• Journal of Advanced Marine Engineering and Technology
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• v.22 no.2
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• pp.219-224
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• 1998

Recently to achieve the anti-corrossive effect in propeller shafts the coating technique with suit-able coating materials is available instead of bronze-sleeved shafts. In this case the coating mate-rials in service must not be delaminated from the shaft and the crack must not be originated. Thus the various performance and security test for coating materials of propeller shaft must be carried out under the real conditions or more severe circumstance. The most important factors effecting on the funtion of coating materials in propeller shaft are the strain and the environment of sea water. In this paper therefore the maximum possible strain which can be occured in real propeller shaft was calculated based on IACA standard classification rule in order to give the proper level of strain to the test samples in performance test of propeller shaft coating materials.

• Special Issue of the Society of Naval Architects of Korea
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• 2009.09a
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• pp.18-23
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• 2009

After the installation of electric cables at block, PE(pre-erection) and hull stages, the coating stains on the electric cable sheath were unavoidably occurred by additional painting process. According to class rules paint or coating applied on the electric cables shall not adversely affect the mechanical, chemical of fire resistant characteristics of the electric cable sheath. However, there has not been quantitatively studied about the effect of coating stains on properties of sheath materials. In this study, we tried to investigate the effect of coating stains on the performance and deterioration of sheath materials by using FTIR, SEM analysis, flame retardant, high potential voltage and tensile test. The results sowed that coating stains, which were occurred during painting work on site could not adversely affect on the performance and deterioration of sheath materials.

• Corrosion Science and Technology
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• v.4 no.5
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• pp.207-210
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• 2005

Coating performance of various coating systems including chlorinated rubber and epoxy/urethane used most for steel structures of highway in Korea, was evaluated by exposing test specimen to complex deterioration factors such as ultraviolet ray, moisture, freeze-thaw cycle and salt. Deteriorated specimens were evaluated by chalking and rust grades according to ASTM, and measurement of color differences and adhesion. In overall coating performances such as corrosion resistance, photochemical stability, and adhesion, ceramic/ urethane, moisture-curable urethane/ urethane, etc. were superior. As for other coating materials tested in this study, superior materials against certain deterioration factors may be inferior against other factors. Accordingly, in order to select suitable maintenance coating materials for the use, it is thought that investigation of suitability through experiment should precede selection of materials, especially for unusual coatings or paints.

• Fire Science and Engineering
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• v.25 no.2
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• pp.95-100
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• 2011

The ultimate purpose of this study is to improve the irrational system related to flame retardant coating performance test of field flame retardant coating articles and to secure the reliability of flame retardant coating through rational flame retardant coating test. To achieve this, the analysis was conducted on the interior finishing materials used in the interior fields and the trends of recent field flame retardant coating, based on the results of flame retardant coating performance test of field flame retardant coating articles which the first-line fire stations have recently conducted. And I attempted to present the methods of field flame retardant coating performance test suitable to current realities and the ways of improvement for securing reliability by analyzing the problems with the methods and procedures of field flame retardant coating articles and the registration system of flame retardant coating business.

• Korean Journal of Materials Research
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• v.9 no.1
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• pp.73-80
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• 1999

The effect of alloy compositions of the bond coating on the plasma sprayed-thermal barrier coatings was investigated. The performance of the coating composed of Rene80/NiCrAl/ZrO$_2$-CeO$_2$-Y$_2$O$_3$ and Rene80/CoNiCrAlY/ZrO$_2$-CeO$_2$-Y$_2$O$_3$was evaluated by isothermal and thermal cyclic test in an ambient atmosphere at 115$0^{\circ}C$. The failure of Rene80/NiCrAl/ZrO$_2$-CeO$_2$-Y$_2$O$_3$ coatings was occurred at the bond coating/ceramic coating interface while Rene80/CoNiCrAlY/ZrO$_2$-CeO$_2$-Y$_2$O$_3$ coating was failed at the substrate/bond coating interface after thermal cyclic test. The lifetime of Rene80/NiCrAl/ZrO$_2$-CeO$_2$-Y$_2$O$_3$coatings was longer than Rene80/CoNiCrAlY/ZrO$_2$-CeO$_2$-Y$_2$O$_3$coating. The oxidation rate of the NiCrAl bond coating examined by TGA was lower than CoNiCrAlY bond coatings. In summary, these results suggest that Rene80/CoNiCrAlY/ZrO$_2$-CeO$_2$-Y$_2$O$_3$system as thermal barrier coating be not suitable considering the durability of the coating layer for high temperature oxidation and thermal stress.

• Corrosion Science and Technology
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• v.6 no.1
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• pp.18-23
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• 2007

DLC coatings have been deposited onto substrate of STS 316L and Ti alloy using r.f. PACVD (plasma-assisted chemical vapor deposition) with a mixture of $C_{6}H_{6}$ and $SiH_{4}$ as the process gases. Corrosion performance of DLC coatings was investigated by electrochemical techniques (potentiodynamic polarization test and electrochemical impedance spectroscopy) and surface analysis (scanning electron microscopy). The electrolyte used in this test was a 0.89% NaCl solution of pH 7.4 at temperature $37^{\circ}C$. The porosity and protective efficiency of DLC coatings were obtained using potentiodynamic polarization test. Moreover, the delamination area and volume fraction of water uptake of DLC coatings as a function of immersion time were calculated using electrochemical impedance spectroscopy. This study provides the reliable and quantitative data for assessment of the effect of substrate on corrosion performance of Si-DLC coatings. The results showed that Si-DLC coating on Ti alloy could improve corrosion resistance more than that on STS 316L in the simulated body fluid environment. This could be attributed to the formation of a dense and low-porosity coating, which impedes the penetration of water and ions.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.11a
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• pp.120-121
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• 2017

Polyurethane coating materials are widely used in waterproofing construction because they ensure easy workability and high performance mechanical properties, and such polyurethane coating materials are in various mixture ratios. This study carried out a test to determine the basic physical property changes of polyurethane coating material based on the amount of charcoal additives to. The results showed that he tensile strength was found to be 3.1 N / ㎟ when the charcoal amount was at 2%, displaying the highest performance rate.

• Journal of Powder Materials
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• v.18 no.3
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• pp.226-237
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• 2011

W-ZrC and W-HfC composite powders were fabricated by the Plasma Alloying & Spheroidization (PAS) method and the powders were sprayed into hybrid coating layers by using Low Vacuum Plasma Spray (LVPS) process, respectively. Microstructure, mechanical properties, and ablation characteristics of the fabricated coating layers were investigated. The LVPS process led to successful production of W-Carbide hybrid coatings, approximately 400 ${\mu}M$ or above in thickness. As the substrate preheating temperature increased from $870^{\circ}C$ to $917^{\circ}C$, the hardness of the W-ZrC coating layer increased due to decreased porosity. Vickers hardness showed higher value (about 108.4 HV) in W-ZrC hybrid coating material compared to that of W-HfC while adhesive strength was found to be similar in both coating layers. The plasma torch test revealed good ablation resistance of the W-Carbide hybrid coating layers. The relatively high performance W-ZrC coating layer at the elevated temperature is thought to be attributed to both the strengthening effect of ZrC particle remained in the layer and the formation of ZrO2 phase with high temperature stability.

• Corrosion Science and Technology
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• v.19 no.1
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• pp.23-30
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• 2020

Heat sinks are most widely used in thermal management systems; however, the heat dissipation efficiency is usually limited. Therefore, in order to increase heat dissipation efficiency of the heat sink, the heat-dissipating paint using 2D materials (hexagonal boron nitride (h-BN) and graphene) as thermally conductive additive was designed and evaluated in the present study. The heat dissipation performance of the paint was calculated from temperature difference between the paint-coated and -uncoated specimens mounted on the heat source. The highest heat dissipation performance was obtained when the ratio of h-BN to resin was 1/10 in the paint. In addition, further reduction in the temperature of the test specimen by 6.5 ℃ was achieved. The highest heat dissipation performance of the paint prepared using graphene was achieved at a 1/50 ratio of graphene to the resin, and a 6.5 ℃ reduction was attained. In addition, graphene exhibited enhanced corrosion resistance property of heat-dissipating paint by inhibiting the growth of the paint blisters.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.849-852
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• 2008

In the wheel tracking test to evaluate abrasion resistance for concrete surface coating materials applied parking lot, weight of the wheel, test temperature, scattered sand amount, wheel speed, etc. various test condition is used for reliable evaluating the abrasion resistance performance of surface coating materials and the results depends on the test condition. In this paper, we carried experimental study as following on abrasion resistance with 2kinds of different environmental conditions. - Commons : real car tire with 300kg of load, 5km/h of speed, 80,000 cycle. - Control A : no other deterioration condition - Control B : scattering 1.0g of sand per every 30rounds from 1m height.