• 한국표면공학회지
• /
• 제51권6호
• /
• pp.354-359
• /
• 2018

NaCl-induced hot corrosion behavior of ASTM T22 (Fe-2.25Cr-1Mo), T91 (Fe-9Cr-1Mo), T92 (Fe-9Cr-1.8W-0.5Mo), 347HFG (Fe-18-Cr-11Ni), and 310H (Fe-25Cr-19Ni) steels was studied after spraying NaCl on the surface. During corrosion at $600-800^{\circ}C$ for 50-100 h, thick, non-adherent, fragile, somewhat porous oxide scales formed. All the alloys corroded fast with large weight gains owing to fast scaling and destruction of protective oxide scales. Corrosion rates increased progressively as the corrosion temperature and time increased. Corrosion resistance increased in the order of T22, T91, T92, 347HFG, and 310H, suggesting that the alloying elements of Cr, Ni, and W beneficially improved the corrosion resistance of steels. Basically, Fe oxidized to $Fe_2O_3$, and Cr oxidized to $Cr_2O_3$, some of which further reacted with FeO to form $FeCr_2O_4$ or with NiO to form $NiCr_2O_4$.

• 신재생에너지
• /
• 제1권1호
• /
• pp.64-71
• /
• 2005

The stability of alumina-coated NiO cathodes was studied in $Li_{0.62}/K_{0.38}$ molten carbonate electrolyte. Alumina was effectively coated on the porous Ni plate using galvanostatic pulse plating method. The deposition mechanism of alumina was governed by the concentration of hydroixde ions near the working electrode, which was controlled by the temperature of bath solution. Alumina-coated NiO cathodes were formed to $A1_2O_3-NiO$ solid solution by the oxidation process and their Ni solubilities were were than that of NiO up to the immersion time of 100h. However, their Ni solubilities increased and were similar to that of the bare NiO cathode after 100h. It was because aluminum into the solid solution was segregated to $\alpha-LiAlO_2$ on the NiO and its Product did not Play a role of the Physical barrier against NiO dissolution.

• 한국표면공학회지
• /
• 제34권3호
• /
• pp.206-214
• /
• 2001

The purpose of this study is to determine the effects of Ni on precipitate formation in a Ni added galvanizing bath, which has various Ni content from 0.03wt.% to 0.5wt.%. The addition of hi in the Ni containing galvanizing bath resulted in the formation of Al-Ni intermetallic compounds such as $Al_3$$Ni_2$ and $Al_2$Ni, which make up most of the top precipitates. At 0.07wt.%Ni, Al-Ni intermetallic compound formed sensitively with small amount of Al addition. By analysing the reaction thickness of galvanized steel, it was found that Ni addition in a Zn-0.18w1.%Al bath tended to suppress the formation of Fe-Zn intermetallic compounds but the formation of these compounds increased with increasing Ni concentration above 0.1wt.%.

• 한국자기학회지
• /
• 제3권4호
• /
• pp.293-297
• /
• 1993

자기 저항 헤드용 자기 교환 결합 $NiFe/TbCo/Sio_{2}$ 박막을 RF diode 스퍼터링 방법을 이용하여 제조하고, 그 자기적 특성을 측정하였다. TbCo 박막은 Co 타겟 위에 Tb 조각을 부착한 복합 타겟을 사용하였다. 30%의 Tb 면적을 갖는 타겟으로 제조된 NiFe($400\AA$)/TbCo($1500\AA$)/$SiO_{2}$($500\AA$) 시편은 기판 바이어스를 인가하지 않았을 때 25 Oe, 기판 바이어스-55 V를 인가했을 때 12 Oe의 교환자장을 나타냈다. 기판 바이어스 -55 V 이하에서 유효 수평 보자력으 TbCo 층의 수직 보자력에 거의 비례하였고, 28%의 Tb 면적비를 갖는 시편에서도 같은 경향을 나타내었다. 그러나, 교환 자장은 기판 바이어스가 인가되지 않은 경우에 4 Oe로, -55 V에서 7 Oe로 각각 감소하 였다. 1000 W, Tb 면적비 36%에서 증착된 시편에서 100 Oe 정도의 교환 자장을 얻었으며, 보자력은 3 Oe로 작았다. 그리고, NiFe의 두께가 두꺼워짐에 따라 교환 자장의 크기가 감소하였다.

• 한국해양공학회지
• /
• 제27권2호
• /
• pp.75-79
• /
• 2013

This study was carried out to investigate the precipitation behavior of the ${\chi}$ phase and the impact toughness of 25%Cr-7%Ni-2%Mo-4%W super duplex stainless steel. The ${\chi}$ phase was precipitated in the early stage of aging, and with the increasing aging time. However, after reaching a maximum value, the number decreased as a result of the gradual transformation of the ${\chi}$ phase into the ${\sigma}$-phase. It was proved that the ${\chi}$ phase was an intermetallic compound, which represented a lower nickel concentration, higher chromium and molybdenum concentrations, and very higher tungsten concentration compared to the matrix phases. It also showed higher molybdenum and tungsten concentrations than the ${\sigma}$ phase. The decomposition of the ferrite phase into the ${\gamma}_2$ and ${\sigma}$ phases was retarded by W substitution for Mo. Thus, the number of ${\chi}$ phases increased. The impact value was decreased by the substitution of W for Mo. The impact toughness rapidly decreased with time when the ${\chi}$ phase began to precipitate in the initial stage of aging. The impact toughness was, therefore, greatly influenced for the precipitation of the ${\chi}$ phase.

• 한국재료학회지
• /
• 제20권6호
• /
• pp.338-343
• /
• 2010

As an alternative to the W plug used in MOSFETs, a Cu plug with a NiSi contact using Ta / TaN as a diffusion barrier is currently being considered. Conventionally, Ni was first deposited and then NiSi was formed, followed by the barrier and Cu deposition. In this study, Ti was employed as a barrier material and simultaneous formation of the NiSi contact and Cu plug / Ti barrier was attempted. Cu(100 nm) / Ti / Ni(20 nm) with varying Ti thicknesses were deposited on a Si substrate and annealed at $4000^{\circ}C$ for 30 min. For comparison, Cu/Ti/NiSi thin films were also formed by the conventional method. Optical Microscopy (OM), Scanning Probe Microscopy (SPM), X-Ray Diffractometry (XRD), and Auger Electron Microscopy (AES) analysis were performed to characterize the inter-diffusion properties. For a Ti interlayer thicker than 50 nm, the NiSi formation was incomplete, although Cu diffusion was inhibited by the Ti barrier. For a Ti thickness of 20 nm and less, an almost stoichiometric NiSi contact along with the Cu plug and Ti barrier layers was formed. The results were comparable to that formed by the conventional method and showed that this alternative process has potential as a formation process for the Cu plug/Ti barrier/NiSi contact system.

• 자원리싸이클링
• /
• 제2권4호
• /
• pp.10-16
• /
• 1993

마이크로파 가열 공정에 의하여 스테인레스강 제조시의 발생하는 분진의 환원거동올 환원제로서 코크스와 목탄을 이용하여 조사하였다. 원래 상태의 펠릿 분진과 환원제로서, 펠릿을 만든 분진을 마이크로파 가열오븐 내에서 $1000^{\circ}C$까지 가열하여 환원시켰다. 코크스에 비하여 목탄의 경우가 더 높은 환원율율을 나타내었다. 마이크로파 오븐에서 500W와 700W의 사용한 경우 유사한 환원율을 나타냈으며 200분 이내에 급속하게 환원되였다. 환원정도는 Fe>Ni>Cr로 감소되었다.

• 한국자기학회지
• /
• 제4권3호
• /
• pp.201-207
• /
• 1994

RF 마그네트론 스퍼터링법으로 제작된 퍼멀로이(NiFe) 박막에 대하여 투입전력, 아르곤 압력, 바이어스 전압등의 스퍼터링 조건이 퍼멀로이 박막의 자기특성에 미치는 영향을 조사하였다. 투입전력에 따른 보자력의 변화는 300~400W에서 낮은 값을 지녔으며 아르곤 압력에 따른 변화는 1~5mTorr에서 낮은 값을 나타내었다. 스퍼터링 조건에 따른 최소의 보자력값은 400 W, 5mTorr 와 300 W, 2mTorr에서 각각 0.10 Oe를 나타내었고 최대의 투자율값은 400 W, 5mTorr에서 2800(1 MHz)을 나타내었다. 또한 저압의 스 퍼터링 압력에서 바이아스를 가할 경우 보자력은 이에 비례해서 오히려 증가하였다. 박막의 Ni 함량의 변화는 아르곤 압력이 증가함에 따라 점차적으로 감소하나 2~10mTorr 범위에서는 다시 증가하는 경향을 보였다. 내부응력은 아르곤 압력이 증가함에 따라 압축응력에서 인장응력으로 변하였으며 5mTorr에서 내 부응력이 거의 사라졌다.

• Bulletin of the Korean Chemical Society
• /
• 제32권9호
• /
• pp.3239-3244
• /
• 2011

Dinuclear Ni(II)-thiophene halides, which contain linear bridging thienylenes, trans,trans-[$(PR_3)_2$(X)Ni-Y-Ni(X)$(PR_3)_2$] {X = Cl, Br; $H_2Y$ = 5,5'-dichloro-2,2'-bithiophene ($H_2bth$); $H_2tth$ = 5,5"-dichloro-2,2':5',2''-terthiophene ($H_2tth$)} were prepared by the oxidative addition of dihalobithiophene ($H_2bth$) or dihaloterthiophene ($H_2tth$) to [$Ni(COD)_2$] in the presence of tertiary phosphines. Subsequent reactions of $NaN_3$ with the dinuclear Ni(II)-thiophene chlorides gave the corresponding Ni(II)-azido complexes, trans,trans-[$(PR_3)_2(N_3)$Ni-Y-Ni$(N_3)(PR_3)_2$], whose reactivity toward trimethylsilyl pseudohalides such as trimethylsilyl isothiocyanates and cyanides was investigated. In addition, the reaction of trans-[$BrNi(PEt_3)_2-C_4H_2S-C_4H_2S$-CHO], a thienyl Ni(II) complex containing a terminal aldehyde group, with phosphonium ylide was examined.

• Progress in Superconductivity
• /
• 제11권2호
• /
• pp.100-105
• /
• 2010

Reel-to-reel deposition of $Y_2O_3$ has been performed on Ni-5%W metal substrates using the RF-sputtering method. The epitaxial orientation of $Y_2O_3$ buffer layers to the base bi-axially textured substrate was well identified using ${\theta}-2{\theta}$, out-of-plane ($\omega$), and in-plane ($\phi$) scans in X-ray diffraction analysis. The optimization of $Y_2O_3$ seed layers in reel-to-reel fashion were investigated varying the deposition temperature, sputtering power, and pressure for its significant roles for the following buffer stacks and superconducting layers. $Y_2O_3$ were all grown epitaxially on bi-axially textured metal substrates at 380 watts and 5 mTorr in the temperature range of $600-740^{\circ}C$ with higher $Y_2O_3$ (400) intensities at ${\sim}710^{\circ}C$. It was found that the $\Delta\omega$ values were $1-2^{\circ}$ lower but the $\Delta\phi$ values were above $1^{\circ}$ higher than that of Ni-W substrates. As the sputtering power increased from 340 to 380 watts, $\Delta\omega$ and $\Delta\phi$ values showed decreased tendency. Even in the small window of deposition pressure of 3-7 mTorr, the $Y_2O_3$ (400) intensities increased and $\Delta\omega$ and $\Delta\phi$ values were reduced as sputtering pressure increased.