• Corrosion Science and Technology
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• v.6 no.5
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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.

• Korean Chemical Engineering Research
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• v.54 no.2
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• pp.145-151
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• 2016

In response to the cavitation caused by the partial vacuum caused by the fluid flow, a paint was developed by dispersing the lamella-shaped glass-flake in resin for anti-cavitation. This composite paint was developed by using the inorganic filler (lamella shaped glass-flake) and the NBR (Acrylonitrile-butadiene rubber) which was modified epoxy resin. Especially, the glass-flake was a thin film with a thickness of about 100~200 nm and length of about $20{\sim}30{\mu}m$, the aspect ratio was about 200 to 300 times that of the plate-shaped. So the paint for anti-cavitation have shown excellent performance in corrosion resistance. The results of evaluating anti-cavitation performance was below, tensile strength $4.8{\sim}6N/mm^2$ or more, rupture elongation 30% or higher, abrasive speed $10mm^2/h$ or less. In particular, it showed more than twice the superior performance compared to existing advanced foreign products in anti-cavitation performance evaluation.

• Journal of Mechanical Science and Technology
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• v.18 no.4
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• pp.592-596
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• 2004

Corrosion is never avoided in the use of materials with various environments. The underwater hull is normally protected against rusting by several coatings of anti-corrosive paint. The purpose of ICCP(Impressed Current Cathodic protection) system is to eliminate the rusting or corrosion, which occurs on metal immersed in seawater. The anode of ICCP system is controlled by an external DC source with converter. The function of anode is to conduct the protective current into seawater. The proposed algorithm includes the harmonic suppression control strategy and the optimum protection strategy and has tried to test the requirement current density for protection, the influence of voltage, the protection potential. This paper was studied the variation of potential and current density with environment factors, time and velocity, and the experimental results will be explained.

• Journal of the Korean institute of surface engineering
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• v.34 no.4
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• pp.281-288
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• 2001

Phosphating treatments have been performed to improve paint adhesion and corrosion resistance of zinc and zinc alloy coated steels for a long time. In this work, the effects of the addition of chelate compound were studied to improve the stability of surface conditioning solution and properties of zinc phosphate films. The coalescence of colloidal Ti-compound and extraneous charged particles (alkaliearth metal cation such as $Mg^{2+}$ , $Ca^{2+}$ ) were suppressed by using a surface conditioning solution with chelate compound. Therefore, after surface conditioning solution containing chelate compound was left standing for one week at room temperature, the formation of a white sediment was decreased comparing to surface conditioning solution without chelate compound. The crystal size of phosphate film was fine and the whiteness value of phosphated zinc coated steel sheets was also high without the decrease of corrosion resistance and anti-patina. It was very effective to use chelate compound improving the stability of surface conditioning solution.

• Journal of the Microelectronics and Packaging Society
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• v.26 no.2
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• pp.1-8
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• 2019

The demand and importance of adhesives and paint coatings applied to solid surfaces such as metals, ceramics, and plastics are increasing. In this study, the influencing factors on the adhesive strength between the polymer coating and the metal adherend were investigated by Dolly test when the adhesive or the paint coating was applied on the metal adherend. Two-component epoxy adhesive was used as the adhesive, and EH2350, a two-component epoxy paint for anti-corrosion, was used as the paint. Especially, the effect of adherend metals(Al, Fe, STS, Cu, Zn), surface roughness and surface contamination(tap water, salt water) on adhesive strength was studied as influencing factors. The adhesive strength between adhesive and adherend was different when the type of metal adherend was different even when the same adhesive was used. It was found that spray water cleaning was necessary before the paint coating process on the surface of the oxide contaminated adherend with tap water or salt water. As a result of this study, it was confirmed that Dolly test can be widely used in the future to measure adhesive strength between paint coating and adherend.

• Journal of the Society of Naval Architects of Korea
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• v.53 no.5
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• pp.400-409
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• 2016

In recent, shipping companies have made an enormous effort to improve the operation of vessel in various approaches, due to recession of shipping market and increasing competition among shipping companies. One of important parameters for improving the efficiency of vessel is the resistance performance that consist of friction and residual resistance. Especially, it is recognized that the friction resistance tends to be affected by conditions of vessel’s surface and occupies approximately 70~90% of the total resistance for slow speed ships. In general, the surface of vessel is covered with various type of paint to reduce fouling and corrosion. As time goes by, however, it is so hull roughness would be increased by fouling over the wetted surface that anti-fouling paints, such as CDP(Controlled Depletion Paint), Tin-Free SPC(Self Polishing Co-polymer) or Foul Release, are applied evenly on the hull surface. Nevertheless, these anti-fouling paints could not prevent fouling absolutely. A fundamental study on evaluating ship resistance performance variation due to hull roughness has been performed using a commercial software, Star-CCM+, which solves the continuity and Navier-Stokes equations for incompressible and viscous flow. The results of present simulation for plate are compared with some experimental data available and the effect of surface roughness to ship resistance performance is discussed.

• Journal of Navigation and Port Research
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• v.30 no.4
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• pp.291-294
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• 2006

Corrosion is never avoided in the use rf materials with various environments. The underwater hull is normally protected against rusting by several coatings of anti-corrosive paint. The purpose of ICCP(Impressed Current Cathodic Protection) system is to eliminate the rusting or corrosion, which occurs on metal immersed in seawater. This thesis is about the ICCP control and monitoring system, which brings protection against the corrosion of the ship's hull in the sea environments. The test system for ICCP is composed of a power supply, anode, reference electrode and controller. The test system is composed power supply, anode, ref electrode, shunt and etc. The protection current is sent to the protection area though anode. Reference electrode senses whether or not the detected potential is within a range of protection of test equipment and then it is automatically controlled to increase or decrease the amount of protective current to be sent to the anode by controller. The monitoring system with LabView is also detected in order to check the normal state of the system at operation period, because an operator does not always watch over this system and thus the system cannot operate well because rf his or her negligent management. This paper was studied the variation of potential and current density with environment factors, velocity and time, and the experimental results will be explained Also, It is suggested that this system can accommodate a ship's automation for SCMS(Ship Control and Management System) and will be very useful.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.5A
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• pp.691-697
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• 2008

Coating the high tension bolted frictional joint has been generally allowed for anti-corrosion purpose. However in case of painting on paying surface of the high tension bolt, the influence on a slip strength of the joint depending on precision of painting has remained controversial. The study thus was intended to identify the slip behavior on high tension bolted frictional joint when applying ceramic painting, which has been currently developed. A slip test was conducted on a high tension bolted frictional joint specimen on which ceramic painting has been applied and a slip load and slip coefficient were measured. Based on result, the safety and usability of ceramic painting-applied high tension bolted frictional joint was evaluated. As a result, a difference to some extent by specimen in terms of load-displacement when a slip occurred was observed but an average slip coefficient appeared to have exceeded 0.4, which is the design frictional coefficient set forth in the specification. To secure the safety and usability of ceramic painting-applied high tension bolted frictional joint, it's necessary to establish the standard for painting as well as to revise the relevant specification.