• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.26 no.4
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• pp.430-435
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• 2017

The effect of the surface profile on CFRP and aluminum metal bonding was studied. A small number of steps were made on the aluminum surface, and the shear stress and elongation were measured using a shear test after bonding with an autoclave method. As the number of surface steps increased, the shear stress and elongation increased. The surface bonding strength increased because of the effect of the mechanical and chemical bonding. When the number of effective stages was exceeded, the shear strength decreased again due to the aspect ratio of the step and the reduction of the penetration effect of the resin into the groove.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.526-530
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• 2004

We report the space charge and the surface potential of the interface between metal and CuPc according to isotropic property and different metal by measuring the microwave reflection coefficients $S_{11}$ of copper(II)-phthalocyanine(CuPc) thin films by using a near-field microwave microscope(NSMM) in order to understand. CuPc thin films were prepared on gold and aluminium substrates using a thermal evaporation method. Two kinds of CuPc thin films were prepared. One was deposited on preheated substrate at $150^{\circ}C$ and the other was annealed after deposition by using thermal evaporation methods. The microwave reflection coefficients $S_{11}$ of CuPc thin films were changed by the dependence on the heat treatment conditions. By comparing reflection coefficient $S_{11}$ we measured electrical conductivity of CuPc thin films and studied this results with respect to the surface potential and space charge of the interface between metal and CuPc thin films.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.2
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• pp.30-37
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• 2020

We propose a practical method for increasing formability of a sheet metal plate using laser heat treatment (LHT) and cladding process. In this work, two kinds of process such as laser-induced heat treatment and cladding were utilized to evaluate the effect on formability of SUS316 sheets with different thickness of 1 and 3 mm. By using a vertically line-patterned tensile specimen that was LHTed or cladded on its surface, the process parameters of each surface treating method were studied and optimized. Through the basic test, we knew that the laser power of 900 W and scanning speed of 500 mm/min was the best condition for increase of formability. As the treatment results, ultimate tensile strength and elongation were increased as approximately 2.1 and 7.0%, respectively. To verify the usefulness of this work in industrial cases, we conducted a bulging test using with and without LHTed SUS316 sheet metal blanks. The results show that the bulging height of LHTed sheet was increased by 73% compared to that of the original one.

• Journal of the Korean institute of surface engineering
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• v.51 no.1
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• pp.1-10
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• 2018

Anodic oxidation treatment of metals is one of typical surface finishing methods which has been used for improving surface appearance, bioactivity, adhesion with paints and the resistances to corrosion and/or abrasion. This article provides fundamental principle, type and characteristics of the anodic oxidation treatment methods, including anodizing method and plasma electrolytic oxidation (PEO) method. The anodic oxidation can form thick oxide films on the metal surface by electrochemical reactions under the application of electric current and voltage between the working electrode and auxiliary electrode. The anodic oxide films are classified into two types of barrier type and porous type. The porous anodic oxide films include a porous anodizing film containing regular pores, nanotubes and PEO films containing irregular pores with different sizes and shapes. Thickness and defect density of the anodic oxide films are important factors which affect the corrosion resistance of metals. The anodic oxide film thickness is limited by how fast ions can migrate through the anodic oxide film. Defect density in the anodic oxide film is dependent upon alloying elements and second-phase particles in the alloys. In this article, the principle and mechanisms of formation and growth of anodic oxide films on metals are described.

• The Journal of Korean Academy of Prosthodontics
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• v.45 no.2
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• pp.216-227
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• 2007

Statement of problem: For the long-term success of removable partial dentures, the bonding between metal framework and denture base resin is one of the important factors. To improve bonding between those, macro-mechanical retentive form that is included metal framework design has been generally used. However it has been known that sealing at the interface between metal framework and denture base resin is very weak, because this method uses mechanical bonding. Purpose: Many studies has been made to find a simple method which induces chemical bond, now various bonding system is applied to clinic. In this experiment, shear bond strengths of heat-cured denture base resin to the surface-treated Co-Cr alloy were measured before and after thermocycling. Chemically treated groups with Alloy $Primer^{TM}$, Super-Bond $C&B^{TM}$, and tribochemically treated group with $Rocatec^{TM}$ system were compared to the beadtreated control group. The data were analyzed with two-way ANOVA. Result: 1. Shear bond strength of bead-treated group is highest, and Alloy $Primer^{TM}$ treated group, Super-Bond $C&B^{TM}$ treated group, RocatecTM system treated group were followed. Statistically significant differences were found in each treated group(p<0.05). 2. Surface treatment and thermocycling affected shear bond strength(p<0.05), however there was no interaction between two factors(p>0.05). 3. Shear bond strengths of bead-treated group and Alloy $Primer^{TM}$ treated group showed no statistically significant difference before and after thermocycling(p>0.05), and those of Super-Bond $C&B^{TM}$ treated group and $Rocatec^{TM}$ system treated group showed statistically significant difference after thermocycling(p<0.05).

• Journal of the Korean institute of surface engineering
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• v.55 no.5
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• pp.261-272
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• 2022

CO₂ electroreduction is considered as a means to overcome climate change by converting CO₂ into value-added chemicals and liquid fuels. Although numerous researchers have screened versatile metal for the use of electrodes, and looked into the reaction mechanism, it is still required to develop highly enhanced electrocatalyst for CO₂ reduction to reach beyond lab-scale. Plasma treatment applying onto the surface of meal electrodes could improve activity, selectivity and stability of the electrocatalysts. This review highlights the effect of plasma pretreatment, and provides insight to design suitable CO₂ electrocatalyst.

• Journal of Technologic Dentistry
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• v.38 no.2
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• pp.69-77
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• 2016

Purpose: This study was to evaluate the shear bond strength of ceramic fused to Ni-Cr alloy(Alophaloy) by heat treatment. Methods: The specimens were divided into 5 groups according to heat treatment conditions prior to porcelain application. Eighteen specimens from each group were subjected to the shear load a universal testing machine using a 0.1mm/min cross-head speed and two specimens from each group were observed with SEM and EDX line profile. Results: The observation of the oxide film on the metal surface by SEM photograph showed a coarsening with an increasing degassing hold time. The diffusion of metal oxide was observed farther from the opaque layer in the heat treated specimen than no heat treated specimen. The shear bond strength measured highest to A5(55.23MPa) in the 10min holding group and measured lowest from A1(24.38MPa) in the no heat treated group, and there was a significant difference(p<0.05). Conclusion: The shear bond strength of Ni-Cr alloy improved in the heat treatment compared to the no heat treatment specimen.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.8
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• pp.704-710
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• 2000

Metal electrode materials for plasma display panel should have low electrical resistivity in order to maintain stable gas discharge and have fast response time. They should also hae good film uniformity adhesion and thermal stability. In this study Cr/Cu/Cr metal electrode structure is formed by DC magnetron sputtering. Cr and Cu films were deposited on ITO coated glasses with various DC power density and main pressures as the major parameters. After metal electrodes were formed a heat treatment was followed at 55$0^{\circ}C$ for 20 min in a vacuum furnace. The intrinsic stress of the sputtered Cr film passed a tensile stress maximum decreased and then became compressive with further increasing DC power density. Also with increasing the main pressure stress turned from compression to tension. After heat the treatment the electrical resistivity of the sputtered Cu film of 2${\mu}{\textrm}{m}$ in thickness prepared at 1 motor with the applied power density of 3.70 W/cm$^2$was 2.68 $\mu$$\Omega$.cm With increasing the main pressure the DC magnetron sputtered Cu film became more open structure. The heat treatment decreased the surface roughness of the sputtered Cr/Cu/Cr metal electrodes.

• Journal of the Korean institute of surface engineering
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• v.25 no.2
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• pp.66-72
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• 1992

Magnetite film on iron surface could be coated in strongly alkaline solution (12M NaH\OH) which contained additives such as NaHCO3, KCl and NaNO2, Iron plate was immersed in boiling solution ($130^{\circ}C$) contained above mentioned additives for 1 hour. There are some microcracks and these cracks proved to be the sites for the initiation of corrosion when immersed in 3% NaCl solution. To improve corrosion resistance of the coated steel plate, chromating was done as a post treatment. Chromate film was formed on magnetite oxide film potentiostatically at-918mV/SCE for five minutes at temperature of $70^{\circ}C$ in the alkaline solution containing 5g/l Na2Cr2O7.2H2O.Cr3O4 was electrodeposited on magnetite oxide film and Cr2O3 was electrodeposited on iron surface which was assumed as surface revealed due to microcracks. Increased corrosion resistance of chromated magnetite oxide film was proved in salt spray test & immersion test.

• The Journal of Korean Academy of Prosthodontics
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• v.18 no.1
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• pp.49-57
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• 1980

The adhesive mechanisms on the metal-ceramic restorations have been reported to be mechanical interlocking, chemical bonding, compressive force, and Van der Waal's force, etc. Of these, the mechanical interlocking and chemical bonding forces are thought to affect the adhesive force between Ni-Cr alloy and porcelain. This study investigates the adhesion of Ni-Cr alloy to porcelain according to surface treatment. For this purpose, the following experiments were made; The compositions of Ni-Cr alloy as cast by emission spectrograph, and the oxides produced on Ni-Cr alloy during degassing at $1850^{\circ}F$ for 30 minutes in air and in vacuum were analyzed by X-ray diffractograph. The metal phases of Ni-Cr alloy were observed according to porcelain-baking cyclic heat treatment by photo microscope and the distribution and the shift of elements of Ni-Cr alloy and porcelain and the failure phases between Ni-Cr alloy and porcelain by scanning electron microscope. The adhesive force between Ni-Cr alloy and porcelain was measured according to surface treatment with oxidization and roughening by Instron Universal Testing Machine. Results were as follows; 1. The metal phases of Ni-Cr alloy as cast and degassing state showed the enlarged and fused core, but when subjected to porcelain-baking cyclic heat treatment, showed a dendrite growing. 2. The kinds of metal oxides produced on Ni-Cr alloy during degassing were found to be NiO and $Cr_2O_3$. 3. The distribution of elements at the interface of Ni-Cr alloy and porcelain in degassing state showed demarcation line, but in roughening state, showed mechanical interlocking phase. 4. The shift of elements at the interface occurred in both states, but the shift amount was found to be larger in roughening than in degassing. 5. The adhesive force between Ni-Cr alloy and porcelain was found to be $3.45{\pm}0.93kg/mm^2$, in degassing and $3.82{\pm}0.99kg/mm^2$, in roughening. 6. The failure phase between Ni-Cr alloy and porcelain showed the mixed type failure.