• 한국자기학회지
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• 제3권3호
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• pp.215-220
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• 1993

RF/DC 스퍼터된 $Co_{69.0}Ni_{18.5}Cr_{12.5}/Cr$ 이중박막의 미세구조와 자기적 성질과의 관계를 조사하였다. Cr 하지층과 CoNiCr 자성층의 두께는 각각 50-200 nm와 10-50 nm였으며, 기판 의 온도는 $100-200^{\circ}C$로 하였다. 기판의 온도, Cr 하지층 두께가 증가함에 따라 결정립은 미세해졌으며 보자력은 증가하였다. 기판의 온도가 $100^{\circ}C$에서 $200^{\circ}C$로 증가함에 따라 Cr(200), CoNiCr(1120) 결정방위가 강하게 나타났다. CoNiCr/Cr 이중박막의 보자력은 CoNiCr(1120) 결정방위 증가와 결정립의 미세 화에 따라 증가한다. 높은 보자력을 나타내는 박막에서 Cr 하지층위에 자성층의 epitaxial growth를 확인하였다.

• 한국표면공학회지
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• 제44권4호
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• pp.125-130
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• 2011

$Cr_2AlC$ compounds were synthesized by hot pressing, and oxidized between 900 and $1200^{\circ}C$ in air for up to 50 hours. They oxidized to a thin $Al_2O_3$ layer containing a small amount of $Cr_2O_3$with the liberation of carbon as CO or $CO_2$ gases. The consumption of Al to form the $Al_2O_3$ layer led to the depletion of Al and enrichment of Cr just below the $Al_2O_3$ layer, resulting in the formation of an underlying $Cr_7C_3$ layer. As the oxidation temperature and time increased, the $Cr_7C_3$ oxide layer and the underlying $Cr_7C_3$ layer thickened. The oxidation resistance of $Cr_2AlC$ was generally good due to the formation of the $Al_2O_3$ barrier layer.

• 한국전기전자재료학회논문지
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• 제17권7호
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• pp.793-796
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• 2004

In order to improve c-axis crystalline orientation and high perpendicular coercivity of deposited ${Co}_77{Cr}_20{Ta}_3$perpendicualr recording layer, Two step method was investigated using a Facing Targets Sputtering System(FTS). The ${\Delta\theta}_50$ of ${Co}_77{Cr}_20{Ta}_3$recording layer deposited on seedlayer prepared at Room Temperature was as low as $5^\circ$, while that of the recording layer without seedlayer was about 11$^{\circ}$. The Two-Step method using ${Co}_77{Cr}_20{Ta}_3$seedlayer prepared at Room Temperature was shown to be very effective in controling the c-axis orientation of ${Co}_77{Cr}_20{Ta}_3$ recording layer with thin thickness.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
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• pp.77-80
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• 2001

Crystallographic and magnetic characteristics of CoCr-based magnetic thin film for perpendicular magnetic recording media were influenced on preparing conditions. In these, there is that substrate temperature was parameter that increases perpendicular coercivity of CoCrTa magnetic layer using recording layer. While preparation of CoCr-based doublelayer, by optimizing substrate temperature, we expect to increase perpendicular anisotropy of CoCr magnetic layer and prepare ferromagnetic recording layer with a good quality by epitaxial growth. CoCrTa/Si doublelayer showed a good dispersion angle of c-axis orientation $\Delta\theta_{50}$ caused by inserting amorphous Si underlayer which prepared at underlayer substrate temperature 250C. Perpendicular coercivity was constant, in-plane coercivity was controlled a low value about 200Oe. This result implied that Si underlayer could restrain growth of initial layer of CoCrTa thin film, which showed bad magnetic properties effectively without participating magnetization patterns of magnetic layer. In case of CoCrTa/Si that prepared with ultra thin underlayer, crystalline orientation of CoCrTa was improved rather underlayer thickness 1nm, it was expected that amorphous Si layer played a important role in not only underlayer but also seed layer.

• 한국표면공학회지
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• 제48권6호
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• pp.260-268
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• 2015

The thermal barrier coating (TBC) for inner wall of liquid-fuel rocket combustor consists of NiCrAlY as bonding layer and $ZrO_2$ as a top layer. In most case, the plasma spray coating is used for TBC process and this process has inherent possibility of cracking due to large difference in thermal expansion coefficients among bonding layer, top layer and metal substrate. In this paper, we suggest crack-free TBC process by using a precise electrodeposition technique. Electrodeposited Ni-P/Cr double layer has similar thermal expansion coefficient to the Cu alloy substrate resulting in superior thermal barrier performance and high temperature oxidation resistance. We studied the effects of phosphorous concentrations (2.12 wt%, 6.97 wt%, and 10.53 wt%) on the annealing behavior ($750^{\circ}C$) of Ni-P samples and Cr double layered electrodeposits. Annealing temperature was simulated by combustion test condition. Also, we conducted SEM/EDS and XRD analysis for Ni-P/Cr samples. The results showed that the band layers between Ni-P and Cr are Ni and Cr, and has no formed with heat treatment. These band layers were solid solution of Cr and Ni which is formed by interdiffusion of both alloy elements. In addition, the P was not found in it. The thickness of band layer was increased with increasing annealing time. We expected that the band layer can improve the adhesion between Cr and Ni-P.

• 한국자기학회지
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• 제13권3호
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• pp.91-96
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• 2003

본 연구에서는 DC 마그네트론 스퍼터를 사용하여 Cr/Co/Al-Ox/Co/Ni-Fe 다층박막에 다양한 두께의 Cr 하지층을 삽입함에 따른 자기적 특성 및 전기적 특성에 관하여 연구하였다. 3 nm 두께의 Cr 하지층 증착시 자기저항비의 변화는 관찰할 수 없었고 적정한 Cr두께가 증가함에 따라 Co의 보자력이 크게 증가되었다 또한, 산화시간이 길수록 두 강자성층간에 보자력 차이 및 절연층의 저항이 점차 증가하였는데, 이는 산화시간에 따라 상부층 계면의 평탄성의 증가에 기인하는 것으로 생각되며 TEM을 통하여 확인할 수 있었다. Cr 하지층 유무에 관계없이 최고 자기저항비가 나타나는 절연층의 산화시간은 60~70초로 비슷하였지만 Cr 두께가 증가할수록 자기저항비는 감소하였다. 이는 전극간 계면의 거칠기의 증가로 인해 미반응 Al의 잔존 확률이 상대적으로 커짐에 따라 터널 전자의 산란이 증가함으로써 나타나는 것으로 생각된다. 이러한 결과로 Cr하지층의 두께는 3 nm로 고정하였으며 하지층의 증착 및 적정산화를 통하여 두 강자성층간에 큰 보자력 차이를 유도할 수 있었다. 이는 재현성에 있어서 가장 큰 문제점을 지닌 TMR 소자에 매우 긍정적인 해결방안을 제시할 수 있게 된다.̄

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.100-103
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• 2001

In order to investigate the magnetic properties of CoCr-based bilayered thin films on kind of underlayer, we introduced amorphous Si layer to Co-Cr(-Ta) magnetic layer as underlayer. With the thickness of CoCr, CoCrTa single layer, crystalline orientation and perpendicular coercivity was improved. It was revealed that by introducing the Si underlayer, the c-axis orientation of CoCr, CoCrTa magnetic layer was improved largely. However, with increasing Si film thickness, perpendicular coercivity and saturation magnetization of Cocr/si, CoCrTa/Si bilayered thin films was decreased. Grain size of bilayered thin films became larger.

• 한국태양에너지학회 논문집
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• 제26권1호
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• pp.57-64
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• 2006

Cr-CrO cermet solar selective coatings with a double cermets layer film structure were prepared using a special direct current (dc) magnetron sputtering technology. The typical films structures from surface to bottom substrate were measured to be an $Al_2O_3$ anti-reflection layer on a double Cr-CrO cermet layer on an Al metal infrared reflection layer. Optical properties of optimized Cr-CrO cermet solar selective coating were absorptance (${\alpha}$) = 0.95 and emittance (${\varepsilon}$) = 0.10 ($100^{\circ}C$). Atomic force microscopy (AFM) image showed that Cr-CrO cermet film was very smooth and their grain size was also very small The results of thermal stability test showed that the Cr-CrO cermet solar selective coatings were stable for use at temperature of $400^{\circ}C$.

• 연구논문집
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• 통권31호
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• pp.127-133
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• 2001

In chromium electrodeposition, crack is inevitably accompanied by chromium layer. Behavior of crack formation and crack density were different from the plating conditions such as current density, temperature, waveform of applied current and so on. And cracks have an influence on the corrosion resistance of chromium deposit, because corrosion occurs through the network of cracks between deposit and substrate. Therefore, many researches have been achieved in order to remove the cracks in chromium deposit. Formation of double layers, Cr/Cr and Ni/Cr were investigated to increase corrosion resistance of chromium deposit in this study. As pretreatment prior to outer chromium coating, acid pickling and current control method were examined. Cracks in cross-section of each sample were observed with SEM and CASS(Copper modified acetic acid salt spray) test was performed to evaluate corrosion resistance. It was found that corrosion resistance of Cr/Cr and Ni/Cr double layers were superior to Cr or Ni single layer from the results of CASS test.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.978-982
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• 2004

We present high aspect ratio 100nm-scale nickel stamper using e-beam lithography process and Cr/Qz mask for the injection molding process of nano grating patterns. Conventional photolithography blank mask (CrON/Cr/Qz) consists of quartz substrate, Cr layer of UV protection and CrON of anti-reflection layer. We have used Cr/Qz blank mask without anti-reflection layer of CrON which is non-conductive material and ebeam lithography process in order to simplify the nickel electroplating process. In nickel electroplating process, we have used Cr layer of UV protection as seed layer of nickel electroplating. Fabrication conditions of photolithography mask using e-beam lithography are optimized with respect to CrON/Cr/Qz blank mask. In this paper, we have optimized e-beam lithography process using Cr/Qz blank mask and fabricated nickel stamper using Cr seed layer. CrON/Cr/Qz blank mask and Cr/Qz blank mask require optimal e-beam dosage of $10.0{\mu}C/cm^2$ and $8.5{\mu}C/cm^2$, respectively. Finally, we have fabricated $116nm{\pm}6nm-width$ and $240nm{\pm}20nm-height$ nickel grating stamper for the injection molding pattern.