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플라즈마 질화에 의한 STS 304강의 표면물성에 관한 연구
孫明淑,尹在弘,李建煥,邊應善 國立 昌原大學校 産業技術硏究所 1996 産技硏論文集 Vol.10 No.-
The most essential point on the ion nitriding of stainless steel is to eliminate passive film. Therefore, it has been studied that passive film was eliminated by changing pre sputtering parameters. Then pre sputtering parameters were pressure, holding time and gas mixing ratio. The degree of elimination of passive film was characterized by using AES and its crystallographic structure by means of XRD. Mechanical property and microstructure were determined by Vickers hardness test and SEM. The results obtained from the experiment are summarized as follows ; 1. Sputtering pressure and holding time had no relation with the behavior of nitride layer and the most effective parameter was observed as gas mixing ratio. 2. The retained O₂concentration in vacuum atmosphere was decreased by deoxidization of H??ion with gas addition. H??ion prevented the oxidization on the surface of stainless steel and reduced oxygen potential of sputtered oxide from the surface. 3. For pre sputtering, H₂gas was more dominant in the nitriding rate than Ar and N₂gas. 4. Ar/H₂gas mixture which gas mixing ratio was 1/2(vol%) was the most effective in all pre sputtering conditions. It was estimated that this resulted from the combination of the mechanical reaction by bombardment massive Ar??ion and the chemical reaction by deoxidization of H??ion. 5. For ion nitriding of the oxidized stainless steel thickness which diffuse easily nitrogen into stainless steel. In this study, the mechanical reaction by bombardment massive Ar??ion was more effective parameter than chemical reaction by deoxidization of H??ion to eliminate oxide layer which grow up to a critical thickness.
MOCVD법에 의해 제조된 Fe₂O₃-TiO₂계 박막의 내식성과 광전류 응답 특성에 관한 연구
金顯洙,尹在弘,金明鎬,杉本克久,邊鷹善 國立 昌原大學校 産業技術硏究所 1998 産技硏論文集 Vol.12 No.-
Fe₂O₃-TiO₂ films were formed by MOCVD technique, and their corrosion resistance and photoelectrochemical property were examined in acidic, neutral and alkaline solutions. The corrosion resistance was examined by an anodic polarization test, and the photocurrent response by a photoelectrochemical polarization test. The photocurrent and quantum yield maximum of the films depend on the titanium cationic fraction(Xη) in the films. They decreased in the range of Xη=0.0-0.70, then increased in the range of Xη=0.70-0.95, and finally decreased in the range of Xη=0.91-1.0 with increasing Xηvalue. The increase in the photocurrent and quuantum yield maximum in the range of Xη=0.70-0.95 was attributed to the amorphous structure. Such a change in the photocurrent and quantum yield maximum was independent to the solution pH. The corrosion resistance of the films increased with increasing Xηvalue of the film in acidic, neutral and alkaline solutions. Therefore, the films with Xη=0370-0.95 can be concluded to have high photocurrent response and high corrosion resistance.
MOCVD법에 의해 제조된 Fe₂O₃-TiO₂계 산화물 박막의 내식특성에 관한 연구
李在鉉,杉本克久,許聖康,尹在弘,金顯洙,邊應善 國立 昌原大學校 産業技術硏究所 1998 産技硏論文集 Vol.12 No.-
Fe₂O₃-TiO₂artificial passive films were formed at the temperatures of 200-350℃ by low pressure MOCVD technique. The relationship between the formation temperature and corrosion resistance of the Fe₂O₃-TiO₂films was examined in acid solutions. Fe₂O₃-TiO₂films deposited above 300℃ were crystalline and the films deposited below 250℃ were amorphous. The dissolution rate of the Fe₂O₃-TiO₂films deposited at 200 and 250℃ decreased with increasing the formation temperature in 5 M HCl, but the films deposited at 300 and 350℃ hardly dissolved in the solution. The films deposited at 200 and 350℃ easily dissolved at cathodic potentials in 1 M H₂SO₄and HCl owing to te selective reduction of iron oxide components in the films. But, the selective reduction in the films deposited at 300 and 350℃ was suppressed. The Fe₂O₃-TiO₂films deposited above 300℃ have higher corrosion resistance than that of the films deposited below 250℃, because the former have high crystallinity and cotain high chemical resistant oxides.
초고온 내열소재 가스터빈 엔진용 고온부품의 열차폐 코팅
변응선 ( Eung Sun Byon ) 한국공업화학회 2014 공업화학전망 Vol.17 No.4
가스터빈을 주축으로 하는 복합발전은 일반 화력발전에 비해 효율이 높고 유해물질 배출량이 적기 때문에 계속적인 설비 증대 및 효율향상이 요구되고 있다. 발전용 가스터빈 엔진의 고온부는 작동온도가 모재인 초내열합금의 허용한계를 넘는 가혹한 고온 환경에 노출되므로, 모재의 열부하 경감, 산화 저항성 확보 등을 위해 열차폐 코팅이 필수적으로 요구되고 있다. 본고에서는 가스터빈의 핵심 요소인 열차폐 코팅에 대해 간략히 소개하고 이의 기술개발현황을 요약하였다. 국내의 열차폐 코팅은 가스터빈 OEM의 면허생산에 종속되어 있으며 연구개발도 실험실 수준에 머물러, 실제 응용 사례는 전무한 실정이다. 하지만 현재 대형가스터빈 국산화 개발사업이 진행 중에 있으며, 여기에 새로운 조성과 성능을 갖는 열차폐 코팅 개발이 개발이 포함되어 있어, 머지않아 기술 자립화를 달성할 것으로 전망하고 있다.
Synthesis and Characterization of Cubic Boron Nitride Thin Films Using the ME - ARE Method
Yoon, Jae Hong,Sugimoto, Katsuhisa,Byon, Eung Sun,Lee, Sung Hun,Lee, Gun Hwan,Lee, Eung Jik,Sung, Chang Mo,Lee, Sang Ro 대한금속재료학회(대한금속학회) 2000 METALS AND MATERIALS International Vol.6 No.5
Cubic boron nitride (cBN) films were deposited by a magnetically enhanced activated reactive evaporation (ME-ARE) technique. Pulsed DC instead of r.f. power was used to bias the substrate. The effect of deposition parameters such as substrate bias voltage, plasma discharge current and gas flow ratio on the formation of cBN was investigated. BN films were characterized by FTIR and TEM. CBN films with a high content of cubic phase were successfiolly synthesized. It was found that formation of cBN film requires the bambardment of ions with both high flux and high energy. TEM observation showed that the cBN film had grain sizes of 15-50 ㎚ and that a non-cubic phase BN, 10-15 ㎚ was initially grown.
다단연소 사이클 엔진 적용을 위한 내산화 코팅에 관한 연구
김영준(Young-June Kim),변응선(Eung-Sun Byon),이병호(Byong-ho Rhee),한영민(Yeoung-Min Han),노용오(Yong-Oh Noh),배병현(Byung-Hyun Bae),현성윤(Seong-Yoon Hyun),조황래(Hwang-Rae Cho),방정석(Jeong-Suk Bang) 한국추진공학회 2017 한국추진공학회 학술대회논문집 Vol.2017 No.5
다단연소사이클 엔진의 추진제는 예연소기에서 일부 연소되고, 연소된 고온의 가스는 터빈을 구동하고 터빈은 터보펌프를 작동시킨다. 터보펌프의 터빈을 통과한 연소가스는 고온 고압의 상태로 연소기로 공급되는데, 이때 연료 또는 산화제의 양에 따라 연소가스는 연료 과잉 또는 산화제 과잉 상태로 공급된다. 산화제 과잉상태의 환경에서 금속 배관은 작은 입자의 충격에 의해서도 발화 또는 폭발될 수 있다. 이를 방지하기 위해 로켓 선진 국가에서는 산화제가 이동하는 공간에 내산화 코팅을 한다. 본 연구에서는 해외 내산화 코팅 물질 분석을 통해 국산 조합분말을 개발하였고, 코팅공정을 수립하였다. 개발된 조합분말을 이용하여 코팅 후 내산화 시험을 수행하였으며, 그 결과 질량변화량이 -0.16%~+0.01% 임을 확인하였다. 본 연구결과로부터 개발된 유약은 실물형 연소기의 내산화 코팅에 적용이 가능할 것으로 판단되며, 향후 연소시험을 통한 개발기술의 검증을 진행할 계획이다. The propellants are burned in the pre-burner of the staged combustion cycle engine, and the resulting hot gas drives the turbine, and the turbine operates the turbo pump. The burned gas passing through the turbo pump is supplied to the combustor at high temperature and high pressure, where the gas is supplied in an excess of fuel or an excess of oxidant depending on the amount of fuel or oxidant. When the cycle works at oxidizer-rich staged combustion, its metal pipe can ignite or explode by the impact of even small particles. In this study, we develop the powder combinations for anti-oxidation coating through the analysis of other coating materials and establish the coating process.
STS 304 스테인리스강의 플라즈마 페이스트 침붕처리에 관한연구
윤재홍,허성강,손명숙,이성도,변응선 대한금속재료학회(대한금속학회) 1997 대한금속·재료학회지 Vol.35 No.5
Various surface properties of boride layer formed by plasma paste boronizing were examined. A boride layer of flat structure was formed on the STS 304 stainless steel substrate by plasma paste boronizing treatment at several different temperatures from 1023K to 1223K under gas mixture of Ar/H₂: 2/1(vol.%). The paste was composed of 30wt% boron and 70wt% borax. The properties of boride layer were evaluated by micro vickers hardness tester, SEM, EPMA, and corrosion tester. Metallographic cross section of the bonded specimen was consisted of the boride layer, Ni rich layer, Cr rich layer, and matrix structure. It was found to form boride layer in a short time as compared with the pack and molten salt boronizing. In XRD analysis of boride surface, various peaks such as FeB, Ni₃B and CrB were presented. Especially, the peak of CrB was more intensive than other peaks. Activation energy for the formation of boride layer was found to be 123kJ/㏖ which is lower than the pack and molten silt boronizing. The microhardness of these boride layers were in the range of HV 1800-2000. However, from the results of anodic polarization curve in 1M H₂SO₄ solution on the bonded specimens, it is found that the corrosion resistance is improved by boronizing treatment. And primary passive current density is increased with the boronizing temperature.