to produce a high power LED. In general, Ag paste spreads or diffuses on anodized Al substrate in the process of screen printing; therefore, the line-width of the printed Ag paste pattern increases in contrast with the ideal line-width of the pattern. Smudges of Ag paste on anodized Al substrate were removed by neutral etching process without surface damage of the anodized Al substrate. Accordingly, the line-width of the printed Ag paste pattern was controlled as close as possible to the ideal line-width. When the etched Ag paste pattern was used as a seed layer for electroless Ni plating, the line width of the plated Ni film was similar to the line-width of the etched Ag paste pattern. Finally, in pattern formation by Ag paste screen printing, we found that the accuracy of the line-width of the pattern can be effectively improved by using an etching process before electroless Ni plating.

• 청정기술
• /
• 제20권2호
• /
• pp.136-140
• /
• 2014

본 연구에서 폴리프로필렌을 모재로 사용하여 Co/Ni/P/Mn 4가지 금속을 무전해도금 방법으로 코팅하였다. 이 때 도금욕의 시약의 양을 조절함으로써 폴리프로필렌 위에 도금된 금속의 조성을 다르게 조정하였다. 이러한 조건으로 만들어진 도금 금속에 대하여 두께, 전기적 표면 저항, 주사형 전자현미경을 사용한 표면상태, 에너지 분산형 분석기를 통한 금속조성을 측정하였다. 인 함량이 높을수록 전지저항이 커지는 것이 관찰되어 인 함량과 전지전도성간의 상관성이 있는 것이 관찰되었다. 또한 코팅 금속의 수용액에서의 부식성을 3.5 wt% 염화나트륨 용액과 5.0 wt% 황산용액에서 비교한 결과 인을 많이 포함할수록 내식성이 강함을 알 수 있었다.

• 폴리머
• /
• 제31권5호
• /
• pp.410-416
• /
• 2007

무유화제중합으로 제조된 폴리(메틸 메타크릴레이트) (PMMA) 시드 고분자 미립자에 가교단량체인 HDDA (1,6-hexanediol diacrylate), triEGDMA [tri(ethylene glycol) dimethacrylate] 또는 triEGDMA와 EGDMA (ethylene glycol dimethacrylate)의 혼합액을 흡수시키고, 이를 중합하여 단분산 가교고분자 미립자를 제조할 시 1) 흡수된 가교단량체와 시드 고분자 미립자의 중량비(흡수율) 변화, 2) 가교단량체의 변화, 3) 무전해 니켈도금 및 4) 무전해 (니켈/금)도금에 따른 단분산 가교고분자 미립자의 기계적 물성인 탄성복원율, 압축탄성률, 파괴강도 및 파괴변형률의 변화를 MCT(micro compression test)를 사용하여 측정하였다. 이번 연구를 통해 가교단량체의 흡수율 증가는 가교고분자 미립자의 파괴강도에만 큰 영향을 미쳤으나, 가교고분자 미립자의 무전해 도금은 도금분체의 탄성복원율 및 파괴강도는 감소시키나, 파괴변형률의 경우에는 거의 영향을 미치지 않으며, 압축탄성률의 경우는 $K_{10}$ 및 $K_{20}$는 크게 증가시키나, $K_{30}$ 이후에는 거의 영향을 미치지 못함을 알 수 있었다.

• 한국표면공학회지
• /
• 제49권1호
• /
• pp.54-61
• /
• 2016

Screen printing of commercially available Ag paste is the most widely used method for the front side metallization of Si solar cells. However, the metallization using Ag paste is expensive and needs high temperature annealing for reliable contact. Among many metallization schemes, Ni/Cu/Sn plating is one of the most promising methods due to low contact resistance and mass production, resulting in high efficiency and low production cost. Ni layer serves as a barrier which would prevent copper atoms from diffusion into the silicon substrate. However, Ni based schemes by electroless deposition usually have low thermal stability, and require high annealing process due to phosphorus content in the Ni based films. These problems can be resolved by adding W element in Ni-based film. In this study, Ni-W-P alloys were formed by electroless plating and properties of it such as sheet resistance, resistivity, specific contact resistivity, crystallinity, and morphology were investigated before and after annealing process by means of transmission line method (TLM), 4-point probe, X-ray diffraction (XRD), and Scanning Electron Microscopy (SEM).

• 한국분말재료학회지
• /
• 제25권5호
• /
• pp.375-378
• /
• 2018

Conductive and dielectric SiC are fabricated using electroless plating of Ni-Fe films on SiC chopped fibers to obtain lightweight and high-strength microwave absorbers. The electroless plating of Ni-Fe films is achieved using a two-step process of surface sensitizing and metal plating. The complex permeability and permittivity are measured for the composite specimens with the metalized SiC chopped fibers dispersed in a silicone rubber matrix. The original non-coated SiC fibers exhibit considerable dielectric losses. The complex permeability spectrum does not change significantly with the Ni-Fe coating. Moreover, dielectric constant is sensitively increased with Ni-Fe coating, owing to the increase of the space charge polarization. The improvements in absorption capability (lower reflection loss and small matching thickness) are evident with Ni-Fe coating on SiC fibers. For the composite SiC fibers coated with Ni-Fe thin films, a -35 dB reflection loss is predicted at 7.6 GHz with a matching thickness of 4 mm.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
• /
• pp.323-323
• /
• 2013

High power light-emitting diodes (LEDs) are widely used in many device applications due to its ability to operate at high power and produce high luminance. However, releasing the heat accumulated in the device during operating time is a serious problem that needs to be resolved to ensure high optical efficiency. Ceramic or Aluminium base metal printed circuit boards are generally used as integral parts of communication and power devices due to its outstanding thermal dissipation capabilities as heat sink or heat spreader. We investigated the characterisation of electroless plating of Ni-B film according to plating bath temperature, ranging from $50^{\circ}C$ to $75^{\circ}C$ on Ag paste/anodised Al ($Al_2O_3$)/Al substrate to be used in metal PCB for high power LED packing systems. X-ray diffraction (XRD), Field-Emission Scanning Electron Microscopy (FE-SEM) and X-ray Photoelectron Spectroscopy (XPS) were used in the film analysis. By XRD result, the structure of the as deposited Ni-B film was amorphous irrespective of bath temperature. The activation energy of electroless Ni-B plating was 59.78 kJ/mol at the temperature region of $50{\sim}75^{\circ}C$. In addition, the Ni-B film grew selectively on the patterned Ag paste surface.

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

• 한국표면공학회:학술대회논문집
• /
• 한국표면공학회 2000년도 춘계학술발표회 초록집
• /
• pp.15-16
• /
• 2000

• 한국재료학회:학술대회논문집
• /
• 한국재료학회 1993년도 추계 학술발표 강연 및 논문 개요집
• /
• pp.132-132
• /
• 1993