• 수산해양기술연구
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• 제43권4호
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• pp.362-369
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• 2007

This paper was studied on the characteristics of acid resistance and thermal shock for epoxy coatings in the strong acidic environment. The exhaust gas system, such as a air preheater, desulfurization equipment, for industrial boiler is damaged by dew point corrosion. To protect the acid corrosion, the coating using nonmetal was applied. The electrochemical polarization test, acid resistance and thermal shock test for epoxy coatings were carried out. And the acid resistance and thermal shock characteristics, aspect, and electrochemical anti-corrosion characteristics for epoxy coatings in the strong acidic environment were considered. The main results are as followings: As the epoxy glass flake coating by acidic thermal shock was damaged to the crack, blistering and elution etc., the current density of epoxy glass flake coating is high. But the damage of epoxy metal complex coating by acidic thermal shock was not occurred. Therefore the characteristics of acid resistance and thermal shock for epoxy metal complex coating is better than those for epoxy glass flake coating.

• 동력기계공학회지
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• 제18권6호
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• pp.58-63
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• 2014

This paper deals with the effects of counterpart materials on the wear behavior of thermally sprayed STS316 coatings. STS316 powders were flame-sprayed onto a carbon steel substrate. Dry sliding wear tests were performed using the applied loads of 15 N. AISI52100, $Al_2O_3$, $ZrO_2$ and $Si_3N_4$ balls were used as counterpart materials. Wear behavior of STS316 coatings against different counterpart materials were studied using a scanning electron microscope(SEM) and energy dispersive X-ray spectroscopy (EDS). The results show that the wear behavior of thermally sprayed STS316 coatings strongly depends on the type of counterpart material. Dominant wear mechanism was similar for all studied materials as failure of adhesion film except for Si3N4 used as counterpart material. In the case of Si3N4 used as counterpart material, dominant wear mechanism was abrasion.

• 한국환경과학회지
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• 제17권8호
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• pp.925-932
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• 2008

Manufactures of automotive repair finishes are tending to reduce more and more the level of volatile organic compounds (VOCs) in their paint processes in order to comply with increasingly strict environmental legislation. The production of high solids paints is a way to solve this problem. However, the application of high-solids paints is limited primarily by the viscosity of resin which is strongly related to painting ability: the higher solid content, the lower desired property. In this study, alkyl copolymer with low viscosity was synthesized by the introduction of the monomers with long-side chains and functional groups which improve flexibility and cross-linking density, respectively. The solid content of the paint prepared with the synthesized resin was 80wt% and its VOCs was reduced by 20%, compared to the commercialized paint. Also, the physical and mechanical properties of coatings on steel sheets were similar to commercialized one.

• 접착 및 계면
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• 제8권2호
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• pp.1-8
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• 2007

자동차의 유리를 폴리카보네이트로 대체하기 위하여 폴리카보네이트 판 위에 하드 코팅을 시도하였다. 본 연구에서는 (3-glycidoxypropyl)trimethoxysilane (GPTMS), colloidal silica (CS), (3-aminopropyl) triethoxysilane (APS)으로부터 졸-겔 과정을 이용하여 코팅을 형성하였는데, 이 때 가장 우수한 물성을 갖는 조건들을 찾아보았다. GPTMS와 CS를 에탄올 용매 안에서 가수분해 시킨 후에, APS를 첨가하여 코팅 액을 제조하고 이 코팅 액을 가지고 폴리카보네이트 판 위에 코팅을 실시하였다. 제조된 코팅 액으로부터 경도 2H의 투명하고 고른 면을 갖는 코팅 막을 형성할 수 있었으며, 형성된 코팅 막은 매우 우수한 내마모성과 접착력을 나타내었다.

• Elastomers and Composites
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• 제54권4호
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• pp.294-298
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• 2019

A three-layered PVC sheet consisting of polyvinyl chloride (PVC) and woven polyester fabric was prepared by extrusion and calendering. The flexibility and durability of the PVC were tuned by adding plasticizers, additives, and surface coatings. The tensile and tear strengths of the three-layered PVC sheet were higher than those of commercial two-layered sheet, while exhibiting low weight. The concentrations of the total volatile organic compounds (TVOCs) and formaldehyde (HCHO) emitted from the sheet were also lowered. The PVC sheet remained stable after prolonged exposure to UV light, signifying that the PVC sheet is suitable for cargo screen applications.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2011년도 추계학술발표대회
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• pp.12.2-12.2
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• 2011

Diamond-like carbon (DLC) coatings are used nowadays in various applications such as a protective coating against wear or corrosion in automotive parts, and recently its use is more and more apparent in particular biomedical applications [1]. The Japanese Ministry of Economy, Trade and Industry has started a program of collaborative study for industrial standardization of DLC films and their evaluation techniques. Japan New Diamond Forum (JNDF), Nanotec Corporation and the Nagaoka University of Technology are conducting this program. This project includes national organizations (businesses, universities, and research facilities), encompassing a wide range of requirements. JNDF organize Japanese project committee and working group. The purpose of this report is to discuss standardization and classification of DLC coatings.

• 동력기계공학회지
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• 제17권6호
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• pp.108-114
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• 2013

This paper describes process optimization for thermal-sprayed Co-based self-flux alloy coating by Taguchi method. Co-based self-flux alloy coatings were fabricated according to $L_9(3^4)$ orthogonal array using flame spray process. Hardness test and wear test were performed, the results were analyzed by analysis of variance(ANOVA) considering a multi response signal to noise ratio(MRSN). From the results of ANOVA, the optimal combination of the flame spray parameters on Co-based self-flux alloy coating could be predicted. The calculated hardness and wear rate of the coatings by ANOVA were found to be close to that of confirmation experimental result.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1996년도 제24회 추계학술대회
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• pp.183-188
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• 1996

Films and coatings are used for an enormous and diverse set of applications including mechanical, electronic and optical devices, protection at high temperature, cutting tools enhancement and automotive use. Many of these applications require the various properties associated with inorganic and metallic / non-metallic materials; i.e., with ceramics. Therefore, a large number of coatings have been developed and used for a long time in the various fields, especially in mechanical one. As one of the mutual surface actions, the problems of contact stresses are complex. The relationship between load and stress are nonlinear. Besides, the material is often apt to deform plastically under low load. However, analytical solutions exist only for some simple problems. If a material has a complicated shape or inhomogeneous properties, numerical method must be used. In this paper, the analysis of the contact stress of the coating layer was solved, using the finite element method.

• 한국세라믹학회지
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• 제55권5호
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• pp.452-460
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• 2018

This study investigate changes in mechanical behaviors such as indentation load-displacement and hardness of thermal barrier coatings (TBCs) using cycling of thermal shock test. Relatively dense and porous TBCs on nickel-based bondcoat/super alloy are prepared using different starting granules, 204C-NS and 204NS commercial powers, and the effect of double layers of 204C-NS on 204NS and 204NS on 204C-NS are investigated. The highest temperature applied during thermal shock test is $1100^{\circ}C$ and the maximum number of cycles is 1,200. The results indicate that bilayered TBC showed a relatively mechanically resistant property during thermal shock cycles and that the mechanical behavior is influenced by the microstructure of TBCs by exposure to high temperature during tests or different starting granules.

• Journal of Ceramic Processing Research
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• 제20권5호
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• pp.499-504
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• 2019

The effect of coating thickness on the contact fatigue and wear of thermal barrier coatings (TBCs) are investigated in this study. The same bondcoat material thickness (250 ㎛) are used for each sample, which allows the effect of the coating thickness of the topcoat to be investigated. TBCs with different coating thicknesses (200, 400, and 600 ㎛) are prepared by changing processing parameters such as the feeding rate of the feedstock, spraying speed, and spraying distance during APS(air plasma spray) coating. The damage size on the surface are strongly affected by the coating thickness effect. Although the damage size from contact fatigue using a spherical indenter diminish at a TBC of 200 ㎛, a high wear resistance such as a low friction coefficient and little mass change are found at a TBC of 600 ㎛. These results indicate that the coating thickness strongly affects the mechanical behavior in TBCs during gas turbine operation.