• Journal of the Korea Safety Management & Science
• /
• v.7 no.1
• /
• pp.211-222
• /
• 2005

The ceramic forming materials are getting more important recently since they are used widely in repairing metal structures, welded metal structures and mechanical components etc. The determination of elastic constants for ceramic coating materials takes much time and efforts in experiment due to the brittleness of ceramic material itself. The aim of this research is to determine the Young's Modulus for ceramic metal coating material. In order to achieve the goal, the hybrid method which uses impulse hammer technique for experimental method and modal analysis of finite element method for computational method was used. The results show good agreement with existing experimental data on Young's Modulus.

• Korean Journal of Materials Research
• /
• v.15 no.1
• /
• pp.37-41
• /
• 2005

Stainless steel fibers with a diameter of $17\;{\mu}m$ and 630 nm were produced from stainless steel wires by the drawing/annealing/exfolitation process. The suitable sheath material to draw the core stainless steel wires to fibers was the Cu coating. The low melting metal of Zn was not a suitable sheath coating. Also, an attempt was made to produce $20\;{\mu}m{\Phi}Ti$ fibers from the core titanium wires. The main obstacles in producing Ti fibers were their resistance to deformation owing to the Ti's hop structure, and high reactivity of Ti with the exfolitation solution.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.21 no.3
• /
• pp.82-87
• /
• 2013

In this work, the 1L grade integrated metal DOC/DPF filter that can install in engine manifold position was developed to investigate the effect of platinum-coating amount of filter on the improvement of filter activation temperature and reduction of particulate matter (PM). This filter was installed in 2.9L CI engine which meets the EURO-4 emission regulation. Tests for PM reduction efficiency of filter were conducted under ND-13 mode with full-load test condition. It was revealed that the time to reach the activation temperature of metal filter ($280^{\circ}C$) was shorter as the amount of platinum-coating increased. This short activation time can be helpful for the reduction of CO and HC emissions during cold start condition. At the same time, PM reduced as the coating amount increased. The reduction percentage of $DOC_{40}$, $DOC_{20}$, and $DOC_0$ were 96.7% (2.34 mg/kW'h), 95.1% (3.47 mg/kW'h), and 94.5% (3.69 mg/kW'h) compared to previous result (71.4 mg/kW'h), respectively.

• Journal of the Korea Institute of Building Construction
• /
• v.21 no.6
• /
• pp.519-527
• /
• 2021

In this study, an electromagnetic pulse shielding effect was obtained by applying the arc metal spraying method to the ordinary concrete. For this study, to evaluate the electrical properties in the thickness of the metal sprayed coating, 8 types of metals(Cu, CuAl, CuNi, CuZn, Al, Zn, ZnAl, AlMg) were sprayed as coatings with a thickness of 100, 200 and 500㎛. The electrical conductivity on the surface was measured with a 4-pin probe, and an electromagnetic wave shielding effect test was performed according to KS. Based on the test results, 200 ㎛ was proposed as an optimal metal coating thickness for electromagnetic pulse shielding, and it was thermally sprayed on a 300×300×100mm concrete specimen to analyze the electromagnetic wave shielding performance. However, in the area of adhesion strength, the maximum was 1.11MPa, which was found to be less than 74% of the target performance.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2002.10a
• /
• pp.521-526
• /
• 2002

In this paper, we described about the characteristic evaluation of environment-friendly ceramic paint with calcium-silicate mineral as a main binder. Particularly, we performed discharge of the environmental poisoning materials(e.g. VOCs, heavy metal, etc.), and properties of paint slurry and coating film of the ceramic paint. In the comparison of the ceramic paint with natural paint and mineral paint which were known as our environment-friendly paints, ceramic paint had good characteristics in the environmental safety and properies of wet slurry and dried coating film.

• Journal of the Korean Society for Precision Engineering
• /
• v.17 no.8
• /
• pp.180-188
• /
• 2000

Fine multi-hole sheet metal product(FMSMP) is a specific metal plate which is used in color TV and computer monitor. Processes of manufacturing FMSMP are generally composed of coating cleaning exposure and etching processes. After a thin metal plate is made by rolling photosensitive liquid is coated on the metal plate in coating process. Then the coated thin metal plate consecutively passes through exposure process in which upper and lower glasses are compressed by vacuuming the space between glasses and metal plate. In this lowered glasses are compressed by vacuuming the space between glasses and metal plate. In this lowered vacuum state certain part of metal plate is desirably exposed to light and will be etched into forming lots of well-arranged holes with a specific diameter, nowadays to manufacture FMSMP of 17 inch braun tube 80 second is required for complete vacuum but 35 second is applied to manufacture FMSMP in reality. In the present study vacuuming time is tried to reduce for improvement of productivity by analyzing vacuum system and proposing several solutions, for faster vacuuming speed degree of vacuum state between glasses and metal plate is improved by the proposed method and experiments using the proposed method are performed for verification. In addition microstructure of FMSMP is investigated to prevent stain phenomena and to improve quality of the product.

• Corrosion Science and Technology
• /
• v.4 no.6
• /
• pp.242-249
• /
• 2005

A lot of parts in FGD (Flue Gas Desulfurization) systems of fossil-fuel power plants show the environments in which are highly changeable and extremely acidic corrosive medium according to time and locations, e.g. in duct works, coolers and re-heaters etc. These conditions are formed when system materials are immersed in fluid that flows on them or when exhausted gas is condensed into thin layered acidic medium to contact materials of the system walls and roofs. These environments make troublesome corrosion and air pollution problems that are occurred from the leakage of the condensed solution. To cathodically protect the metallic structures in extremely acidic fluid, the properties of the protective coatings on the metal surface were very important, and epoxy Novolac coating was applied in this work. On the base of acid immersion tests, hot sulfuric acid decreased the hardness of the coatings and reduced greatly the content of $Na_2O$, $Al_2O_3$, and $SiO_2$ among the main components of the coating. A special kind of CP(Cathodic Protection) system has been developed and tested in a real scale of the FGD facility. Applied coating for this CP system was peeled off and cracked in some parts of the facility. However, the exposed metal surface to extremely acidic fluid by the failure of the coatings was successfully protected by the new CP system.

• KSBB Journal
• /
• v.32 no.2
• /
• pp.160-167
• /
• 2017

Coating of individual cells with organic or inorganic materials has drawn a great deal of attention, because it provides the cells with physicochemical durability, which would contribute to the development of bioreactors, biosensor, and lab-on-a-chip, as well as to the fundamental studies in single cell-based biology. Although many strategies have been developed for coating of microbial cells, limited methods are available to coat mammalian cells because most mammalian cells do not have a robust membrane or exoskeleton. Instead, they are enclosed in a lipid bilayer, which is fluidic and vulnerable to changes in its environments. It is more difficult to treat mammalian cells in vitro than microbial cells because the surfaces of mammalian cells are not protected or reinforced by a tough coat. In this work, we report a cytocompatible and degradable nanocoat for mammalian cells. Three types of mammalian cells (HeLa cells, NIH 3T3 fibroblasts, and Jurkat T cells) were individually coated within metal-polyphenol. To maintain the viability of the mammalian cells, we performed the whole processes under strictly physiological culture conditions, and carefully selected nontoxic materials.

• Journal of the Korean Society for Precision Engineering
• /
• v.27 no.12
• /
• pp.28-32
• /
• 2010

Technical demands for aspheric glass lens formed in market increases its application from simple camera lens module to fiber optics connection module in optical engineering. WC is often used as a metal core of the aspheric glass lens, but the long life time is issued because it fabricated in high temperature and high pressure environment. High hard thin film coating of lens core increases the core life time critically. Diamond Like Carbon(DLC) thin film coating shows very high hardness and low surface roughness, i.e. low friction between a glass lens and a metal core, and thus draw interests from an optical manufacturing industry. In addition, DLC thin film coating can removed by etching process and deposit the film again, which makes the core renewable. In this study, DLC films were deposited on the SiC ceramic core. The process variable in FVA(Filtered Vacuum Arc) method was the substrate bias-voltage. Deposited thin film was evaluated by raman spectroscopy, AFM and nano indenter and measured its crystal structure, surface roughness, and hardness. After applying optimum thin film condition, the life time and crystal structure transition of DLC thin film was monitored.

• Journal of Welding and Joining
• /
• v.16 no.5
• /
• pp.86-92
• /
• 1998

High speed wire seam weldability of tin coated thin gage sheet steels was investigated. Thickness and coating weight ranges of the test materials were 0.21~0.35mm and 1.1/1.1~2.8/11.2g/$m^2$, respectively. Test results indicated that the surface roughness value, Rz decreased as increasing the coating weight. The Rz was thought to be one of the important factors to influence the optimum welding condition range, $\triangle$Q. The $\triangle$Q showed close relationship with welding conditions such as welding pressure and travel speed. Higher welding pressure widened the $\triangle$Q while higher travel speed reduced the $\triangle$Q value. Results also demonstrated that tin coating weight should be optimized based on the weldability or the serviceability after welding. At th HAZ of sheet materials with thinner coating layer, tin depleted zone was produced since molten film of the coating material on the base metal agglomerated by the surface tension, which could result in reducing the corrosion resistance of the HAZ in the service environment.