• Structural Engineering and Mechanics
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• v.83 no.4
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• pp.551-561
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• 2022

In this paper, the effect of fire conditions according to ISO 834 standard on the behavior of carbon fibre-reinforced plastic (CFRP) reinforced steel beams coated with gypsum-based mortar has been investigated numerically. To study the efficiency of these beams, 3D coupled temperature-displacement finite element analyzes have been conducted. Mechanical and thermal characteristics of three different parts of composite beams, i.e., steel, CFRP plate, and fireproof coating, were considered as a function of temperature. The interaction between steel and CFRP plate has been simulated employing the adhesion model. The effect of temperature, CFRP plate reinforcement, and the fireproof coating thickness on the deformation of the beams have been analyzed. The results showed that within the first 120 min of fire exposure, increasing the thickness of the fireproof coating from 1 mm to 10 mm reduced the maximum temperature of the outer surface of the steel beam from 380℃ to 270℃. This increase in the thickness of the fireproof layer decreased the rate of growth in the temperature of the steel beam by approximately 30%. Besides excellent thermal resistance and gypsum-based mortar, the studied fireproof coating method could provide better fire resistance for steel structures and thus can be applied to building materials.

• Current Photovoltaic Research
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• v.8 no.1
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• pp.1-5
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• 2020

The most important factor in enhancing the performance of an optical device is to minimize reflection and increasing transmittance of light for a broad wavelength range. The choice of appropriate coating material is crucial in decreasing reflection losses at the substrate. The purpose of this review is to highlight anti-reflection coating (ARC) materials that can be applied to silicon solar cell and glass substrate for minimizing reflection losses. The optical and electrical behavior of ARC on a substrate is highly dependent on thickness and refractive index (RI) of ARC films that are being deposited on it. The coating techniques and performance of single and multi-layered ARC films after coated on a substrate in a wide range of wavelength spectrum will be studied in the paper.

• Proceedings of the KIEE Conference
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• 2002.11c
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• pp.92-95
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• 2002

A study on the system automation for the nitrogen splash slag coating in Basic Oxygen Blowing Furnace (BOF) is described. The engineers are trying to do their best efforts to increase the life of converter lining by developing improved refractory material and optimal operation techniques in the steel plants, A new slag coating method is needed to reduce the erosion rates of the refractory. In the current slag costing method, the BOF was swung back and forth. The new method uses the oxygen lance to blow the residual slag to the walls and cone of the converter. The nitrogen gas is used for blowing. This method is developed based on the automation process at factory in POSCO dated on the May 1998. The test results of nitrogen splash slag coating system for the BOF at POSCO are show to show the effectiveness of the system.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.12a
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• pp.103-106
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• 2006

Semiconductor laser diode has a reflective facet in a both-ends side fundamentally. Laser performance for improving, Anti-Reflection and High-reflection coating on the facet of semiconductor laser diode. To prevent internal feedback from both facets for realizing superluminescent diode and reducing the reflection-induced intensity noise of laser diode, it's key techniques are AR/HR coatings. In the study AR coating film were manufactured by Ion-Assisted Deposition(IAD) system. Then manufactured coating film measurement electrical properties(L-I-V, Se, Resistor) and Optical properties (wavelength FFP)

• Proceedings of the Korean Reliability Society Conference
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• 2005.06a
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• pp.199-208
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• 2005

In the calendar and the advertising catalog, the surface Is usually coated by coating polypropylene film. The delamination failure of coating film depends on surface roughness and quality of the substrate paper. In this paper, the mechanisms of delamination failure between the coating film and the paper is investigated by using the root cause analysis as one of techniques of reliability evaluation. The papers used in failure analysis are three kind products made by two domestic and one foreign companies. It found that the main causes of delamination failure between the coating film and the paper were the creation of microvoids caused by shape of filler and their growth caused by contraction of paper.

• Journal of Advanced Marine Engineering and Technology
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• v.24 no.4
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• pp.393-404
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• 2000

• Bulletin of the Korean Chemical Society
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• v.31 no.2
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• pp.355-359
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• 2010

A $Li[Co_{1/3}Ni_{1/3}Mn_{1/3}]O_2$ cathode was modified by applying a $ZrF_x$ coating. The surface-modified cathodes were characterized by XRD, SEM, EDS, TEM techniques. XRD patterns of $ZrF_x$-coated $Li[Co_{1/3}Ni_{1/3}Mn_{1/3}]O_2$ revealed that the coating did not affect the crystal structure of the parent powder. SEM and TEM images showed that $ZrF_x$ nano-particles were formed as a coating layer, and EDS data confirmed that $ZrF_x$ distributed uniformly on the surface the powder. Capacity retention of coated samples at high C rates was superior to that of pristine sample. However, as the coating concentration increases beyond the optimum concentration, the rate capability was deteriorated. Whereas, as the increase of coating concentration to 2.0 wt %, the cyclic performances of the electrodes under the severe conditions (high cut-off voltage, 4.8 V, and high measurement temperature, $55^{\circ}C$) were improved considerably.

• Journal of the Korean Ceramic Society
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• v.45 no.4
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• pp.238-244
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• 2008

Modeling and FEM analysis on Boron Nitride and/or Pyrolytic Carbon coating layers on SiC fibers under indentation contact loadings are investigated. Especially this study attempts to model the mechanical behavior of the SiC fibers with and without coatings. Tyranno S grade and Tyranno LoxM grade of SiC are selected for fiber and Boron Nitride and/or Pyrolytic Carbon as coating material. The modeling is performed by SiC fiber without coating layer, which includs single(BN or PyC) and double(BN-PyC or PyC-BN) coating layer. And then the analysis is performed by changing a type of coating layer, a type of fiber and coating sequence. In this study, the concepts of modeling and analysis techniques for optimum design of BN and PyC coating process on SiC fiber are shown. Results show that stresses are reduced when indentation contact loading applies on the material having lower elastic modulus.

• Journal of the Korean institute of surface engineering
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• v.49 no.1
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• pp.1-13
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• 2016

This review deals with one of the surface modification techniques, chemical conversion coating and particularly cerium-based conversion coatings (CeCC) as a promising substitute for chromium and phosphate conversion coating on magnesium and its alloys. The CeCCs are commonly considered environmentally friendly. The effects of surface preparation, coating thickness, bath composition, and e-paint on the corrosion behavior of CeCCs have been studied on the AZ31 magnesium alloy. This review also correlates the coating microstructural, morphological, and chemical characteristics with the processing parameters and corrosion protection. Results showed that the as-deposited coating system consists of a three layer structure (1) a nanocrystalline MgO transition layer in contact with the Mg substrate, (2) a nanocrystalline CeCC layer, and (3) an outer amorphous CeCC layer. The nanocrystalline CeCC layer thickness is a function of immersion time and cerium salt used. The overall corrosion protection was crucially dependent on the presence of coating defects. The corrosion resistance of AZ31 magnesium alloy was better for thinner CeCCs, which can be explained by the presence of fewer and smaller cracks. On the other hand, maximum corrosion protection was achieved when AZ31 magnesium samples with thin CeCCs are e-painted. The e-paint layer further restricts and hinders the movement of chloride and other aggressive ions present in the environment from reaching the magnesium surface.

• Corrosion Science and Technology
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• v.18 no.5
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• pp.182-189
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• 2019

A thin spray coating of inorganic black lithium polysilicate (IBLP) on black anodized AZ31B magnesium alloy was fabricated for better corrosion resistance and thermo-optical properties for thermal control of spacecraft components. The morphology of the specimens with and without IBLP-based spray coating was characterized by SEM-EDS techniques. Impedance and potentiodynamic measurements on the specimens revealed better corrosion resistance for the specimen with a thin coating of lithium polysilicate. This was primarily due to the presence of lithium polysilicate inside the micro-cracks of the black anodized specimen, restricting the diffusion paths for corrosive media. Environmental tests, namely, humidity, thermal cycling, thermo vacuum performance, were used to evaluate the space-worthiness of the coating. The thermo-optical properties of the coating were measured before and after each environmental test to ascertain its stability. The specimen with an IBLP-based spray coating showed enhanced thermo-optical properties, greater than ~0.90. Hence, the proposed coating demonstrated better handling, better corrosion resistance, and space-worthiness during the pre-launch phase owing to its improved thermo-optical properties.