• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2000년도 춘계학술발표회 초록집
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• pp.49-50
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• 2000

• Corrosion Science and Technology
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• 제10권1호
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• pp.30-36
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• 2011

The effect of dynamic flow or forced convection were investigated and compared on the formation of inhibition layer, galvanizing and galvannealing reactions through the hot-dip galvanizing simulator with the oscillation of specimen in zinc bath, continuous galvanizing pilot plant with zinc pumping system through the snout and continuous galvanizing operation with Dynamic $Galvanizing^{TR}$ system. The interfacial Al pick-up was not consistent between the results of simulator, pilot plant and line operation, but the morphology of inhibition layer became compact and refined by the forced convection. The growth of Fe-Zn intermetallics at the interface was inhibited by the forced convection, whereas the galvannealing rate would be a little promoted.

• 한국표면공학회지
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• 제30권5호
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• pp.320-332
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• 1997

The development of colored surface on zinc coating by the oxidation of a melten alloy of zinc with a minor amount of oxygen-avid additive such as tianium has been studied. Using a galvanizing Zinc alloy containing 0.1 to 0.3wt%Ti, gold, purple or blue color was developed clearly and stably, depending upon the extent of oxidation, by air cooling after hot dipping in a bath at temperature of $550^{\circ}C$ to $600^{\circ}C$. The source of the color is light interference with surface oxide layer. THe final color depends on the thickness of the color depends on the thickness of $TiO_2$, played So compositing, temperature and time at elevated temperature after are all controlling variables. Since oxidation film such as $TiO_2$ played role of passivation film, the corrosion resistance in a colored galvanized steel sheet. It is also thought that surface oxide layer of $TiO_2$ inhibited dissolution of the coating layer.

• 한국표면공학회지
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• 제34권4호
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• pp.303-312
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• 2001

Composition and microstructure of the tin-zinc alloys electroplated in gluconate bath were studied according to pulse current parameters. The cathode current efficiency increased with both the mean current density and the off-time decrease. Zinc content of the alloy deposits increased with increasing mean current density, while it decreased noticebly with increasing the off-time from 10-30ms to 100-150ms. The preferred orientation of the alloy deposits changed with the increase of peak current density in the sequence of (220)longrightarrow(220)+(420) or (220)+(420)+(321) mixed structure. The equiaxed grain size of the alloy increased with the increase of off-time and the decrease of mean current density.

• 한국표면공학회지
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• 제16권4호
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• pp.173-187
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• 1983

Zinc was electrodeposited at temperature from 20$^{\circ}C$ to 60$^{\circ}C$ over the ranges of the current density from 2 to 20 A/dm2 in acid chloride bath. The cathode overpotentials increased with increasing current density and decreasing tem-perature. The (10$.$3)-(10$.$2) preferred orientation developed at cathode overpotentials below about 450mV, the (10$.$3)(10$.$2)-(10$.$1) texture developed at overpotentials between 500mV and 950mV, and the (00$.$1) (10$.$3) texture developed at cathode overpotentials about 1000mV. The (00$.$1) (10$.$3) preferred orientation was also formed at the lower potentials between 400mV and 850mV at temperatures above 40$^{\circ}C$. The preferred orientations of the zinc deposits was discussed was discussed with both cathode overpo-tential and surface energy of deposit lattice planes. The pyramid type of structure with macrostep developed at low cathode overpotentials and the truncated pyramidal type developed at higher overpotenial.

• 한국표면공학회지
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• 제20권1호
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• pp.4-14
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• 1987

The nickel-zinc alloy depositions have been studied in nickel chloride added chloride baths, to find out the effects of ultrasonic irradiation for the electrodeposition processes. The compositions of deposited alloys, the current efficiencies and the metallographic appearances in various conditions of Electrodeposition were investigated, in the range of ultrasonic irradiation of 50,500 and 1,000 Kc/s respectively. The results obtained are as follows; 1. Generally the nickel deposition process is more preferably activated than that of zinc by the ultrasonic irradiation. 2. The radios of nickel to zinc in the deposit are higher according to increase of nickel ion concentration and bath temperatures in irradiated baths. 3. The current efficiencies are also higher in the irradiated baths, so that the depolarization effect is noticeable. 4. The brightness and leveling effect of the deposits are appreciably better in the irradiated baths than in non-irradiated in 0.3M and 0.6M of nickel chloride and zinc chloride solutions and the current density of 3A/$dm^2$. 5. The mechanism of alloy deposition has been tentatively suggested in the case of ultrasonic irradiation.

• 한국표면공학회지
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• 제49권3호
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• pp.245-251
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• 2016

Galvanizing method has been extensively used to the numerous constructional steels such as a guard rail of high way, various types of structural steel for ship building and various types of steels for the industrial fields etc.. However, the galvanized structures would be inevitably corroded rapidly with increasing exposed time because an acid rain due to environmental contamination has been much dropped more and more. Therefore, it has been made an effort to improve the corrosion resistance of the galvanizing film through various methods. In this study, comparison evaluation on the corrosion resistance of three types of the samples, that is, the hot dip galvanizing with pure zinc(GI), the hot dip galvanizing of alloy bath with zinc and aluminum(GL) and the pure zinc galvanizing steel immersed again to chromate treatment bath(Chro.)were investigated using electrochemical methods in 1% $H_2SO_4$ solution. The Chro. and GI samples exhibited the highest and lowest corrosion resistance respectively in 1% $H_2SO_4$ solution, however, the GI sample revealed the highest impedance at 0.01 Hz due to its high resistance polarization caused by corrosion products deposited on the surface, while Chro. sample exhibited the lowest impedance at 0.01 Hz because of little corrosion products on the surface. Consequently, it is suggested that the chromate treated steel has a better corrosion resistance in acid environment compared to pure galvanizing(GI) or galvalume(GL) steels.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2009년 추계학술발표대회
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• pp.95-95
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• 2009

Zinc coatings provide the most effective and economical way of protecting steel against corrosion. There are three types of galvanizing lines typically used in production line in galvanizing industries,Galvanize (GI) coating (Zn-0.1-0.3%Al), Galfan coating (Zn-5%Al), Galvalume(GL) coating (45%Zn-Al). In continuous Galvanizing lines, the immersed bath hardware (e.g. bearings, sink, stabilizer, and corrector rolls, and also support roll arms and snout tip) are subjected to corrosion and wear failure. Understanding the reaction of these materials with the molten Zn alloy is becomes scientific and commercial interest. To investigate the reaction with molten Zn alloys, static immersion test performed for 4, 8, 16, and 24 Hr. Two different baths used for the static immersion, which are molten Zn and molten Zn-55%Al. Microstructures characterization of each of the materials and intermetallic layer formed in the reaction zone was performed using optical microscope, SEM and EDS. The thickness of the reaction layer is examined using image analysis to determine the kinetics of the reaction. The phase dominated by two distinct phase which are eutectic carbide and matrix. The morphology of the intermetallic phase formed by molten Zn is discrete phase showing high dissolution of the material, and the intermetallic phase formed by Zn-55wt%Al is continuous. Aluminum reacts readily with the materials compare to Zinc, forming iron aluminide intermetallic layer ($Fe_2Al_5$) at the interface and leaving zinc behind.

• Applied Science and Convergence Technology
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• 제27권2호
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• pp.38-41
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• 2018

We demonstrate the growth of a sheet-like ZnO membrane on ZnO nano rod layers. The growth process is composed of 3 steps of ZnO seed formation, ZnO nano rod growth and sheet-like ZnO membrane formation on those nano rods. To confirm the fundamental growth mechanism, the lattice structures of each step were analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM) measurement. Analysis of the relation between the texture coefficient and the surface shape of the ZnO membrane on the ZnO nano rods shows that the surface morphology of ZnO nano structures can be controlled using the temperature of the growing solution and the concentration of the chemical solution.

• 대한치과보철학회지
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• 제38권5호
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• pp.618-630
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• 2000

As Fiber-reinforced composite restorations cannot be made without leaving a marginal gap, luting cements play a pivotal role in sealing the margins as a prevention against margnal leakage. A recently introduced adhesive resin cement system is claimed to adhere chemically, as well as mechanically, to tooth substances, dental alloys and porcelain. But when considering the clinical variation conventional cementation using Zinc Phosphate and Glass-Ionomer can be requested. A vitro study was undertaken to compare microleakage and marginal fitness of Fiber-reinforced composite crowns(Targis/Vectris) depending upon luting cements. Fifty non-carious human premolar teeth were randomly divided into five experimental groups of 10 teeth each and luted with five luting cements. ($Bistite\;II^(R),\;Super-bond^(R),\;Variolink\;II^(R)$), Zinc phosphate and Glass-Ionomer cement) After 24 hours of being luted, all specimens were thermocycled 300 times through water bath of $5^{\circ}C\;and\;55^{\circ}C$ in each bath, then the quality of the marginal fitness was measured by the Digital Microscope and marginal leakage was characterized using Dye Penetration technique and the Digital Microscope The results were as follows : 1. The mean values of marginal fit were Bistite II($46.78{\mu}m$), Variolink II($56.25{\mu}m$), Super-Bond($56.78{\mu}m$), Glass-Ionomer($99.21{\mu}m$), Zinc Phosphate($109.49{\mu}m$) indicated a statistically significant difference at p<0.001. 2. The mean microleakage values of tooth-cement interface, restoration-cement interface were increased in the order of Variolink II, Bistite II, Super-Bond, Glass-Ionomer, Zinc Phosphate 3. Crowns luted with resin cement (Bistite II, Super-Bond, Variolink II, etc) exhibited less marginal gap and marginal leakage than those luted with conventional Glass-Ionomer and Zinc Phosphate cement. 4. The results indicated that all five luting systems yielded comparable and acceptable marginal fit.