• Corrosion Science and Technology
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• 제6권5호
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• pp.219-226
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• 2007

Pre-construction primer (PCP), or shopprimer, have been applied to steel plates to control temporary corrosion during ship fabrication. For surface preparation at ship block stage, in common shipyard practices, welding beads, burnt and rusted areas shall be blasted or power tool cleaned and the contamination such as zinc salt shall be removed with blasting or power tool. Whereas, the sound film of PCP needs not to be removed or roughened as the paint having good compatibility with PCP is used for the first coat. In many cases, however, full blasting or sweep blasting on the sound PCP treated block assemblies was requested. There still has been argument about the legitimacy of this practice, thus, it is critical to evaluate the quality of the coating system applied on the sound PCP retained condition, comparing with the one applied on the full blasted or sweep blasted condition. In this study, two different epoxy systems for water ballast tank were applied on the surfaces with sound PCP condition, full blasted condition, and sweep blasted condition. Coating performances such as durability, anti-corrosion, cathodic disbondment resistance were evaluated. The test results clearly indicated that the sound film of PCP needed not to be removed or roughened as the paint having good compatibility with PCP based on inorganic zinc silicate.

• Advances in environmental research
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• 제8권1호
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• pp.71-84
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• 2019

Effective waterproofing of structures was a compulsory constraint to avoid leaks and dampness or humidity in walls, ceilings, roofs underground tank and underground room. Traditionally used methods of roof waterproofing were bitumen with tinny seared clay tiles are very troublesome, overwhelming time and involving high labor cost. These waterproofing methods are not allocation the purpose due to their intrinsic disadvantages. Prepackaged polymer modified slurries (PPPMS) are now attainment the vogue and easy to use, easily available in the market, cheaper in cost and more workable than the traditional methods of waterproofing. An experimental study has shown that prepackaged polymer modified slurries (PPPMS) are superior in cost and performance to as a roof water proof coatings. Bituminous coatings were mixed with water and different combination of prepackaged polymer modified slurries and primer respectively, to find optimum coverage underneath worst atmospheric conditions. Every specimen of different proportioned was applied on plane roofs and through the passage of time, their performance was checked, assessed and associated with each other. The roof of approximately 40000 ft² area of prepackaged polymer modified slurries was used will give us hundred percent result (no water seepage or no water absorption) therefore no complaints as compare to roofs area of approximately 24000 ft² bituminous coating was used for waterproofing they have shown the result of 30 to 40 percent water seepage. This result shows that prepackaged polymer modified slurries were two times cheaper than bituminous coating. Comparing an equal number of surfaces coated with a polymer modified prepackaged mortar and bitumen the prepackaged polymer modified slurries (PPPMS) showed excellent performance, ease of application and low bitumen coating cost.

• The Journal of Advanced Prosthodontics
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• 제5권4호
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• pp.382-387
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• 2013

PURPOSE. Although several surface treatments have been recently investigated both under in vitro and in vivo conditions, controversy still exists regarding the selection of the most appropriate zirconia surface pre-treatment. The purpose of this study was to evaluate the effect of alumina (Al) and aluminium nitride (AlN) coating on the shear bond strength of adhesive resin cement to zirconia core. MATERIALS AND METHODS. Fifty zirconia core discs were divided into 5 groups; air particle abrasion with 50 ${\mu}m$ aluminum oxide particles ($Al_2O_3$), polishing + Al coating, polishing + AlN coating, air particle abrasion with 50 ${\mu}m$ $Al_2O_3$ + Al coating and air particle abrasion with 50 ${\mu}m$ $Al_2O_3$ + AlN coating. Composite resin discs were cemented to each of specimens. Shear bond strength (MPa) was measured using a universal testing machine. The effects of the surface preparations on each specimen were examined with scanning electron microscope (SEM). Data were statistically analyzed by one-way ANOVA (${\alpha}$=.05). RESULTS. The highest bond strengths were obtained by air abrasion with 50 ${\mu}m$ $Al_2O_3$, the lowest bond strengths were obtained in polishing + Al coating group (P<.05). CONCLUSION. Al and AlN coatings using the reactive magnetron sputtering technique were found to be ineffective to increase the bond strength of adhesive resin cement to zirconia core.

• 한국세라믹학회지
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• 제44권7호
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• pp.368-374
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• 2007

CVD-SiC coating has been introduced as a protective layer in TRISO nuclear fuel particle of high temperature gas cooled reactor (HTGR) due to its excellent mechanical stability at high temperature. In order to prevent the failure of the TRISO particles, it is important to evaluate the fracture strength of the SiC coating layer. It is needed to develop a new simple characterization technique to evaluate the mechanical properties of the coating layer as a pre-irradiation step. In present work, direct strength measurement method with the specimen of hem i-spherical shell configuration was suggested. The indentation experiment on a hemisphere shell with a plate indenter was conducted. The fracture strength of the coating layer is related with the critical load for radial cracking of the shell. The finite element analysis was used to drive the semi-empirical equation for the strength measurement. The SiC hemispherical shells were successfully recovered from the section-grinding of TRISO coated particle and successive heat treatment in air. The strength of CVD-SiC coating layer was evaluated from the experimentally measured critical load during the indentation on SiC hemisphere shell. Weibull diagram of fracture strength was also constructed. This study suggested a new strength equation and experimental method to measure the fracture strength of CVD-SiC coating of TRISO coated fuel particles.

• 한국재료학회지
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• 제14권9호
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• pp.676-681
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• 2004

In-situ observation in SBM on the microfracture behavior of coating layer was performed for GA steel sheets that have various Fe contents and thickness of coating layer. In case of cross sectional side of coating layer that was in a tensile stress state during bending, fine perpendicular crack pre-induced during galvannealing grew and propagated rapidly toward the coating surface with the increase of strain. And then it grew and propagated along the ${\Gamma}/Fe$ matrix interface, and combined with the nearest another perpendicular crack. Consequently, flaking occurred. The more Fe content and thickness of coating layer increased, the more average crack interval and flaking resistivity increased. Exfoliation was little observed at coating surface in a tensile stress state.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.240-245
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• 2004

Tensile properties of hard coating material, TiN, were evaluated using micro-tensile testing system. TiN has been known as a hard coating material commonly used today. Micro-tensile testing system consisted of a micro tensile loading system and a micro-ESPI(Electronic Speckle Pattern Interferometry) system. Micro-tensile loading system had a maximum load capacity of 500mN and a resolution of 4.5 nm in stroke. TiN thin film $1{\mu}m$ thick was deposited on the Si wafer pre-deposited of $Si_3N_4$ film substrate by the closed field unbalanced magnetron sputtering (CFUBMS) process. Three kinds of micro-tensile specimen with the respective width of $50{\mu}m$, $100{\mu}m$ and $500{\mu}m$ were fabricated by MEMS process. The mechanical properties including tensile strength and elastic modulus were determined using the micro-tensile testing system and compared by those obtained by nano-indentation

• 한국주조공학회지
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• 제24권4호
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• pp.187-193
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• 2004

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2013년도 임시총회 및 하계학술연구발표회
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• pp.79-80
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• 2013

• Composites Research
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• 제37권3호
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• pp.238-245
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• 2024

본 연구에서는 강관의 효율적 유지관리를 위한 모니터링 시스템 개발 연구의 일환으로 개질 폴리에틸렌 코팅 처리된 강관의 성능 평가를 위한 실험적 연구를 수행하였다. 기존 방식인 기계적 전처리 코팅의 경우 확관시 폴리에틸렌 부착이 저하되는 현상이 발생하여 이를 해결하고자 칼슘 혼입 인산 아연 피막을 활용한 화학적 전처리 공정이 적용되었다. SEM 및 EDX 분석결과, Zn/Ca 비 1.0에서 가장 치밀한 구조가 확인되었다. 또한, 확관 시의 코팅 이탈 방지를 위한 그라프트 처리 무수말레산을 기반으로 엘라스토머, 금속산화물, 블로킹방지제, 슬립제를 각기 다른 조합으로 혼입하여 개질된 폴리에틸렌 코팅 강관에 대한 부착 및 연신율 평가를 실시하였다. 그 결과, 모든 개질 재료를 혼입한 시험체(S4)에서 금속산화물만 혼입한 시험체(S2)대비 25% 이상 향상된 성능을 확인하였다. 마지막으로, 공정이 완료된 코팅 파이프에 대하여 표면부 코팅 손상 방지를 위한 파이프 고정 부속 일부인 쐐기형 소켓링과 이탈 방지 압륜을 개발하고 성능평가를 수행하였다.

• 한국염색가공학회지
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• 제18권1호
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• pp.1-9
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• 2006

Treatment of PET fabrics with alkali, chitosan and Al-mordanting has been carried out and the role of the chitosan coating in the dyeing process was clarified. The pre-treatment was effectively evaluated differences in dyeing behavior between its treated and untreated PET fabrics using wood of Caesalpinia sappan. The pre-treated on PET fabrics has been examined by SEM and evidence for the presence of chitosan sought using a air permeability test. Similar colour fastness by computer color matching(CCM) obtained on both untreated and pre-treated PET fabrics. The pre-treated PET was found to be of a deeper hue to that of its dyed untreated PET and, despite of its better colour depth, the wash fastness of the pre-treated dyeing was comparable to that of its dyed untreated PR. The application of chitosan or mordanting reveled that pre-treatment imparted to the PET additional functional groups that were available for coordination with the Brazilin.