터빈블레이드 형상 mock-up의 기하학적 배치조건에 따른 전자빔 물리기상증착법으로 제조된 7 wt% YSZ 열차폐 코팅의 코팅 균일성

오윤석,채정민,류호림,한윤수,안종기,손명숙,김홍규,Oh, Yoon-Suk,Chae, Jung-Min,Ryu, Ho-lim,Han, Yoon-Soo,An, Jong-Kee,Son, Myung-Sook,Kim, Hong-Kyu 한국결정성장학회 2019 한국결정성장학회지 Vol.29 No.6

전자빔 물리기상증착기술(EBPVD)은 주상형 성장거동과 같이 고온에서의 구조 안정성에 기여할 수 있는 특성으로 인해 터빈블레이드 등과 같은 항공기 엔진 고온부품의 열차폐 코팅(TBC) 제조기술로 개발되어 상용화된 기술이다. 전자빔 증착으로 열·기계적 특성이 상용화 가능한 수준에 만족하는 고품질 열차폐 코팅제조를 위해서는 성장거동, 균일두께형성 등과 같은 구조적 요소의 제어가 반드시 수반되어야 한다. 본 연구에서는 실품형상에 근사한 터빈 블레이드 mock-up에 대한 기하학적 코팅인자 조건에 따른 7YSZ(7 wt% 이트리아 안정화 지르코니아) 열차폐 코팅의 성장거동과 구조변화를 고찰하였으며, 전산모사 기법을 활용한 기하학적 코팅인자 조건에 따른 코팅성장거동 모델링을 수행하여 실제 코팅결과와 비교하였다. Electron beam physical vapor deposition (EBPVD) is a conventional method to fabricate thermal barrier coating (TBC) of high temperature airfoil engine parts, such as blade etc. for its high temperature structural stability from the nature of columnar growth behavior. For the high quality of TBC by EBPVD, the structural factors, such as growth behavior, thickness uniformity and so on, should be managed to obtain the coating which satisfied the required specifications of usable level of mechanical and thermal properties. In this study, the growth behavior and structure variations of 7YSZ (7 wt% yttria stabilized zirconia) coatings with different configurational deposition parameters for the specimens which have turbine blade shape mock-up were investigated. Growth behavior of coatings were studied by comparing computational modeling of evaporation behavior with actual deposition process using e-beam source.

가스 터빈용 복합재-금속 접착구조물을 위한 표면처리 기법 연구

최현석(Hyeon-Seok Choe),박성민(Seong-Min Park),손명숙(Myung-Sook Son),김학인(Hak-Inn Kim),권진회(Jin-Hwe Kweon) 한국항공우주학회 2018 한국항공우주학회 학술발표회 논문집 Vol.2018 No.11

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.

Notes 기반의 가상대학시스템 구현에 관한 연구

손명숙 신라대학교 교육과학연구소 1999 교육과학연구 Vol.- No.4

PLASMA 이온 질화처리 한 Ti-6Al-4V의 표면물성에 관한 연구

손명숙,허성강,윤재홍,이영생,박노광 國立 昌原大學校 産業技術硏究所 1997 産技硏論文集 Vol.11 No.-

The purpose of this study is to improve the surface hardness and corrosion resistance of Ti-6Al-4V by ion nitriding treatment. As well known, the ion nitriding is widely used an effective surface hardening method and principal parameters of the ion nitriding are temperature and time. Ti-6Al-4V alloys were ion-nitrided under the atmosphere of the nitrogen-hydrogen mixture gas and surface modified layers were observed. Experimental results represent that the surface modified layers are formed as a multiphases of TiN and Ti₂N. The hardness of the layers are in the range Hv of 1000 to 2000. The multiphase layers also showed excellent corrosion resistance in 2 Mol HCl solution at room temperature, comparing to the non-coated layers. The kinetics show that the growth of the layers by N₂ diffusion were proportional to t½. The kinetics energy for the formation of nitride layers was 174KJ/mol.

STS 304 스테인리스강의 플라즈마 페이스트 침붕처리에 관한 연구

李聖道,李贊揆,孫明淑,尹在弘,許聖康 國立 昌原大學校 産業技術硏究所 1997 産技硏論文集 Vol.11 No.-

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 with several different temperature 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 borided 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 to conventional boronizing methode. 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/mol which is lower than the conventional boronizing treatment. The microhardness of these boride layers were in the range of HV 1800∼2000. However, from the results of anodic polarization curve in 1M H₂SO₄solution on the borided specimens, it is found that the corrosion resistance is improved by boronizing treatment. Primary current density is, however, increased with the Boronizing temperature.

STS304 스테인리스강의 이온질화시 초기 스퍼터링조건이 질화층 형성거동에 미치는 영향

윤재홍,손명숙,이건환 대한금속재료학회(대한금속학회) 1997 대한금속·재료학회지 Vol.35 No.4

Stainless steels in general has passive film having strong corrosion resistance on surface. Therefore it must be mesessarily removed by etching in mixing solution of sulfuric and chloric acid before nitriding treatment. But in the ion nitriding, nitride layer was easily formed because passive film was removed without difficult by sputtering effect. The removal extent of these passive films was greatly effected by gas mixing ratios and pressure and holding times of presputtering factors in presputtering stage. Thus we have examined the effect of the pre sputtering factors in contrast to ion nitriding behviour of next stage. As a results of experiment it has been known that presputtering pressure and holding time was not nearly effective on the formation behavior of nitride layer. But when Ar/H₂ gas mixing ratios was ½(vol%) was the most effective of the all presputtering conditions. It was resulted from the combination of mechanical reaction by argon bombardment and chemical reaction by reduction of hydregen on the passive film. For the ion nitriding of the STS304 having artificial oxide layers which was grown more thick than natural passive film, first of all, the oxide layer must be removed to the appropriate thickness which could easily diffuse nitrogen into matrix by bombardment of Argon ion.

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.

응급실 환자의 내원 및 응급처치 소요에 관한 조사연구

탁기천,배대경,고영관,손명숙,정두채 대한응급의학회 1993 대한응급의학회지 Vol.4 No.1

This study consists of time consuming of arrival and emergency treatment of the 495 patients, who were admitted to the emergency rooms of 3 university hospitals in Seoul from July 6, 1992 to July 29, 1992. These results were obtained by investigating and analysing the questionaires through the patients, or/and their accompanist by the emergency room nurses. 1. Distribution of time consuming. 1) Consumed time from development of the symptom to visiting emergency room was 31.5 hours. 2) Male patients visited much earlier than female patients.(statistically significant) 3) The patients of under the age of 6 visited earlier than any other age group.(Nearly 30% of them came within 60 minutes.(Statistically significant) 4) The patients visted most early when a symptom developed on road.(42.9%: significant) 5) A taxi was the most frequently used transportation.(45.9%) In case of visiting by walking, patients arrived within 60 minutes(48.4%: significant) 6) Fourty three % of injured patients arrived within 60 minutes and they visited much earlier than diseased patients. 7) Orthopedic patients visited within 60 minutes, which was earlier than other department patients and occupied 45.3%.(significant) 8) Non-first-aided patients at home visited earlier than first aided ones at home. (nonsignificant) 2. Time interval from arrival to initial emergency care. 1) Seventy % of the patients were initially cared within 30 minutes. 2) Time to initial care according to the symptoms and signs was not statistically significant. 3) Fifty nine % OB/GYN patients were cared within 10 minutes and earlier than other department patients, however, statistcally nonsignificant. 3. Time interval from initial care to completion. 1) Emergency care was completed within 180 minutes in sixty three % of the patients. 2) Although, a distribution of the time to completion of emergency care was statistically nonsignificant, diseased patients were completed a little bit earlier than injured patients. 3) Pediatric patients were completed earlier than any other department patients and 37.3% of them were completed within 60 minutes.

Paste 법에 의한 STD61 강종의 Boronizing 처리에 관한 연구

윤재홍,남기석,차병묵,손명숙 대한금속재료학회(대한금속학회) 1996 대한금속·재료학회지 Vol.34 No.4

STD 61 steel was boronized in Boronizing paste mainly consisted of B₄C and Na₂B₄O_7 at various temperatures and times. Microhardness and thickness of boride layers were measured and distributions of B, Si, Cr, and V on the cross section of specimens were observed by EPMA line analysis. Microscopic examination and results of EPMA showed that the boride layer consisted of two layers outer layer of FeB and inner layer of Fe₂B. Microhardness of these boride layers was in the range of Hv 1800∼2300. Thickness of the boride layer increased with a square root of time for treatment at constant temperature. Activation energy for diffusion of B in the specimen obtained from the slope of Arrhenius plots was 260kJ/㏖. Si-rich α layer was formed between boride layer and matrix. Element such as Cr concentrated as Cr_(23)(B, C)_6 beneath the boride layer.