• 한국표면공학회지
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• 제28권5호
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• pp.267-275
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• 1995

Electron beam can provide convenient way to heat the substrate during Hollow Cathode Discharge (HCD) ion plating of Ti(C, N)films. Densification of columnar structrue is enhanced by longer duration of electron beam heating(EBH). While strong(111) texture is identified always to be formed, the amount of (200) oriented grains which coherently interfaced with carbide particles of the substrate increased with heating(EBH). In turns, these crystallogaphical change lead to the increase of micro hardness and adhesion of coating. Adhesion of Ti(C, N) films increased more dramatically in case of ASP30 substrate of which carbide particles dispersed more finely than M42. Therefore, it could be concluded that both the density of film and interfacial structure can affect the adhesion property. Overheating of substrate could be resulted in low adhesion resistance due to high residual stress developed in the film.

• 한국표면공학회지
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• 제29권4호
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• pp.253-260
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• 1996

Regular spangle hot dip galvanized steel sheets were made in the zinc bath containing a small amount of Al and with the addition of Pb, Sb, Sb-Mg, Sb-Cu and Bi respectively whose average glosses were measured. Zero-spangle hot dip galvanized steel sheets were also made by spraying a 2% $NH_4H_2PO_4$ solution on molten coating surfaces with exactly the same chemical compositions as above used for regular spangle and whose glosses and corrosion losses were also evaluated. For manufacturing zero- spangle hot dip galvanized steel sheets with high brightness, the zinc bath with 0.02%Sb and the spraying of a 2% $NH_4H_2PO_4$ solution were proposed and for better brightness and corrosion resistance, the zinc bath with 0.02% Sb-0.50%Mg and the spraying of a 2% $NH_4H_2PO_4$ solution were also proposed.

• 한국세라믹학회지
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• 제32권3호
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• pp.349-358
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• 1995

The ceramic composite membrane was synthesized by thermal oxidation after evaporation of Al on the support prepared by slip casting process. Oxidation was performed at $700^{\circ}C$ and 80$0^{\circ}C$ under dry oxygen atmosphere. It was considered as optimum oxidation condition that the membrane showed a knudsen behaviro. A further oxidation resulted in an increase of gas permeability because top layer became densified. Then, a multi-layered composite membrane was synthesized through a sol-gel method, evaporation and thermal oxidation of Al coating processes. While the membrane was thermally stable up to 80$0^{\circ}C$, gas permeability was rapidly decreased even at a slight amount of deposition of Al.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.1442-1447
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• 2004

A significant amount of labor hour is being spent for clean up spent abrasives after blasting. So, for improving the efficiency of abrasive(grit) recovery process which acts as the neck of a battle in preceding coating stage, it was established the theoretical background for pneumatic transport technology in the abrasive recovery system as well as experimentally evaluated the effect of design parameters such as flow pattern, saltation velocity and pressure drop on the efficiency of the abrasive recovery system. And, by optimizing the operating parameter such as the length and diameter of suction hose, specification of recovery device, recovery mouth and hose connection method, a method which can dramatical1y increase the efficiency of abrasive recovery system, is derived.

• 펄프종이기술
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• 제30권4호
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• pp.59-68
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• 1998

This study was to investigate the effect of chitosan molecular weight, its charge density, and its surface coating treatment on the antibacterial properties of paper. For this study, E.coil was used for antibacterial experiment. Results obtained were as follows : 1. The antibacterial properties of chitosan was significant on the surface-treated sheet. 2. Antibacterial property surface treatment was appeared to be effective when film was formed on the paper surface. 3. The antibacterial properties of chitosan-treated paper was dependent on the amount and the molecular weight of chitosan used. The lower the molecular weight of the chitosan down to 30,000 the better the antibacterial properties in this experiment. 4. Determination of the degree of chitosan-deacetylation by colloidal titration method was consistent with the more complicated and conventional FT-IR method.

• 한국대기환경학회지
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• 제16권4호
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• pp.389-398
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• 2000

Photocatalytic removal of benzene from air was examined using titanium dioxide photocatalyst films prepared on soda lime glass(50$\times$50$\times$2 mm) by spin coating and chemical vapor deposition. For the measurement of photocatalytic reactivity titanium dioxide coated glass was placed into a batch reactor and concentration of benzene in the reactor was set to abuot 100 ppm, and then illuminated with UV. It was found that catalytic reactivity of titanium dioxide films increased with the increase of titanium dioxide film thickness and then level off beyond a certain film thickness. UV absorption by the films showed the similar trend. The formation of stoichiometric amount of carbon dioxide was confirmed by measurement of carbon dioxide concentration in the reactor. In general spin coated films revealed better photocatalytic reactivity than chemically deposited one within the experimental ranges covered in this study. Morphology and crystal structure of prepared films were investigated by XRD and SEM and they showed significant difference between spin coated films and CVD films. Highest quantum efficiency of prepared titanium dioxide photocatalyst was close to 50%.

• 한국표면공학회지
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• 제28권1호
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• pp.23-33
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• 1995

AISI 304 stainless steel has high resistance to corrosion due to the presence of a self-healing chromium oxide film on the surface, which also accounts for the difficulty in plating. Surface cleaning of this alloy is of fundamental importance in gold plating since its effectiveness puts an upper limit on the quality of the final coating. The cleaning of AISI 304 stainless steel was investigated with elimination of artificial passive oxide film and degreasing of remaining buffing wax as stearic acid. The familiar cleaning methods i.e. ultrasonic cleaning, electro-cleaning and activation treatment were fabricated in this study. Activation treatment showed best cleaning efficiency for elimination of passive oxide film among these methods, which was also confirmed by AES (Auger electron spectrometer) analysis. However, the best condition of cleaning was obtained by combining these methods. Electrocleaning time, for degreasing the stearic acid layer, was decreased with increasing amount of added KCN.

• 한국표면공학회지
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• 제29권1호
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• pp.26-35
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• 1996

The Ni-SiC composite plating was performed in a Watt nickel solution and the wear resistance of the composite layer was studied on a pin-on-flat type wear tester. The volume losses and friction coefficients were measured. It was found that the quantity of SiC powder in the composite layers was affected by SiC concentration, pH, temperature, and agitation speed in the Watt nickel solution. The hardness and wear resistance of the coatings increased with SiC content. The quantity of SiC powder in the coating from a nickel sulfamate solution is larger than that of the Watt nickel solution, because the amount of nickel ions absorbed on the SiC powder in the nickel sulfamate solution is greater than that in the Watt's solution.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2011년도 춘계학술발표대회
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• pp.1.2-1.2
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• 2011

With recent advances in materials and products, materials processing experiences new challenges. More particles and polymers in material side and thinner and faster deformations in processing side. It happens in most emergying industries such as manufacturing of batteries, solar cells, multi-layer chips, displays, printed electronics, to list a few. In most cases, they are manufactured by coating or printing process, which is defined as a process in which gas is replaced by liquid on a substrate. In this sense, casting, inkjet printing, and roll-to-roll printing are all included. The printing process consists of three unit processes. As the materials used in the above mentioned applications typically contain a large amount of particles with polymers and solvents, they continuously change microstructures during preparation, flow, and even drying. However, little is known about the flow characteristics of such complex fluids and less is known about how to design and control the process. Therefore, for better control of the process and for better quality of the product, we need to understand the flow characteristics of these complex fluids under extremely fast flow environment.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.133-134
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• 2006

In contrast to paints, the surface appearance of adhesive materials is of minor importance, because the adhesive is invisible between the two substrates. Therefore, the rheological properties needed to apply an adhesive dispersion by spray coating can be quite different. The influence of three different kinds of thickeners on the spraying behaviour of polyurethane adhesive dispersions was investigated. The associative thickener showed only minor changes, whereas the higher molecular weight soluble thickeners dramatically changed the spraying angle and the amount of overspray. Determination of the elongational viscosity by means of the CaBER rheometer proved to be of limited use for thickened dispersions.