• 한국전기전자재료학회논문지
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• 제15권3호
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• pp.281-286
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• 2002

In odder 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. First, we prepared CoCr and CoCrTa single layer using the Facing Targets Sputtering system to investigate theirs properties. It was revealed that with increasing the film thickness of CoCr, CoCrTa single layer, crystalline orientation and perpendicular coercivity was improved. The CoCrTa thin film showed bettor crystalline and magnetic characteristics than CoCr thin film. As a result of investigating magnetic properties of CoCr and CoCrTa magnetic layer on introducing the Si underlayer, perpendicular coercivity and saturation magnetization of CoCr/Si and CoCrTa/Si bilayered thin film were decreased due to the increased grain size and diffusion of Si atoms to magnetic layer. And they showed constant with increasing the film thickness of Si thin film. However, in case of CoCrTa/Si bilayered thin film, in-plane coercivity was controlled low at about 250Oe. The c-axis orientations of CoCr/si and CoCrTa/Si bilayered thin film showed a good crystalline characteristics as about $2^{\circ}$.

• 대한방사선기술학회지:방사선기술과학
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• 제29권4호
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• pp.241-247
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• 2006

최근 유방 영상 검사는 의료영상저장전송시스템(Picture Archiving and Communication System, PACS)의 도입과 특수의료장비에 관한 정도관리 실시로 인해 Computed Radiography(CR)과 Digital Radiography(DR)에 관한 관심도와 이용도가 증가하고 있는 추세이다. 본 연구는 유방영상검사에 이용되고 있는 각 시스템별 검출기의 영상 화질을 정도관리 시 사용되는 ACR 팬텀을 이용하여 비교 분석하였다. 평가 방법은 심리적인 방법으로 ACR 팬텀을 이용한 영상의 수치 값을 SPSS 통계프로그램을 이용하여 유의성과 신뢰도를 분석한 결과는 다음과 같다. 1. Fiber에서는 Screen-Film인 경우 3.9점, CR($50\;{\mu}m$)인 경우 4.2점, CR($100\;{\mu}m$)인 경우 3.2점, DR인 경우 4.2점을 얻어 CR($50\;{\mu}m$), DR, Screen-Film, CR($100\;{\mu}m$)순으로 높은 점수를 받았다(P<0.05). 2. Calcification은 Screen-Film인 경우 2.7점, CR($50\;{\mu}m$)인 경우 2.5점, CR($100\;{\mu}m$)인 경우 2.0점, DR인 경우 2.9점을 얻어 DR, Screen-Film, CR($50\;{\mu}m$), CR($100\;{\mu}m$) 순으로 높은 점수를 받았다(0.025(P<0.05). 3. Mass는 Screen-Film인 경우 3.8점, CR($50\;{\mu}m$)인 경우 3.8점, CR($100\;{\mu}m$)인 경우 3.6점, DR인 경우 4.5점을 얻어 DR, CR($50\;{\mu}m$), Screen-Film, CR($100\;{\mu}m$) 순으로 높은 점수를 받았다(P<0.1). 4. 합계점수 평가는 Screen-Film인 경우 10.4점, CR($50\;{\mu}m$)인 경우 10.6점, CR($100\;{\mu}m$)인 경우 8.7점, DR인 경우 11.3점을 얻어 DR, CR($50\;{\mu}m$), Screen-Film, CR($100\;{\mu}m$) 순으로 높은 점수를 받았다. 이상의 결과는 DR, Screen-Film시스템이 CR($100\;{\mu}m$)에 비해 화질이 우수하다는 것을 알 수 있다. 하지만 DR은 소자에 의한 불안정성, Screen-Film은 artifact에 의한 화질 저하 등 단점을 가지고 있으며, 화질 저하가 문제였던 CR시스템 중 Dual-Side방식의 CR($50\;{\mu}m$)을 사용한 경우에는 Screen-Film 시스템과 차이가 없는 것으로 나타났다. 향후 방사선 영상검사가 디지털화 되는 추세이므로 유방영상검사도 각 시스템의 발전과 보완이 필요할 것으로 사료된다.

• 한국표면공학회지
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• 제26권3호
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• pp.149-157
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• 1993

In the study of TAB(Tape Automated Bonding)technologies, Cu-Cr sputtered seed layer has been used to improve the adhesion between Polyimide and Cu film and electrical properties. But the Cu electrodeposit on Cu-Cr film had poor adhesion or powder-like form due to the surface Cr oxides on the Cu-Cr film. By means of activating the Cu-Cr film with the oxalic acid and phosphoric acid, the Cu film with the improved adhesion could be coated on the Cu-Cr sputtered film in CuSO4 solution. The etching rate was compared with increasing the Cr content of the sputtered Cu-Cr film, and anodic polarization curve in FeCl3 solution was investigated. With increasing the Cr content, the etching rate was reduced. The clean etching cross section could be obtained with increasing the concentration of FeCl3 solution. But above the 13 w/o Cr content, Cu-Cr sputtered film could not bed etched cleanly only with FeCl3 solution and additives were needed.

• International Journal of Ocean System Engineering
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• 제2권2호
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• pp.106-115
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• 2012

In the present study, TiN and CrN films were coated by arc ion plating equipment onto aluminum alloy substrate, A2024. The film thickness was about 4.65 ${\mu}m$. TiN and CrN films were analyzed by X-ray diffraction and energy dispersive X-ray equipments. The Young's modulus and the micro-Vickers hardness of aluminum substrate were modified by the ceramic film coatings. The difference in Young's modulus between substrate and coating film would affect on the wear resistance. The critical load, Lc, was 75.8 N for TiN and 85.5 N for CrN. It indicated from the observation of optical micrographs for TiN and CrN films that lots of cracks widely propagated toward the both sides of scratch track in the early stage of MODE I. TiN film began to delaminate completely at MODE II stage. The substrate was finally glittered at MODE III stage. For CrN film, a few crack can be observed at MODE I stage. The delamination of film was not still occurred at MODE II and then was happened at MODE III. This agrees with critical load measurement which the adhesive strength was greater for CrN film than for TiN film. Consequently, it was difficult for CrN to delaminate because the adhesive strength was excellent against Al substrate. The wear process, which the film adheres and the ball transfers, could be enhanced because of the increase in loading. The wear weight of ball was less for CrN than for TiN. This means that the wear damage of ball was greater for TiN than for CrN film. It is also obvious that it was difficult to delaminate because the CrN coating film has high toughness. The coefficient of friction was less for CrN coating film than for TiN film.

• Corrosion Science and Technology
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• 제12권4호
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• pp.163-170
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• 2013

In NaCl solutions acidified with $H_2SO_4$, Fe20Cr1.1N alloy showed enhanced pitting corrosion resistance than Fe20Cr alloy. An XPS analysis revealed that the passive film of Fe20Cr1.1N alloy contained higher cationfraction of Cr than that of Fe20Cr alloy, and nitrogen was incorporated into the film. In addition, it was found that the passive film of Fe20Cr1.1N alloy was thinner and had higher oxygen vacancy density than that of Fe20Cr alloy. Based on these observations, it was concluded that the chemical composition was the determining factor for the protectiveness of the passive film of Fe20Cr based alloy in dilute $H_2SO_4$ solution.

• 한국자기학회지
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• 제3권3호
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• pp.208-214
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• 1993

Ta을 미량 첨가한 Co-Cr-Ta 박막의 높은 수직보자력의 원인을 알아보기위하여 회전우력자력계 (torque magnetometer)와 진동시료형 자력계(VSM)를 이용하여 Co-Cr 박막과 Co-Cr-Ta 박막의 수직자기이방 성에너지를 조사하였다. Co/sub 81.7/Cr/sub 16.7/Ta/sub 1.6/ 박막의 수직이방성에너지는 동일 기판온도에 서 성막한, 비슷한 용질원자량의 Co/sub 81/Cr/sub 19/ 박막보다 높았다. 그 원인을 분석하기 위하여 as- sputtered 상태의 박막들을 annealing 처리한 후 수직자기이방성에너지의 변화를 조사하였다. annealing 처 리에 의해 수직자기이방성에너지는 감소하였다. 이러한 annealing 처리에 의한 수직자기이방성에너지의 감 소량은 CoCrTa 박막의 경우 더 켰으며, annealing 처리후의 수직자기이방성에너지는 이원계 및 삼원계 박막 에서 비슷한 값을 보였다. 이는 Ta 첨가에 의해 as-sputtered 박막내 용질원자의 편석(segregation) 정도가 증가하며, 이러한 편석 의 증가로 박막내에 형태자기이방성의 기여가 증가하여 수직자기이방성에너지의 증가가 있었던 것으로 해석 된다. 또한 이 러한 용질원자의 편석의 증가에 의한 수직자기이방성에너지의 증가로 박막의 보자력도 증가 한 것으로 생각된다.

• 전기화학회지
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• 제12권3호
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• pp.258-262
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• 2009

The composition and semiconducting properties of the passive films formed on Ni- (15, 30)Cr-5Mo alloys in pH 8.5 buffer solution were examined. The depth concentration profile of passive films formed on Ni-(15, 30)Cr-5Mo in pH 8.5 buffer solution showed that Mo enhances the enrichment of Cr. The Mott-Schottky plot for the passive film on Ni-(15, 30)Cr- 5Mo closely resembled that for the film on Cr, whereas those for the less Cr-enriched film on Mo-free alloys showed similar behavior to that for the film on Ni. The acceptor density was reduced by increasing Cr content in Ni-(15, 30)Cr-(0, 5)Mo alloys, but addition of Mo considerably increased the acceptor density.

• 한국전기전자재료학회논문지
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• 제18권8호
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• pp.714-719
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• 2005

NiCr thin film was deposited by DC magnetron sputtering on $A;_2O_3$/Si substrate with NiCr (80:20) alloy target. NiCr thin films were annealed at $300^{\circ}C,\;400^{\circ}C,\;500^{\circ}C,\;600^{\circ}C,\;and\;700^{\circ}C$ for 6 hr in $H_2$ after annealing at $500^{\circ}C$ for 6hr in air atmosphere, respectively. To analyze NiCr thin film properties, the changes of its micro structure were Investigated through field emission scanning electron microscope (FESEM). X-ray photoelectron spectroscopy (XPS) was used to analyze a surface of NiCr thin film. Resistance of NiCr thin film was measured by 4-point probe technique. The generated heats were measured by infrared thermometer through the application of DC voltage (5 V/l2 V). NiCr thin film treated by gradational double annealing process had uniform and small grains. Maximum temperature generated heat by NiCr micro heater was $173^{\circ}C$. We expect that our results will be a useful reference in the realization of NiCr micro heater.

• 한국전기전자재료학회논문지
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• 제20권6호
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• pp.520-526
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• 2007

In order to acquire fundamental informations to fabricate high precision thin film resistors, NiCr/NiCrSi alloy films were prepared using Ni and Cr targets. Effect of composition on the electrical properties of the NiCr/NiCrSi alloy film were then investigated. Considering the effect of Si doping on the electrical and material characteristics, the lower TCR (temperature coefficient of resistance) values could be achieved for samples with Ni/Cr ratio of $0.8{\sim}1.5$ (in a range of relative higher specific resistivity and Cr composition of $40\;wt%{\sim}55\;wt%$) and with Si doping. Consequently, the sample prepared using a DC power showed a good TCR of $-25\;ppm/^{\circ}C$, which implies that increase of specific resistivity and decrease of TCR would be achieved more efficiently not for Ni-Cr binary material but for Si doped Ni-Cr ternary material, and not using RF power but using DC power in the sputtering process.

• 한국재료학회지
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• 제16권8호
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• pp.461-465
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• 2006

Chromium (Cr) films were deposited on plain carbon steel sheets by DC and RF magnetron sputtering as well as by electroplating. Effects of DC or RF sputtering power on the deposition rate and properties such as, hardness, surface roughness and corrosion-resistance of the Cr films were investigated. X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microcopy (SEM) analyses were performed to investigate the crystal structure, surface roughness, thickness of the Cr films. Salt fog tests were used to evaluate the corrosion resistance of the samples. The deposition rate, hardness, and surface roughness of the Cr film deposited by either DC or RF sputtering increase with the increase of sputtering power but the adhesion strength is nearly independent of the sputtering power. The deposition rate, hardness, and adhesion strength of the Cr film deposited by DC sputtering are higher than those of the Cr film deposited by RF sputtering, but RF sputtering offers smoother surface and higher corrosion-resistance. The sputter-deposited Cr film is harder and has a smoother surface than the electroplated one. The sputter-deposited Cr film also has higher corrosion-resistance than the electroplated one, which may be attributed to the smoother surface of the sputter-deposited film.