• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2000년도 추계학술대회논문집
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• pp.116-119
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• 2000

The advantage of plasma-sprayed coating is their good resistance against thermal shock due to the porous state of the coated layer with a consequently low Youngs modulus. However, the existence of many pores with a bimodal distribution and a laminar structure in the coating reduces coating strength and oxidation protection of the base metals. In order to counteract these problems, there have been many efforts to obtain dense coatings by spraying under low pressure or vacuum and by controlling particle size and morphology of the spraying materials. The aim of the present study is to survey the effects of the HIP treatment between 1100 and 130$0^{\circ}C$ on plasma-sprayed oxide coating of A1$_2$O$_3$, A1$_2$O$_3$-SiO$_2$on the metal substrate (type C18N10T stainless steel). These effects were characterized by phase identification, Vickers hardness measurement, and tensile test before and after HIPing. These results show that high-pressure treatment has an advantage for improving adhesive strength and Vickers hardness of plasma-sprayed coatings.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 추계학술대회 논문집
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• pp.116-119
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• 2000

The advantage of plasma-sprayed coating is their good resistance against thermal shock due to the porous state of the coated layer with a consequently low Youngs modules. However, the existence of many pores with a bimodal distribution and a laminar structure in the coating reduces coating strength and oxidation protection of the base metals. In order to counteract these problems, there have been many efforts to obtain dense coatings by spraying under low pressure or vacuum and by controlling particle size and morphology of the spraying materials. The aim of the present study is to survey the effects of the HIP treatment between 1100 and 130$0^{\circ}C$ on plasma-sprayed oxide coating of A1$_2$O$_3$, A1$_2$O$_3$-SiO$_2$ on the metal substrate (type C18N10T stainless steel). These effects were characterized by phase identification, Vickers hardness measurement, and tensile test before and after HIPing, These results show that high-pressure treatment has an advantage for improving adhesive strength and Vickers hardness of plasma- sprayed coatings.

• Journal of Welding and Joining
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• 제33권2호
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• pp.23-31
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• 2015

Stainless steel is used in automobile muffler and exhaust systems. However, in comparison with other steels it has a high thermal expansion rate and low thermal conductivity, and undergoes excessive thermal deformation after welding. To address this problem, we evaluated the use of arc brazing in place of welding for the processing of an exhaust system, and investigated the parameters that affect the joint characteristics. Muffler parts STS439 and hot-dipped Al coated steel were used as test specimens, and CuAl brazing wire was used as the filler metal for the cold metal transfer (CMT) welding machine, which is a low heat input arc welder. In addition, a Box-Behnken design of experiment was used, which is a response surface methodology. The main process parameters (current, speed, and torch angle) were used to determine the appropriate welding quality and the mechanical properties of the brazing part was evaluated at the optimal welding condition. The optimal processing condition for arc brazing was 135A current, 51cm/min speed and $74^{\circ}$ torch angle. The process was applied to an actual exhaust system muffler and the prototype was validated by thermal fatigue, thermal shock, and endurance limit tests.

• 수산해양기술연구
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• 제34권2호
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• pp.223-230
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• 1998

Recently, with the rapid development in the industries such as mechanical plants, automobiles, ships and marine structures, it is enlarged by the use of the SS 41 steel. This mechanical plants and marine structures are exposed m corrosion because of Cl-under marine environments. To protect their accidents, mainly applied anti-corrosion epoxy coating and various protective its structures. In this study, corrosion control characteristics on the epoxy coating were investigated by the galvanic corrosion of impressed voltage tester under marine environments The main results obtained are as follows; 1. Corrosion current density of amine-epoxy coating becomes more increased than that of other epoxy coating and the time area rate of pin hole and pit until 5% becomes most rapid. 2. The potential of SUS 304 stainless steel(cathode) for Al-epoxy coating is nearly zero potential. 3. Corrosion current density of Amine-epoxy by shot blast becomes more decreased than that of not shot blast and cathodic potential becomes more noble. 4. As distance of anode and cathode is more decreased, corrosion current density of epoxy coating is more increased and cathodic potential becomes less noble.

• 한국세라믹학회지
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• 제50권6호
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• pp.460-465
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• 2013

Plate-shaped inorganic particles are coated onto a stainless steel substrate by the electrophoretic deposition of a precursor slurry which includes the inorganic particles of $Al_2O_3$ and polymer resin in mixed solvents to mimic the abalone shell structure, which is a composite of plate-shaped inorganic particles and organic interlayer binding materials with a layered orientation. The process parameters of the electrophoretic deposition include the voltage, coating time, and conductivity of the substrate. In addition, the suspension parameters are the particle size, concentration, viscosity, conductivity, and stability. We prepared an organic-inorganic composite coating with a high inorganic solid content by arraying the plate-shaped $Al_2O_3$ particles and electrophoretic resin via an electrophoretic deposition method. We analyzed the effect of the slurry composition and the electrophoretic deposition process parameters on the physical, mechanical and thermal properties of the coating layer, i.e., the thickness, density, particle orientation, Young's modulus and thermogravimetric analysis results.

• 한국안광학회지
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• 제5권2호
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• pp.187-192
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• 2000

본 연구에서는 물 유리의 경제성을 바탕으로 광학적 및 기계적인 특성을 조사하여 투명하고 높은 경도를 가진 표면 보호막의 기능을 검토하기 위하여 $SiO_2-Na_2O-R_mO_n$계 박막을 제조하였다. 물 유리에 CaO와 $Al_2O_3$를 소량의 1 N HCl 1N $NH_4OH$와 함께 각각 첨가하여 코팅용 졸을 준비하였다. Stainless steel. Si wafer. soda-lime-silica glass등 다양한 기판 위에 spin-coating 한 후 질소 분위기 하에서 500, 750 및 $900^{\circ}C$로 최종 열처리를 행했다. 제조된 막은 Knoop 경도계로 micro-hardness를 측정하였다. 막의 표면 질소 함유량을 알아보기 위하여 EDX 분석을 행하였다. 그리고 Field Emission Scanning Electron Microscope(FE-SEM)을 이용하여 막의 표면구조를 관찰하였으며, UV-VIS 스펙트라 측정을 통하여 막의 두께와 반사 특성을 조사하였다.

• 융합정보논문지
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• 제11권3호
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• pp.167-173
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• 2021

최근 폴리이미드가 기판으로 사용되어 유기발광다이오드 디스플레이가 구현된 폴더블 스마트폰이 출시되고 있다. 이와 같이 굽힘이 가능한 기판위에 다양한 전자소자를 제작하기 위한 관심이 증가하고 있기 때문에 본 논문에서는 굽힘성이 우수한 127㎛ 두께의 얇은 스테인리스 금속 기판을 이용하여 먼저 크롬을 코팅하고 알루미늄을 형성한 샘플과 알루미늄 구현 후 크롬을 증착한 2가지 샘플을 급속 열처리 장비를 이용하여 150도, 350도, 550도의 온도에서 각각 20분간 어닐링을 진행하여 표면의 형상을 관찰하였다. 고분해능 SEM과 nm까지 거칠기를 측정할 수 있는 AFM을 이용하여 표면에 대한 데이터를 추출하였다. 350도까지는 열처리하지 않은 샘플과 차이가 없지만, 550도에서는 결정립의 변화를 확인할 수 있다. 향후 본 실험 결과는 플렉서블 광전자분야로의 적용을 위해 전기전도도, 반사도와 같은 특성 분석 및 광소자 제작을 통해 금속 소재의 플렉서블 전자소자로의 적용 가능성을 모색할 것이다.

• 공업화학
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• 제17권5호
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• pp.458-464
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• 2006

팔라듐 합금 복합막의 제조는 니켈 분말과 무기화합물의 혼합물로 개질된 튜브형 다공성 스테인레스 스틸 지지체 표면 위에 무전해 도금법(elctroless plating technique)에 의해 팔라듐 - 니켈 - 은을 박막으로 도금하는 형태로 이루어졌다. 일반적인 다공성 금속 지지체는 기공이 크기 때문에 그 자체로서 도금에 적합한 지지층이 되기가 어렵고, 결함이 없는 팔라듐 복합막의 제조가 쉽지 않아 본 연구에서는 금속 지지체와 팔라듐 사이에 중간층(intermediate layer)을 형성하여 이와 같은 문제점을 극복하고자 하였다. 중간층의 소재인 실리카 졸, 알루미나 졸, 이산화티타늄 졸 등의 무기화합물과 니켈 분말의 혼합물로 다공성 금속 지지체 위에 코팅하여 박막을 형성하고 제조 조건에 따른 질소 투과도를 측정하고 비교하였다. SEM 분석법에 의해 니켈과 무기화합물 혼합물의 표면층의 형성 모습도 측정하였다. 제조된 중간층 가운데 이산화티타늄 졸과 니켈의 혼합물이 가장 낮은 질소 투과도와 치밀한 표면층을 나타내었다. 최종적으로 니켈과 실리카의 혼합 중간층으로 이루어진 팔라듐-니켈-은 합금 복합막을 제조하고 수소와 질소의 투과도를 측정하였다. 1기압 이하에서 질소에 대한 수소 선택도는 무한대였으며 수소투과 속도는 1 기압, $500^{\circ}C$에서 $1.39{\times}10^{-2}mol/m^2{\cdot}s$의 값을 나타냈다.

• 한국재료학회지
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• 제17권5호
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• pp.256-262
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• 2007

Effects of interlayer and the combination of different coating methods on the mechanical and corrosion behaviors of TiN and CrN coated on 420 stainless steel have been studied. STS 420 specimen were tempered at $300^{\circ}C$ for 1 hr in vacuum furnace. The TiN and CrN thin film with 2 ${\mu}m$ thickness were coated by arc ion plating and DC magnetron sputtering following the formation of interlayer for pure titanium and chromium with 0.2 ${\mu}m$ thickness. The microstructure and surface analysis of the specimen were conducted by using SEM, XRD and roughness tester. Mechanical properties such as hardness and adhesion also were examined. XRD patterns of TiN thin films showed that preferred TiN (111) orientation was observed. The peaks of CrN (111) and $Cr_2N$ (300) were only observed in CrN thin films deposited by arc ion plating. Both TiN and CrN deposited by arc ion plating had the higher adhesion and hardness compared to those formed by magnetron sputtering. The specimen of TiN and CrN on which interlayer deposited by magnetron sputtering and thin film deposited by arc ion plating had the highest adhesion with 22.2 N and 19.2 N. respectively. TiN and CrN samples shown the most noble corrosion potentials when the interlayers were deposited by using magnetron sputtering and the metal nitrides were deposited by using arc ion plating. The most noble corrosion potentials of TiN and CrN were found to be approximately -170 and -70 mV， respectively.

• 한국수소및신에너지학회논문집
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• 제9권4호
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• pp.169-176
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• 1998

Ni/MH 2차전지의 음극용 금속간화합물전극의 부식특성에 미치는 합금원소와 결합제의 영향을 조사하였다. 전극의 재료는 $(LM)Ni_{4.49}Co_{0.1}Mn_{0.205}Al_{0.205}$와 $(LM)Ni_{3.6}Co_{0.7}Mn_{0.3}Al_{0.4}$의 $AB_5$ type합금을 모재로 하였다. 여기에 Si sealant 또는 PTFE를 결합제로 첨가한 것과 원재료 분말에 구리를 20% 무전해도금한 것을 냉간 압착하여 전극을 제조하였다. 부식특성을 조사하기위해 탈공기된 6M의 KOH 용액에서 동전위법과 순환전위법을 이용하여 부식전류와 전류밀도를 측정하였다. 모재에 Co가 많이 함유되면 전극의 내식성을 향상시키고 Ni이 많이 함유되면 충전과 방전을 반복하는 동안에 전극의 안정성을 저하시켰다. 부식전류밀도는 Si sealant를 결합제로 사용한 전극의 경우가 PTFE를 사용한 전극의 경우보다 낮았고 Cu가 도금된 전극은 내식성에서 가장 우수하게 나타났다.