• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.1
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• pp.32-38
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• 2014

In the present study, immersion corrosion characteristics of Zn and Al thermal spray coating with sealer for the seawater heat exchanger are experimentally investigated. Total 8 coating types of Zn and Al thermal spray coating with silicone and epoxy sealer were tested with immersion corrosion testing in $80^{\circ}C$ 3.5%w NaCl solution and compared the corrosion characteristics between each coatings. To investigate the corrosion characteristics of the specimens, AC impedance, SEM, and thermal diffusivity were acquired and analyzed. As a result, on the surface of the specimens with silicone and epoxy sealer, blister did not occurred, so the sealers might be effective at increasing the corrosion resistance of the specimens immersed in the NaCl solution.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.224-224
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• 2014

최근 기존의 아연 도금 강판의 성능을 향상시키기 위하여 다른 금속과의 합금 박막의 연구가 활발히 진행 중에 있다. 기존 아연 도금 강판에 비해 Mg를 함유한 Zn-Mg 합금 박막이 내식성이 우수하다고 알려져 있으며, 본 연구에서는 다양한 Mg 함량의 Zn-Mg 합금 타겟을 사용하여 Zn-Mg 박막을 합성하였다. 합성된 박막들의 내식성을 평가하기 위해서 Electrochemical Impedance Spectroscopy (EIS) 분석을 실시하였으며, 도출된 Nyquist plot 과 Bode phase angle plot 결과를 등가회로 피팅과 시뮬레이션을 실시하여 Mg 함량에 따른 Zn-Mg 박막의 내식성을 비교 분석하였다. Zn-Mg 박막은 Mg 함량이 증가할수록 내식성 또한 증가하였으며, 이는 Mg 함량에 따라 치밀해지는 미세구조에 의한 것으로 판단된다.

• Bulletin of the Korean Chemical Society
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• v.29 no.5
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• pp.939-942
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• 2008

Photoelectrochemical deposition of CdZnSe thin films on the Se-modified Au electrode using electrochemical quartz crystal microgravimetry (EQCM) and voltammetry is described. Corrosion of pre-deposited Se electrodes by illumination at a fixed potential resulted in $Se^{2-}$ species, which was manifest from the EQCM frequency changes. $Se^{2-}$ species generated from the photocorrosion reacted with $Cd^{2+}$ and $Zn^{2+}$ ions in the electrolyte to form CdZnSe films on the Au electrode. The effect of electrolyte composition on the composition and band gap of CdZnSe films was studied in detail. Also, photoelectrochemistry, EDX, Raman spectroscopy were used for the characterization of CdZnSe thin films.

• Restorative Dentistry and Endodontics
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• v.19 no.1
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• pp.1-26
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• 1994

The purpose of this study was to investigate the dissolution components during corrosion of amalgams and to identify surface corrosion products in the modified Fusayama artificial saliva. Four type of amalgam alloys were used: low copper lathe cut amalgam alloy (Cavex 68), low copper spherical amalgam alloy (Caulk Spherical Alloy), high copper admixed amalgam alloy (Dispersalloy) and high copper single composition amalgam alloy (Tytin). Each amalgam alloy and Hg were triturated according to the manufacturer's direction by means of mechanical amalgamator (Capmaster, S.S.White), and then the triturated mass was inserted into the cylindrical metal mold which was 10mm in diameter and 2.0mm in height and condensed with compression of 150kg/$cm^2$ using oil pressor. The specimens were removed from the mold and stored at room temperature for 7 days and cleansed with distiled water for 30 minutes in an ultrasonic cleaner. The specimens were immersed in the modified Fusayama artificial saliva for the periods of 1 month, 3 months and 6 months. The amounts of Hg, Cu, Sn and Zn dissolved from each amalgam specimen immersed in the artificial saliva for the periods of 1 month, 3 months and 6 months were measured using Inductivity Coupled Plasma Atomic Emission Spectrometry (ICPQ-1000, Shimadzu, Japan) and amount of Ag dissolved from amalgam specimen was measured using Atomic Absorption Spectrophotometry (Atomic Absorption/Flame emission spectrophotometer M-670, Shimadzu, Japan). A surface corrosion products of specimens were analysed using Electron Spectroscopy Chemical Analyser (ESCA PHI-558, PERKIN ELMER, U.S.A.). The secondary image and back scattered image of corroded surface of specimens was observed under the SEM, and the corroded surface of specimens was analysed with the EDX. The following results were obtained. 1. The dissolution amount of Cu was the most in high copper admixed amalgam(Dispersalloy) and the least in high copper single composition amalgam(Tytin). 2. Sn and Zn were dissolved during all the experiment periods, and dissolution amounts were decreased as the time elapsed. 3. Initial surface corrosion products were ZnO and SnO. 4. Corrosion of ${\gamma}$ and ${\gamma}_2$ phase in low copper amalgams was observed and Ag-Cu eutectic alloy phase was corroded in low copper spherical amalgam(Caulk Sperical Alloy). 5. Corrosion of ${\gamma}$ and $\eta$' phase in high copper amalgams was observed and Ag-Cu eutectic alloy phase was corroded in high copper admixed amalgam(Dispersalloy). 6. Sn-Cl was produced in the subsurface of low copper amalgams and high copper admixed amalgam.

• Corrosion Science and Technology
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• v.9 no.2
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• pp.98-103
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• 2010

In order to further reduce the cost without reducing the corrosion resistance, a high-manganese austenitic alloy for sink roll or stabilizer roll in continuous hot-dip coating lines was developed. A systematic study of corrosion behavior of the high-manganese austenitic alloy in pure zinc bath at $490^{\circ}C$ was carried out. The results shows that, the high-manganese austenitic alloy shows better corrosion resistance than 316L steel. The corrosion rate of the high-manganese austenitic alloy in pure zinc bath is calculated to be approximately $6.42{\times}10^{-4}g{\cdot}cm^{-2}{\cdot}h^{-1}$, while the 316L is $1.54{\times}10^{-3}g{\cdot}cm^{-2}{\cdot}h^{-1}$. The high-manganese austenitic alloy forms a three-phase intermetallic compound layer morphology containing ${\Gamma$}, ${\delta}$ and ${\zeta}$ phases, while the 316L is almost ${\zeta}$ phase. The ${\Gamma}$ and ${\delta}$ phases of the high-manganese austenitic alloy contain about 8.5 wt% Cr, the existence of Cr improve the stabilization of phases, which slow down the reaction of Fe and Zn, improve the corrosion resistance of the high-manganese austenitic alloy. So substitute the nickel with the manganese to manufacture the high-manganese austenitic alloy of low cost is feasible.

• Journal of the Korean Electrochemical Society
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• v.6 no.3
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• pp.196-202
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• 2003

We investigated the effect of both 4 types additives and $0.5wt\%\;Pb_3O_4$ which have been reported to show an improvement on the performance of Zinc anode. And Experimental methods such as corrosion potential measurement, potentiodynamic polorization test and charging-discharging cycle life test were carried out in $40 wt\%$ KOH with $Pb_3O_4(0.5, \;10\;&\;2.0wt\%)$ and 4 types additives $(0.4wt\%\;of\;Ca(OH)_2$, 0.025M of Citrate, Tartrate and Gluconate). Corrosion potential was shifted to high direction and also changed to high and low direction repeatedly with increasing of $Pb_3O_4$ quantity. However by adding $0.5wt\%\;Pb_3O_4$, corrosion potential shifted to low direction and showed stable condition. Furthermore it was well known that corrosion resistance was predominantly increased compared to no addition and improved charging-discharging property with adding additives. By SEM analysis, it was concluded that the morphology of surface in case of only $0.5wt\%\;Pb_3O_4$ addition was nearly the same as that of Tartrate additive and in the other additives such as $Ca(OH)_2$, Citrate, Tartrate and Gluconate, their morphologies showed dendrite growth. Eventually it was thought that the additive of Tartrate indicated comparatively good corrosion resistance effect as well as charging-discharging property improvement among those four types additives.

• Journal of Advanced Marine Engineering and Technology
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• v.9 no.3
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• pp.240-249
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• 1985

This paper presents the results of the galvanic anode's characteristicsin the Al-Zn-In-Mg and Al-Zn-In-Mg system anodes used aluminium ingot of low purity, 99.5% grade. The results of thses performance tests are as follows: 1) Zn, In and Mg are an available elements to improve the performance of Aluminium alloy anodes. 2) When the range of zinc content in the Al-Zn-In-Mg system anode is 2-5% the more zinc content, the more improve the anode performance. 3) Al-Zn-In-Mg system anode requires a long term over 50 days for the performance test. 4) The composition of Al-Zn-In-Mg system anode which shows the most excellent performance is Al-(2-3%) Zn-(0.02%) In-(1.0%) Mg. 5) When the Al-Zn-In-Mg system anode is annealed for an hour in 500 to 550 .deg. C, the anode performance is improved. 6) The lower average potential and the better corrosion pattern in the Al-Zn-Mg, Al-Zn-In and Al-Zn-In-Mg system anodes, the more current efficiency is improved.

• Proceedings of the Korean Sanitation Conference
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• 2001.11a
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• pp.119-140
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• 2001

This experiment from March 1, 1998 to August 31, 2001 through XRD, XRF, SEM, EDS had effects as follows. 1. According to the results of test using XRD and EDS, we found that the main ingredients causing corrosion of steel pipe was ${Fe_2}{O_3}$, that of cast iron pipe was $CaCO_3$. 2. The main ingredient of corrosion products in a water pipe was Fe. On an average Fe occuied 93.36% of corrosion products in case of steel pipe while it did 85.47% in case of cast iron pipe. 3. In case of a piped water passed through SCALE BUSTER over 10 times, the corrosion products decreased largely by the galvanic effect and sacrifical anode caused by the concerntration of Zn.

• Journal of Urban Science
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• v.7 no.1
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• pp.23-27
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• 2018

This research was carried out to investigate the corrosion prevention effect in the water distribution system by galvanized zinc-brass pipe which is using potential between brass and zinc. As a result of this study, pH and conductivity of influent were constant in spite of its installation, and it was difficult to estimate the effect of the installation with temporary increased and reduced concentration of Zn and Fe ions, respectively. However, since the corrosion rate of the steel coupon with galvanized zinc-brass pipe was relatively low, it has an effect of inhibiting corrosion.

• Corrosion Science and Technology
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• v.2 no.3
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• pp.135-140
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• 2003

The effect of temperature on stress corrosion cracking o f Al-brass used in vessel heat exchanger tube was studied in 3.5% NaCI + 0.1% $NH_4OH$ solution. The SCC test using a CDT(constant displacement test) and the specimens using a SEN(single edge notched) specimens. For setting the environment similar to working environment of a heat exchanger, the specimens was immersed in solution and solution flow onto the specimens were performed. The results are as follows : The latent time of stress corrosion crack occurrence gets shorter, as the temperature gets higher. Dezincification phase showed around the crack occupy wider range, as the temperature gets higher. Zn composition falls under 4% at the dezincifiction area.