• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.552-553
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• 2005

In order to improve energy efficiency in the dilute trichloroethylene removal using the nonthermal plasma process, the barrier discharge treatment combined with manganese dioxide was experimentally studied. Reaction kinetics in this process was studied on the basis of final byproducts distribution. Decomposition efficiency was improved to about 99% at the specific energy 40J/L with passing through manganese dioxide. C=C $\pi$ bond cleavage in TCE gave DCAC (single bond, C-C) through oxidation reaction during the barrier discharge plasma treatment. Those DCAC were broken easily in the subsequent catalytic reaction due to the weak bonding energy about 3 ~ 4 eV compared with the double bonding energy in TCE molecules. Oxidation byproducts of DCAC and TCAA from TCE decomposition are generated from the barrier discharge plasma treatment and catalytic surface chemical reaction, respectively. Complete oxidation of TCE into $CO_X$ is required to about 400J/L.

• Corrosion Science and Technology
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• 제22권4호
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• pp.257-264
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• 2023

Ti-6Al-4V alloys are mainly used as dental materials due to their excellent biocompatibility, corrosion resistance, and chemical stability. However, they have a low bioactivity with bioinertness in the body. Therefore, they could not directly bond with human bone. To improve their applications, their bone bonding ability and bone formation capacity should be improved. Thus, the objective of this study was to improve the bioinert surface of titanium alloy substrate to show bioactive characteristics by performing surface modification using wollastonite powder. Commercial bioactive wollastonite powder was successfully deposited onto Ti-6Al-4V alloy using a room temperature spray process. It was found that wollastonite-coated layer showed homogeneous microstructure and uniform thickness. Corrosion resistance of Ti-6Al-4V alloy was also improved by plasma electrolytic oxidation treatment. Its wettability and bioactivity were also greatly increased by wollastonite coating. Results of this study indicate that both plasma electrolytic oxidation treatment and wollastonite coating by room temperature spray process could be used to improve surface bioactivity of Ti-6Al-4V alloy substrate.

• 한국재료학회지
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• 제11권4호
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• pp.324-328
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• 2001

아크이온 플레이팅 장치를 이용하여 STD61강 기판 위에 이온질화 전처리를 행하거나 하지 않은 후, CrN 박막을 증착하고, 대기중 $700~900^{\circ}C$의 온도에서 40시간동안 이들에 대한 산화거동을 연구하였다. 산화거동은 열중량분석기, X선회절기, EDS, SEM을 이용하여 조사하였다. 증착된 CrN박막은 CrN과 $Cr_2$N의 두 상으로 구성되어 있었다. CrN박막은 보호적 $Cr_2$O$_3$층을 형성하여 기판을 산화로부터 보호하였다. 이온질화처리는 CrN박막의 내산화성에 영향을 주지 않았다.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2015년도 추계학술대회 논문집
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• pp.190-190
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• 2015

본 연구에서는 AZ31 마그네슘 합금의 내식성을 향상시키기 위하여 플라즈마 전해산화(PEO, plasma electrolytic oxidation)법을 이용하여 다양한 용액에서 양극 및 음극 펄스전류를 인가하여 형성하였다. PEO피막 내부에 형성된 기공의 모양 및 크기를 에폭시 레플리카법을 이용하여 관찰하였다. PEO 피막 내부의 기공의 크기는 용액의 pH가 증가할수록 작아졌으며 균열의 크기는 증가하였다.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2013년도 춘계학술대회 논문집
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• pp.74-74
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• 2013

본 연구에서는 AZ31 마그네슘 합금의 내식성을 향상시키기 위하여 플라즈마 전해산화(PEO, plasma electrolytic oxidation)법을 이용하여 $5{\sim}50{\mu}m$ 두께의 산화피막을 형성시켰으며, 염수침지법, 동전위 분극실험 및 a.c. 임피던스 측정법을 이용하여 형성된 산화피막의 특성을 평가하였다. 플라즈마 전해산화 피막은 다양한 용액에서 펄스전류를 인가하여 형성하였으며, 플라즈마 전해산화 처리된 AZ31 마그네슘 합금 시편은 증류수에서 실링 처리할 경우 0.5 M NaCl용액에 침지 시 600 시간동안 부식이 일어나지 않았다.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2015년도 춘계학술대회 논문집
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• pp.34-34
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• 2015

본 연구에서는 AZ31 마그네슘 합금의 내식성을 향상시키기 위하여 플라즈마 전해산화(PEO, plasma electrolytic oxidation)법을 이용하여 다양한 용액에서 양극 및 음극 펄스전류를 인가하여 형성하였다. 형성된 PEO피막의 두께는 용액 중 음이온의 종류에 가장 크게 의존하였으며, PEO 피막의 표면거칠기는 피막의 두께가 두꺼울수록 더 커지는 결과를 얻었다. PEO피막의 경도는 규산이온이 포함된 용액에서 형성된 피막이 가장 높게 나타났으며, 알루미나 입자들과 같이 단단한 입자들을 용액 중에 포함시킬 경우 피막 내부에 함침되어 피막의 경도를 향상 시킬 수 있었다.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2012년도 춘계학술발표회 논문집
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• pp.320-321
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• 2012

본 연구에서는 마그네슘 합금의 내식성을 향상시키기 위하여 플라즈마전해산화 (Plasma Electrolytic Oxidation, PEO) 처리를 하였다. PEO 피막 형성 조건으로는 전류밀도, 전해질의 종류 및 합금성분을 변수로 하였으며, 형성된 PEO 피막의 구조, 경도 및 내식성을 평가하여 PEO피막의 특성과 표면 및 단면 구조를 관찰하였다.

• 한국연소학회지
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• 제8권1호
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• pp.9-16
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• 2003

Carbon soot emission from combustion processes, especially from diesel engines, is a subject of growing concern since soot is known to seriously affect human health. Efforts have been made to oxidize soot particles utilizing Non-Thermal Plasma(NTP) techniques. When oxygen is carried into a plasma device, electrons generated by the plasma dissociate the oxygen, resulting in the formation of oxygen atoms. These highly activated atoms, called O radicals, are known as strong oxidizing agent. This paper presents concentration variations of CO and $CO_2$ at the exit of the plasma device, resulting from the soot oxidation by O radicals, with variations of inlet oxygen concentration, gas temperature, and gas flow rate. Based on the data, Arrehenious rate constants of reactions between C(s)+O and C(s)+O+O were proposed.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.692-693
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• 2006

Behavior of stoichiometric and near-stoichiometric NiAl at plasma spray deposition, without and with a bond coat, for coating layers realization on a low alloyed steel substrate, has been investigated. In all variants, NiAl particle melting and subsequent welding at the impact with substrate were observed, forming a relatively compact and adherent coating layer with the NiAl stability maintaining - all assuring the coating layer oxidation and corrosion resistance. Good results from these points of view, also validated through corrosion tests, were obtained for 45:55 Ni:Al composition without a bond coat but adopting an Ar protective surrounding of plasma jet.

• 한국재료학회지
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• 제11권10호
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• pp.900-906
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• 2001

We prepared tunnel magnetoresistance(TMR) devices of Ta($50\AA$)/NiFe($50\AA$)/IrMn(150$\AA$)/CoFe($50\AA$)/Al ($13\AA$)-O/CoFe($40\AA$)/NiFe($400\AA$)/Ta(50$\AA$) structure which has 100$\times$100 $\mu\textrm{m}^2$ junction area on $2.5\Times2.5 cm^{2}$ $Si/SiO_2$ ($1000\AA$) substrates by a inductively coupled plasma(ICP) magnetron sputter. We fabricated the insulating layer using a ICP plasma oxidation method by varying oxidation time from 80 sec to 360 sec, and measured resistances and magnetoresistance(MR) ratios of TMR devices. We used a high resolution transmission electron microscope(HRTEM) to investigate microstructural evolution of insulating layer. The average resistance of devices increased from 16.38 $\Omega$ to 1018 $\Omega$ while MR ratio decreased from 30.31 %(25.18 %) to 15.01 %(14.97 %) as oxidation time increased from 80 sec to 360 sec. The values in brackets are calculated values considering geometry effect. By comparing cross-sectional TEM images of 220 sec and 360 sec-oxidation time, we found that insulating layer of 360 sec-oxidized was 30 % and 40% greater than that of 150 sec-oxidized in thickness and thickness variation, respectively. Therefore, we assumed that increase of thickness variation with oxidation time is major reason of MR decrease. The resistance of 80 sec-oxidized specimen was 160 k$\Omega$$\mu\textrm{m}^2$ which is appropriate for industrial needs of magnetic random access memory(MRAM) application.