• Transactions on Electrical and Electronic Materials
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• v.16 no.5
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• pp.264-267
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• 2015

AlCrNO cermet films were prepared on aluminum substrates using a DC-reactive magnetron sputtering method and a water-cooled Al:Cr target. The Al₂O₃/AlCrNO (LMVF)/AlCrNO (MMVF)/AlCrNO (HMVF)/Al/substrate of the 5 multi-layers was prepared according to the Ar and (N₂ + O₂) gas-mixture rates. The Al₂O₃ of the top layer is the anti-reflection layer of triple AlCrNO (LMVF)/AlCrNO (MMVF)/AlCrNO (HMVF) layers, and an Al metal forms the infrared reflection layer. In this study, the crystallinity and surface properties of the AlCrNO thin films were estimated using X-ray diffraction (XRD) and field-emission scanning electron microscopy (FESEM), while the composition of the thin films was systematically investigated using Auger electron spectroscopy (AES). The optical properties of the wavelength spectrum were recorded using UH4150 spectrophotometry (UV-Vis-NIR) at a range of 0.3 μm to 2.5 μm.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2003.11a
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• pp.355-359
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• 2003

In this paper, we investigated the wear lift, wear rate, and its transition on the Hertz pressure. In the experiment, we used TiAlCrN coating deposited by the sputtering technique and ball diameter of 10mm, 7.94mm and 4.76mm for the various Hertz pressure. Ball-on-disk sliding tests wire performed under the unlubricated condition. As the diameter of a ball decreased, the failure load of TiAlCrN coating decreased. However, a good correlation was observed between the wear life and Hertz pressure, and all ball specimens showed the infinite wear life at about 450MPa. In measurement of wear rate, as the diameter of the ball inclosed, the wear transition appeared in bigger load. However, a good correlation was observed between the wear rate and Hertz pressure. The transition appeared in the range from 550MPa to 600MPa at all ball speimens.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2007.04a
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• pp.122-123
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• 2007

Bias voltage를 달리하여 cathodic arc plasma 방법으로 Si 기판 위에 성장시킨 TiCrAlSiN 코팅막의 미세구조를 투과전자현미경으로 관찰하였다. -200 V에서 0 V로 bias voltage가 변화함에 따라 'nano-multilayered' 구조가 무너지면서 '주상형(columnar)'구조로 코팅막의 미세구조가 변함을 알 수 있었고, EDS line scan을 통해 multilayer의 화학적 조성 변화를 확인하였다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2012.11a
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• pp.187-188
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• 2012

magnetron-sputtering법을 사용하여 $Cr_{1-x}Al_xN$ 박막을 증착함에 있어 Al 함량의 변화를 주었다. 그 후 열처리를 통하여 thermal inkjet 방식 print head의 heater resistor 소재로서의 특성 향상을 도모하였다. Al의 함량이 증가할수록 결정구조는 NaCl에서 wurtzite HCP 구조로 변화하였으며 전기적 특성 또한 다르게 나타났다. 비열처리 시 Al 함량이 클수록 결정성은 떨어진다는 것을 확인하였고, 열처리 시 Al 함량이 적을 수 록 더 안정한 온도 저항 계수를 나타내는 것을 확인하였다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2018.06a
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• pp.131-131
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• 2018

최근 절삭공구산업은 자동차, 항공기, IT, 선박, 에너지 등 첨단산업의 증가로 인해 CGI, CFRP, 내열합금 등 난삭재의 수요가 증가하고 있다. 난삭재는 고내열, 고경도, 초경량 같은 특성을 지니며 우수한 기계적 물성을 갖지만 가공의 어려움이 있어 산업에 적용하는데 한계가 있다. 이러한 한계를 극복하기 위해 개발된 가공기술 중 하드 코팅은 공구코팅비용 대비 공구의 표면경도와 수명을 효율적으로 향상시킬 수 있다고 알려져 있다. 대표적인 하드코팅으로는 AlN계, TiN계 코팅이 있다. 이러한 코팅의 경우 높은 기계적 물성과 우수한 내마모성으로 인해 절삭공구의 성능을 향상시킬 수 있기 때문에, 많은 연구가 진행되고 있으며 절삭공구산업에서 각광받고 있다. 기존 선행연구 결과에 따르면 질화물 코팅의 우수한 물성은 질화물(Nitride) 생성 및 질화 공정에 의한 코팅층의 고밀도화에 의해 나타난다고 알려져 있다. 그 중에서 AlCrN coating은 우수한 내마모성 및 향상된 고온경도를 갖고 있다. AlCrN based coating에 미량의 원소를 첨가하여 기존 AlCrN coating의 기계적 특성을 더욱 향상 시킨 coating은 일반적인 고성능 코팅 대비 공구수명이 길다고 알려져 있으며, 전반적으로 우수한 특성에 의해 전 세계적으로 습식 및 건식 기계 가공 용도로 사용되고 있다. 본 연구에서는 AlCrN based coating에 미량의 원소를 첨가한 coating의 우수한 기계적 특성의 원인을 규명하기 위해 텅스텐카바이드(WC) 기판 위에 아크 이온 플레이팅 장비를 이용하여 AlCrN based coating을 증착 시킨 sample을 분석하였다. 결정구조 및 상 분석을 위해 X선 회절분석(XRD)을 실시하였으며, 미세 구조를 분석하기 위해 전계방출형 주사전자현미경(FE-SEM), 투과 전자현미경(TEM) 분석을 실시하였다. 또한 코팅층의 화학적 성분 분석을 위해 EDX분석을 실시하였으며 기계적 특성 평가를 위해 나노압입시험(Nano-indentation test)을 진행하였다.

• Journal of the Korean Society for Heat Treatment
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• v.18 no.3
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• pp.183-189
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• 2005

The effects of duplex-treatment of plasma carburization and CrN coating onto Ti-6Al-4V alloy on its creep properties were investigated by means of a constant stress creep tester. Applying duplex-treatment, specimens having an inner carburized layer of about $150{\mu}m$ in depth and outer CrN layer of about $7.5{\mu}m$ in thickness were prepared. The hardness of duplex-treatment surface was about 1,960 VHN. It also appeared that the duplex-treatment improved the roughness of the surface significantly; $Ra=0.045{\mu}m$ for treated alloy while $Ra=0.321{\mu}m$ for untreated alloy. The steady-state creep behaviors were investigated in a temperature range of $510{\sim}550^{\circ}C$ ($0.42{\sim}0.44T_m$) under an applied stress range of 200~275 MPa. The stress exponent, n, was derived assuming the power law creep behavior. The surface treatment showed a decrease in a value from 9.32 (untreated) to 8.79 (treated). Also the activation energy obtained from an Arrhenius plot increased from 238 to 257 kJ/mol.

• Proceedings of the Materials Research Society of Korea Conference
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• 2005.05a
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• pp.271-271
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• 2005

• Transactions of Materials Processing
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• v.8 no.3
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• pp.319-319
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• 1999

From isothermal and cyclic oxidation tests on thermomechanically treated Ti-5%Al, Ti47%Al-4%Cr, and Ti-48%Al-2%Cr-2%Nb alloys at 800, 900, 1000℃ in air, it was found that Ti-48%Al-2%Cr-2%Nb and Ti-47%Al-4%Cr had the best and the worst oxidation resistance, respectively. The oxide scales consisted primarily of TiO₂and Al₂O₃, with and without a small amount of dissolved Cr and 7b ions, depending on the alloy composition. These ions were slightly enriched inside the inner oxide layer, and strongly enriched around the scale-matrix interface. The outer TiO₂-rich layer was formed by the outward diffusion of Ti ions, while the inner (TiO₂+A1₂O₃,) mixed layer was formed by the inward transport of oxygen. The outward movement of Al ions farmed the intermediate Al₂O₃-rich Iayer, above talc prepared alloys.

• Journal of the Korean institute of surface engineering
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• v.36 no.6
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• pp.480-490
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• 2003

Effects of plasma-nitriding on the pitting corrosion of Fe-30at%Al-5at%Cr alloy containing Ti, Hf, and Zr were investigated using potentiostat in 0.1M HCl. The specimen was casted by the vacuum arc melting. The subsequent homogenization was carried out in Ar gas atmosphere at $1000^{\circ}C$ for 7days and phase stabilizing heat treatment was carried out in Ar gas atmosphere at $500^{\circ}C$ for 5 days. The specimen was nitrided in the $N_2$, and $H_2$, (1:1) mixed gas of $10^{-4}$ torr at $480^{\circ}C$ for 10 hrs. After the corrosion tests, the surface of the tested specimens were observed by the optical microscopy and scanning electron microscopy(SEM). For Fe-30at%Al-5Cr alloy, the addition of Hf has equi-axied structure and addition of Zr showed dendritic structure. For Fe-30at%Al-5Cr alloy containing Ti, plasma nitriding proved beneficial to decrease the pitting corrosion attack by increasing pitting potential due to formation of TiN film. Addition of Hf and Zr resulted in a higher activation current density and also a lower pitting potential. These results indicated the role of dendritic structure in decreasing the pitting corrosion resistance of Fe-30Al-5Cr alloy. Ti addition to Fe-30Al-5Cr decreased the number and size of pits. In the case of Zr and Hf addition, the pits nucleated remarkably at dendritic branches.

• Journal of the Korean institute of surface engineering
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• v.47 no.5
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• pp.252-256
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• 2014

The TiAlCrSiN film was deposited on the WC-20%TiC-10%Co carbide, and its oxidation behavior was examined at $700-1000^{\circ}C$. It displayed relatively good oxidation resistance owing to the formation of $TiO_2$, $Al_2O_3$, $Cr_2O_3$, and $SiO_2$ up to $900^{\circ}C$. However, at $1000^{\circ}C$, the fast oxidation rate and partial oxidation of WC in the substrate led to the formation of the thick, fragile oxide scale.