• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2017년도 춘계학술대회 논문집
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• pp.153-153
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• 2017

The application of the coating supports the mechanical characteristics of the implant, and various materials and coatings are currently being used in the implant in a way to accelerate adhesion. Especially, plasma electrolytic oxidation (PEO) coating has been proposed continually with good surface treatment of titanium alloys. Also, the PEO process can incorporate Ca and P ions on the titanium surface through variables varied factor. PEO process for bioactive surface has carried out in electrolytes containing Ca and P ions. Natural bone is composed of mineral elements such as Mg, Si, Zn, Sr, and Mn, etc. Especially, Mg and Si of these elements play role in bone formation and growth after clinical implantation of bio-implants. In this study, corrosion charateristics of PEO-treated Ti-6Al-4V alloy in solution containing Si and Mg ions has been investigated using several experimental techniques. The PEO-treated surfaces were identified by X-ray diffraction, using a diffractometer (XRD, Philips X' pert PRO, Netherlands) with Cu $K{\alpha}$ radiation. The morphology was observed by field-emission scanning electron microscopy (FE-SEM, Hitachi 4800, Japan) and energy-dispersive X-ray spectroscopy (EDX, Oxford ISIS 310, England). The potentiodynamic polarization and AC impedance tests for electrochemical degradations were carried out in 0.9% NaCl solution at similar body temperature using a potentiostat with a scan rate of 1.67mV/s and potential range from -1500mV to + 2000mV.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2017년도 춘계학술대회 논문집
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• pp.154-154
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• 2017

Ti-6Al-4V alloys are widely used as metal-lic biomaterials in dentistry and orthopedics due to its excellent biocompatibility and me-chanical properties. However, because of low biological activity, it is difficult to form bone growth directly on the surface of titanium implants. For this reason, surface treatment of plasma electrolytic oxidation(PEO) was used for dental implants. To enhance bioac-tivity on the surface, strontium(Sr) and sili-con(Si) ions can be added to PEO treated sur-face in the electrolyte containing these ions. The presence of Sr in the coating enhances osteoblast activity and differentiation, where-as it inhibits osteoclast production and prolif-eration. And Si has been found to be essen-tial for normal bone, cartilage growth, and development. In this study, electrochemical characteristics of Ca, P, Sr, and Si ions from PEO-treated Ti-6Al-4V alloy surface was re-searched using various experimental instruments. DC power is used and Ti-6Al-4V al-loy was subjected to a voltage of 280 V for 3 minutes in the electrolyte containing 5, 10, 20M% Sr ion and 5M% Si ion. The morphol-ogies of PEO-treated Ti-6Al-4V alloy by electrochemical anodization were examined by field-emission scanning electron micro-scopes (FE-SEM), energy dispersive x-ray spectroscopy (EDS), x-ray diffraction (XRD) and corrosion analysis using AC impedance and potentiodynamic polarization test in 0.9% NaCl solution at similar body tempera-ture using a potentiostat with a scan rate of 1.67mV/s and potential range from -1500mV to + 2000mV.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.281-281
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• 2011

산업 환경에서 친환경 및 에너지효율성을 중요한 조건이 되면서 고효율성 및 다기능을 가진 재료에 대한 연구가 활발히 진행 되고 있다. 특히 Al-Ti-N 코팅은 이미 경도 측면에서 우수 하여 고속 공구 부품에 널리 사용되고 있고 최근에 Al-TiN에서 Si 첨가는 40GPa이상의 고경도와 1000도 이상의 산화온도를 지닌 나노 혼합물 코팅을 형성 시키는 것으로 알려져 있다. 본 연구에서 Al-Ti에 Si, Cu, Cr 을 첨가하였을 때 코팅을 형성하였을 때 바뀌는 물성 변화을 확인하였다. 이러한 연구를 위해 Al-Ti 합금 조성 중 가장 우수한 것으로 알려진 60:40으로 타겟을 만들어 스퍼터 장비를 이용해 코팅을 형성하여 기초 실험을 진행하였다. 그 근거로 하여 3원계인 Si, Cu, Cr 을 첨가하여 각각의 단일 타겟으로 만들고 코팅을 형성하였다. 타겟과 코팅의 성분이 동일한지 확인하기 위해 EPMA분석을 하였고 그 결과 오차 범위 내에 동일한 것으로 확인하였다. 또 내산화성 테스트를 위해 400도에서 1000도로 가열된 대기 중에 코팅 층을 1시간씩 노출시키는 공정을 통해 확인하였고 내식성 테스트는 SUS 304계열 위에 코팅을 하여 Potentiodynamic polarization scan 장비로 비교해 보았다. 표면경도는 3원계 코팅인 경우 질소비율이 증가할수록 30GPa ~ 35GPa까지 증가하였고 XRD 분석 결과와 비교 시 (111), (200) peak가 명확할수록 경도 값이 높은 것으로 확인하였다. 마모테스트 결과 3원계인 코팅 층이 dry상태에서 감소하는 경향을 보였다. 특히 0,26까지 감소한 Si 을 첨가한 코팅 층은 H/E지수도 좋아 마모트랙의 길이도 짧아 우수한 것으로 알 수 있었다. 이런 결과에서 보듯 3원소 이상 첨가 시 특성변화가 차이가 있다는 것을 알 수 있었다.

• 한국재료학회지
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• 제25권5호
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• pp.253-257
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• 2015

The implanting of metal products is performed with numerous surface treatments because of toxicity and adhesion. Recently, the surface modification of metal products has been actively studied by coating the surface of the TiC or TiN film. We prepared a Ti(10%)Ag Target which may be used in dental oral material by, using the AIP(arc ion plating) system TiAgN coating layer that was deposited on Ti g.23. The purpose of this study was to establish the optimal bias voltage conditions of the coated TiAgN layer formed by the AIP process. The TiAgN coatings were prepared with different bias voltage parameters (0V to -500V) to investigate the effect of bias voltage on their mechanical and chemical properties. The SEM(scanning electron microscope), EDS(energy dispersive X-ray spectrometer), XRD(X-ray diffraction), micro-hardness, and potentiodynamic polarization were measured and the surface characteristics of the TiAgN coating layers were evaluated. The TiAgN coating layer had different mechanical characteristics based on the bias voltage, which also showed differences in thickness and composition.

• 한국표면공학회지
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• 제41권2호
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• pp.69-75
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• 2008

Electrochemical behaviors of surface modified and MC3T3-E1 cell cultured Ti-30Ta alloys have been investigated using various electrochemical methods. The Ti alloys containing Ta were melted by using a vacuum furnace and then homogenized for 6 hrs at $1000^{\circ}C$. MC3T3-E1 cell culture was performed with MC3T3-E1 mouse osteoblasts for 2 days. The microstructures and corrosion resistance were measured using FE-SEM, XRD, EIS and potentiodynamic test in artificial saliva solution at $36.5{\pm}1^{\circ}C$. Ti-Ta alloy showed the martensite structure of ${\alpha}+{\beta}$ phase and micro-structure was changed from lamellar structure to needle-like structure as Ta content increased. Corrosion resistance increased as Ta content increased. Corrosion resistance of cell cultured Ti-Ta alloy increased predominantly in compared with non cell cultured Ti- Ta alloy due to inhibition of the dissolution of metal ion by covered cell. $R_p$ value of MC3T3-E1 cell cultured Ti-40 Ta alloy showed $1.60{\times}10^6{\Omega}cm^2$ which was higher than those of other Ti alloy. Polarization resistance of cell-cultured Ti-Ta alloy increased in compared with non-cell cultured Ti alloy.

• Corrosion Science and Technology
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• 제5권6호
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• pp.218-221
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• 2006

Influence of microstructure on the corrosion property of Mg-Al-Zn alloy was investigated using potentiodynamic polarization experiments, galvanic coupling experiments, and scanning electron microscopy in sodium chloride solutions. Pitting was the most common form of attack in chloride solution, and filiform corrosion was also occurred in AZ91D-T4 alloy. On the contrary, filiform attack in the bulk matrix was predominant corrosion form in AZ91D-T6 alloy, and the number and size of pit were decreased than those of AZ91D-T4 alloy. Galvanic coupling effect between $Mg_{17}Al_{12}$ and matrix was existed, but the propagation of galvanic corrosion was localized only near the $Mg_{17}Al_{12}$ phase in AZ91D-6T alloy. The corrosion resistance of Mg-Al matrix increased with decreasing Al content in the matrix. And, it could be regarded that Al content in the matrix is decreased by precipitation of $Mg_{17}Al_{12}$ during the aging treatment and it decreases the anodic reaction rate of the matrix and galvanic effect in AZ91D-T6 alloy. It could be considered that the composition and microstructure of surface protective layer would be varied by precipitation of $Mg_{17}Al_{12}$ and subsequent decreasing of Al content in the matrix. And it would contribute the corrosion resistance of AZ91D-T6 aging alloy.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2013년도 춘계학술대회 논문집
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• pp.62-62
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• 2013

Magnesium alloys exhibit many attractive properties such as low density, high strength/weight ratio, high thermal conductivity, very good electromagnetic features and good recyclability. However, most commercial magnesium alloys require protective coatings because of their poor corrosion resistance. Attempts have been made to improve the corrosion resistance of the Mg alloys by surface treatments, such as chemical conversion coatings, anodizing, plating and metal coatings. Among them, chemical conversion coatings are regarded as one of the most effective and cheapest ways to prevent corrosion of Mg alloys. In this study, the effects of various $Zn^{2+}$ concentrations and pH levels on the formation of zinc phosphate conversion coatings (ZPCCs) on AZ31 magnesium alloy were investigated, and corrosion resistances of the coated samples were evaluated by immersion test and potentiodynamic polarization experiment. The corrosion resistance of the coated AZ31 samples was found to increase with increasing $Zn^{2+}$ concentration and the lowest corrosion rate was obtained for the samples coated at pH of 3.07, independent of $Zn^{2+}$ concentration. The best coatings on AZ31 were obtained at [$Zn^{2+}$] = 0.068 M and pH 3.07. At the conditions of [$Zn^{2+}$] = 0.068 M and pH 3.07, the formation and growth processes of ZPCCs on AZ31 Mg alloy are divided into four stages: formation of a dense layer, precipitation of fine crystals on the dense layer, growths of the inner and outer layers, and reorganization of outer crystalline layer.

• 대한치과기공학회지
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• 제23권1호
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• pp.55-64
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• 2001

This study is focusing on the improvement of problems of Ti-6Al-4V alloy. A new Ti based alloy, Ti-15Sn-4Nb, have designed to examine any possibility of improving the mechanical properties and biocompatibility. Specimens of Ti alloys were melted in vacuum arc furnace and homogenized at $100^{\circ}C$ for 24h. All specimens were solution treated at $812^{\circ}C$ and aged at $500^{\circ}C$ for 10h. The corrosion resistance of Ti alloys was evaluated by potentiodynamic polarization test and immersion test inl%Lactic acid solutions. Ti-15Sn-4Nb system alloys showed Widmanstatten microstructure after solution treatment which is typical microstructure of ${\alpha}+{\beta}$ type Ti alloys. Analysing the corrosion resistance of Ti alloys, it was concluded that the passive films of Ti-15Sn-4Nb system alloys are more stable than that of Ti-6Al-4V alloys. Also, the corrosion resistance of Ti-15Sn-4Nb system alloys was improved with adding elements, Hf. It was analysed that the passive film of the Ti-15Sn-4Nb alloy which was formed in air atmosphere was consisted of TiO2, SnO and NbO through X-ray photoelectron spectroscopy(XPS) analysis.

• 대한화학회지
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• 제59권2호
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• pp.142-147
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• 2015

Two new chitosan derivatives, polyamine grafted chitosan copolymers have been synthesized for corrosion protection of carbon steel in acidic medium. First, methyl acrylate graft chitosan copolymer (CS-MAA) was prepared by the reaction of chitosan (CS) and methyl acrylate (MAA) via the Michael addition reaction. Then, CS-MAA was reacted with ethylene diamine (EN) and triethylene tetramine (TN) respectively to synthesize ethylene diamine grafted chitosan copolymer (CS-MAA-EN) and triethylene tetramine grafted chitosan copolymer (CS-MAA-TN), and the structures were characterized by Fourier-transform infrared spectroscopy (FT-IR). At last, the corrosion inhibition activities on Q235 carbon steel were investigated by using gravimetric measurements, metallographic microscope, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) measurements. The compounds CS-MAA-EN and CS-MAA-TN show an appreciable corrosion inhibition property against corrosion of Q235 carbon steel in 5% HCl solution at $25^{\circ}C$. It has been observed that CS-MAA-EN shows greater corrosion inhibition efficiency than CS-MAA-TN. The inhibition efficiency of CS-MAA-EN was close to 90% when the mass fraction concentration was 0.2%~0.3%; the inhibition efficiency of CS-MAA-TN was close to 85% when the mass fraction concentration was 0.02%. The present work provided very promising results in the preparation of green corrosion inhibitors.

• Journal of Advanced Marine Engineering and Technology
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• 제37권5호
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• pp.484-492
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• 2013

세계 각국은 산업 고도화에 따라 해수환경에 내식성, 내마모성을 갖는 재료에 대한 수요가 지속적으로 증가하고 있다. 특히 표면이 미려하고 내식성이 강한 스테인리스강은 선박, 해양 플랜트 및 조류발전 등 다양한 산업분야에 널리 사용되고 있다. 그러나 해양환경에서 $Cl^-$ 이온에 의한 부식 손상과 고속회전에 따라 캐비테이션 손상이 발생하기 쉽다. 따라서 이 연구에서는 해수 내 빠른 유속 환경에 사용되는 304 스테인리스강에 대해 캐비테이션 침식-부식실험을 실시하여 외부 조건이 스테인리스강의 내식성에 미치는 영향을 종합 분석하였다. 캐비테이션이 발생된 조건에서 워터캐비테이션 피닝효과에 의한 시험편 내에 압축잔류응력 형성으로 높은 경도를 나타냈으나, 물리적 충격으로 인한 산화피막 파괴로 동전위 분극 실험에서는 높은 전류밀도를 나타냈다. 따라서 해수 내 캐비테이션에 대한 저항성을 향상시키기 위해서는 전기화학적 특성뿐만 아니라 기계적 특성도 복합적으로 고려한 재료의 선택이 필요하다.