• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.121-121
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• 2011

Graphene formed by chemical vapor deposition was exposed to the various plasmas of Ar, O2, N2, and H2 to examine its effects on the bonding properties of graphene to metal. Upon the Ar plasma exposure of patterned graphene, the subsequently deposited metal electrodes remained intact, enabling successful fabrication of field effect transistor (FET) arrays. The effects of enhancing adhesion between graphene and metals were more evident from O2 plasmas than Ar, N2, and H2 plasmas, suggesting that chemical reaction of O radicals induces hydrophilic property of graphene more effectively than chemical reaction of H and N radicals and physical bombardment of Ar ions. From the electrical measurements (drain current vs. gate voltage) of field effect transistors before and after Ar plasma exposure, it was confirmed that the plasma treatment is very effective in controlling bonding properties of graphene to metals accurately without requiring buffer layers.

• Korean Journal of Materials Research
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• v.13 no.2
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• pp.120-125
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• 2003

A low melting borosilicate glass frit was used as an adhesion promoter, which enables $MnWO_4$to be sintered with in a reasonable sintering temperature range ($800∼1000^{\circ}C$). The glass was evaluated for glass transition temperature ($Τ_{g}$ X) and thermal expansion coefficient($\alpha$). Mechanical property (Vickers hardness), grain growth, the comparison of lattice parameter and pore distribution of sintered $MnWO_4$ with the frit were methodically discussed. As sintering temperature increased, a typical liquid phase sintering showed the rapid grain growth and high densification of X$MnWO_4$grain, improvement of hardness (until $920^{\circ}C$) and different pore size distribution. Resistance of sintered $MnWO_4$varied from 450k$\Omega$ to 8.8M$\Omega$ under the measuring humidify ranging from 30 to 90%. Thus, the results will contribute to the application of glass frit containing sensor materials and their future use.

• Journal of the Korean institute of surface engineering
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• v.50 no.4
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• pp.266-271
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• 2017

In this study, the corrosion resistance of Zn-3wt.%Mg coating was enhanced by controlling the density of coating. During the deposition the substrate temperature was controlled via an intermittent deposition process, resulting in the improvement of coating density. The maximum substrate temperature during this intermittent deposition process could be controlled from $200^{\circ}C$ to $80^{\circ}C$, depending upon the number of coating layer. The density of Zn-3 wt.%Mg coating increased from 76.1 % to 95.8 % as the substrate temperature was controlled. The salt spray test results revealed that the corrosion resistance of Zn-Mg coated steel could increase 3 times by increasing the density in coatings, while adhesion strength of coating was not changed significantly during 0-T bending test.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2012.11a
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• pp.17-17
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• 2012

Magnesium alloys exhibit many attractive properties such as low density, high strength/weight ratio, high thermal conductivity, very good electromagnetic features and good recyclability. However, most commercial magnesium alloys require protective coatings because of their poor corrosion resistance. Attempts have been made to improve the corrosion resistance of the Mg alloys by surface treatments, such as chemical conversion coatings, anodizing, plating and metal coatings, are commonly applied to magnesium alloys in order to increase the corrosion resistance. Among them, chemical conversion coatings are regarded as one of the most effective and cheapest ways to prevent corrosion resistance. In this study, zinc phosphate conversion coatings on various Mg alloys have been developed by selecting proper phosphating bath composition and concentration and by optimizing phosphating time, temperature. Morphology, coatings composition, corrosion resistance, adhesion and its formation and growth mechanism of the zinc phosphate conversion coatings were studied. Results have shown some attractive properties such as simplicity in operation, significantly increased corrosion protective property. However, adhesions between coatings and substrate and also between coatings and paint are still not satisfied. Resolving the problems and understanding the mechanism of phosphating process are targets of our study.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2007.04a
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• pp.141-145
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• 2007

The part in the structure that is most affected by changes of external temperature is the protective concrete layer that protects a waterproofing layer. Also, the waterproofing layer that is situated under or on the back of such a protective concrete layer is affected by temperature and the behavior of the protective concrete layer under the condition of consolidation or close adhesion. In particular, in many cases, the damage is serious mainly around the projection (such as a parapet), crack, and joint (expansion joint). However, there is no proper way of examining again the non-exposed waterproofing layer once it has been constructed. Therefore, there is an assessment only on the physical property of materials and the capability of the layer in construction, and there is no actual assessment in consideration of its environmental condition or the condition of the use of buildings after construction. Therefore, in order to create more pleasant buildings and to enhance the durability of structures, this study conducts research into the change of capability of non-exposed waterproofing material after the application of a static load and moving load on the waterproofing layer situated under or on the back of protective concrete.

• Korean Journal of Materials Research
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• v.3 no.5
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• pp.451-458
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• 1993

Wear resistant titanium nirridc(TiN) coatings Were depositecd onto bearing stcel(AISI 52100) by plasma assisted chemical vapor deposition using the gaseous mixtyre of $TiCI_4, N_2, H_2$ and Ar. The In- fluences of the choorine on the crystallinity, microhardness, adhesion. Wear. property of coatings were studied. It was found that the TiN coatings had an outstanding resistance to wear but the mechanical properties of the coatings deteriorated with the increase in the chlorine content. From wear test, many cracks in the trailing edge which was under tensile stress was investigated.

• The Korean Journal of Ceramics
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• v.3 no.1
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• pp.47-51
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• 1997

The dense sintered bodies of Si/SiC composite with various Si contents could be fabricated by changing the green density in the forming process. The Si/SiC/graphite composites with various graphite contents could be also fabricated by changing a graphite content in the starting composition. Their mechanical and tribological properties were characterized and wear mechanism was also studided. The hardness and strength of the Si/SiC and the Si/SiC/graphite were decreased with increasing the contents of free Si and graphite, respectively. However, the friction coefficient and specific wear rate had no specific relations to their hardness and strength. Adhesion of free Si was a main factor to determine a wear resistance of the Si/SiC composite. In the case of the Si/SiC/graphite, solid lubricationl and liquid reservoir of the graphite particles played the main role of the reduction of the friction force. In the torque test to estimate the possibility of practical of practical applications, the value of torque between the Al2O3 disk and Si/SiC/graphite disk was 1/6 lower compared with two $Al_2O_3$ disks on the basis of 100,000 cycles.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.12
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• pp.1027-1033
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• 2007

In this research, the polishing pad for W CMP has been analyzed to understand stabilization of polishing performance. For stabilization of process, the polishing pad condition is one of important factors. The polishing pad plays a key role in polishing process, because it contact with reacted surface of wafer[1]. The physical property of pad surface is ruled by conditioning tool which makes roughness and profile of pad surface. Pad surface affects on polishing performance such as RR(Removal Rate) and uniformity in CMP. The stabilized pad surface has stable roughness. And its surface has high level of wettability which can increase the probability of abrasive adhesion on pad. The result of this research is that the reduction of break-in and dummy polishing process were achieved by artificial machining to make stable pad surface. In this research, urethane polishing pad which is named IC pad(Nitta-Haas Inc.) and has micro pore structure, is studied. Because, this type of pad is the most conventional type.

• Carbon letters
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• v.5 no.1
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• pp.1-5
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• 2004

The effects of fiber surface-treatment and sizing on the dynamic mechanical properties of unidirectional and 2-directional carbon fiber/nylon 6 composites by means of dynamic mechanical analysis have been investigated in the present study. The interlaminar shear strengths of 2-directional carbon/nylon 6 composites sized with various thermosetting and thermoplastic resins are also measured using a short-beam shear test method. The result suggests that different surface-treatment levels onto carbon fibers may influence the storage modulus and tan ${\delta}$ behavior of carbon/nylon 6 composites, reflecting somewhat change of the stiffness and the interfacial adhesion of the composites. Dynamic mechanical analysis and short-beam shear test results indicate that appropriate use of a sizing material upon carbon fiber composite processing may contribute to enhancing the interfacial and/or interlaminar properties of woven carbon fabric/nylon 6 composites, depending on their resin characteristics and processing temperature.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.12
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• pp.1091-1098
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• 1998

Thermal stability of the electroless deposited Cu thin film was investigated. Cu/TaN/Si multilayer was fabricated by electroless-depositing Cu thin layer on TaN diffusion barrier layer which was deposited by MOCVD on the Si substrate, and was annealed in $H_2$ ambient to investigate the microstructure of Cu film with a post heat-treatment. Cu thin film with good adhesion was successfully deposited on the surface of the TaN film by electroless deposition with a proper activation treatment and solution control. Microstructural property of the electroless-deposited Cu layer was improved by a post-annealing in the reduced atmosphere of $H_2$ gas up to $600^{\circ}C$. Thermal stability of Cu/TaN/Si system was maintained up to $600^{\circ}C$ annealing temperature, but the intermediate compounds of Cu-Si were formed above $650^{\circ}C$ because Cu element passed through the TaN layer. On the other hand, thermal stability of the Cu/TaN/Si system in Ar ambient was maintained below $550^{\circ}C$ annealing temperature due to the minimal impurity of $O_2$ in Ar gas.