Laser Cladding Novel NiCrSiFeBW–CeO2 Coating with Both High Wear and Corrosion Resistance

Min Guo,Suiyuan Chen,Fanmin Shang,Jing Liang,Tong Cui,Changsheng Liu,Mei Wang 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.8

In order to obtain the high wear- and corrosion-resistant nickel based alloy coatings for laser remanufacturing fretting damaged metal parts which are serviced under high-temperature corrosion and wear conditions, a novel NiCrSiFeBW–CeO2alloy powder was designed by increasing the content of B and Si, adding tungsten and CeO2 using JMatpro software onthe basis of Ni60 alloy powder composition, and the NiCrSiFeBW–CeO2 coating was successfully cladded on 45# steelunder diferent laser energy area densities. The microstructure, wear and corrosion behaviors of the NiCrSiFeBW–CeO2coatings were systematically studied. The results show that novel NiCrSiFeBW–CeO2 coating produced by laser claddingnot only has no cracks but also has both high wear resistance and corrosion resistance due to some ultra-fne compoundparticle phases in situ generated in its structure. Among these phases, the B3Cr5, CrB4, (Cr, Ni)3C2, Cr7C3, W3Cr12Si5 and(Fe, Ni)5Si3 played a signifcant role in reinforcing the wear resistance of the coating, while the B3Cr5, W3Cr12Si5 and CrB4enhanced the corrosion resistance of the coating. The novel NiCrSiFeBW–CeO2 coating prepared under 100 J/mm2EADhas the best comprehensive performance, the wear loss is 7.53×10−5 mm3/N, the Ecorr is − 0.1738 V. Compared with Ni60alloy coating, the novel Ni-based coating not only has a better laser cladded formability but also similar wear resistance andbetter corrosion-resistance. It provides a reference for repairing fretting damaged metal parts by laser cladding the nickelbased coating with high wear and corrosion resistance.

Experimental evaluation of coating delamination in vinyl-coated metal forming

Young-ki Son,Chan-joo Lee,Jung-min Lee,Sang-doek Byoen,Soen-bong Lee,Byung-MinKim 대한기계학회 2012 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.26 No.10

In this paper, a new evaluation and prediction method for coating delamination during sheet metal forming is presented. On the basis of the forming limit diagram (FLD), the current study evaluates the delamination of PET coating by using a cross-cut specimen, dome test, and rectangular-cup drawing test. Dome test specimens were subjected to biaxial, plane strain, and uniaxial deformation modes. Rectangular cup- drawing test specimens were subjected to the deep-drawing deformation mode, and compression deformation mode. A vinyl-coated metal (VCM) sheet consists of three layers of polymer on the sheet metals: a protective film, a PET layer and a PVC layer. The areas with coating delamination were identified, and the results of the evaluation were plotted according to major and minor strain values, depicting coating delamination. The constructed delamination limit diagram (DLD) can be used to determine the forming limit of VCM during the complex press-forming process. ARGUS (GOM) was employed to identify the strain value and deformation mode of the delaminated surface after the press forming. After identifying the areas of delamination, the DLD of the PET coating can be constructed in a format similar to that of the FLD. The forming limit of the VCM sheet can be evaluated using the superimposition of the delamination limit strain of the coating onto the FLD of VCM sheet. The experimental results showed that the proposed test method will support the sheet metal forming process design for VCM sheets. The assessment method presented in this study can be used to determine the delamination limit strain under plastic deformation of other polymer coated metals. The experimental results suggested that the proposed testing method is effective in evaluating delamination for specific applications.

Protective coating based on manganese–copper oxide for solid oxide fuel cell interconnects: Plasma spray coating and performance evaluation

Waluyo, Nurhadi S.,Park, Seong-Sik,Song, Rak-Hyun,Lee, Seung-Bok,Lim, Tak-Hyoung,Hong, Jong-Eun,Ryu, Kwang Hyun,Bin Im, Won,Lee, Jong-Won Elsevier 2018 Ceramics international Vol.44 No.10

<P><B>Abstract</B></P> <P>A solid oxide fuel cell (SOFC) stack requires metallic interconnects to electrically connect unit cells, while preventing fuel from mixing with oxidant. During SOFC operations, chromia scales continue to grow on the interconnect surfaces, resulting in a considerable increase of interfacial resistance, and at the same time, gaseous Cr species released from the chromia scales degrades the cathode performance. To address these problems, in this study, protective Mn<SUB>2</SUB>CuO<SUB>4</SUB> coatings are fabricated on metallic interconnects (Crofer 22 APU) <I>via</I> a plasma spray (PS) process. The PS technique involves direct spray deposition of molten Mn<SUB>2</SUB>CuO<SUB>4</SUB> onto the interconnect substrate and leads to the formation of high-density Mn<SUB>2</SUB>CuO<SUB>4</SUB> coatings without the need for post-heat-treatment. The thickness, morphology, and porosity of the PS-Mn<SUB>2</SUB>CuO<SUB>4</SUB> coating are found to depend on the processing parameters, including plasma arc power, gas flow rate, and substrate temperature. The PS-Mn<SUB>2</SUB>CuO<SUB>4</SUB> coating fabricated with optimized parameters is completely impermeable to gases and has high adhesion strength on the interconnect substrate. Furthermore, no resistive chromia scales are formed at the coating/substrate interface during the PS process. As a result, the PS-Mn<SUB>2</SUB>CuO<SUB>4</SUB>-coated interconnects show a very low area-specific resistance below 10 mΩ cm<SUP>2</SUP> at 800 °C in air and excellent stability during both continuous operation and repeated thermal cycling. This work suggests that an appropriate combination of the material and coating process provides a highly effective protective layer for SOFC interconnects.</P>

고온 열차폐 합금을 이용한 도자타일용 금속 유약 개발에 관한 연구

김진호,한규성,황광택,이원준 한국도자학회 2017 한국도자학연구 Vol.14 No.2

In porcelain tile for building construction, glaze material is a very important to improve aesthetic property of product. Recently, the needs of porcelain tile, which shows metallic and opaque surface properties, is increasing in the market. Here, we synthesized metallic glaze using NiCoCrAlY, which is generally used for thermal barrier coating(TBC). The synthesized metallic glaze was coated on the porcelain tile surface, and then industrial firing process(fast firing process) was applied. The fired sample initially showed dark grey colored matt surface, however metal-shining surface was started to be observed after polishing process. Microstructural analysis revealed that metal particles were uniformly distributed and bonded with glaze phase. The prepared glaze with NiCoCrAlY metal particles also showed an improved resistance to chemicals and frost. 건축용 도자타일에서 표면 유약의 심미성은 소비자의 제품 선택에 매우 중요한 요소이며, 최근 금속성 광택을 나타내는 제품에 대한 소비자 요구가 시장에서 커지고 있다. 본 연구에서는 고온 열차폐 코팅(Thermal barrier coating, TBC)에 사용하는 NiCoCrAlY 금속 합금 분말을이용하여 금속 유약(metallic glaze)을 제조하고, 이를 도자타일에 시유한 후 양산 공정에 적용되는 신속 소성 공정(fast firing process)을 이용하여 금속성 광택의 도자타일을 제조하였다. 소성 후 도자타일 표면은 짙은 회색의 매트(matt) 유약이 형성되지만, 이 후에 폴리싱(polishing) 처리가 진행되면서 화려한 금속성 광택의 유약 표면이 관찰되었다. 미세구조 관찰결과 유약의 유리상 내에 NiCoCrAlY 금속 합금 입자가 균일하게 분포되어 있으며, 유리상과견고한 결합을 하고 있는 것으로 확인되었다. 이와 같은 NiCoCrAlY 금속 합금 분말이 포함된금속 유약은 내화학성 평가 및 내동해성 평가에서도 우수한 결과를 나타내었다.

Failure and Phase Transformation Mechanism of Multi-Layered Nitride Coating for Liquid Metal Injection Casting Mold

Jeon, Changwoo,Lee, Juho,Park, Eun Soo Materials Research Society of Korea 2021 한국재료학회지 Vol.31 No.6

Ti-Al-Si target and Cr-Si target are sputtered alternately to develop a multi-layered nitride coating on a steel mold to improve die-casting lifetime. Prior to the multi-layer deposition, a CrN layer is developed as a buffer layer on the mold to suppress the diffusion of reactive elements and enhance the cohesive strength of the multi-layer deposition. Approximately 50 nm CrSiN and TiAlSiN layers are deposited layer by layer, and form about three ㎛-thickness of multi-layered coating. From the observation of the uncoated and coated steel molds after the acceleration experiment of liquid metal injection casting, the uncoated mold is severely eroded by the adhesion of molten metallic glass. On the other hand, the multi-layer coating on the mold prevents element diffusion from the metallic glass and mold erosion during the experiment. The multi-layer structure of the coating transforms the nano-composite structured coating during the acceleration test. Since the nano-composite structure disrupts element diffusion to molten metallic glass, despite microstructure changes, the coating is not eroded by the 1,050 ℃ molten metallic glass.

유체기기의 표면 금속코팅 적용에 따른 구조건전성 평가

이한섭(Han-Seop Lee),임병철(Byung-Chul Lim),김민태(Min-Tae Kim),이범순(Beom-Soon Lee),박상흡(Sang-Heup Park) 한국산학기술학회 2019 한국산학기술학회논문지 Vol.20 No.8

본 연구에서는 선박 및 해양플랜트에 사용되어지는 유체기기에 관하여 공동에 의한 손상을 줄이기 위해 표면금속코팅을 적용할 경우 구조건전성을 평가하고 효율개선을 위한 수치해석적 결과에 대해 기술하였다. 소재 경량화 및 표면 코팅을 통해 날개 두께 등이 얇아지더라도 구조 강도와 성능이 확보됨을 간접적으로 입증하기 위해 코팅 하지 않은 경우, 코팅 후 동일 두께, 코팅 후 두께 3% 경량화 그리고, 코팅 후 두께 5% 경량화 것의 4 가지 모델에 대해 코팅의 유효성을 해석적 방법으로 평가하였다. 코팅 전 · 후 및 두께를 3% 줄여 무게를 경량화한 경우에 대해 구조해석을 수행한 결과, 응력은 7% 증가하였고 안전율은 2.7%로 나타났으며 기준 안전율인 1보다 큰 값이 도출되었다. 코팅 전 · 후 및 두께를 5% 줄여 무게를 경량화한 경우에 대해 구조해석을 수행한 결과, 응력은 12%까지 증가하였고 안전율은 0.99% 로 나타났으며 0.1% 정도 차이로 안전율이 확보되지 않음에 따라 구조건전성이 부족한 것으로 나타났다. 하지만 부족한 안전율은 좀 더 좋은 소재를 선정하거나 코팅두께를 현재보다 두껍게 한다면 충분한 안전율을 확보할 수 있다고 판단된다. 최종적으로 코팅을 함으로 인해 구조건전성이 개선되는 것을 확인하였고, 5% 경량화한 경우에도 코팅의 효과로 인해 충분히 구조건전성이 확보될 수 있음을 확인하였다. The structural integrity of a surface metal coating was evaluated through numerical results to improve the efficiency and reduce the damage caused by cavitation in ships and marine plants. The goal was to ensure structural strength and performance, even if the thickness of the wing is reduced to reduce the weight of the material and surface coating. Analytical methods were used for four models: a non-coating model, one with the same thickness after coating, one with a thickness reduction of 3% after coating, and one with thickness reduction of 5% after coating. With a thickness reduction of 5% after coating, the stress was increased to 12%, and the safety factor was 0.99%, so the structural integrity was insufficient. However, a better material or a thicker coating could allow a sufficient safety factor to be secured. The structural integrity was improved by the coating, and even when the weight was reduced up to 5%, the structural integrity could be sufficiently secured due to the coating effect.

금속공예에서 DLC 코팅을 활용한 색상 표현 연구 -백동과 적동 바탕 금속을 중심으로-

오나은 ( Oh¸ Naun ),송오성 ( Song¸ Oh Sung ),민복기 ( Min¸ Bog Ki ) 한국기초조형학회 2021 기초조형학연구 Vol.22 No.5

금속 공예가들은 금속의 색상표현을 위해 다양한 착색기법을 연구해 왔다. 많은 착색 방법들 가운데 애노다이징 기법을 이용한 알루미늄 착색은 간섭색을 이용한 착색이나 넓은 판재의 애노다이징에는 고가의 장비와 다공성 표면에 유해한 염료 투입후 봉공처리가 필요한 공정상의 제한이 있었다. 이에 연구자는 내마모성이 뛰어나고 두께에 따라 다양한 간섭색을 나타내는 diamond-like carbon(DLC) 박막에 주목하였다. 이 연구의 목적은 두께에 따라 비철금속인 백동과 적동 기판에 충분한 접합성과 간섭색이 나는지 확인하기 위함이다. 연구 방법은 백동과 적동 판재를 이용하여 네 가지의 도형을 조합한 패턴을 부식시켜 준비하고 공정시간을 달리하여 네 가지의 두께로 DLC 박막을 코팅하였다. 각 조건에서의 두께와 색상을 주사전자현미경, 색 분석기를 이용하여 확인하고. DLC 박막의 반사모드만을 고려한 모델로 간섭색을 예측해보았다. DLC 코팅 후 코팅된 금속 시편을 10개의 색상 팔레트로 사용해 색을 조합하여 두 개의 브로치를 제작하였고 직경 25cm로 성형된 기물에 보라색 DLC 코팅을 적용해 제작 가능성을 확인 하였다. 브로치의 제안에서는 코팅한 표면 위를 일부 연마해 본래의 금속색과 코팅된 색의 차이를 대비시켜 연출하여 생동감 있는 표현과 DLC 코팅을 연마용 버로 일부 제거하고 바탕 금속이 부분 노출되게 하여 입사법과 비슷한 색상의 대비효과를 얻을 수 있었다. 또한 이 연구를 통해 큰 직경의 기물에서는 그동안 표현되기 어려웠던 남보라 계열의 색상 표현과 반복된 마스킹 작업 없이 높이에 따른 간섭색의 그라데이션을 통해 풍부한 색상 표현이 가능하였다. Metalsmiths have studied various surface treatments for the color expression of metals. Among many coloring methods, aluminum anodizing coloring technique employing interference color had limitations in which it requires costly equipment for applying on a wide metal plate, and not ecologically friendly sealing treatment after injecting harmful dyes on the porous surface. Therefore, the researchers paid attention to the diamond-like carbon(DLC) film that showed excellent wear resistance and various interference colors depending on the thickness. This research also investigated whether sufficient adhesion and interference color were achieved depending on the thickness by using nonferrous metals, nickel and copper plates. Four different pattern images using figures were etched on nickel and copper sheets and nano-thin DLC films were coated with four different thicknesses by varying the coating process time. It showed thicknesses and colors under each condition by using a scanning electron microscopy and a colorimetry and predicted the interference color with a model that considered only the reflection mode of the DLC film. After the DLC coating, two brooches were made by combining the coated metal specimens from 10 color palettes, and navy-purplish DLC coating was applied to a formed object with a diameter of 25cm to confirm the possibility of feasible manufacturing. In the brooch’s proposal, some of the coated surfaces were taken off to enhance the vivid contrast between the original metal color and the coated color. Furthermore, by removing some of the DLC coating films with a polishing burr and partially exposing the background, it was possible to obtain a color contrast effect similar to the inlay ‘Ipsa’ technique. With the large-diameter object, it was possible to express the colors of the navy purple series, which had been difficult to express so far. Moreover, without repeated masking processes, diverse color expressions were available through the gradation of interference colors according to the height of the object during the DLC coating.

WC/C 박막의 윤활접촉하의 마멸기구

안효석(Hyo-Sok Ahn),김두인(Doo-In Kim) 한국트라이볼로지학회 2008 한국윤활학회지(윤활학회지) Vol.24 No.6

The running-in behaviour of the metal carbon coating (WC/C) was evaluated with regard to its applicability as wear-resistant coating for key components in engines. Reciprocating wear tests under lubricated condition employing an oscillating friction wear tester were performed to investigate the tribological behaviors of the coatings in ambient environment. Confocal microscopy and scanning electron microscopy were used to observe worn surfaces and the wear scars on the steel balls. Elemental composition of the coating and worn surfaces were characterized using Auger electron spectroscopy. The friction behavior of WC/C coating was comparable to common carbon-based coatings. Thin tribofilm was formed on the worn surface of the steel ball due to material transfer and tribochemical reaction whereas there was no evidence of tribofilm generation on the coating surface. indicating the chemical innertness of WC/C coating.

INTERACTION STUDIES OF CERAMIC VACUUM PLASMA SPRAYING FOR THE MELTING CRUCIBLE MATERIALS

Kim, Jong Hwan,Kim, Hyung Tae,Woo, Yoon Myung,Kim, Ki Hwan,Lee, Chan Bock,Fielding, R.S. Korean Nuclear Society 2013 Nuclear Engineering and Technology Vol.45 No.5

Candidate coating materials for re-usable metallic nuclear fuel crucibles, TaC, TiC, ZrC, $ZrO_2$, and $Y_2O_3$, were plasmasprayed onto a niobium substrate. The microstructure of the plasma-sprayed coatings and thermal cycling behavior were characterized, and U-Zr melt interaction studies were carried out. The TaC and $Y_2O_3$ coating layers had a uniform thickness, and high density with only a few small closed pores showing good consolidation, while the ZrC, TiC, and $ZrO_2$ coatings were not well consolidated with a considerable amount of porosity. Thermal cycling tests showed that the adhesion of the TiC, ZrC, and $ZrO_2$ coating layers with niobium was relatively weak compared to the TaC and $Y_2O_3$ coatings. The TaC and $Y_2O_3$ coatings had better cycling characteristics with no interconnected cracks. In the interaction studies, ZrC and $ZrO_2$ coated rods showed significant degradations after exposure to U-10 wt.% Zr melt at $1600^{\circ}C$ for 15 min., but TaC, TiC, and $Y_2O_3$ coatings showed good compatibility with U-Zr melt.

탄소 나노튜브가 코팅된 은 메탈-메쉬 전극의 특성

김부종,박종설,황영진,박진석 한국반도체디스플레이기술학회 2015 반도체디스플레이기술학회지 Vol.14 No.1

This study demonstrates hybrid-type transparent electrodes for touch screen panels. The hybrid-type electrodes were fabricated by coating carbon nanotubes (CNTs) on metal meshes. To form the metal-meshes, thin films of silver (Ag) were deposited on glass substrates using the sputtering method and then patterned via photolithography to obtain mesh structures whose line width was 10 µm and line-to-line spacing was 300 µm. CNTs were coated on Ag-meshes by using two different methods, such as spray coating and electrophoretic deposition (EPD). For the samples of a Ag-meshes and CNTs-coated Ag-meshes, their surface morphologies, electrical sheet resistances, and visible-range transmittances and reflectances were characterized and compared. The experimental results indicated that the reflectance of Ag-mesh electrodes was substantially reduced by coating of CNTs. Especially, the hybrid electrodes of Ag-meshes with EPD-coated CNTs showed excellent properties such as sheet resistance lower than 20 /□, transmittance higher than 90 %, and reflectance lower than 8 %.