• Journal of the Korean Magnetics Society
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• v.9 no.4
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• pp.203-209
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• 1999

Effects of Mo and Si addition in Cr underlayer on magnetic properties of CoCrTa/CrMo and CoCrTa/Si thin films media were investigated. Thin films were prepared with DC magnetron sputtering system. The thickness of CoCrTa magnetic layer and Cr underlayer were fixed at 300 $\AA$ and 700 $\AA$, respectively. The substrate heating temperature was kept constant at 26$0^{\circ}C$ for both magnetic layer and underlayer preparation. The coercivity increase of CoCrTa film was realized due to Mo addition in Cr underlayer. Si addition made a small decrease in coercivity. Coercivity increase seems to be attributed by the improvement of preferred orientation of Cr(200) plane. It is found that lattice fit between Cr(200) and CoCrTa(1120) of CrMo underlayer is better than that of CrSi underlayer. This small misfit may also contribute coercivity increase.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1992.11a
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• pp.7-10
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• 1992

CoNiCr/Cr and CoCrTa/Cr for longitudinal magnetic recording media were. prepared on Coming 7059 glass by RF magnetron sputtering. The thickness of Cr underlayer was varied from 500 to $3000{\AA}$ and. that of magnetic layer was $700{\AA}$. Coercivity and squareness were measured using V.S.M.(vibrating sample magnetometer). The coercivity of films increased with increasing Cr thickness when the films were unannealed. The coercivity of the films annealed in a 10 mtorr vacuum increased initially with annealing time and then saturated with further increase in annealing time. The coercivity value difference between the unannealed and annealed films increased with increasing the thickness of Cr underlayer No significant change was found in squareness after anneal, regardless of Cr underlayer thickness.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2007.11a
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• pp.128-129
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• 2007

Cr-Al-N, Cr-Si-N 그리고 Cr-Al-Si-N 코팅막을 WC-Co 모재위에 AIP법과 DC 마그네트론 스퍼터링 법을 결합한 하이브리드 시스템을 이용하여 합성하였으며, Si함량에 따른 Cr-Al-Si-N 코팅막의 미세구조, 기계적 특성과 마찰 거동에 관해 비교 연구하였다. Cr-Si-N(${\sim}35GPa$)과 Cr-Al-Si-N(${\sim}55GPa$) 코팅막의 경도값은 CrN(${\sim}23GPa$)과 Cr-Al-N(${\sim}25GPa$) 코팅막과 비교하여 각각 증가하였고, CrN(${\sim}0.50$)과 Cr-Al-N(${\sim}0.84$)의 평균 마찰계수는 Si 함량이 9 at.% 일때, Cr-Si-N(${\sim}0.30$)과 Cr-Al-Si-N(${\sim}0.57$)으로 각각 감소하였다.

• Journal of the Korean Magnetics Society
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• v.3 no.3
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• pp.215-220
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• 1993

Microstructural dependence of magnetic property of RF/DC sputtered $Co_{69.0}Ni_{18.5}Cr_{12.5}/Cr$ double layer thin film was studied. Grain size was found to be decreased with substrate temperature in the range of $100-200^{\circ}C$ and Cr underlayer thickness(from $500\;{\AA}-2000\;{\AA}$). The peaks (200) and (1120) of X-ray diffraction patterns were evidently grown with the substrate temperature for the Cr underlayer and magnetic layer, respectively. The CoNiCr magnetic layer was found to be well epitaxialy grown on Cr underlayer, and subsequently the coercivity was enhanced.

• Journal of the Korean Magnetics Society
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• v.3 no.4
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• pp.314-319
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• 1993

The Effects of additional element X (X = Si, Mo, Cu, Gd) on magnetic properties and microstructure of Co-1Zat%Cr-Zat%Ta/Cr-X magnetic thin film were investigated. The thickness changes of Cr-X underlayer and CoCrTa magnetic layer were in the range of $1000~2000\AA$ and $200~800\AA$. respectively. Substrate temperatures were controlled from $100^{\circ}C$ to $200^{\circ}C$. Increase of coercivity by about 100~200 Oe was observed in CoCrTa/Cr-X thin films compared to those without additional X element. Cu was the most effective additional element for increasing coercivity. CoCrTa/Cr-Cu thin film shows relatively high coercivity in $1500\AA$ underlayer thickness and $600\AA$ magnetic layer thickness.

• Tribology and Lubricants
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• v.38 no.4
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• pp.162-169
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• 2022

Cobalt-chromium (CoCr)-based alloys have been used for wear applications because of their excellent mechanical properties and wear resistance. With growing concern over environmental problems, CoCr alloys are expected to be used for various tribological applications in degraded lubrication states. To expand the applicability of the materials, data should be accumulated across a broad spectrum of experimental parameters. In this work, the friction and wear characteristics of cobalt-chromium-tungsten (CoCrW) and cobalt-chromium-molybdenum (CoCrMo) alloys are investigated experimentally. The tests are conducted using a pin-on-reciprocating-plate tribotester in dry lubrication. CoCrW and CoCrMo are used as pin and plate materials to investigate the effect of the counter material. The results show that the friction coefficients between CoCrW and CoCrMo generally range from 0.4 to 0.5. The friction coefficient between the CoCrW pin and plate is found to be slightly small. However, the total wear between the CoCrW pin and plate is found to be the largest. In contrast, the total wear between the CoCrW pin and plate is relatively small. Furthermore, CoCrW may cause a faster wear progression of CoCrMo, especially for the case in which CoCrMo is used as the pin material. The results of this work provide a better understanding of the tribological properties of CoCrW and CoCrMo alloys. In addition, this work provides a practical guideline for the use of CoCrW and CoCrMo from the tribological design viewpoint.

• Elastomers and Composites
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• v.46 no.2
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• pp.152-157
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• 2011

Effects of CR contents in NR/CR blends on the vulcanization kinetics and miscibility were studied by dynamic DSC and TGA, as well as the mechanical properties. While the vulcanization activation energy showed a constant value of $77.5{\pm}2.5$ kcal/mol regardless of CR contents, reaction rate, however, was observed to be somewhat lowered at increased CR contents. Partial miscibility was found between NR and CR phases at lower CR content of 3 wt%, but immiscibility was observed at higher CR content of 21 wt%. Mechanical properties were also affected by this miscibility, showing linear increase of compression set but decrease of tensile strength with CR contents in the blends.

• Journal of the Korean Magnetics Society
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• v.3 no.4
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• pp.320-324
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• 1993

The effect of sputtering conditions on magnetic properties of CoCrMo/Cr magnetic thin film was investigated. Substrate temperature were controlled from R. T to $250^{\circ}C$. The thickness changes of Cr underlayer and CoCrMo magnetic layer were in the range of $1000-2500\AA$ and $300-800\AA$, respectively. Grain size was found to be decreased with increasing magnetic layer thickness(from $500\AA$ to $800\AA$). CoCrMo magnetic layer microstructure showed relatively small dependence on Cr underlayer thickness, substrate temperature. Coercivity increased with increasing Cr underlayer, magnetic layer thickness and substrate temperature. CoCrMo/Cr thin film showed a coercivity of 880 Oe in $700\AA$ magnetic layer thickness and $1000\AA$ Cr underalyer thickness.

• Journal of Surface Science and Engineering
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• v.36 no.6
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• pp.423-429
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• 2003

It has been investigated corrosion resistance and crystal structure of Zn-Cr coatings fabricated by electroplating method and electron-beam physical vapor deposition method(EB-P VD). The electroplated Zn-Cr alloy consists mainly of η'-Zn phase for the lower Cr content than 7.9 wt% Cr and ${\gamma}$'-ZnCr phase for the higher Cr content. In the Zn-Cr alloy fabricated by EB-PVD the ${\gamma}$'-ZnCr phase appeared clearly at 3 wt% Cr and it became the sole phase at 50 wt%Cr. The amount of η'-Zn phase decreased obviously with increasing Cr content when it exceeded 15 wt% Cr. The electrochemical measurement of the electroplated Zn-Cr film has shown corrosion potential of about -1000 mV. The current density of active region and the amount of dissolved Zn and Cr decreased significantly with increasing Cr content. The electrochemical characteristics of Zn-Cr alloy fabricated by EB-PVD have shown that the alloy of 50 wt% Cr had the highest corrosion potential(-500 mV) and the lowest critical passive current density than that of the electroplated.

• Korean Journal of Materials Research
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• v.31 no.11
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• pp.635-641
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• 2021

Cr thin films with O added are deposited on sapphire substrate by DC sputtering and are nitrided in NH₃ atmosphere between 300 and 900 ℃ for various times. X-ray diffraction results show that nitridation begins at 500 ℃, forming CrN and Cr₂N. Cr oxides of Cr₂O₃ are formed at 600 ℃. And, at temperatures higher than 900 ℃, the intermediate materials of Cr₂N and Cr₂O₃ disappear and CrN is dominant. The atomic concentration ratios of Cr and O are 77% and 23%, respectively, over the entire thickness of as-deposited Cr thin film. In the sample nitrided at 600 ℃, a CrN layer in which O is substituted with N is formed from the surface to 90 nm, and the concentrations of Cr and N in the layer are 60% and 40%, respectively. For this reason, CrN and Cr₂N are distributed in the CrN region, where O is substituted with N by nitridation, and Cr oxynitrides are formed in the region below this. The nitridation process is controlled by inter-diffusion of O and N and the parabolic growth law, with activation energy of 0.69 eV.