• 공업화학
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• 제25권2호
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• pp.198-203
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• 2014

본 연구에서는 Ni metal foam 플레이트의 수증기 개질반응 및 표면 특성을 조사하였다. 전처리를 통하여 Ni의 산화상태를 변화시킬 수 있었으며, 활성 site로서 표면에 노출된 metallic Ni 종은 수증기 개질 반응활성에 중요한 역할을 한다. 또한 Ni metal foam 플레이트의 기공제어 및 촉매 기능을 부여하기 위하여 Ni metal foam 플레이트와 Ni-YSZ 촉매를 혼합하여 다공성 촉매 분리막을 제조하였다. SEM 분석 결과 metal foam 플레이트의 기공을 제어할 수 있었으며, 표면에 Ni-YSZ 촉매는 고르게 잘 분포되어 있었다. Ni 기반 다공성 촉매 분리막은 공간속도에 상관없이 상용촉매와 유사한 수증기 개질 활성을 가진다.

• 한국수소및신에너지학회논문집
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• 제20권5호
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• pp.361-370
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• 2009

Ni-PTFE composite plated on graphite (C/Ni-PTFE) and PTFE (PTFE/Ni-PTFE) particles were prepared uniformly by electroless composite plating. The conductivity of C/Ni-PTFE particles was 280 S/m higher than 95 S/m of PTFE/Ni-PTFE particles at same composite plating condition (Ni:35~36 wt%, PTFE:8 wt%). The C/Ni-PTFE particles were formed into the C/Ni-PTFE plate using heat treatment at $350^{\circ}C$ under 10~$1000\;kg/cm^2$. The C/Ni-PTFE plate showed 1) high conductivity of $5.7\;{\times}\;10^4\;S/m$ due to the existence of graphite as conducting aid and the formation of 3-dimensional Ni network 2) good gas diffusion caused by various pore volumes (0.01~$100\;{\mu}m$) in the plate. The plate could be useful for an electrode in an alkaline fuel cell (AFC). The current density of C/Ni-PTFE electrode indicated $84\;mA/cm^2$ at 0.3V and it was 3.0 times higher than that of PTFE/Ni-PTFE electrode.

• 한국재료학회지
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• 제21권5호
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• pp.288-294
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• 2011

Simultaneous Ni and C codeposition by electrolysis was investigated with the aim of obtaining better corrosion resistivity and surface conductivity of a metallic bipolar plate for application in fuel cells and redox flow batteries. The carbon content in the Ni-C composite plate fell in a range of 9.2~26.2 at.% as the amount of carbon in the Ni Watt bath and the roughness of the composite were increased. The Ni-C composite with more than 21.6 at.% C content did not show uniformly dispersed carbon. It also displayed micro-sized defects such as cracks and crevices, which result in pitting or crevice corrosion. The corrosion resistance of the Ni-C composite in sulfuric acid is similar with that of pure Ni. Electrochemical test results such as passivation were not satisfactory; however, the Ni-C composite still displayed less than $10^{-4}$ $A/cm^2$ passivation current density. Passivation by an anodizing technique could yield better corrosion resistance in the Ni-C composite, approaching that of pure Ni plating. Surface resistivity of pure Ni after passivation was increased by about 8% compared to pure Ni. On the other hand, the surface resistivity of the Ni-C composite with 13 at.% C content was increased by only 1%. It can be confirmed that the metal plate electrodeposited Ni-C composite can be applied as a bipolar plate for fuel cells and redox flow batteries.

• 한국생산제조학회지
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• 제21권4호
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• pp.547-555
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• 2012

This paper focuses on the research of the anode and cathode in the Ni-MH secondary battery. In this paper, the proposed method employs a continuous wave Nd : YAG laser based on the pure Ni instead of the low carbon steel to improve the conductivity although the conventional secondary battery is based on the resistance spot welded with low carbon steel SS41. It welds a sandwich panel using the pure Ni and the porous thin plate, and the tested optimal conditions for the laser power and irradiation speed were 300 and 350 Watt, and 1.0~1.6m/min, respectively. Finally, we observed a ratio, heat input and cross-section and measured the conductivity of the welding section to test the weldability.

• 한국자동차공학회논문집
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• 제21권3호
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• pp.134-141
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• 2013

Reflow soldering process is essential in electronic package. Reflow process for a long time results from the decrease of reliability because IMC is formed excessively. Solder alloys of Sn-37Pb and Sn-Ag with different kinds of Cu contents (0, 0.5 and 1 wt.%) as compared with Ni and Cu plate joints are investigated according to varying reflow time. The interfaces of solder joints are observed to analyze IMC (intermetallic compound) growth rate by scanning electron microscope (SEM). Shear test is also performed by using SP (Share-Punch) tester. The test results are compared with the solder joints of two different plates (Ni and Cu plate). $Cu_6Sn_5$ IMCs are formed on Cu plate interfaces after reflows in all samples. Ni3Sn4 and $(Cu,Ni)_6Sn_5$ IMCs are also formed on Ni plate interfaces. The IMC layer forms are affected by reflow time and contents of solder alloy. These results show that mechanical strength of solder joints strongly depends on thickness and shape of IMC.

• 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.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 1999년도 특별강연 및 추계학술발표대회 개요집
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• pp.220-224
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• 1999

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2000년도 특별강연 및 춘계학술발표대회 개요집
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• pp.151-154
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• 2000

• Journal of Advanced Marine Engineering and Technology
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• 제25권2호
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• pp.344-350
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• 2001

This paper was studied on the characteristics of galvanic corrosion and its protection on heat exchanger tube plate in the sea water. In this paper, behavior of pitting corrosion of Ni-al bronze connected with Ti tube was measured af flow velocity of 0 m/s and 2.4 m/s. To protect galvanic corrosion, the protection characteristics of Ni-Al bronze connected with Ti tube by Zn-base alloys galvanic anode and hexagonal nylon insert was investigated. Main results obtained asre al follows: 1) The galvanic corrosion of Ni-Al bronze connected with Ti-tube is more active than single Ni-al bronze. 2) As the circuit resistance increase under the cathodic protection employing Zn-base alloys galvanic anode, Ni-al bronze connected with Ti tube is cathodically unpolarized. 3) The corrosion of Ni-Al bronze connected with Ti tube by nylon insert controls approximately 73% than not nylon insert.

• Journal of Advanced Marine Engineering and Technology
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• 제25권2호
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• pp.345-345
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• 2001

This paper was studied on the characteristics of galvanic corrosion and its protection on heat exchanger tube plate in the sea water. In this paper, behavior of pitting corrosion of Ni-al bronze connected with Ti tube was measured af flow velocity of 0 m/s and 2.4 m/s. To protect galvanic corrosion, the protection characteristics of Ni-Al bronze connected with Ti tube by Zn-base alloys galvanic anode and hexagonal nylon insert was investigated. Main results obtained asre al follows: 1) The galvanic corrosion of Ni-Al bronze connected with Ti-tube is more active than single Ni-al bronze. 2) As the circuit resistance increase under the cathodic protection employing Zn-base alloys galvanic anode, Ni-al bronze connected with Ti tube is cathodically unpolarized. 3) The corrosion of Ni-Al bronze connected with Ti tube by nylon insert controls approximately 73% than not nylon insert.