• Journal of the Korean institute of surface engineering
• /
• v.29 no.6
• /
• pp.648-653
• /
• 1996

Hydrogenated amorphous carbon(a-C:H) films are prepared by rf plasma CVD in a $CH_4$ source gas system diluted with Ar of $H_2$. The spectra of emissive and reactive species in the plasma are detected using in stiu optical emission spectroscopy. Inaddition, the relationship between the film properties which can be varied by the deposition parameters and the Raman spectra is studied. In the $CH_4/H_2$ gas system, the emission intensities of CH and $H \tau$ decrease and those of $H \alpha$, $H \beta$, $C_2$ and Ar increase with increasing $H_2$ concentration, The formation of $C_2$ and CH in the $CH_4/Ar/H_2$ gas system is greatly suppressed by hydrogen addition and the excess of hydrogen addition is found to form graphite structure. The $C_2$ formation in the gas phase enhances a-C:H film formation.

• Journal of the Korean institute of surface engineering
• /
• v.24 no.1
• /
• pp.18-24
• /
• 1991

In the present work the adhesion failure of a hot-dip galvanized coating has been studied as a function gas composition temperature of strip and of atmospheric gas in furnace. The adhesion failure of the hot-dip galvani-zed coating is classified as three mechanisms : carbon deposition, oxide film formation and alloy layer formation. The adhesion failure due to oxide film formation decreased markedly by increasing the gases temperature of direct fired furnace(DFF) in order to improve the reducing ability of steel strip. Optimum conditions of operating and manufacturing facilities for improving the coating adherence are suggested by analyzing the interface between steel substrate and coating layer.

• Proceedings of the KIEE Conference
• /
• 1987.11a
• /
• pp.207-209
• /
• 1987

This paper reports the effect of additive elements such as Bi, Sb on degradation and hole formation of the Te-Se thin films. Changes in light transmission were used to monitor the degradation rate of thin Te films in an accelerated temperature-humidity environment. In thin accelerated temperature-humidity environment, $(Te_{86}Se_{14})_{70}Bi_{30}$ thin film was stable and $(Te_{86}Se_{14})_{50}Sb_{50}$ thin film was unstable in comparison with the other films that used in this experiment. The hole formation was carried out in the Te-based thin films.

• Proceedings of the KIEE Conference
• /
• 1993.07b
• /
• pp.1271-1273
• /
• 1993

$SiO_2$ and SiON films are formed by Laser CVD for inter-level dielectrics in submicron VLSI. This technique is noticeable that film formation can be done at low temperatures, below $300^{\circ}C$ with less damage. An ArF Excimer Laser with wave length of 193nm is used to excite and dissociate reactant gases. After film formation growth rate, refractive index, I-V curve, and step coverage characteristics of the films were evaluated.

• Corrosion Science and Technology
• /
• v.7 no.1
• /
• pp.40-44
• /
• 2008

Passive metal forms an interfacial diffuse layer on the surface of passive film by its reaction with $H^+$ or $OH^-$ ions in solution depending on solution pH. There is a critical pH, called pH point of iso-selectivity ($pH_{pis}$) at which the nature of the diffuse layer is changed from the anion-permeable at pH<$pH_{pis}$ to the cation-permeable at pH>$pH_{pis}$. The $pH_{pis}$ for a passivated Fe was determined by examining the effects of pH on the thickness of passive film and on the dissolution reaction occurring on the passive film under a gavanostatic reduction in borate-phosphate buffer solutions at various pH of 7~11. The steady-state thickness of passive film formed on Fe showed the maximum at pH 8.5~9, and further the nature of film dissolution reaction was changed from a reaction producing $Fe^{3+}$ ion at $pH\leq8.5$ to that producing $FeO_2{^-}$ at $pH\geq9$, suggesting that the $pH_{pis}$ of Fe is about pH 8.5~9. In addition, the passive film formed at pH 8.5~9, $pH_{pis}$, was found to be the most protective with the lowest defect density as confirmed by the Mott-Schottky analysis. Pitting potential was decreased with increasing $Cl^-$ concentration at $pH\leq8.5$ due probably to the formation of anion permeable diffuse layer, but it was almost constant at $pH\geq9$ irrespective of $Cl^-$ concentration due primarily to the formation of cation permeable diffuse layer on the film, confirming again that $pH_{pis}$ of Fe is 8.5~9.

• Journal of the korean Society of Automotive Engineers
• /
• v.14 no.6
• /
• pp.81-90
• /
• 1992

This paper deals with an experimental study on the initial condition of liquid film surface waves disintegration and investigation on the behavior of liquid film surface waves formed by the high speed air flow on the solid plane surface. The authors conducted the qualitative and quantitative study to in vestigate the liquid film flow phenomena, the liquid film disintegration mechanism, and droplet formation process with breaking the liquid film surface wave. The newly devised transparent rectangular test section which has semi-two-dimensional flow at the center of the bottom was introduced to perform the experimental study, and it can generate the uniform thickness liquid film at the bottom. The strobo streak camera was used to obtain the instantaneously transformed photographs. The electronic measuring device was also used to measure the liquid film thickness variation in order to perform the easy and effective analysis of complex flow phenomena in the air-water cocurrent flow.

• Tribology and Lubricants
• /
• v.2 no.1
• /
• pp.53-60
• /
• 1986

The methods to prevent or suppress the initial failure of the sliding surfaces by the formation of the protection film during the manufacturing process were studied. Now it has been known that the surface protection film which was formed during the running-in process is mainly $Fe_3O_4$ and its film was formed only at the limited oxygen ability during the lubricated sliding. So it was tried to form the same oxide film before the sliding by heat treatment at 300$\circ$C with the wetted specimen by oil. The results show that a thin oxide film ($Fe_3O_4$) was formed on the surface beneath the solid oil film and the specimen with this film has much better friction properties than those prepared with heat treatment at 500$\circ$C and 700$\circ$C or the original one.

• Proceedings of the KIEE Conference
• /
• 1998.07g
• /
• pp.2509-2511
• /
• 1998

In this study, we formed the piezoelectric film and estimated its characteristics for sensor application. The $Pb(Zr,Ti)O_3(PZT)$ was chosen as piezoelectric material and we used Sol-Gel method to form film. To increase film thickness, the multiple coatings were performed, and the good characteristics obtained in thick film compared to thin film. Because PZT film showed fine etching property as well as other good characteristics, it was thought that it was appropriate material for sensor fabrication.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 1999.08a
• /
• pp.236-241
• /
• 1999

The characteristics of the deterioration and oxidation of high speed steel(

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
• /
• 2007.11a
• /
• pp.313-317
• /
• 2007