• 한국수소및신에너지학회논문집
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• 제17권1호
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• pp.31-38
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• 2006

There are two types of metal hydride electrodes as a negative electrode in a Ni-MH battery, $AB_2$ Zr-based Laves phases and $AB_5$ LM(La-rich mischmetal)-based alloys. The $AB_5$ alloy electrodes have characteristic properties such as a large discharge capacity per volume, easiness in activation, long cycle life and a low cost of alloy. However they have a relatively small discharge capacity per weight. The $AB_2$alloy electrodes have a much higher discharge capacity per weight than $AB_5$ alloy electrodes, however they have some disadvantages of poor activation behavior and cycle life. Therefore, in order to improve the discharge capacity of the $AB_5$ alloy electrode the Zr, Ti and V which are the alloying elements of the $AB_2$ alloys were added to the $LaNi_{3.6}Ai_{0.4}Co_{0.7}Mn_{0.3}$ alloy which was chosen as a $AB_5$ alloy with a high capacity. The addition of Zr, Ti and V to $LaNi_{3.6}Ai_{0.4}Co_{0.7}Mn_{0.3}$ alloy improved the activation to be completed in two cycles. The discharge capacities of Zr 0.02, Ti 0.02 and V 0.1 alloys in $LaNi_{3.6}Ai_{0.4}Co_{0.7}Mn_{0.3}M_y$ (M = Zr, Ti, V) were respectively 346, 348 and 366 mAh/g alloy. The alloy electrodes, Zr 0.02, Ti 0.05 and V 0.1 in $LaNi_{3.6}Ai_{0.4}Co_{0.7}Mn_{0.3}M_y$ (M = Zr, Ti, V), have shown good cycle property after 200 cycles. The rate capability of the $LaNi_{3.6}Ai_{0.4}Co_{0.7}Mn_{0.3}M_y$ (M = Zr, Ti, V) alloy electrodes were very good until 0.6 C rate and the alloys, Zr 0.02, Ti 0.05 and V 0.1, have shown the best result as 92 % at 2.4 C rate. The charge retention property of the $LaNi_{3.6}Ai_{0.4}Co_{0.7}Mn_{0.3}M_y$ (M = Zr, Ti, V) alloys was not good and the alloys with M content from 0.02 to 0.05 showed better charge retention properties.

• 멤브레인
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• 제21권3호
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• pp.290-298
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• 2011

팔라듐이 코팅된 $V_{53}Ti_{26}Ni_{21}$ 합금 분리막을 통해 수소 투과시 혼합가스의 영향에 대해 알아보았다. 순수 수소, 수소, 이산화탄소 및 일산화탄소의 혼합가스를 공급가스로 주입할 때, $450^{\circ}C$, 1-3 bar의 압력에서 팔라듐이 코팅된 $V_{53}Ti_{26}Ni_{21}$ 합금 분리막의 수소 투과 실험을 수행하였다. 수소만을 공급한 투과 실험에서 팔라듐 코팅된 $V_{53}Ti_{26}Ni_{21}$ 합금 분리막(두께: 0.5 mm)의 수소 투과량은 3 bar, $450^{\circ}C$ 조건에서 $5.36mL/min/cm^2$였다. 또한 수소/이산화탄소, 수소/일산화탄소 및 수소/이산화탄소/일산화탄소를 공급한 투과실험에서 $V_{53}Ti_{26}Ni_{21}$ 합금 분리막의 수소 투과량은 각각 4.46, 5.20, $3.91mL/min/cm^2$였다. 따라서, 수소/이산화탄소, 수소/일산화탄소 및 수소/이산화탄소/일산화탄소 혼합가스를 각각 공급할 때 투과량은 온도와 압력에 상관없이 수소 분압 감소만큼 감소하였고 모든 경우 Sievert 법칙을 잘 만족시켰다. 투과 후 분리막의 XRD 결과로부터 $V_{53}Ti_{26}Ni_{21}$ 합금 분리막은 여러 혼합가스에 대해 안정성과 내구성이 우수하다는 것을 알 수 있었다.

• 한국분말재료학회지
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• 제11권5호
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• pp.376-382
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• 2004

Nanoscale Cu-Ni alloy nanopowders have been produced by a pulsed wire evaporation method in an inert gas. The effect of Cu-Ni alloy nanopowders as additives to motor oil on the tribological properties was studied at room temperature. The worn surfaces were characterized by Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray Spectroscopy (EDS). Cu-Ni alloy nanopowders as additives lowered coefficient of friction and wear rate. It was found that a copper containing layer on the worn surface was formed, and deposited layers of the metal cladding acted as lubricant on the worn surface, reducing the friction coefficient. It was clearly demonstrated that Cu-Ni alloy nanopowders as additives are able to restore the worn surface and to preserve the friction surfaces from wear.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2003년도 추계학술대회 논문집
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• pp.24-26
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• 2003

We fabricated Ni and Ni alloy substrates for YBCO coated conductors. The Ni and Ni alloy substrate was fabricated by powder metallurgy technique and cold rolling. The texture of substrates had a strong 4-fold symmetry and ［111］∥ND texture after annealing temperature of 100$0^{\circ}C$. The measured full-width half-maximum (FWHM) of in-plane and out-of-plane was in the range of 6$^{\circ}$-10$^{\circ}$. The powder metallurgy technique is fabrication of the substrates for considered to be suitable for the application of YBCO coated conductors.

• 소성∙가공
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• 제16권5호통권95호
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• pp.375-380
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• 2007

The bimetals of home appliances are mainly manufactured by cladding process and these are almost consisted with Cu alloy and Ni alloy. But it is very difficult to clad these alloys, because the brittle $Cu_3O_4$ oxide film formed easily on Cu alloy surface during cladding process. Clad rolling and heat treatment processes were applied for the development of bimetals by using the Ni alloy and the 3 types of Cu alloys. Optical microstructure, micro-hardness, specific resistance, and deflection and line profile of newly processed bimetals specimens were observed and measured in this paper. Inter-diffusion was observed between Cu and Ni element in the interface of heat treated Cu alloy and Ni alloy clad material. The C1220 and Invar36 clad material showed the best property of deflection among the 3 kind of clad materials.

• 한국분말재료학회지
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• 제6권2호
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• pp.171-177
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• 1999

Ti-45.2at.%Ni-5at.%Cu and Ti-40.2at.%Ni-10atat.%Cu alloy powders were fabricated by gas atomization process. The microstructures, Shape, hardness and phase transformation behaviors of the powders were investigated by means of optical microscopy, scanning electron microscopy, micro-hardness measurement, x-ray diffraction analyses and differential scanning calorimetry. The hardness of the Ti-Ni-XCu alloy powders decreased as Cu-content increased. The x-ray diffraction analyses were carried out for powders without heat treatment, and those that treated at 85$0^{\circ}C$ for an hour in a vaccum state($10^5$ torr) and then quenched into ice water. The intensity of B$19^t$ phase increased with heat treating. The monoclinic B$19^t$ martensite was formed in the Ti-Ni-XCu alloy powders during cooling.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1998년도 춘계학술발표회논문집(2)
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• pp.84-89
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• 1998

Alloy 600 및 alloy 690과 Ni-8Cr-lOFe 합금 등의 응력부식(stress corrosion cracking, SCC) 거동을 고온의 염기성 분위기에서 C-ring 시편을 사용하여 연구하였다. Alloy 600과 alloy 690을 여러 조건에서 열처리하여 etching한 후 탄화물의 분포와 입계 주변의 Cr고갈 정도 등의 미세조직을 광학현미경과 주사 전자현미경(SEM)으로 관찰하였다. 이들 재료에 대한 SCC 시험을 315$^{\circ}C$의 40% NaOH 수용액에서 일정한 부하전위(부식전위 + 200㎷)를 가하면서 수행하였으며, 동일 조건에서의 분극거동도 측정하였다. Alloy 600 MA(mill anneal) 및 TT(thermal treatment)의 SCC 저항성은 alloy 690 TT와 Ni-8Cr-10Fe SA(solution anneal)보다 낮았다. Alloy 600 TT 재료는 alloy 600 MA 및 SA 재료에 비해 SCC 저항성이 더 컸다. 고용 탄소농도는 alloy 600의 SCC 저항성에 큰 영향을 주지 못했다. 대부분의 Alloy 600은 균열전파 입계균열을 보였으나, 일부에서는 입계 및 입내 혼합양상(mixed mode cracking)을 보였다. 염기성 분위기에서 Ni기 합금의 SCC 거동을 미세조직, 분극거동의 관점에서 고찰하였다.

• 한국수소및신에너지학회논문집
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• 제10권4호
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• pp.225-232
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• 1999

Ni-MH 2차 전지의 음극재료로 사용되는 수소저장합금중 이론 방전용량이 가장 높은 $Mg_2Ni$를 기계적 합금법으로 제조하여 각종 첨가물의 첨가에 따른 전기화학적 특성을 조사하였다. $Mg_2Ni$는 고에너지 볼밀인 SPEX 8000을 이용하여 두가지 방법으로 제조하였다. 하나는 Mg, Ni 분말에 첨가물인 $AB_5$, $AB_2$계 수소저장합금과 Ni, Co, Cu를 첨가하여 12시간 볼밀링한 경우이고, 다른 하나는 먼저 Mg, Ni 분말을 1시간동안 볼밀링한 후 $300{\sim}400^{\circ}C$에서 열처리하여 $Mg_2Ni$를 제조한 후 여기에 첨가물을 10wt% 첨가하여 12 시간동안 볼밀할 경우이다. 이 볼밀링한 복합분말을 상온에서 $754tons/cm^2$의 압력으로 냉간압착하여 디스크 모양의 전극을 제조하였다. 실험결과 볼밀링 후 열처리를 거친 합금분말의 경우가 그렇지 않은 경우에 비해 전극의 방전용량이 높았으며, Ni을 첨가한 경우는 방전용량을 증가시키고 Co를 첨가한 경우는 싸이클 특성이 향상되었다. 특히 $Mg_2Ni$에 Ni을 10wt%를 첨가하여 12시간 볼밀한 경우 $Mg_2Ni$의 최대 방전용량은 546mAh/g.alloy으로 이론용량의 약 55%에 달했다.

• Journal of Welding and Joining
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• 제12권4호
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• pp.85-101
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• 1994

Effect of Cr, Cu and Ni metal powders addition on the alloyed layer of aluminum alloy (AC2B) has been investigated with the plasma transferred arc (PTA) overlaying process. The overlaying conditions were 125-200A in plasma arc current, 150mm/min in process speed and 5-20g/min in powder feeding rate. Main results obtained are summarized as follows: 1) It was made clear that formation of thick surface alloyed layer on aluminum alloy is possible by PTA overlaying process. 2) The range of optimum alloying conditions were much wider in case of Cu and Ni powder additions than the case of Cr powder addition judging from the surface appearance and the bead macrostructure. 3) Alloyed layer with Cu showed almost the homogeneous microstructure through the whole layer by eutectic reaction. alloyed layers with Cr and Ni showed needle-like and agglomerated microstructures, the structure of which has compound layer in upper zone of bead by peritectic and eutectic-peritectic reactions, respectively. 4) Microconstituents of the alloyed layer were analyzed as A1+CrA $l_{7}$ eutectics, C $r_{2}$al sub 11/, CrA $l_{4}$, C $r_{4}$A $l_{9}$ and C $r_{5}$A $l_{*}$ 8/ for Cr addition, Al+CuA $l_{2}$(.theta.) eutectics and .theta. for Cu addition, and Al+NiA $l_{3}$ eutectics. NiA $l_{3}$, N $i_{2}$A $l_{3}$ and NiAl for Ni addition. 5) Concerning defect of the alloyed layer, many blow holes were seen in Cr and Ni additions although there was lesser in Cu addition. Residual gas contents in blow hole for Cu and Ni alloyed layer were confirmed as mainly $H_{2}$ and a littie of $N_{2}$ Cracking was observed in compound zone of the alloyed layer in case of Cr and Ni addition but not in Cu alloyed layer.r.r.

• 한국분말재료학회지
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• 제15권1호
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• pp.23-30
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• 2008

Ni-20Cr-20Fe-5Nb alloy with or without $Y_2O_3$ was manufactured by mechanical alloying process and consolidated by spark plasma sintering (SPS). The grain size of the alloy with $Y_2O_3$ was smaller than that of alloy without $Y_2O_3$ which results from the effect of $Y_2O_3$ suppressing grain growth. The tensile strength at room temperature was increased by the addition of $Y_2O_3$ but decreased abruptly at temperature above $600^{\circ}C$. It seems to result from the change of deformation mechanism due to fine grain size, that is, grain boundary sliding is predominant at above $600^{\circ}C$ while internal dislocation movement is predominant at below $600^{\circ}C$. After conventional heat treatment process of solution treatment and aging, a small amount of ${\delta}(Ni_3Nb)$ phase was formed in Ni-20Cr-20Fe-5Nb alloy while a large amount of ${\gamma}"(Ni_3Nb)$ was formed in Inconel 718 in the previous report. This is due to exhaustion of Nb content by the formation of NbC during consolidation.